The effects of quality improvement interventions on inhospital mortality after acute myocardial infarction

Objective: To evaluate the effects of quality improvement interventions on inhospital mortality after admission for acute myocardial infarction (AMI). Design: Before-and-after study (with concurrent controls) based on hospital discharge data from a routinely maintained, administrative database. Setting: All Queensland public hospitals, July 1991 - June 1999. Study population: Patients with AW admitted through the emergency department. Intervention: Development and promulgation of clinical practice guidelines at one hospital, combined with regular audit and feedback, commencing November 1995. Main outcome measures: Inhospital mortality (adjusted for age, sex and comorbidities) for four-year periods before (1991-92 to 1994-95) and after (1995-96 to 1998-99) initiation of quality improvement interventions. Results: Before the intervention, the adjusted odds ratio (OR) for inhospital death at the intervention hospital was about the same as at other public hospitals (adjusted OR, 0.99; 95% Cl, 0.80-1.24), but was more than 40% lower after the intervention (adjusted OR, 0.59; 95% Cl, 0.45-0.78). After the intervention, the risk of death at the intervention hospital was lower compared with hospitals with cardiologists as admitting practitioners (adjusted OR, 0.63; 95% Cl, 0.48-0.83), with onsite revascularisation facilities (adjusted OR, 0.66; 95% Cl, 0.49-0.88), and with large numbers (greater than or equal to 250 per year) of annual admissions of patients with AMI (adjusted OR, 0.72; 95% Cl, 0.54-0.97). Conclusions: Quality improvement interventions lower the risk of inhospital death in patients with AMI. Implementation of such interventions in all hospitals may confer a risk of death lower than that achieved by admitting all patients under the care of cardiologists, or to hospitals with revascularisation facilities or a high volume of admissions of patients with AMI.