Table 2.
Association between H2RA use and adverse outcomes of COVID-19 in the subgroup meta-analysis by various factors
| Factors | No. of studies | Summary HR (95% CI) | Heterogeneity, I2 (%) | Meta-regression |
|---|---|---|---|---|
| All9,13,22,24–27 | 7 | 0.90 (0.56–1.44) | 74.6 | |
| Mean age | 0.10 | |||
| < 60 years24–26 | 3 | 1.36 (0.88–1.10) | 62.3 | |
| > 60 years9,13,22 | 3 | 0.57 (0.33–0.98) | 36.7 | |
| Administration time of H2RAs | 0.43 | |||
| At-home9,13,22,24 | 4 | 0.76 (0.39–1.45) | 78.3 | |
| In-hospital25–27 | 3 | 1.73 (1.29–2.30) | 0.0 | |
| Specific type of H2RAs | 0.42 | |||
| Famotidine9,22,25–27 | 5 | 0.74 (0.33–1.66) | 82.2 | |
| All13,24 | 2 | 1.31 (0.98–1.76) | 0.0 | |
| Geographical region | 0.17 | |||
| North America9,22,24,26 | 4 | 0.64 (0.31–1.33) | 80.3 | |
| Europe13 | 1 | 1.07 (0.46–2.47) | NA | |
| Asia25,27 | 2 | 1.79 (1.27–2.52) | 53.9 | |
| Number of participants | 0.46 | |||
| Small (≤ 1000)22,27 | 2 | 0.61 (0.25–1.49) | 26.1 | |
| Large (> 1000)9,13,24–26 | 5 | 1.00 (0.60–1.65) | 75.9 | |
| Confounding adjustment | ||||
| BMI7,13,22,24 | 4 | 0.76 (0.39–1.45) | 78.3 | |
| Smoking status13,22 | 2 | 0.69 (0.31–1.54) | 53.2 | |
| Steroid use22,27 | 2 | 0.61 (0.25–1.49) | 26.1 | |
| Comorbidity7,13,22,24,26 | 5 | 0.71 (0.40–1.28) | 73.8 | |
| Gastrointestinal disease13,24 | 2 | 1.31 (0.98–1.76) | 0.0 |
BMI body mass index, CI confidence interval, COVID-19 coronavirus disease 2019, HR hazard ratio, NA not applicable, H2RA histamine H2 receptor antagonist