How to impute study-specific standard deviations in meta-analyses of skewed continuous endpoints?

Table 4 Comparison of results obtained from the four methods of approximation of study-specific means and standard deviations in a meta-analysis of a continuous outcome

	Standardized pooled estimate, (standard error)	P value1(unadjusted)	P value1(Tukey-Kramer adjustment)	P value1(Bonferroni adjustment)	P value1(Scheffé adjustment)
Conservative SD	4.5 (3.5)	0.14	0.7	0.9	0.8
Less conservative SD	7.8 (2.9)	0.01	0.056	0.07	0.12
Mean SD	6.1 (3.3)	0.04	0.3	0.6	0.5
IQR	4.5 (2.2)	0.13	0.2	0.4	0.4

¹P values were derived from a test on the “method” effect in a repeated measures model including also adjustment by “dataset” and “distribution” effects. IQR: Interquartile range.