Study quality based on the Newcastle-Ottawa Quality Assessment Scale
| Reference . | 14 . | 15 . | 16 . | 17 . | 18 . | 19 . | 20 . | 21 . | 22 . | 6 . | 7 . | 4 . | 23 . | 24 . | 25 . | 26 . | 27 . | 28 . | 29 . | 30 . | 31 . |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Selection | |||||||||||||||||||||
| Representativeness of exposed (LMWH) cohort | • | • | • | N/A | N/A | N/A | • | • | • | N/A | N/A | • | N/A | • | • | • | N/A | N/A | • | • | • |
| Selection of the nonexposed (no LMWH) cohort | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | N/A | • | • | • | • |
| Ascertainment of exposure | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | — | — | • | • | • | • |
| Outcome not present at beginning of study | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • |
| Comparability | |||||||||||||||||||||
| Comparability of cohorts | — | — | — | N/A | N/A | N/A | — | — | — | N/A | N/A | — | N/A | — | — | — | N/A | N/A | — | — | — |
| Outcome | |||||||||||||||||||||
| Assessment of outcome | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • |
| Was follow-up long enough? | • | • | — | — | • | • | • | • | — | • | • | • | • | • | • | • | • | • | • | • | • |
| Adequacy of follow-up | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Reference . | 14 . | 15 . | 16 . | 17 . | 18 . | 19 . | 20 . | 21 . | 22 . | 6 . | 7 . | 4 . | 23 . | 24 . | 25 . | 26 . | 27 . | 28 . | 29 . | 30 . | 31 . |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Selection | |||||||||||||||||||||
| Representativeness of exposed (LMWH) cohort | • | • | • | N/A | N/A | N/A | • | • | • | N/A | N/A | • | N/A | • | • | • | N/A | N/A | • | • | • |
| Selection of the nonexposed (no LMWH) cohort | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | N/A | • | • | • | • |
| Ascertainment of exposure | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | — | — | • | • | • | • |
| Outcome not present at beginning of study | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • |
| Comparability | |||||||||||||||||||||
| Comparability of cohorts | — | — | — | N/A | N/A | N/A | — | — | — | N/A | N/A | — | N/A | — | — | — | N/A | N/A | — | — | — |
| Outcome | |||||||||||||||||||||
| Assessment of outcome | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • | • |
| Was follow-up long enough? | • | • | — | — | • | • | • | • | — | • | • | • | • | • | • | • | • | • | • | • | • |
| Adequacy of follow-up | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |