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Hundreds of articles have been published over the last few weeks, making well-meaning attempts to determine whether patients with different comorbidities are more susceptible for SARS-CoV-2 infection or at higher risk for severe disease. This deluge of scientific publications has resulted in worldwide uncertainty. For a number of reasons, many studies must be interpreted with extreme caution.

First, in many articles, the number of patients with specific comorbidities is low. Small sample sizes preclude accurate comparison of COVID-19 risk between these patients and the general population. They may also overestimate mortality, especially if the observations were made in-hospital (reporting bias). Moreover, the clinical manifestation and the relevance of a condition may be heterogeneous. Is the hypertension treated or untreated? What is the stage of the COPD, only mild or very severe with low blood oxygen levels? Is the “cancer” cured, untreated or actively being treated? Are we talking about a seminoma cured by surgical orchiectomy years ago or about palliative care for pancreatic cancer? What is a “former” smoker: someone who decided to quit 20 years ago after a few months puffing during adolescence or someone with 40 package-years who stopped the day before his lung transplantation? Does “HIV” mean a well controlled infection while on long-lasting, successful antiretroviral therapy or an untreated case of AIDS? Unfortunately, many researchers tend to combine these cases, in order to get larger numbers and to get their paper published.

Second, there are numerous confounding factors to consider. In some case series, only symptomatic patients are described, in others only those who were hospitalized (and who have per se a higher risk for severe disease). In some countries, every patient with SARS-CoV-2 infection will be hospitalized, in others only those with risk factors or with severe COVID-19. Testing policies vary widely between countries. The control group (with or without comorbidities) is not always well-defined. Samples may not be representative, risk factors not correctly taken into account. Sometimes, there is incomplete information about age distribution, ethnicity, comorbidities, smoking, drug use and gender (there is some evidence that, in female patients, comorbidities have no or less impact on the course of the disease, compared to male (Meng 2020)). All these issues present important limitations and only a few studies have addressed all of them.

Third, comorbidity papers have led to an information overload. Yes, virtually every medical discipline and every specialist has to cope with the current pandemic. And yes, everybody has to be alert these days, psychiatrists as well as esthetic surgeons. Hundreds of guidelines or position papers have been published in recent weeks, trying to thoughtfully balance fear of COVID-19 against the dire consequences of not treating other diseases than COVID-19 in an effective or timely manner – and all this in the absence of data. On May 15, a PubMed search yielded 530 guidelines or considerations about specific diseases in the context of COVID-19, among them those for grade IV glioma (Bernhardt 2020, bottom line: do not delay treatment), but also for dysphonia and voice rehabilitation (Mattei 2020: can be postponed), infantile hemangiomas (Frieden 2020: use telehealth), ocular allergy (Leonardi 2020: very controversial), high resolution anoscopy (Mistrangelo 2020: also controversial), migraine management (Szperka 2020: use telehealth) and breast reconstruction (Salgarello 2020: defer “whenever possible”), to name just a few.

These recommendations are usually not helpful. They apply for a few weeks, during acute health crisis scenarios as seen in overwhelmed health care systems in Wuhan, Bergamo, Madrid or New York. In other cities or even a few weeks later, proposed algorithms are already outdated. And nobody needs a 60-page recommendation, concluding that “clinical judgment and decision making should be exercised on a case-by-case basis”. However, some important papers have been published during the last months, a couple of them with very helpful data, supporting the management of patients with comorbidities. In the following, we will briefly go through these.

Hypertension and cardiovascular comorbidities

From the beginning of the pandemic, hypertension and/or cardiovascular disease (CVD) have been identified as potential risk factors for severe disease and death (at least two studies had performed a multivariate analysis (Table 1)). However, all studies were retrospective, included only hospitalized patients and did not distinguish between uncontrolled and controlled hypertension or used different definitions for CVD. Multivariate analyses adjusting for confounders were performed in only a few studies. Moreover, different outcomes and patient groups were analyzed.

According to some experts, current data do not necessarily imply a causal relationship between hypertension and severity of COVID-19. It is also “unclear whether uncontrolled blood pressure is a risk factor for acquiring COVID-19, or whether controlled blood pressure among patients with hypertension is or is not less of a risk factor” (Schiffrin 2020). The same applies to CVD, with the difference that the numbers here are even lower.

From a mechanistic point of view, however, it seems very plausible that patients with underlying cardiovascular diseases and pre-existing damage to blood vessels such as artherosclerosis may face higher risks for severe diseases. During recent weeks, it has become clear that SARS-CoV-2 may directly or indirectly attack the heart, kidney and blood vessels.


Table 1. Hypertension in larger cohort studies, prevalence and outcome
Study Setting Hypertension present? Multivariate, hazard or odds ratio (95% CI) for endpoint
Wang 2020 344 ICU pts,
Tongji, China
Survivors vs Non-Survivors: 34 vs 52% Not done
Grasselli 2020 521 ICU pts,
72 hospitals in Italy
Discharge from ICU vs death at ICU: 40 vs 63% Not done
Guan 2020 1,099 hospitalized pts, 522 hospitals in China Non-severe disease vs severe: 13 vs 24% Not done
Zhou 2020 191 hospitalized pts from Jinyintan and Wuhan Survivors vs Non-Survivors: 23 vs 48% Not done
Shi 2020 487 hospitalized pts
in Zhejing Province
Non-severe disease at admission vs severe:
17 vs 53%
OR 2.7 (1.3-5.6) for severe disease at admission
Guan 2020 1,590 hospitalized pts, 575 hospitals in China Non-severe vs severe courses: 13 vs 33% HR 1.6 (1.1-2.3) for severe course (ICU, IMV, death)
Goyal 2020 393 hospitalized pts,
2 hospitals in New York
No IMV vs IMV during stay: 48 vs 54% Not done

IMV invasive mechanical ventilation, ICU intensive care units


Various cardiac manifestations of COVID-19 do occur contemporarily in many patients (see chapter Clinical Manifestations). Infection may lead to cardiac muscle damage, blood vessel constriction and to elevated levels of inflammation-inducing cytokines. These direct and indirect adverse effects of the virus may be especially deleterious in those with already established heart disease. During the next months, we will learn a lot more about the role and contributions of arteriosclerosis in the pathogenesis of COVID-19.

