Number of Cardiologists per Cardiovascular Beds and In‐Hospital Mortality for Acute Heart Failure: A Nationwide Study in Japan

Abstract

Background Little evidence is available about the number of cardiologists required for appropriate treatment of heart failure (HF). Our objective was to determine the association between the number of cardiologists per cardiology beds for treating patients with acute HF and in‐hospital mortality. Methods and Results This was a cross‐sectional study, and we used the Japanese Registry of All Cardiac and Vascular Diseases Diagnosis Procedure Combination discharge database. The data of patients with HF on emergency admission from April 1, 2012, to March 31, 2014, were extracted. The patients were categorized into 4 groups by the quartiles of the numbers of cardiologists per 50 cardiovascular beds (first group: median, 4.4 [interquartile range, 3.5–5.0]; second group: median, 6.7 [interquartile range, 6.5–7.5]; third group: median, 9.7 [interquartile range, 8.8–10.1]; and fourth group: median, 16.7 [interquartile range, 14.0–23.8]). Using multilevel mixed‐effect logistics regression, we determined adjusted odds ratios for in‐hospital mortality. We identified 154 290 patients with HF on emergency admissions. There were 29 626, 36 587, 46 451, and 41 626 patients in the first, second, third, and fourth groups, respectively. HF severity, on the basis of New York Heart Association classification, was similar in the 3 groups. Adjusted odds ratios (95% CIs) for in‐hospital mortality were 0.92 (0.82–1.04; P=0.20), 0.82 (0.72–0.92; P<0.001), and 0.70 (0.61–0.80; P<0.001) for the second, third, and fourth groups, respectively. The proportion of medication used, including angiotensin‐converting enzyme inhibitors or angiotensin receptor blockers, β blockers, and mineralocorticoid receptor antagonists, was positively correlated to the number of cardiologists. Conclusions Patients hospitalized for HF in hospitals with larger numbers of cardiologists per cardiovascular beds had lower 30‐day mortality.