Pitfalls in evidence assessment: the case of chlorhexidine and alcohol in skin antisepsis

Chlorhexidine has attracted increasing attention for its role in skin antisepsis in recent years. It was tested in several prominent clinical trials and subsequently recommended in important guidelines for blood culture collection, vascular catheter insertion and surgical skin preparation. We noticed and subsequently reported a widespread misinterpretation of evidence surrounding chlorhexidine and its role in skin antisepsis. Multiple clinical trial reports and systematic reviews that had assessed the clinical efficacy of chlorhexidine/alcohol combinations for skin antisepsis had attributed efficacy solely to the chlorhexidine component. This misinterpretation was carried over into the tertiary literature, including evidence-based guidelines. Here we discuss some of the scientific, ethical, patient safety and infection control implications of this misinterpretation, as well as broader implications for evidence-based medicine.