Treatment of hypertension during the pandemic

There has hardly been a topic in the last months that has kept doctors and their patients as busy as the question of whether antihypertensive drugs such as ACE inhibitors (ACEIs) or angiotensin-receptor blockers (ARBs) can cause harm to patients. The uncontrolled observations of increased mortality risk in patients with hypertension, CVD (see above) and diabetes raised concerns. These conditions share underlying renin-angiotensin-aldosterone system pathophysiology that may be clinically insightful. In particular, activity of the angiotensin-converting enzyme 2 (ACE2) is dysregulated (increased) in cardiovascular disease (Vaduganathan 2020). As SARS-CoV-2 cell entry depends on ACE2 (Hoffmann 2020), increased ACE2 levels may increase the virulence of the virus within the lung and heart.

ACEIs or ARBs may alter ACE2, and variation in ACE2 expression may in part be responsible for disease virulence. However, the first substantial study to examine the association between plasma ACE2 concentrations and the use of ACEIs/ARBs does not support this hypothesis: in two large cohorts from the pre-COVID-19 era, plasma concentrations of ACE2 were markedly higher in men than in women, but not with ACEI/ARB use (Sama 2020). A recent review of 12 animal studies and 12 human studies overwhelmingly implies that administration of both drug classes does not increase ACE2 expression (Sriram 2020).

However, some concerns on deleterious effects remain and some media sources and even scientific papers have called for the discontinuation of these drugs. This is remarkable as clinical data actually points in the opposite direction. Some small retrospective studies from China have shown no negative effect (Meng 2020, Yang 2020). In the largest study, 188 patients taking ACEI/ARBs were compared with 940 patients who did not use them. Of note, unadjusted mortality rate was lower in the ACEI/ARB group (3.7% vs. 9.8%) and a lower risk was also found in a multivariate Cox model (Zhang 2020).

By early May, two large studies were published in the NEJM (a third was later retracted). Although both were observational (with the possibility of confounding), their message was consistent – none showed any evidence of harm (Jarcho 2020). One study analyzed 2,573 COVID-19 patients with hypertension from New York City, among them 25% with severe disease (Reynolds 2020). After looking at different classes of antihypertensive medications – ACE inhibitors, ARBs, beta-blockers, calcium-channel blockers, and thiazide diuretics, the authors ruled out any substantial difference in the likelihood of severe COVID-19, with at least 97.5% certainty for all medication classes.

The second study looked at a possible independent relationship between ACEI/ARBs and the susceptibility to COVID-19 (Mancia 2020). The authors matched 6,272 Italian cases (positive for SARS-CoV-2) with 30,759 beneficiaries of the Regional Health Service (controls) according to sex, age, and municipality of residence. There was no evidence that ACE inhibitors or ARBs modify susceptibility to COVID-19. The results applied to both sexes as well as to younger and older persons.

In conclusion, ACE inhibitors and/or ARBs should not be discontinued (Bavishi 2020, Sriram 2020, Vaduganathan 2020). At least four registered randomized trials plan to evaluate ACEIs and ARBs for treatment of COVID-19 (Mackey 2020). According to a brief review, adjuvant treatment and continuation of pre-existing statin therapy could improve the clinical course of patients with COVID-19, either by their immunomodulatory action or by preventing cardiovascular damage (Castiglion 2020).

Treatment of coronary heart disease during the pandemic

Myocardial injury, evidenced by elevated cardiac biomarkers, was recognized among early cases and myocardial infarction (STEMI or NSTEMI) and may represent the first clinical manifestation of COVID-19 (Reviews: Bonow 2020, Valente 2020). Of note, a culprit lesion is often not identifiable by coronary angiography. In a study of 28 patients with STEMI, this was the case in 39% (Stefanini 2020). According to the authors, a dedicated diagnostic pathway should be delineated for COVID-19 patients with STEMI, aimed at minimizing procedural risks and healthcare providers’ risk of infection. There are already preliminary reports on a significant decline of 32% in the number of percutaneous coronary interventions for acute coronary syndromes (Piccolo 2020). Other authors have suggested that, in settings with limited resources to protect the work force, fibrinolytic therapies may be prefered over primary percutaneous coronary interventions (Daniels 2020).

Of note, several studies have found a spectacular drop in admissions for STEMI during the peak of the epidemic. In France a steep decline of 25% was found for both acute (< 24hrs) and late presentation (> 24 hrs) STEMI (Rangé 2020). Similar observations have been made in Italy (De Filippo 2020) and the US (Solomon 2020). Possible explanations for this phenomenon may be patients’ fear of coming to the hospital or disturbing busy caregivers, especially in the case of mild STEMI clinical presentation. Other hypothetical reasons are reduced air pollution, better adherence to treatment, limited physical activity or absence of occupational stress during lockdown. However, there is some evidence that the lower incidence does not reflect a true decline but just one more collateral damage of the pandemic. For example, Italian researchers have found a 58% increase of out-of-hospital cardiac arrests in March 2020 compared to the same period in 2019 (Baldi 2020).


