Table 3 Newcastle–Ottawa Scale (NOS) for assessing the quality of non-randomized studies in meta-analyses — Good quality: 3 or 4 stars (*) in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome domain; Fair quality: 2 stars in selection domain AND 1 or 2 stars in comparability domain AND 2 or 3 stars in outcome/exposure domain; Poor quality: 0 or 1 star in selection domain OR 0 stars in comparability domain OR 0 or 1 stars in outcome/exposure domain
Study | Selection | Comparability of cohorts | Outcome | Quality/total score | |||||
|---|---|---|---|---|---|---|---|---|---|
Representativeness of exposed cohort | Selection of non-exposed cohort | Ascertainment of exposure | Outcome not present at baseline | assessment of outcome | Sufficient follow-up duration | Adequate follow-up | |||
Ripoll | * | * | * | – | – | * | * | – | Poor/5 |
Eriksson | * | * | * | – | – | * | * | – | Poor/5 |
Langner | * | * | * | – | * | * | – | – | Poor/5 |
Larssen | * | * | * | – | – | * | – | – | Poor/4 |
Defreyene | * | * | * | – | – | * | * | – | Poor/5 |
Venclauskas | * | * | * | – | – | * | – | – | Poor/4 |
Wong | * | * | * | – | – | * | – | – | Poor/4 |
Ang | * | * | * | – | – | * | * | – | Poor/5 |
Jairath | * | * | * | – | – | * | * | – | Poor/5 |
Jailani | * | * | * | – | – | * | – | – | Poor/4 |
Laursen | * | * | * | – | – | * | – | – | Poor/4 |
Griffiths | * | * | * | – | – | * | * | * | Poor/6 |
Nykänen | * | * | * | – | – | * | – | – | Poor/4 |