People with cardiovascular disease or risk factors are at increased risk when exposed to SARS-CoV-2. Most are treated with statins, but the impact of these drugs on clinical outcomes of COVID-19 remains unclear. This report is therefore based on meta-analyses of retrospective observational studies aimed at investigating the impact of previous statin therapy in patients hospitalized for COVID-19.

In studies reporting on the clinical outcomes of COVID-19 in statin users vs non-users, two endpoints have been used—in-hospital death rates, and disease severity as assessed by admission to intensive care units (ICUs)—with a special focus on patients with diabetes.

Regarding mortality, 13 studies were included in the meta-analysis for a total of 10,829 statin users (2517 deaths) and 31,893 non-users (7516 deaths): univariate analysis showed no statistically significant reduction in deaths (OR: 0.97, 95% CI: 0.92–1.03), although between-study heterogeneity was high (I² = 97%). As for disease severity, 11 studies were selected for a total of 3462 statin users (724 endpoints) and 10,560 non-users (1763 endpoints): here again, univariate analysis showed no reduction in severity (OR: 1.09, 95% CI: 0.99–1.22; I² = 93%). Collectively, in 10 studies using multivariable analysis adjusted for the more prevalent baseline risk factors among statin users, lower OR values were reported than with univariate analyses (0.73 ± 0.31 vs 1.44 ± 0.84, respectively; P =  0.0028; adjusted OR: P =  0.0237 vs non-users). Limited but conflicting findings were observed for diabetes patients.

Although no significant reductions in either in-hospital mortality or COVID-19 severity were reported among statin users compared with non-users after univariate comparisons, such reductions were observed after adjusting for confounding factors. These highly heterogeneous observational findings now require confirmation by ongoing randomized clinical trials.