Variation in Inpatient Consultation Among Older Adults in the United States.

ABSTRACT

BACKGROUND: Differences among hospitals in the use of inpatient consultation may contribute to variation in outcomes and costs for hospitalized patients, but basic epidemiologic data on consultations nationally are lacking. OBJECTIVE: The purpose of the study was to identify physician, hospital, and geographic factors that explain variation in rates of inpatient consultation. DESIGN: This was a retrospective observational study. SETTING AND PARTICIPANTS: This work included 3,118,080 admissions of Medicare patients to 4,501 U.S. hospitals in 2009 and 2010. MAIN MEASURES: The primary outcome measured was number of consultations conducted during the hospitalization, summarized at the hospital level as the number of consultations per 1,000 Medicare admissions, or "consultation density." KEY RESULTS: Consultations occurred 2.6 times per admission on average. Among non-critical access hospitals, use of consultation varied 3.6-fold across quintiles of hospitals (933 versus 3,390 consultations per 1,000 admissions, lowest versus highest quintiles, p < 0.001). Sicker patients received greater intensity of consultation (rate ratio [RR] 1.18, 95% CI 1.17-1.18 for patients admitted to ICU; and RR 1.19, 95% CI 1.18-1.20 for patients who died). However, even after controlling for patient-level factors, hospital characteristics also predicted differences in rates of consultation. For example, hospital size (large versus small, RR 1.31, 95% CI 1.25-1.37), rural location (rural versus urban, RR 0.78, CI 95% 0.76-0.80), ownership status (public versus not-for-profit, RR 0.94, 95% CI 0.91-0.97), and geographic quadrant (Northeast versus West, RR 1.17, 95% CI 1.12-1.21) all influenced the intensity of consultation use. CONCLUSIONS: Hospitals exhibit marked variation in the number of consultations per admission in ways not fully explained by patient characteristics. Hospital "consultation density" may constitute an important focus for monitoring resource use for hospitals or health systems.