Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study

Objectives Use of cumulative mortality adjusted for case mix in patients wi th acute myocardial infarction for early detection of variation in clinical practice. Design Observational study. Setting 20 hospitals across the former Yorkshire region. Participants All 2153 consecutive patients with confirmed acute myocardial infarction identified during three months. Main outcome measures Variable life-adjusted displays showing cumulative di fferences between observed and expected mortality of patients; expected mor tality calculated from risk model based on admission characteristics of age . heart rate, and systolic blood pressure. Results The performance of two individual hospitals over three months was e xamined as an example. One, the smallest district hospital in the region, h ad a series of 30 consecutive patients but had five more deaths than predic ted. The variable life-adjusted display showed minimal variation from that predicted for the first 15 patients followed by a run of unexpectedly high mortality. The second example was the main tertiary referral centre for the region, which admitted 188 consecutive patients. The display showed a peri od of apparently poor performance followed by substantial improvement, wher e the plot rose steadily from a cumulative net lives saved of - 4 to 7. The se variations in patient outcome are unlikely to have been revealed during conventional audit practice. Conclusions Variable life-adjusted display has been integrated. into surgic al care as a graphical display of risk-adjusted survival for individual sur geons or centres. In combination with a simple risk model, it may have a ro le in monitoring performance and outcome in patients with acute myocardial infarction.