Limited adverse occurrence screening: an effective and efficient method of medical quality control.

The objective of the present study was to determine the rate of adverse patient occurrences in a medium sized hospital and to assess the effectiveness and efficiency of limited adverse occurrence screening as a method of medical quality control. The medical records of inpatients discharged from a base hospital in Horsham, Victoria, were screened by the medical records department using eight general outcome criteria. Histories found to meet a criterion were sent to a medical reviewer to determine if an adverse patient occurrence had taken place. A random sample of histories not meeting any criteria was also reviewed. The main outcome measures were the rate of adverse patient occurrences and the proportion of these events detected by limited occurrence screening, the accuracy of the screening process, the time taken and the cost of finding adverse events. The total adverse patient occurrence rate was estimated to be 2.75% (95% CI 1.36-4.14%). Limited adverse occurrence screening using eight screening criteria detected 49.1% (95% CI 32.6-99.3%) of all adverse patient occurrences and 64.4% (95% CI 37.8-100%) of all adverse occurrences of major severity. This was achieved by reviewing the records of 9.72% of all patients discharged. Screening was quick and accurate (false positive rate 2.0%, false negative rate 0.4%). Medical review took on average 5 min (s.d. +/- 3.03). The method required 500 h of staff time over one year and cost $22000 (0.1% of total hospital budget). The proportion of adverse patient occurrences found by limited screening was much higher than that found by traditional quality assurance methods. Limited adverse occurrence screening using retrospective review requires a small proportion of total budget that should be available to most hospitals for medical quality assurance activities.