Table 2

The Grading of Recommendations Assessment, Development and Evaluation evidence quality for each outcome

Quality assessment							Number of patients		Effect		Quality	Importance
Number of studies	Design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	New comparison	Control	Relative (95% CI)	Absolute	Quality	Importance
The optimal period (6 to 12 months)—lumbar spine (better indicated by higher values)
5	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	275	341	N/A	SMD 0.13 higher (0.17 lower to 0.43 higher)	Low	Critical
The optimal period (6 to 12 months)—total hip (follow-up 9 to 18 months; better indicated by higher values)
5	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	276	339	N/A	SMD 0.42 higher (0.26 to 0.58 higher)	Low	Critical
The optimal period (6 to 12 months)—femoral neck (better indicated by higher values)
5	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	283	344	N/A	SMD 0.3 higher (0.14 to 0.46 higher)	Low	Critical
The full period (18 to 24 months)—lumbar spine (better indicated by higher values)
4	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	100	94	N/A	SMD 0.06 lower (0.71 lower to 0.59 higher)	Low	Important
The full period (18 to 24 months)—total hip (better indicated by higher values)
4	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	100	94	N/A	SMD 0.05 higher (0.71 lower to 0.82 higher)	Low	Important
The full period (18 to 24 months)—femoral neck (better indicated by higher values)
4	Randomised trials	Serious	No serious inconsistency	No serious indirectness	No serious imprecision	Reporting bias	107	99	N/A	SMD 0.32 lower (1.15 lower to 0.5 higher)	Low	Important

N/A, not applicable; SMD, standardised mean difference.