Evaluation of quality improvement interventions for reducing adverse outcomes of carotid endarterectomy.

Abstract

Clinical and health services interventions should be evaluated for their effectiveness. The objectives of this study were to evaluate the effectiveness of quality improvement interventions for reducing the adverse outcome of the carotid endarterectomy (CEA) procedure, and to study the relationship between pre- and postintervention 30-day mortality and stroke rates. These interventions were implemented in 1997-1998 by the Peer Review Organizations (PRO) for 7 states. In a quasiexperimental study, a control state was matched with each of the 7 intervention states. Pretest-posttest analyses compared the preintervention outcome rates in each intervention and control state with the corresponding postintervention rates. In a time (1991-2001) series analysis, the trends in the preintervention 30-day, 7-state mortality in intervention and control states were compared with the trends in the corresponding postintervention rates. We studied Medicare beneficiaries aged 65 years and older who had a CEA procedure in 14 states during 1991-2001. There was no correlation between the state-specific, preintervention 30-day mortality and the corresponding postintervention mortality. After interventions, there was no significant decline in 30-day mortality in any intervention or control state, or in all 7 intervention states combined or all control states combined. Similarly, the 30-day stroke rate did not decrease after interventions in any state. The trend in the 7-state, 30-day mortality also did not show further decline after interventions. After PRO interventions, the post-CEA 30-day mortality and stroke rates did not decrease in any individual intervention state or in all states combined.