METHODS
Two authors independently performed a systematic literature search in PubMed, and Google Scholar and two preprint servers (medRxiv and SSRN) up to 2nd May 2020. Search terms are depicted inTable S1 . The titles and abstracts of the resulting articles were examined to exclude irrelevant studies. The full texts of the remaining articles were read to determine if these articles meet our eligibility criteria. Bibliographies of retrieved articles were also reviewed for additional studies. The studies eligible for this review reported on exposure to ACEIs/ARBs and the risk of mortality from COVID-19 as well as the severity of COVID-19. We also aim to review the definitions of severe/ critical disease used in the included studies. Any discrepancies were addressed by a joint re-evaluation of the original article. Articles were excluded if they did not report mortality risk and severity as two independent outcomes, or without original data. Two authors independently reviewed the primary studies to assess the appropriateness for inclusion and data were extracted. However, studies in the Chinese language were only assessed by CSK (native Chinese). The information extracted from each study is presented in Table 1 .