Table 2.
Subgroup analysis for studies included in the analysis
| Subgroup analysis | Number of studies | Number of estimates | Pooled OR (95% CI), I2 statistics (%), P value for the heterogeneity Q test |
|---|---|---|---|
| All estimates combined | 9 | 21 | 1.88 (1.39, 2.54); I2 = 98%, P < 0.001 |
| Elimating Lin et al.'s study [18] | 8 | 20 | 1.65 (1.38, 1.97); I2 = 85.3%, P < 0.001 |
| Elimating Wu et al.'s study [20] | 8 | 19 | 1.85 (1.40, 2.46); I2 = 97.9%, P < 0.001 |
| Study design | |||
| Case–control | 4 | 12 | 1.20 (1.03, 1.40); I2 = 79.4%, P < 0.001 |
| Cohort | 3 | 3 | 2.42 (0.89, 6.60); I2 = 88.8%, P < 0.001 |
| SCCS | 2 | 10 | 1.62 (1.34, 1.95); I2 = 55.2%, P = 0.017 |
| Case–crossover | 2 | 3 | 2.51 (2.36, 2.67); I2 = 0%, P = 0.565 |
| Type of antipsychotic drugs | |||
| typical | 7 | 11 | 2.19 (1.46, 3.28); I2 = 98.4%, P < 0.001 |
| atypical | 5 | 7 | 1.72 (0.96, 3.07); I2 = 97%, P < 0.001 |
| Diagnostic category | |||
| Schizophrenia | 3 | 3 | 2.48 (1.66, 3.69); I2 = 94.7%, P < 0.001 |
| Mood disorder | 2 | 2 | 1.66 (0.86, 3.22); I2 = 71.2%, P < 0.001 |
| Dementia | 3 | 7 | 1.82 (1.16, 2.84); I2 = 92.1%, P < 0.001 |
| Exposure time | |||
| 1–30 days | 3 | 4 | 2.64 (2.48, 2.81); I2 = 0%, P = 0.904 |
| 1–60 days | 2 | 3 | 1.59 (1.17, 2.18); I2 = 0%, P = 0.447 |
| 1–90 days | 3 | 7 | 1.35 (1.09, 1.67); I2 = 0%, P = 0.447 |