Table 2.
NOS scores of the cohort studies included.
| Cohort study | Selection representativeness of the exposed cohort | Selection of the unexposed cohort | Ascertainment of exposure | Outcome of interest not present at start of study | Comparability control for important factor or additional factor∗ | Outcome assessment | Was follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | Total quality scores |
|---|---|---|---|---|---|---|---|---|---|
| Liu 2018 | / | ★ | ★ | ★ | ★ | ★ | / | ★ | 6 |
| Bob 2018 | / | ★ | ★ | ★ | / | ★ | / | / | 4 |
| Fountoulakis 2018 | / | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 8 |
| Qian 2018 | / | ★ | ★ | ★ | ★★ | ★ | / | ★ | 7 |
| Drew 2017 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 9 |
| Kim 2016 | / | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 7 |
| Kim 2013 | / | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 8 |
| Seiler 2012 | / | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 8 |
Note: ∗2 stars could be awarded for this item. Studies that controlled for age or eGFR were awarded one star, respectively. Abbreviation: NOS: Newcastle–Ottawa Scale.