Baldi E, Sechi GM, Mare C, et al. Out-of-Hospital Cardiac Arrest during the Covid-19 Outbreak in Italy. N Engl J Med. 2020 Apr 29. PubMed: . Full-text:

Bavishi C, Maddox TM, Messerli FH. Coronavirus Disease 2019 (COVID-19) Infection and Renin Angiotensin System Blockers. JAMA Cardiol. 2020 Apr 3. pii: 2764299. PubMed: . Full-text:

Bonow RO, Fonarow GC, O´Gara PT, Yancy CW. Association of Coronavirus Disease 2019 (COVID-19) With Myocardial Injury and Mortality. JAMA Cardiol. 2020 Mar 27. pii: 2763844. PubMed: . Full-text:

Castiglion V, Chiriacò M, Emdin M, et al. Statin therapy in COVID-19 infection. European Heart Journal Cardiovascular Pharmacotherapy, 2020, 29 April. Full-text:

Daniels MJ, Cohen MG, Bavry AA, Kumbhani DJ. Reperfusion of STEMI in the COVID-19 Era – Business as Usual? Circulation. 2020 Apr 13. PubMed: Full-text:

De Filippo O, D’Ascenzo F, Angelini F, et al. Reduced Rate of Hospital Admissions for ACS during Covid-19 Outbreak in Northern Italy. NEJM, April 28, 2020. Full-text:

Frieden IJ, Puttgen KB, Drolet BA, et al. Management of Infantile Hemangiomas during the COVID Pandemic. Pediatr Dermatol. 2020 Apr 16. PubMed: . Full-text:

Goyal P, Choi JJ, Pinheiro LC, et al. Clinical Characteristics of Covid-19 in New York City. N Engl J Med. 2020 Apr 17. PubMed: . Full-text:

Grasselli G, Zangrillo A, Zanella A, et al. Baseline Characteristics and Outcomes of 1591 Patients Infected With SARS-CoV-2 Admitted to ICUs of the Lombardy Region, Italy. JAMA. 2020 Apr 6. pii: 2764365. PubMed: . Full-text:

Guan WJ, Liang WH, Zhao Y, et al. Comorbidity and its impact on 1590 patients with Covid-19 in China: A Nationwide Analysis. Eur Respir J. 2020 Mar 26. PubMed: . Full-text:

Guan WJ, Ni ZY, Hu Y, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020 Feb 28. PubMed: . Full-text:

Hoffmann M, Kleine-Weber H, Schroeder S, et al. SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Blocked by a Clinically Proven Protease Inhibitor. Cell. 2020 Mar 4. PubMed: . Full-text:

Jarcho JA, Ingelfinger JR, Hamel MB, D´Agostino RB Sr, Harrington DP. Inhibitors of the Renin-Angiotensin-Aldosterone System and Covid-19. N Engl J Med. 2020 May 1. PubMed: . Full-text:

Leonardi A, Fauquert JL, Doan S, et al. Managing ocular allergy in the time of COVID-19. Allergy. 2020 May 13. PubMed: . Full-text: 32332004

Mackey K, King VJ, Gurley S. Risks and Impact of Angiotensin-Converting Enzyme Inhibitors or Angiotensin-Receptor Blockers on SARS-CoV-2 Infection in Adults. A Living Systematic Review. Annals Internal Medicine 2020, May 15. Full-text:

Mancia G, Rea F, Ludergnani M, Apolone G, Corrao G. Renin-Angiotensin-Aldosterone System Blockers and the Risk of Covid-19. N Engl J Med. 2020 May 1. PubMed: . Full-text:

Mattei A, Amy de la Breteque B, Crestani S, et al. Guidelines of clinical practice for the management of swallowing disorders and recent dysphonia in the context of the COVID-19 pandemic. Eur Ann Otorhinolaryngol Head Neck Dis. 2020 Apr 20. PubMed: . Full-text: 32389541

Meng J, Xiao G, Zhang J, et al. Renin-angiotensin system inhibitors improve the clinical outcomes of COVID-19 patients with hypertension. Emerg Microbes Infect. 2020 Dec;9(1):757-760. PubMed: . Full-text:

Meng Y, Wu P, Lu W, et al. Sex-specific clinical characteristics and prognosis of coronavirus disease-19 infection in Wuhan, China: A retrospective study of 168 severe patients. PLOS Pathogens 2020, April 28, 2020. Full-text:

Mistrangelo M, Naldini G, Morino M. Do we really need guidelines for HRA during COVID-19 pandemic? Colorectal Dis. 2020 May 7. PubMed: . Full-text:

Piccolo R, Bruzzese D, Mauro C, et al. Population Trends in Rates of Percutaneous Coronary Revascularization for Acute Coronary Syndromes Associated with the COVID-19 Outbreak. Circulation. 2020 Apr 30. PubMed: . Full-text:

Rangé G, Hakim R, Motreff P. Where have the STEMIs gone during COVID-19 lockdown? European Heart Journal – Quality of Care and Clinical Outcomes, April 29, 2020. Full-text:

Reynolds HR, Adhikari S, Pulgarin C, et al. Renin-Angiotensin-Aldosterone System Inhibitors and Risk of Covid-19. N Engl J Med. 2020 May 1. PubMed: . Full-text:

Salgarello M, Adesi LB, Visconti G, Pagliara DM, Mangialardi ML. Considerations for performing immediate breast reconstruction during the COVID-19 pandemic. Breast J. 2020 May 7. PubMed: . Full-text:

Sama IE, Ravera A, Santema BT, et al. Circulating plasma concentrations of angiotensin-converting enzyme 2 in men and women with heart failure and effects of renin–angiotensin–aldosterone inhibitors. European Heart Journal 2020, May 10. Full-text:

Schiffrin EL, Flack J, Ito S, Muntner P, Webb C. Hypertension and COVID-19. Am J Hypertens. 2020 Apr 6. pii: 5816609. PubMed: . Full-text:

Shi Y, Yu X, Zhao H, Wang H, Zhao R, Sheng J. Host susceptibility to severe COVID-19 and establishment of a host risk score: findings of 487 cases outside Wuhan. Crit Care. 2020 Mar 18;24(1):108. PubMed: . Full-text:

Solomon MD, McNulty EJ, Rana JS, et al. The Covid-19 Pandemic and the Incidence of Acute Myocardial Infarction. NEJM 2020, May 19. DOI: 10.1056/NEJMc2015630 . Full-text:

Sriram K, Insel PA. Risks of ACE inhibitor and ARB usage in COVID-19: evaluating the evidence. Clin Pharmacol Ther. 2020 Apr 22. PubMed: . Full-text:

Stefanini GG, Montorfano M, Trabattoni D, et al. ST-Elevation Myocardial Infarction in Patients with COVID-19: Clinical and Angiographic Outcomes. Circulation. 2020 Apr 30. PubMed: . Full-text:

