Chronic respiratory disease and coronavirus disease 2019 in developing countries: A systematic review

The proportion of coronavirus disease 2019 (COVID-19) patients having a chronic respiratory disease (CRD), and its impact on COVID-19 related patient outcomes, is unclear. We conducted this systematic review to evaluate the proportion of patients with asthma or chronic obstructive pulmonary disease (COPD) among COVID-19 patients, and to assess if comorbid CRD worsens COVID-19 outcomes, in developing countries. We queried PubMed database for studies conducted in developing countries and provided data on the proportion of COVID-19 patients with CRD, or severe disease or mortality among COVID-19 patients with and without CRD. We calculated proportion of CRD patients and relative risk (RR) for each reported outcome of interest. We used random-effects models to summarize our data. We retrieved 1947 citations and included 22 studies from developing countries in our review. The pooled estimate for proportion of asthma and COPD was 2.32% (95% confidence interval [CI] 1.86%–2.83%) and 3.52% (95% CI 2.14%–5.20%), respectively. COVID-19 patients with asthma had a higher risk of severe COVID-19 (summary RR 1.21, 95% CI 1.17–1.25), but not of mortality (summary RR 1.01, 95% CI 0.80–1.28), as compared to COVID-19 patients without asthma. COVID-19 patients with COPD had a higher risk of severe COVID-19 (summary RR 1.48, 95% CI 1.30–1.69) and mortality (summary RR 2.69, 95% CI 1.57–4.61), as compared to COVID-19 patients without COPD. Patients with asthma (but not COPD) in developing countries may be less likely to acquire COVID-19. Both diseases may increase the risk of severe COVID-19, and COPD may increase risk of COVID-19-related mortality.