Factors contributing to variation in intensive care service utilization among patients with acute myocardial infarction

Research Objective:

The American College of Cardiology/American Heart Association (ACC/AHA) has outlined specific guidelines for the management of patients with acute myocardial infarction (AMI) including the use of intensive care services. There remains however, wide variation in intensive care resource utilization among patients with AMI. This study examined the patient and hospital characteristics contributing to variation in intensive care services among patients with AMI.

Study Design:

A retrospective analysis of cross-sectional data was carried out to assess the degree to which intensive care services are utilized by AMI patients. The study used 2006 Maryland State Inpatient Database (SID) from the Healthcare Cost Utilization Project (HCUP) and the sample consisted of 10,709 AMI patients from 46 general acute care hospitals out of 751,986 patients (51 hospitals). Risk-adjusted logistic regression models using robust procedures were estimated to determine hospital and patient characteristics associated with admission to an intensive care or cardiac care unit (ICU/CCU). Hospital characteristics such as size, teaching status, technological status, ownership, and rural/non-rural location were investigated. Generalized linear models with a logit link and the binomial family evaluated patient and hospital factors affecting the proportion of ICU charges to total charges among patients with AMI who were treated in the ICU/CCU.

Principal Findings:

A total of 3938 (37%) patients spent no time in the ICU or CCU. There was negligible difference (38%) when patients that died, were transferred, or discharged against medical advice were excluded. Adjusted for age, sex, comorbidities, AMI characteristics, and procedures, patients were more likely to be admitted to the ICU/CCI in smaller less technologically-advanced non-profit teaching hospitals. The ratio of ICU/CCU charges to total charges was determined and on average, ICU/CCU charges accounted for 21% of charges for AMI patients' service utilization compared to 56% medical/surgical or general ward charges. The total charges for the patients who received ICU/CCU care was $191,617,088 but their ICU/CCU charges were $47,688,736. Hospital factors contributing significantly to ICU/CCU resource utilization included non-profit ownership (OR 1.54, SE.01, 95% CI 1.13-2.09) and lower technological status (OR 1.52, SE.01, 95% CI 1.14-2.03).

Conclusions:

Despite guidelines outlining hospital-based care protocols for patients with AMI, there is risk-adjusted variation ICU/CCU service utilization. Institutional review of evidence-based guideline utilization and best practices for the effective and efficient use of ICU/CCU use should be undertaken across institutions in order to ensure cost effective outcomes.