Szperka CL, Ailani J, Barmherzig R, et al. Migraine Care in the Era of COVID-19: Clinical Pearls and Plea to Insurers. Headache. 2020 May;60(5):833-842. PubMed: . Full-text:

Vaduganathan M, Vardeny O, Michel T, McMurray JJV, Pfeffer MA, Solomon SD. Renin-Angiotensin-Aldosterone System Inhibitors in Patients with Covid-19. N Engl J Med. 2020 Mar 30. PubMed: . Full-text:

Valente S, Anselmi F, Cameli M. Acute coronary syndromes during COVID-19. Eur Heart J. 2020 May 25:ehaa457. PubMed: . Full-text:

Wang Y, Lu X, Chen H, et al. Clinical Course and Outcomes of 344 Intensive Care Patients with COVID-19. Am J Respir Crit Care Med. 2020 Apr 8. PubMed: . Full-text:

Yang G, Tan Z, Zhou L, et al. Effects Of ARBs And ACEIs On Virus Infection, Inflammatory Status And Clinical Outcomes In COVID-19 Patients With Hypertension: A Single Center Retrospective Study. Hypertension. 2020 Apr 29. PubMed: . Full-text:

Zhang P, Zhu L, Cai J, et al. Association of Inpatient Use of Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers with Mortality Among Patients With Hypertension Hospitalized With COVID-19. Circ Res. 2020 Apr 17. PubMed: . Full-text:

Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet. 2020 Mar 11. PubMed: . Full-text:


Diabetes mellitus

Diabetes mellitus is a chronic inflammatory condition characterized by several macrovascular and microvascular abnormalities. As with hypertension and CVD, many of the above cited studies have also revealed that diabetic patients were overrepresented among the most severely ill patients with COVID-19 and those succumbing to the disease. Current data suggest that diabetes in patients with COVID-19 is associated with a two-fold increase in mortality as well as severity of COVID-19, as compared to non-diabetics. In a meta-analysis of 33 studies and 16,003 patients (Kumar 2020), diabetes was found to be significantly associated with mortality of COVID-19 with a pooled odds ratio of 1.90 (95% CI: 1.37-2.64). Diabetes was also associated with severe COVID-19 and a pooled odds ratio of 2.75 (95% CI: 2.09-3.62). The pooled prevalence of diabetes in patients with COVID-19 was 9.8% (95% CI: 8.7%-10.9%). However, it is too early to whether diabetes is acting as an independent factor responsible for COVID severity and mortality or if it is just a confounding factor.

The hitherto by far largest retrospective study on the impact of typ 2 diabetes (T2D) has carefully analyzed 7,337 cases of COVID-19 in Hubei Province, China, among them 952 with pre-existing T2D (Zhu 2020). The authors found that subjects with T2D required more medical interventions and had a significantly higher mortality (7.8% versus 2.7%; adjusted hazard ratio, 1.49) and multiple organ injury than non-diabetic individuals. Of note, well-controlled blood glucose was associated with markedly lower mortality (in-hospital death rate 1.1% versus 11.0%) compared to individuals with poorly controlled blood glucose.

A recent review has made some suggestions on the possible pathophysiological mechanisms of the relationship between diabetes and COVID-19, and its management (Hussain 2020). Rigorous glucose monitoring and careful consideration of drug interactions might attenuate worsening of symptoms and adverse outcomes. Some treatment strategies for COVID-19 such as steroids and lopinavir/r bear a risk for hyperglycemia. On the other hand, hydroxychloroquine may improve glycemic control in decompensated, treatment-refractory patients with diabetes (Gerstein 2002, Rekedal 2010). However, it remains unclear which COVID-19 treatment strategy works best and if treatment of diabetic patients have to be different from those without diabetes. It is also unclear whether specific diabetes drugs such as DPP4 inhibitors increase or decrease the susceptibility or severity of SARS-CoV-2 infection.


Gerstein HC, Thorpe KE, Taylor DW, Haynes RB. The effectiveness of hydroxychloroquine in patients with type 2 diabetes mellitus who are refractory to sulfonylureas–a randomized trial. Diabetes Res Clin Pract. 2002 Mar;55(3):209-19. PubMed: . Full-text:

Hussain A, Bhowmik B, do Vale Moreira NC. COVID-19 and diabetes: Knowledge in progress. Diabetes Res Clin Pract. 2020 Apr;162:108142. PubMed: . Full-text:

Kumar A, Arora A, Sharma P, et al. Is diabetes mellitus associated with mortality and severity of COVID-19? A meta-analysis. Diabetes Metab Syndr. 2020 May 6;14(4):535-545. PubMed: . Full-text:

Rekedal LR, Massarotti E, Garg R, et al. Changes in glycosylated hemoglobin after initiation of hydroxychloroquine or methotrexate treatment in diabetes patients with rheumatic diseases. Arthritis Rheum. 2010 Dec;62(12):3569-73. PubMed: . Full-text:

Zhu L, She ZG, Cheng X. Association of Blood Glucose Control and Outcomes in Patients with COVID-19 and Pre-existing Type 2 Diabetes. Cell Metabolism, April 30, 2020. Full-text:


COPD and smoking

Chronic Obstructive Pulmonary Disease (COPD) is a common and preventable dysfunction of the lung associated with limitation in airflow. It is a complex disease associated with abnormalities of the airway and/or alveoli which is predominantly caused by exposure to noxious gases and particulates over a long period. A meta-analysis of 15 studies, including a total of 2,473 confirmed COVID-19 cases showed that COPD patients were at a higher risk of more severe disease (calculated RR 1.88) and with 60% higher mortality (Alquahtani 2020). Unfortunately, the numbers in this review were very small and only 58 (2.3%) had COPD.

A meta-analysis of 5 early studies comprising 1,399 patients observed only a trend but no significant association between active smoking and severity of COVID-19 (Lippi 2020). However, other authors have emphasized that current data do not allow to draw firm conclusions about the association of severity of COVID-19 with smoking status (Berlin 2020). In a more recent review, current smokers were 1.45 times more likely to have severe complications compared to former and never smokers. Current smokers also had a higher mortality rate (Alquahtani 2020).

