Table 1.
Characteristics of included studies reported the risk of COPD in RA
| Author | Year | Region | Number of cases | Number of controls | Age of cases(Y) | Age of controls(Y) | Female proportion (%) | Follow up duration(Y) | Quality |
|---|---|---|---|---|---|---|---|---|---|
| Sparks JA [17] | 2017 | America | 843 | 8399 | 59.8 | 59.8 | 100.0 | 7.0 | 9 |
| Mcguire K [18] | 2017 | Canada | 24625 | 25396 | 57.2 | 57.3 | 67.0 | 18.6 | 9 |
| Hemminki K [26] | 2011 | Sweden | NA | NA | NA | NA | NA | NA | 6 |
| Nannini C [15] | 2013 | America | 594 | 596 | 57.8 | 58.2 | 73.4 | 16.3 | 9 |
| Ursum J [27] | 2013 | Netherlands | 3356 | 6708 | 55.0 | 55.0 | 63.7 | 2.8 | 8 |
| Shen TC [28] | 2014 | China | 28725 | 114900 | 53.8 | 53.2 | 78.0 | 5.1 | 9 |
NA Not available, Y year