Table 1.

 Assessment of trial quality and availability of individual patient data in trials included in meta-analysis of naftidrofuryl compared with placebo for treatment of intermittent claudication

References	Disease specific criteria*				General criteria for internal validity	Individual patient data		Overall quality grade‡
	Sample size	Duration	Variability†			Outcome	Covariables
Excluded studies:
Ruckley et al 1978w1	0	1	2		2	Incomplete	Not available	C
Pohle et al 1979w2	1	1	0		1	Incomplete	Not available	C
Clyne et al 1980w3	0	0	0		1	Incomplete	Not available	C
Karnik et al 1988w4	1	1	2		2	Incomplete	Not available	C
Included studies:
Maass et al 1984w5	0	1	0		1	Available	Available	B
Adhoute et al 1990w6	0	0	0		1	Available	Available	B
Kriessman and Neiss 1988w7	0	1	0		1	Available	Available	B
Adhoute et al 1990w8	0	0	0		1	Available	Available	B
Moody et al 1994w9	0	0	2		2	Available	Available	B
Boccalon et al 2001w10	0	0	1		0	Available	Available	B
Kieffer et al 2001w11	0	0	1		0	Available	Available	B

*Flaws: 0, none; 1, minor; 2, major.

†Risk of bias: grade A, no or low risk; grade B, moderate risk; and grade C, high risk.

‡No or incomplete reporting of variability is a major flaw but was disregarded in evaluation when individual patient data were available.