Quality assessment of included studies.
| Study reference number | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Quality criteria | 41 | 34 | 35 | 32 | 36 | 27 | 37 | 42 | 30 | 38 | 39 | 40 | 43 |
| Sample selection | |||||||||||||
| Representative of the community | Y | Y | U | Y | Y | Y | Y | Y | Y | U | Y | Y | Y |
| Study population adequately defined | Y | Y | Y | Y | Y | Y | Y | Y | Y | U | Y | Y | Y |
| Information recorded prospectively | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Ascertainment of sample described | Y | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Assessment of outcome described | Y | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Follow-up | |||||||||||||
| Loss to follow-up <10% | N | Y | N | C | N | C | C | C | C | C | U | Y | C |
| Reason for loss to follow-up given | N | N | Y | n/a | Y | n/a | n/a | n/a | n/a | n/a | – | N | n/a |
| Characteristics of patient loss to follow-up described | Y | N | N | n/a | Y | n/a | n/a | n/a | n/a | n/a | – | N | n/a |
| Other biases | |||||||||||||
| Design-specific sources of bias mentioned | Y | Y | Y | N | N | Y | Y | Y | Y | N | Y | Y | Y |
| Design-specific bias corrected | Y | Y | N | Y | N | Y | Y | Y | Y | N | Y | Y | Y |
| Chronicity | |||||||||||||
| CKD defined to be chronic (≥3 months) | N | Y | Y | Y | Y | N | N | N | Y | U | N | Y | N |
| Measurement of renal impairment | |||||||||||||
| Difference in assays over time or between labs accounted for | N | N | N | U | Y | Y | Y | Y | U | Y | N | N | Y |
| Overall quality | M | G | P | G | G | G | G | G | G | M | M | G | G |
C = complete. CKD = chronic kidney disease. G = good. M = moderate. N = no. n/a = not applicable. P = poor. U = unclear. Y = yes.