Ever-smoking significantly and substantially increased pulmonary ACE2 expression by 25% (Cai 2020). The significant smoking effect on ACE2 pulmonary expression may suggest an increased risk for viral binding and entry of SARS-CoV-2 in lungs of smokers. Cigarette smoke triggers an increase in ACE2 positive cells by driving secretory cell expansion (Smith 2020). The overabundance of ACE2 in the lungs of smokers may partially explain a higher vulnerability of smokers.

However, it’s not that easy – both quitting smoking and finding clinical correlations to the above cell experiments. Within a surveillance centre primary care sentinel network, multivariate logistic regression models were used to identify risk factors for positive SARS-CoV-2 tests (Lusignan 2020). Of note, active smoking was associated with decreased odds (yes, decreased: adjusted OR 0.49, 95% CI 0.34–0.71). According to the authors, their findings should not be used to conclude that smoking prevents SARS-CoV-2 infection, or to encourage ongoing smoking. Several explanations are given, such as selection bias (smokers are more likely to have a cough, more frequent testing could increase the proportion of smokers with negative results). Active smoking might also affect RT-PCR test sensitivity.


Alqahtani JS, Oyelade T, Aldhahir AM, et al. Prevalence, Severity and Mortality associated with COPD and Smoking in patients with COVID-19: A Rapid Systematic Review and Meta-Analysis. PLoS One. 2020 May 11;15(5):e0233147. PubMed: . Full-text:

Berlin I, Thomas D, Le Faou AL, Cornuz J. COVID-19 and smoking. Nicotine Tob Res. 2020 Apr 3. pii: 5815378. PubMed: . Full-text:

Cai G, Bosse Y, Xiao F, Kheradmand F, Amos CI. Tobacco Smoking Increases the Lung Gene Expression of ACE2, the Receptor of SARS-CoV-2. Am J Respir Crit Care Med. 2020 Apr 24. PubMed: . Full-text:

Lippi G, Henry BM. Active smoking is not associated with severity of coronavirus disease 2019 (COVID-19). Eur J Intern Med. 2020 Mar 16.  PubMed: . Full-text:

Lusignan S, Dorward J, Correa A, et al. Risk factors for SARS-CoV-2 among patients in the Oxford Royal College of General Practitioners Research and Surveillance Centre primary care network: a cross-sectional study. Lancet Inf Dis 2020, May 15. Full-text:

Smith JC, Sauswille EL, Girish V, et al. Cigarette smoke exposure and inflammatory signaling increase the expression of the SARS-CoV-2 receptor ACE2 in the respiratory tract. Development Cell, May 16, 2020. Full-text:


HIV infection

HIV infection is of particular interest in the current crisis. First, many patients take antiretroviral therapies that are thought to have some effect against SARS-CoV-2. Second, HIV serves as a model of cellular immune deficiency. Third, and by far the most important point, the collateral damage caused by COVID-19 in the HIV population may be much higher than that of COVID-19 itself.

Inexplicably, information on the HIV population is still scarce. However, preliminary data suggest no elevated incidence of COVID-19. In 5,700 patients from New York, only 43 (0.8%) were found to be HIV-positive (Richardson 2020). Similar findings were reported from Chicago (Ridgeway 2020). In Barcelona where a local protocol included HIV serology for all hospitalized COVID-19 patients, 32/2102 (1.5%) were HIV-infected, among them only one single new HIV diagnosis (Miro 2020). Given the fact that HIV+ patients may be at higher risk for other infectious diseases such as STDs, these percentages were so low that some experts have already speculated on potential “protective” factors (i.e., antiviral therapies or immune activation). Moreover, a defective cellular immunity could paradoxically be protective for severe cytokine dysregulation, preventing the cytokine storm seen in severe COVID-19 cases.

Appropriately powered and designed studies that are needed to draw conclusions on the effect of COVID-19 are still lacking. However, our own retrospective analysis of 33 confirmed SARS-CoV-2 infections between March 11 and April 17 in 12 participating German HIV centers revealed no excess morbidity or mortality (Haerter 2020). The clinical case definition was mild in 25/33 cases (76%), severe in 2/33 cases (6%), and critical in 6/33 cases (18%). At the last follow up, 29/32 of patients with documented outcome (90%) had recovered. Three out of 32 patients had died. One patient was 82 years old, one had a CD4 T cell count of 69/µl and one suffered from several comorbidities. A similar observation was made in Milan, Italy, where 45/47 patients with HIV and COVID-19 (only 28 with confirmed SARS-CoV-2 infection) recovered (Gervasoni 2020). In another single center study from Madrid on 51 HIV patients with COVID-19 (35 confirmed cases), six patients were critically ill and two died (Vizcarra 2020).

In these studies, as in our cohort, severe immune deficiency was rare. The last median CD4 count was 670/µl (range, 69 to 1715) and in 30/32 cases in our cohort, the latest HIV RNA was below 50 copies/mL (Härter 2020). It remains to be seen whether HIV+ patients with uncontrolled viremia and/or low CD4 cells are at higher risk for severe disease. It is also unclear whether immunity after infection remains impaired. However, there are case reports on delayed antibody response in HIV+ patients (Zhao 2020).

