Table 2.

Pooled standardized mean difference of pain reduction for corticosteroid injection versus placebo injection

Time	Number of studies	Total number of patients	Hedges’s g (CI)	p Value	NNT (CI)
Less than 4 weeks	8	578	0.44 (0.15–0.73)	0.003	NA
4–8 weeks	11	691	0.52 (0.27–0. 78)	< 0.001	4.9 (3.3 −9.5)
8–12 weeks	8	564	0.23 (−0.09 to 0. 56)	0.162	NA

NNT = number needed to treat; NA = not applicable owing to either minimal control event rate (less than 0.1%) or nonsignificant results.