Newcastle-Ottawa Quality Assessment Scale for cohort studies.
| Author, Year | Selection (4 stars) | Comparability (2 stars) | Outcome (3 stars) | Score (9 stars) | Risk of Bias |
|---|---|---|---|---|---|
| Alemao 201738 | ★★★ | ★★ | ★★★ | 8 | Moderate |
| Arts 201535 | ★★★ | ★★ | ★★ | 7 | Moderate |
| Arts 201636 | ★★★ | ★★ | ★★ | 7 | Moderate |
| Crowson 201233 | ★★★★ | ★★ | ★★★ | 9 | Low |
| Crowson 201740 | ★★★ | ★★ | ★ | 6 | High |
| Crowson 201734 | ★★★ | ★★ | ★ | 6 | High |
| Finckh 201237 | ★★★ | ★★ | ★★ | 7 | Moderate |
| Ljung 201832 | ★★★★ | ★★ | ★★★ | 9 | Low |
| Navarini 201831 | ★★★ | ★★ | ★★ | 7 | Moderate |
| Solomon 201539 | ★★★ | ★★ | ★★★ | 8 | Moderate |
| Urowitz 201641 | ★★★★ | ★★ | ★★ | 8 | Moderate |
Risk of bias was assessed using the Newcastle-Ottawa scale. Studies were judged on 3 broad perspectives: the selection of study groups, the comparability of the groups, and the ascertainment of the outcome of interest for cohort studies. A study is awarded stars for items within each category for a maximum of 9 stars. We rated studies as low risk of bias if they received 9 stars, moderate risk of bias if they received 7 or 8 stars, and high risk of bias if they received < 7 stars.