Another issue making HIV+ patients an interesting population is a potential effect of antiretroviral therapies against SARS-CoV-2. For lopinavir/r, some reports on beneficial effects in patients with SARS, MERS and COVID-19 exist, but the evidence remains poor. Several studies on lopinavir are still underway (see Treatment chapter). According to both the US DHHS and EACS statement, an ART regimen should not be changed to include a PI to prevent or treat COVID-19 (EACS 2020, US 2020). In our cohort, 4/33 (12%) patients were on darunavir when they developed COVID-19 symptoms. In the Milan Cohort, the rate of patients on a PI was 11% (Gervasoni 2020). Both studies indicate that PIs do not protect from SARS-CoV-2 infection. Beside the PI, we did not find any clear evidence for a protective effect of tenofovir. Tenofovir alafenamide has some chemical similarities to remdesivir and has been shown to bind to SARS-CoV-2 RNA polymerase (RdRp) with binding energies comparable to those of native nucleotides, similar to remdesivir. Consequently, tenofovir has recently been suggested as a potential treatment for COVID-19 (Elfiky 2020). In Spain, a large randomized Phase III placebo-controlled study (EPICOS, NCT04334928) compares the use of tenofovir disoproxil fumarate/emtricitabine, hydroxychloroquine or the combination of both versus placebo as prophylaxis for COVID-19 in healthcare workers. Our observation that the majority (22/33) of HIV+ patients with COVID-19 were treated with tenofovir, including those developing severe or critical disease, indicate no or only minimal clinical effect against SARS-CoV-2 (Härter 2020). In the cohorts from Milan and Madrid, there was no evidence that any specific antiretroviral drug (such as tenofovir or PIs) affected COVID-19 susceptibility or severity (Gervasoni 2020, Vizcarra 2020).

The most serious concern regarding HIV, however, is the collateral damage induced by COVID-19. In Western countries, there exist few reports of HIV+ patients having problems in gaining access to their HIV medications or having trouble taking them due to COVID-19 or the plans to manage it (Sanchez 2020). In contrast, disruption to delivery of health care in sub-Saharan African settings could well lead to adverse consequences beyond those from COVID-19 itself. Lockdown, transport restrictions and fear of coronavirus infection have already led to a dramatic drop in HIV and TB patients collecting medication in several African countries (Adepoju 2020). Using five different existing mathematical models of HIV epidemiology and intervention programmes in sub-Saharan Africa, investigations have already estimated the impact of different disruptions to HIV prevention and treatment services. Predicted average relative excess in HIV-related deaths and new HIV infections (caused by unsuppressed HIV RNA during treatment interruptions) per year over 2020-2024 in countries in sub-Saharan Africa that would result from 3 months of disruption of HIV-specific services, were 1.20-1.27 for death and 1.02-1.33 for new infections, respectively. A 6-month interruption of ART would result in over 500,000 excess HIV deaths in sub-Saharan Africa (range of estimates 471,000 – 673,000). Disrupted services could also reverse gains made in preventing mother-to-child transmission. According to WHO, there is a clear need for urgent efforts to ensure HIV service continuity and preventing treatment interruptions due to COVID-19 restrictions in sub-Saharan Africa.


Adepoju P. Tuberculosis and HIV responses threatened by COVID-19. Lancet HIV. 2020 May;7(5):e319-e320. PubMed: Full-text:

EACS & BHIVA. Statement on risk of COVID-19 for people living with HIV (PLWH).

Elfiky AA. Ribavirin, Remdesivir, Sofosbuvir, Galidesivir, and Tenofovir against SARS-CoV-2 RNA dependent RNA polymerase (RdRp): A molecular docking study. Life Sci. 2020 Mar 25;253:117592. PubMed: Full-text:

Gervasoni C, Meraviglia P, Riva A, et al. Clinical features and outcomes of HIV patients with coronavirus disease 2019. Clin Infect Dis. 2020 May 14:ciaa579. PubMed: Full-text:

Härter G, Spinner CD, Roider J, at al. COVID-19 in people living with human immunodeficiency virus: a case series of 33 patients. Infection 2020, May 11. Full-text:

Jewell B, Mudimu E, Stover J, et al. Potential effects of disruption to HIV programmes in sub-Saharan Africa caused by COVID-19: results from multiple models. Pre-print, +

Miró JM, Ambrosioni J, Blanco JL. COVID-19 in patients with HIV – Authors’ reply. Lancet HIV. 2020 May 14:S2352-3018(20)30140-5. PubMed: Full-text:

Richardson S, Hirsch JS, Narasimhan M, et al. Presenting Characteristics, Comorbidities, and Outcomes Among 5700 Patients Hospitalized With COVID-19 in the New York City Area. JAMA. 2020 Apr 22:e206775. PubMed: Full-text:

Ridgway JP, Schmitt J, Friedman E, et al. HIV Care Continuum and COVID-19 Outcomes Among People Living with HIV During the COVID-19 Pandemic, Chicago, IL. AIDS Behav. 2020 May 7:1-3. PubMed: Full-text:

Sanchez TH, Zlotorzynska M, Rai M, Baral SD. Characterizing the Impact of COVID-19 on Men Who Have Sex with Men Across the United States in April, 2020. AIDS Behav. 2020 Apr 29:1-9. PubMed: Full-text:

Vizcarra P, Pérez-Elías M, Quereda C, et al. Description of COVID-19 in HIV-infected individuals: a single-centre, prospective cohort. Lancet HIV. Published: May 28, 2020

U.S. Department of Health and Human Services. Interim Guidance for COVID-19 and Persons with HIV.–interim-guidance-/554/interim-guidance-for-covid-19-and-persons-with-hiv

Zhao J, Liao X, Wang H, et al. Early virus clearance and delayed antibody response in a case of COVID-19 with a history of co-infection with HIV-1 and HCV. Clin Infect Dis. 2020 Apr 9:ciaa408. PubMed: Full-text:


Immunosuppression (other than HIV)

Immunosuppression may bear a higher risk for SARS-CoV-2 infection and severe COVID-19. But the story is not that simple. Neither is it clear what immunosuppression actually means, nor are the available data sufficient to draw any conclusion. We just don’t know enough. Nevertheless, some authors are trumpeting the news that there is an increased risk. A bad example? A systematic review and meta-analysis on 8 studies and 4,007 patients came to the conclusion that “immunosuppression and immunodeficiency were associated with increased risk of severe COVID-19 disease, although the statistical differences were not significant” (Gao 2020). The authors also state that “in response to the COVID-19 pandemic, special preventive and protective measures should be provided.” There is null evidence for this impressive statement. The total number of patients with immunosuppression in the study was 39 (without HIV: 11!), with 6/8 studies describing less than 4 patients with different modalities of immunosuppression.

