A comparison of iatrogenic injury studies in Australia and the USA II: reviewer behaviour and quality of care

Objective. To better understand the remaining three-fold disparity between adverse event (AE) rates in the Quality in Australia Health Care Study (QAH CS) and the Utah-Colorado Study (UTCOS) after methodological differences ha d been accounted for. Setting. Iatrogenic injury in hospitalized patients in Australia and Americ a. Design. Using a previously developed classification, all AEs were assigned to 98 exclusive descriptive categories and the relative rates compared betw een studies; they were also compared with respect to severity and death. Main outcome measures. The distribution of AEs amongst the descriptive and outcome categories. Results. For 38 categories, representing 67% of UTCOS and 28% of QAHCS AEs, there were no statistically significant differences. For 33, representing 31% and 69% respectively, there was seven times more AEs in QAHCS than in U TCOS. Rates for major disability and death were very similar (1.7% and 0.3% of admissions for both studies) but the minor disability rate was six time s greater in QAHCS (8.4% versus 1.3%). Conclusions. A similar 2% core of serious AEs was found in both studies, bu t for the remaining categories six to seven times more AEs were reported in QAHCS than in UTCOS. We hypothesize that this disparity is due to differen t thresholds for admission and discharge and to a greater degree of under-r eporting of certain types of problems as AEs by UTCOS than QAHCS reviewers. The biases identified were consistent with, and appropriate for, the quite different aims of each study. No definitive difference in quality of care was identified by these analyses or a literature review.