Failure of a continuous quality improvement intervention to increase the delivery of preventive services. A randomized trial.

CONTEXT Although there has been enormous interest in continuous quality improvement (CQI) as a measure to improve health care, this enthusiasm is based largely on its apparent success in business rather than formal evaluations in health care. OBJECTIVE To determine whether a managed care organization can increase delivery of eight clinical preventive services by using CQI. DESIGN Primary care clinics were randomly assigned to improve delivery of preventive services with CQI (intervention group) or to provide usual care (control group). INTERVENTION Through leadership support, training, consulting, and networking, each intervention clinic was assisted to use CQI multidisciplinary teams to develop and implement systems for delivery of preventive services. SETTING 44 primary care clinics in greater Minneapolis-St. Paul. PATIENTS Patients 19 years of age and older completed surveys at baseline (n = 6830) and at follow-up (n = 6431). Medical chart audits were completed on 4777 patients at baseline and 4546 patients at follow-up. MAIN OUTCOME MEASURES The proportion of patients who were up-to-date (according to chart audit) and the proportion of patients who were offered a service if not up-to-date (according to patient report) for 8 preventive services. RESULTS Compared with the control group, based on the proportion of patients who were up-to-date, use of only one preventive service--pneumococcal vaccine--increased significantly in the intervention group (17.2% absolute increase from baseline to follow-up compared with a 0.3% absolute increase in the control group, P = 0.003). Similarly, based on patient report of being offered a service if not up-to-date, delivery of only one preventive service--cholesterol testing--significantly increased in the intervention group compared with the control group (4.6% increase vs. 0.4% absolute decrease in the control group; P = 0.006). CONCLUSION In this trial, CQI methods did not result in clinically important increases in preventive service delivery rates.