Despite the large absence of data, numerous viewpoints and guidelines have been published on how to manage immunosuppressed patients that may be more susceptible to acquire COVID-19 infection and develop severe courses. There are recommendations for intranasal corticosteroids in allergic rhinitis (Bousquet 2020), immunosuppressants for psoriasis and other cutaneous diseases (Conforti 2020, Torres 2020)), rheumatic diseases (Favalli 2020, Figuera-Parra 2020) or inflammatory bowel diseases (Kennedy 2020, Pasha 2020). The bottom line of these heroic attempts to balance the risk of immune-modifying drugs with the risk associated with active disease: what is generally needed, has to be done (or to be continued). Exposure prophylaxis is important.

However, two studies have indeed found evidence for deleterious effects of glucocorticoids, indicating that these drugs should be given with particular caution these days. The largest study published to date, analysed 525 patients with inflammatory bowel disease (IBD) from 33 countries (Brenner 2020). Thirty-seven patients (7%) had severe COVID-19, and 16 patients died (3% case fatality rate). Risk factors for severe COVID-19 among IBD patients included increasing age, ≥ 2 comorbidities, systemic corticosteroids (adjusted odds ratio 6.9, 95% CI 2.3-20.5), and sulfasalazine or 5-aminosalicylate use (aOR 3.1, 95% CI 1.3-7.7). Notably, TNF antagonist treatment was not associated with severe COVID-19. Another larger case series looked at 86 patients with immune-mediated inflammatory disease and symptomatic COVID-19, among them 62 receiving biologics or Janus kinase (JAK) inhibitors (Haberman 2020). The percentage of patients who were receiving biologics or JAK inhibitors at baseline was higher among the ambulatory than among the hospitalized patients. In contrast, hospitalization rates were higher in patients treated with oral glucocorticoids, hydroxychloroquine and methotrexate.


Bousquet J, Akdis C, Jutel M, et al. Intranasal corticosteroids in allergic rhinitis in COVID-19 infected patients: An ARIA-EAACI statement. Allergy. 2020 Mar 31. PubMed: Full-text:

Brenner Ej, Ungaro RC, Gearry RB, et al. Corticosteroids, but Not TNF Antagonists, Are Associated With Adverse COVID-19 Outcomes in Patients With Inflammatory Bowel Diseases: Results From an International Registry. Gastroenterology 2020 May 18. Full-text:

Conforti C, Giuffrida R, Dianzani C, Di Meo N, Zalaudek I. COVID-19 and psoriasis: Is it time to limit treatment with immunosuppressants? A call for action. Dermatol Ther. 2020 Mar 11. Fulltext:

Favalli EG, Ingegnoli F, De Lucia O, Cincinelli G, Cimaz R, Caporali R. COVID-19 infection and rheumatoid arthritis: Faraway, so close! Autoimmun Rev. 2020 Mar 20:102523. PubMed: . Fulltext:

Figueroa-Parra G, Aguirre-Garcia GM, Gamboa-Alonso CM, Camacho-Ortiz A, Galarza-Delgado DA. Are my patients with rheumatic diseases at higher risk of COVID-19? Ann Rheum Dis. 2020 Mar 22. PubMed: . Fulltext:

Gao Y, Chen Y, Liu M, Shi S, Tian J. Impacts of immunosuppression and immunodeficiency on COVID-19: a systematic review and meta-analysis. J Infect. 2020 May 14:S0163-4453(20)30294-2. PubMed: . Full-text:

Haberman R, Axelrad J, Chen A, et al. Covid-19 in Immune-Mediated Inflammatory Diseases – Case Series from New York. N Engl J Med. 2020 Apr 29. PubMed: . Full-text:

Kennedy NA, Jones GR, Lamb CA, et al. British Society of Gastroenterology guidance for management of inflammatory bowel disease during the COVID-19 pandemic. Gut. 2020 Apr 17. PubMed: . Full-text:

Pasha SB, Fatima H, Ghouri YA. Management of Inflammatory Bowel Diseases in the Wake of COVID-19 Pandemic. J Gastroenterol Hepatol. 2020 Apr 4. PubMed: . Full-text:

Torres T, Puig L. Managing Cutaneous Immune-Mediated Diseases During the COVID-19 Pandemic. Am J Clin Dermatol. 2020 Apr 10. pii: 10.1007/s40257-020-00514-2. PubMed: . Full-text:



During a health crisis such as the COVID pandemic, it is crucial to carefully balance cost and benefits in performing a transplantation (Andrea 2020). There is no doubt that the current situation has deeply affected organ donation and that this represents an important collateral damage of the pandemic. All Eurotransplant countries have implemented preventive screenings policies for potential organ donors. For detailed information on the national policy, please visit Preliminary data indicate a significant reduction in transplantation rates even in regions where COVID-19 cases are low, suggesting a global and nationwide effect beyond the local COVID-19 infection prevalence (Loupy 2020). During March and April, the overall reduction in deceased donor transplantations since the COVID-19 outbreak was 91% in France and 51% in the USA, respectively. In both France and the USA, this reduction was mostly driven by kidney transplantation, but a substantial effect was also seen for heart, lung, and liver transplants, all of which provide meaningful improvement in survival probability.

Solid organ transplant recipients are generally at higher risk for complications of respiratory viral infections (in particular influenza), due to their chronic immunosuppressive regimen, and this may hold particularly true for SARS-CoV-2 infection. The first larger cohort of COVID-19 in transplant recipients from the US indeed indicated that transplant recipients appear to have more severe outcomes (Pereira 2020). Of 90 patients (median age of 57 years), 46 were kidney recipients, 17 lung, 13 liver, 9 heart and 5 dual-organ transplants. Sixteen patients died (18% overall, 24% of hospitalized, 52% of ICU). It remains unclear whether these high mortality and morbidity rates derived from reporting or selection bias. However, a single center experience with 36 kidney transplant recipients found even higher rates. After 21 days, 10/36 had died (Akalin 2020). Patients appear to have less fever as an initial symptom, lower CD3/4/8 cell counts and more rapid clinical progression. In a case series of 28 patients who had received heart transplant in a large academic center in New York, 22 patients (79%) were hospitalized. At the end of the follow-up, 4 remained hospitalized and 7 (25%) had died (Latif 2020).

