Comorbid Chronic Diseases are Strongly Correlated with Disease Severity among COVID-19 Patients: A Systematic Review and Meta-Analysis.

Aging and disease. 2020;11(3):668-678

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Plain language summary

Symptomatic COVID-19 infection is accompanied by a cluster of flu-like symptoms and life-threatening severe illnesses including acute respiratory distress syndrome, acute kidney injury, myocarditis, and organ failure. The aim of this study was to provide a systematic evaluation and detailed estimate on the prevalence and effects of pre-existing chronic conditions in COVID-19 patients. This study is a systemic review and meta-analysis of 24 studies (with a total of 10948 COVID-19 patients) for qualitative and quantitative synthesis. Results show that: - male participants were more susceptible to COVID-19. - both sexes exhibited clinical presentations similar in symptomatology. - diabetes and coronary artery disease/cardiovascular disease were prevalent in 10.0% and 8.0% of the patients, respectively. - pre-existing chronic diseases were strongly correlated with the increased disease severity and increased admittance to ICU. Authors conclude that patients with pre-existing chronic diseases may have a higher risk for developing severe COVID-19 and should be given close attention.


Coronavirus disease 2019 (COVID-19) has resulted in considerable morbidity and mortality worldwide since December 2019. In order to explore the effects of comorbid chronic diseases on clinical outcomes of COVID-19, a search was conducted in PubMed, Ovid MEDLINE, EMBASE, CDC, and NIH databases to April 25, 2020. A total of 24 peer-reviewed articles, including 10948 COVID-19 cases were selected. We found diabetes was present in 10.0%, coronary artery disease/cardiovascular disease (CAD/CVD) was in 8.0%, and hypertension was in 20.0%, which were much higher than that of chronic pulmonary disease (3.0%). Specifically, preexisting chronic conditions are strongly correlated with disease severity [Odds ratio (OR) 3.50, 95% CI 1.78 to 6.90], and being admitted to intensive care unit (ICU) (OR 3.36, 95% CI 1.67 to 6.76); in addition, compared to COVID-19 patients with no preexisting chronic diseases, COVID-19 patients who present with either diabetes, hypertension, CAD/CVD, or chronic pulmonary disease have a higher risk of developing severe disease, with an OR of 2.61 (95% CI 1.93 to 3.52), 2.84 (95% CI 2.22 to 3.63), 4.18 (95% CI 2.87 to 6.09) and 3.83 (95% CI 2.15 to 6.80), respectively. Surprisingly, we found no correlation between chronic conditions and increased risk of mortality (OR 2.09, 95% CI 0.26 to16.67). Taken together, cardio-metabolic diseases, such as diabetes, hypertension and CAD/CVD were more common than chronic pulmonary disease in COVID-19 patients, however, each comorbid disease was correlated with increased disease severity. After active treatment, increased risk of mortality in patients with preexisting chronic diseases may reduce.

Lifestyle medicine

Fundamental Clinical Imbalances : Hormonal ; Immune and inflammation
Patient Centred Factors : Triggers/Pre-existing chronic diseases
Environmental Inputs : Diet ; Nutrients
Personal Lifestyle Factors : Not applicable
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Journal Article ; Review