Stephen J.LurieMD, PhD, Senior Editor
To the Editor: Dr Parienti and colleagues1 found that hand-rubbing with an aqueous alcoholic solution was as effective as traditional surgical hand-scrubbing in preventing surgical site infections (SSI).
This type of study is difficult to perform because SSI rates are low and therefore a very large number of patients would be required to find a difference in infection rates. In this randomized but nonblinded study, 4387 patients were studied based on a power analysis assuming an SSI rate of 4%. However, the results showed an SSI rate of only 2.46%, a result similar to other studies cited by the authors. Indeed, the authors could not cite any studies with an SSI rate of 4% for routine surgery. Therefore, their power analysis was incorrect and the result showing no statistically significant difference may simply be a type 2 error due to an insufficient number of patients studied.
Sosis MB. Preoperative Hand-Rubbing vs Hand-Scrubbing. JAMA. 2002;288(21):2688. doi:10.1001/jama.288.21.2688-JLT1204-5-1