Hospital-acquired infections in the United States. The importance of interhospital comparisons.

To use infection rates as a basis for measuring quality of care, the rates must be meaningful for interhospital comparison. A crude, overall nosocomial infection rate of a hospital provides no means of adjustment for patients' intrinsic or extrinsic risks. Before interhospital comparison, rates should be adjusted for nosocomial infection risk factors. Interhospital comparison of rates requires that a hospital participate in a multicenter surveillance system or aggregated national database. This article outlines a series of questions for hospital administrations to pose before entering such an endeavor.