Background—Since the broad dissemination of practice guidelines, the association of specialty care with the treatment of patients with acute coronary syndromes has not been studied.

Methods and Results—We evaluated 55 994 patients with non–ST-segment elevation acute coronary syndromes (ischemic ST-segment changes and/or positive cardiac markers) included in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines) Quality Improvement Initiative from January 2001 through September 2003 at 301 tertiary US hospitals with full revascularization capabilities. We compared baseline characteristics, the use of American College of Cardiology/American Heart Association guidelines class I recommendations, and in-hospital outcomes by the specialty of the primary in-patient service (cardiology versus noncardiology). A total of 35 374 patients (63.2%) were primarily cared for by a cardiology service, and these patients had lower-risk clinical characteristics, but they more commonly received acute (24 hours) medications, invasive cardiac procedures, and discharge medications and lifestyle interventions. Acute care processes were improved when care was provided by a cardiology service regardless of the propensity to receive cardiology care. The adjusted risk of in-hospital mortality was lower with care provided by a cardiology service (adjusted odds ratio 0.80, 95% confidence interval 0.73 to 0.88), and adjustment for differences in the use of acute medications and invasive procedures partially attenuated this mortality difference (adjusted odds ratio 0.92, 95% confidence interval 0.83 to 1.02).

Conclusions—Non–ST-segment elevation acute coronary syndrome patients primarily cared for by a cardiology inpatient service more commonly received evidence-based treatments and had a lower risk of mortality, but these patients had lower-risk clinical characteristics. Results from the present analysis highlight the difficulties with accurately determining how specialty care is associated with treatment patterns and clinical outcomes for patients with acute coronary syndromes. Novel methodologies for evaluating the influence of specialty care for these patients need to be developed and applied to future studies.