ACCURACY OF REPORTING NOSOCOMIAL INFECTIONS IN INTENSIVE-CARE-UNIT PATIENTS TO THE NATIONAL-NOSOCOMIAL-INFECTIONS-SURVEILLANCE-SYSTEM - A PILOT-STUDY

OBJECTIVE: To assess the accuracy of nosocomial infections data report ed on patients in the intensive-care unit by nine hospitals participat ing in the National Nosocomial Infections Surveillance (NNIS) System. DESIGN: A pilot study was done in two phases to review the charts of s elected intensive-care-unit patients who had nosocomial infections rep orted to the NNIS System. The charts of selected high-and low-risk pat ients in the same cohort who had no infections reported to the NNIS Sy stem also were included. In phase I, trained data collectors reviewed a sample of charts for nosocomial infections. Retrospectively detected infections that matched with previously reported infections were deem ed to be true infections. In phase II, two Centers for Disease Control and Prevention (CDC) epidemiologists reexamined a sample of charts fo r which a discrepancy existed. Each sampled infection either was confi rmed or disallowed by the epidemiologists. Confirmed infections also w ere deemed to be true infections. True infections hom both phases were used to estimate the accuracy of reported NNIS data by calculating th e predictive value positive, sensitivity, and specificity at each majo r infection site and the ''other sites,'' RESULTS: The data collectors examined a total of 1,136 patients' charts in phase I. Among these ch arts were 611 infections that the study hospitals had reported to the CDC. The data collectors retrospectively matched 474 (78%) of the pros pectively identified infections, but also detected 790 infections that were not reported prospectively. Phase II focused on the discrepant i nfections: the 137 infections that were identified prospectively and r eported but not detected retrospectively, and the 790 infections that were detected retrospectively but not reported previously. The CDC epi demiologists examined a sample of 113 of the discrepant reported infec tions and 369 of the discrepant detected infections, and estimated tha t 37% of all discrepant reported infections and 43% of all discrepant detected infections were true infections. The predictive value positiv e for reported bloodstream infections, pneumonia, surgical-site infect ion, urinary tract infection, and other sites was 87%, 89%, 72%, 92%, and 80%, respectively; the sensitivity was 85%, 68%, 67%, 59%, and 30% , respectively; and the specificity was 98.3%, 97.8%, 97.7%, 98.7%, an d 98.6%, respectively.CONCLUSIONS: When the NNIS hospitals in the stud y reported a nosocomial infection, the infection most likely was a tru e infection, and they infrequently reported conditions that were not i nfections. The hospitals also identified and reported most of the noso comial infections that occurred in the patients they monitored, but ac curacy varied by infection site. Primary bloodstream infection was the most accurately identified and reported site. Measures that will be t aken to improve the quality of the infection data reported to the NNIS System include reviewing the criteria for definitions of infections a nd other data fields, enhancing communication between the CDC and NNIS hospitals, and improving the training of surveillance personnel in NN IS hospitals (Infect Control Hosp Epidemiol 1998;19:308-316).