Table 4.
Subgroup analysis of risk ratio and prevalence of COPD
| Subgroups | N | Effect size[95% CI] | Z | P | Test of heterogeneity | |
|---|---|---|---|---|---|---|
| I 2 | P | |||||
| Risk ratio | ||||||
| Region | ||||||
| North America | 3 | 1.560 [1.320, 1.769] | 14.58 | < 0.001 | 0.0% | 0.968 |
| Europe | 2 | 2.194 [1.439, 2.948] | 5.70 | < 0.001 | 84.7% | 0.011 |
| Asia | 1 | 1.850 [1.695, 2.005] | 23.39 | < 0.001 | NA | NA |
| Overall | 6 | 1.822 [1.546, 2.099] | 12.92 | < 0.001 | 75.4% | 0.001 |
| RA diagnosis | ||||||
| Database code | 3 | 1.560 [1.320, 1.769] | 14.58 | < 0.001 | 0.0% | 0.968 |
| Universal criteria | 3 | 2.062 [1.608, 2.517] | 8.89 | < 0.001 | 82.9% | 0.003 |
| Overall | 6 | 1.822 [1.546, 2.099] | 12.92 | < 0.001 | 75.4% | 0.001 |
| COPD diagnosis | ||||||
| Database code | 5 | 1.881 [1.569, 2.192] | 11.82 | < 0.001 | NA | NA |
| Self-reported | 1 | 1.520 [1.120, 1.920] | 7.45 | < 0.001 | 77.7% | 0.001 |
| Overall | 6 | 1.822 [1.546, 2.099] | 12.92 | < 0.001 | 75.4% | 0.001 |
| Prevalence | ||||||
| Region | ||||||
| Asia | 2 | 0.092 [0.081, 0.104] | 15.78 | < 0.001 | 92.1% | < 0.001 |
| Europe | 3 | 0.052 [0.033, 0.070] | 5.58 | < 0.001 | 93.1% | < 0.001 |
| North America | 2 | 0.048 [0.013, 0.084] | 2.65 | 0.008 | 99.5 | < 0.001 |
| Multination | 1 | 0.040 [0.034, 0.046] | 12.79 | < 0.001 | NA | NA |
| Overall | 8 | 0.062 [0.041, 0.083] | 5.74 | < 0.001 | 99.5% | < 0.001 |
| RA diagnosis | ||||||
| Database code | 5 | 0.067 [0.040, 0.094] | 4.86 | < 0.001 | 99.7% | < 0.001 |
| ACR criteria | 3 | 0.041 [0.031, 0.051] | 7.90 | 0.039 | 69.3% | < 0.001 |
| Overall | 8 | 0.062 [0.041, 0.083] | 5.74 | < 0.001 | 99.5% | < 0.001 |
| COPD diagnosis | ||||||
| Database code | 6 | 0.062 [0.038, 0.086] | 4.99 | < 0.001 | 99.6% | < 0.00 |
| NA | 2 | 0.065 [0.007, 0.123] | 2.19 | 0.028 | 81.8% | 0.002 |
| Overall | 8 | 0.062 [0.041, 0.083] | 5.74 | < 0.001 | 99.5% | < 0.001 |
CI Confidence interval, N Number of study