Acetylcysteine in the prevention of contrast-induced nephropathy: a case study of the pitfalls in the evolution of evidence.

During the past 5 years, 19 randomized controlled trials, 4 prospective nonrandomized studies, and 11 meta-analyses that explored the role of acetylcysteine for prevention of contrast-induced nephropathy have been published. Herein, we summarize this literature and demonstrate that these 34 empirical studies have not yet conclusively resolved this research question. We use the evidence on acetylcysteine as a case study of how research evidence accumulates and consider whether an alternative approach to investigating the question of acetylcysteine's efficacy could have resulted in a more definitive conclusion. We consider the broader lessons learned from this acetylcysteine case study for the medical and research communities and propose specific steps that could be taken to improve the future coordination of research activity to ultimately yield more meaningful and definitive evidence on important clinical questions.