Subgroup analyses for cardiac death
| Variable | Group | Number of cohorts | RRR and 95% CI | P value | I2 (%) | P value for heterogeneity | P value for meta-regression |
| Publication year | Before 2010 | 10 | 1.49 (1.11 to 2.00) | 0.009 | 31.9 | 0.153 | – |
| 2010 or after | 0 | – | – | – | – | ||
| Country | Western | 7 | 1.84 (1.45 to 2.32) | <0.001 | 3.6 | 0.399 | 0.010 |
| Eastern | 3 | 0.97 (0.62 to 1.51) | 0.891 | 0.0 | 0.870 | ||
| Sample size | ≥10 000 | 2 | 1.96 (1.54 to 2.49) | <0.001 | 0.0 | 0.591 | 0.015 |
| <10 000 | 8 | 1.18 (0.85 to 1.64) | 0.322 | 0.0 | 0.433 | ||
| Assessment of DM | Self-reported | 2 | 2.05 (1.59 to 2.64) | <0.001 | 0.0 | 0.568 | 0.016 |
| Measured | 7 | 1.10 (0.78 to 1.54) | 0.588 | 0.0 | 0.586 | ||
| Both | 1 | 1.68 (0.93 to 3.06) | 0.087 | – | – | ||
| Follow-up duration (years) | ≥10 | 8 | 1.57 (1.18 to 2.09) | 0.002 | 21.8 | 0.256 | 0.257 |
| <10 | 2 | 1.41 (0.42 to 4.68) | 0.576 | 66.5 | 0.084 | ||
| Adjusted other CVD risk factors | Yes | 8 | 1.42 (1.02 to 1.98) | 0.040 | 44.0 | 0.085 | 0.575 |
| No | 2 | 2.18 (0.79 to 6.03) | 0.132 | 0.0 | 0.524 | ||
| Study quality | High | 4 | 1.97 (1.56 to 2.48) | <0.001 | 0.0 | 0.864 | 0.006 |
| Low | 6 | 1.10 (0.78 to 1.55) | 0.593 | 0.0 | 0.417 |
CVD, cardiovascular disease; DM, diabetes mellitus.