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Table 1 Quality criteria of the randomized controlled trials assessed

From: EDTA chelation therapy for cardiovascular disease: a systematic review

Reference Randomization Sample size determination Drop outs Intention to treat analysis Blinding Allocation concealment
Kitchell 1963 [17] Not described (nor stated) Not described 33% of the treatment group upon cross-over No Allegedly participants blinded, but impossible to adequately assess Unclear
Olszewer 1990 [18] Described Not described None Yes Initially double blinded but code was broken after 10 treatments and study was completed with single blind for remaining 10 treatments Unclear
Sloth-Nielsen 1991 [19] Described Not described None Yes Double Unclear
Guldager 1992 [16] Described Not described 4 drop outs by 3 months; 30 drop outs by 6 months No Double: code broken at 3 months Unclear
Guldager 1993 [15] Not described Not described Not mentioned No Double Unclear
Van Rij 1994 [20] Described Yes None Yes Double Unclear
Knudtson 2002 [4] Described Yes 4 in placebo, 2 in treatment group Yes Double Well described