Study characteristics
The literature search identified 452 articles. However, only 27 studies
were eligible for inclusion (Figure 1). A total of 72,372 patients were
included in these 27 studies of which 10,197 (14.1%) patients were on
ACEIs or ARBs. The average age of the population in these studies was 61
years and men represented 52.24% of them (Table 1). Twenty-one studies
(77.8%) focused on comparing COVID-19 related outcomes between ACEI/ARB
users vs. non-users among patients with COVID-19 while the remining six
studies (22.2%) focused on comparing outcomes between ACEIs/ARBs users
in patients with and without COVID-19 infection (Table 1). ACEIs/ARBs in
the included studies were indicated for a wide range of chronic
conditions such as hypertension, coronary artery diseases, heart
failure, diabetes or chronic kidney disease.
In terms of outcomes, nine studies (33.3%) reported three to five
COVID-19 related outcomes (20, 23, 25, 26, 37-41), while another nine
studies (33.3%) reported only two outcomes (17, 19, 22, 24, 27, 42-45)
with another one-third reported only one outcome [19,22,29,46-51].
Overall, the 27 studies reported data on 15 unique outcomes including
death in 12 studies (18, 21, 28, 46-51), ICU admission in seven studies
(23, 25, 37-41), death/ICU admission as a composite outcome in four
studies (21, 37, 42, 51), risk of acquiring COVID-19 infection in nine
studies (22, 25, 26, 39-41, 45, 46, 50), risk of severe COVID-19
infection in seven studies (17-19, 22, 24, 45, 47), risk of severe
pneumonia in two studies (26, 48), risk of hospitalisation in eight
studies (26, 39-44, 49), hospital discharge in three studies (23, 26,
27), use of ventilator in four studies (19, 23, 38, 41), duration of
hospital stay in two studies (25, 26), and each of acute respiratory
distress syndrome (ARDS), septic shock, cardiac shock, acute kidney
injury (20), and hospital readmission (23) in one study, respectively.
In terms of the exposure, the effects of ACEIs and ARBs were assessed as
one class (ACEIs/ARBs) in 17 studies (63%) (17, 20, 22-28, 37, 40, 41,
44, 47, 48, 50, 51), as separate classes in five studies (18.5%) 52,
74, 78, 80, 84), and both as one and separate classes in another five
studies (18, 19, 38, 42, 46).
The majority of the 27 eligible studies were conducted in Asia (44.4%,
n=12 with 10 studies from China, one from each of in Korea and Israel),
followed by nine studies (33.3%) from Europe (four in Italy, three in
the United Kingdom and one from each of France and Belgium) and the
remaining six (22.3%) from the USA. Furthermore, the reported measure
of effects were crude/un-adjusted measures in the majority of the
studies (77.8%, n=21) (18, 19, 21-28, 37-43, 45, 50, 51); with most of
them (59.3%, n=16) being non-peer reviewed articles published as
preprints on medRivix (24, 26, 27, 37-40, 42-45, 47-51), and only four
rated as a good quality studies based on the Newcastle-Ottawa Quality
Assessment risk of bias (21, 37, 44, 45) (Table 2).