Preliminary data from Switzerland, however, were more hopeful (Tschopp 2020). Overall, 21 patients were included with a median age of 56 years (10 kidney, 5 liver, 1 pancreas, 1 lung, 1 heart and 3 combined transplantations). Ninety‐five percent and 24% of patients required hospital and ICU admission, respectively. After a median of 33 days of follow‐up, 16 patients were discharged, 3 were still hospitalized and only 2 patients died.


Akalin E, Azzi Y, Bartash B. Covid-19 and Kidney Transplantation. N Engl J Med. 2020 Apr 24. PubMed: . Full-text:

Andrea G, Daniele D, Barbara A, et al. Coronavirus Disease 2019 and Transplantation: a view from the inside. Am J Transplant. 2020 Mar 17. PubMed: . Fulltext:

Latif F, Farr MA, Clerkin KJ, et al. Characteristics and Outcomes of Recipients of Heart Transplant With Coronavirus Disease 2019. JAMA Cardiol. Published online May 13, 2020. Full-text:

Loupy A, Aubert O, Reese PP, et al. Organ procurement and transplantation during the COVID-19 pandemic. Lancet May 11, 2020. Full-text:

Pereira MR, Mohan S, Cohen DJ, et al. COVID-19 in Solid Organ Transplant Recipients: Initial Report from the US Epicenter. Am J Transplant. 2020 Apr 24. PubMed: . Full-text:

Tschopp J, L´Huillier AG, Mombelli M, et al. First experience of SARS-CoV-2 infections in solid organ transplant recipients in the Swiss Transplant Cohort Study. Am J Transplant 2020 May 15. PubMed: Full-text:


Other comorbidities

Ultimately, the current situation might lead to substantial changes in how research and medicine are practiced in the future. The SARS-CoV-2 pandemic has created major dilemmas in almost all areas of health care. Scheduled operations, numerous types of treatment and appointments have been cancelled world-wide or postponed to prioritise hospital beds and care for those who are seriously ill with COVID-19. Throughout the world, health systems had to consider rapidly changing responses while relying on inadequate information. In some settings such as HIV or TB infection, oncology or solid organ transplantation, these collateral damages may have been even greater than the damage caused by COVID-19 itself. Treatment interruptions, disrupted drug supply chains and consequent shortages will likely exacerbate this issue. During the next months, we will learn more and provide more information on the consequences of this crisis on various diseases. In the meantime, please refere to the key papers listed below.


Coles CE, Aristei C, Bliss J, et al. International Guidelines on Radiation Therapy for Breast Cancer During the COVID-19 Pandemic. Clin Oncol (R Coll Radiol). 2020 May;32(5):279-281. PubMed: . Full-text:

Dholaria B, Savani BN. How do we plan hematopoietic cell transplant and cellular therapy with the looming COVID-19 threat? Br J Haematol. 2020 Mar 16. Fulltext:

Francesco C, Pettke A, Michele B, Fabio P, Helleday T. Managing COVID-19 in the oncology clinic and avoiding the distraction effect. Ann Oncol. 2020 Mar 19. Fulltext:

Kuderer NM, Choueiri TK, Shah DP, et al. Clinical impact of COVID-19 on patients with cancer (CCC19): a cohort study. Lancet. 2020 May 28:S0140-6736(20)31187-9. PubMed: Full-text:

Liang W, Guan W, Chen R, et al. Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China. Lancet Oncol. 2020 Mar;21(3):335-337. Fulltext:

Paul S, Rausch CR, Jain N, et al. Treating Leukemia in the Time of COVID-19. Acta Haematol. 2020 May 11:1-13. PubMed: Full-text:

The Lancet Oncology. COVID-19: global consequences for oncology. Lancet Oncol. 2020 Apr;21(4):467. PubMed: Full-text:

Tian J, Yuan X, Xiao J, et al. Clinical characteristics and risk factors associated with COVID-19 disease severity in patients with cancer in Wuhan, China: a multicentre, retrospective, cohort study. Lancet Oncol. 2020 May 29:S1470-2045(20)30309-0. PubMed: Full-text:

Ueda M, Martins R, Hendrie PC, et al. Managing Cancer Care During the COVID-19 Pandemic: Agility and Collaboration Toward a Common Goal. J Natl Compr Canc Netw. 2020 Mar 20:1-4. PubMed: Full-text:

Xia Y, Jin R, Zhao J, Li W, Shen H. Risk of COVID-19 for patients with cancer. Lancet Oncol. 2020 Apr;21(4):e180. PubMed: Full-text:



Basile C, Combe C, Pizzarelli F, et al. Recommendations for the prevention, mitigation and containment of the emerging SARS-CoV-2 (COVID-19) pandemic in haemodialysis centres. Nephrol Dial Transplant. 2020 Mar 20. pii: 5810637. PubMed: Fulltext:

Xiong F, Tang H, Liu L, et al. Clinical Characteristics of and Medical Interventions for COVID-19 in Hemodialysis Patients in Wuhan, China. J Am Soc Nephrol. 2020 May 8. PubMed: . Full-text:


Dave M, Seoudi N, Coulthard P. Urgent dental care for patients during the COVID-19 pandemic. Lancet. 2020 Apr 3. PubMed: . Full-text:

French JA, Brodie MJ, Caraballo R, et al. Keeping people with epilepsy safe during the Covid-19 pandemic. Neurology. 2020 Apr 23. PubMed: . Full-text:

Little P. Non-steroidal anti-inflammatory drugs and covid-19. BMJ. 2020 Mar 27;368:m1185. PubMed: Fulltext:

Wang H, Li T, Barbarino P, et al. Dementia care during COVID-19. Lancet. 2020 Apr 11; 395(10231):1190-1191. PubMed: . Full-text:

Yao H, Chen JH, Xu YF. Patients with mental health disorders in the COVID-19 epidemic. Lancet Psychiatry. 2020 Apr;7(4):e21. Full-text: