Lawrance, R.A., Dorsch, M.F., Sapsford, R.J., Mackintosh, A.F., Greenwood, D.C., Jackson, B.M., Morrell, C., Robinson, M.B. and Hall, A.S. (2001) Use of cumulative mortality data in patients with acute myocardial infarction for early detection of variation in clinical practice: observational study. BMJ, 323 (7308). pp. 324-327. ISSN 0959-8138
OBJECTIVES: Use of cumulative mortality adjusted for case mix in patients with 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 lifeadjusted displays showing cumulative differences between observed and expected mortality of patients; expected mortality 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 examined as an example. One, the smallest district hospital in the region, had a series of 30 consecutive patients but had five more deaths than predicted. The variable lifeadjusted 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 period of apparently poor performance followed by substantial improvement, where the plot rose steadily from a cumulative net lives saved of - 4 to 7. These variations in patient outcome are unlikely to have been revealed during conventional audit practice.
CONCLUSIONS: Variable lifeadjusted display has been integrated into surgical care as a graphical display of riskadjusted survival for individual surgeons or centres. In combination with a simple risk model, it may have a role in monitoring performance and outcome in patients with acute myocardial infarction.