IMPACT OF LEGAL REGULATIONS ON THE QUALIT Y OF CLINICAL-TRIALS IMPLEMENTED IN SPAIN

BACKGROUND: In Spain since 1982 laws require that clinical trials invo lving drugs be approved before implementation. We studied the impact o f regulations on the quality of published trials. METHODS: Four sets o f trials were chosen: trials implemented after 1982 and registered as approved; trials implemented after 1982 but not registered; trials imp lemented before 1982; and trials conducted outside Spain. Trials were identified via MEDLINE, EMBASE, and indice Medico Espanol. Sets were c ompared with regard to indicators of quality, as obtained from the inf ormation in the published reports. The comparison was based on a total of 273 Spanish trials published between 1988 and 1990, 85 approved an d 188 unregistered; 97 old trials, published between 1980 and 1982; an d 152 non-Spanish trials published between 1988 and 1990. RESULTS: App roved trials, compared to their unregistered and old counterparts, wer e more often informed randomised, more of their published reports incl uded lists of reasons for exclusions and information on consent and ac hieved higher scores of a quality index. Approved trials, compared to non-Spanish trials, had lower proportion of sample size justification, greater discrepancies between randomised and analyzed cases and a tre nd to lower quality scores. Multiple logistic regression analysis of q uality scores showed that approved trials had higher scores than unreg istered trials when single-centre trials (odds ratio for reaching scor es in the upper quartile: 2.90; 95 % confidence interval: 1.27 - 6.64) and similar when multicentre trials. CONCLUSIONS: Approved trials ach ieved better indicators of quality than unregistered trials but did no t achieve the standards of quality prevailing in the international com munity.