Effect of comorbid pulmonary disease on the severity of COVID‐19: A systematic review and meta‐analysis

Coronavirus disease 2019 (COVID‐19) caused by infection with severe acute respiratory syndrome coronavirus 2 was first detected in Wuhan, China, in late 2019 and continues to spread worldwide. Persistent questions remain about the relationship between the severity of COVID‐19 and comorbid diseases, as well as other chronic pulmonary conditions. In this systematic review and meta‐analysis, we aimed to examine in detail whether the underlying chronic obstructive pulmonary diseases (COPD), asthma and chronic respiratory diseases (CRDs) were associated with an increased risk of more severe COVID‐19. A comprehensive literature search was performed using five international search engines. In the initial search, 722 articles were identified. After eliminating duplicate records and further consideration of eligibility criteria, 53 studies with 658,073 patients were included in the final analysis. COPD was present in 5.2% (2191/42,373) of patients with severe COVID‐19 and in 1.4% (4203/306,151) of patients with non‐severe COVID‐19 (random‐effects model; OR = 2.58, 95% CI = 1.99–3.34, Z = 7.15, p < 0.001). CRD was present in 8.6% (3780/44,041) of patients with severe COVID‐19 and in 5.7% (16,057/280,447) of patients with non‐severe COVID‐19 (random‐effects model; OR = 2.14, 95% CI = 1.74–2.64, Z = 7.1, p < 0.001). Asthma was present in 2.3% (1873/81,319) of patients with severe COVID‐19 and in 2.2% (11,796/538,737) of patients with non‐severe COVID‐19 (random‐effects model; OR = 1.13, 95% CI = 0.79–1.60, Z = 0.66, p = 0.50). In conclusion, comorbid COPD and CRD were clearly associated with a higher severity of COVID‐19; however, no association between asthma and severe COVID‐19 was identified.