Influence of physician specialty on adoption and relinquishment of calciumchannel blockers and other treatments for myocardial infarction

Objective: Recent reports have linked calcium channel blockers (CCBs) with an increased risk of acute myocardial infarction (AMI). We sought to determ ine to what extent physicians relinquished CCBs following these adverse rep orts and if there were differences in the use of CCBs and other AMI therapi es across 3 levels of specialist involvement: generalist attendings, collab orative care (generalist with cardiologist consultation), and cardiologist attendings. Design: We measured use of CCBs during hospitalization for AMI before (1992 -1993) and after (1995-1996) the adverse CCB reports, controlling for hospi tal-, physician-, and patient-level variables. We also examined use of effe ctive medications (aspirin, beta -blockers, thrombolytic therapy) and ineff ective AIM treatments (lidocaine). Setting: Thirty-seven community-based hospitals in Minnesota. Patients: Population-based sample of 5,347 patients admitted with AIM. Measurements: The primary outcome was prescription of a CCB at the time of discharge from hospital. Secondary outcomes included use of other effective and ineffective AMI therapies during hospitalization and at discharge. Main Results: Compared with cardiologists, generalist attendings were less likely to use aspirin (37% vs 68%; adjusted odds ratio [OR], 0.58; 95% conf idence interval [95% CI], 0.42 to 0.80) and thrombolytics (29% vs 64%; adju sted OR, 0.18: 95% CI, 0.13 to 0.25), but not beta -blockers (20% vs 46%; a djusted OR, 0.93; 95% CI, 0.66 to 1.31). From 1992-1993 to 1995-1996, the u se of CCBs in patients with AMI decreased from 24% to 10%, the net result o f physicians starting CCBs less often and discontinuing them more often. In multivariate models, the odds of CCB relinquishment after the adverse repo rts (adjusted OR, 0.33; 95% CI, 0.27 to 0.39) were independent of, and not modified-by, the involvement of a cardiologist. Conclusions: Compared with cardiologists, generalist physicians were less l ikely to adopt some effective AMI therapies, particularly those associated with risk such as thrombolytic therapy. However, generalists were as likely as cardiologists to relinquish CCBs after the adverse reports. This patter n of practice may be the generalist physicians' response to an expanding, b ut increasingly risky and uncertain, pharmacopoeia.