Table 2. Results of subgroup analyses.
| Overall results | Studies, N | Participants,N | HR (95% CI) | p value | p of heterogeneity | I2 (%) | |
|---|---|---|---|---|---|---|---|
| 9 | 440.911 | 1.40 (1.16-1.70) | 0.001 | <0.001 | 76.1 | ||
| Study design | |||||||
| Prospective cohort | 4 | 54.060 | 1.27 (1.09-1.48) | 0.003 | 0.603 | 0 | |
| retrospective cohort | 5 | 386.851 | 1.51 (1.09-2.09) | 0.013 | <0.001 | 87.3 | |
| Country | |||||||
| Sweden | 1 | 15.333 | 1.47 (1.04-2.07) | 0.028 | NA | NA | |
| Turkey | 2 | 6.449 | 2.07 (1.23-3.46) | 0.006 | 0.255 | 22.7 | |
| USA | 3 | 38.727 | 1.22 (1.03-1.45) | 0.023 | 0.621 | 0 | |
| Taiwan | 2 | 192.468 | 1.45 (0.70-3.01) | 0.323 | <0.001 | 95 | |
| Korea | 1 | 187.934 | 1.14 (1.00-1.30) | 0.048 | NA | NA | |
| PD therapy | |||||||
| Included | 3 | 162.282 | 1.22 (0.86-1.73) | 0.272 | 0.056 | 65.2 | |
| Unreported | 6 | 278.629 | 1.49 (1.17-1.91) | 0.001 | <0.001 | 79.2 | |
| PD ascertainment | |||||||
| Self-report | 3 | 42.732 | 1.25 (1.07-1.46) | 0.005 | 0.552 | 0 | |
| Clinical and radiographic parameters | 3 | 194.383 | 1.61 (0.99-2.61) | 0.056 | 0.004 | 82.1 | |
| Clinical diagnosis | 3 | 203.796 | 1.52 (0.83-2.79) | 0.177 | <0.001 | 90.2 | |
| Follow-up period | |||||||
| >15 years | 2 | 35.266 | 1.26 (1.02-1.56) | 0.030 | 0.276 | 15.8 | |
| <15 years | 4 | 25.243 | 1.64 (1.17-2.29) | 0.004 | 0.126 | 47.5 | |
| NA | 3 | 380.402 | 1.32 (0.92-1.92) | 0.136 | <0.001 | 90.9 | |
CI = confidence interval; HR = Hazard Ratio; NA = not applicable; PD = periodontal disease