Variation in critical care unit admission rates and outcomes for patients with acute coronary syndromes or heart failure among high- and low-volume cardiac hospitals.
BACKGROUND
Little is known about cross-hospital differences in critical care units admission rates and related resource utilization and outcomes among patients hospitalized with acute coronary syndromes (ACS) or heart failure (HF).


RESULTS
Using a population-based sample of 16,078 patients admitted to a critical care unit with a primary diagnosis of ACS (n=14,610) or HF (n=1467) between April 1, 2003 and March 31, 2013 in Alberta, Canada, we stratified hospitals into high (>250), medium (200 to 250), or low (<200) volume based on their annual volume of all ACS and HF hospitalization. The percentage of hospitalized patients admitted to critical care units varied across low, medium, and high-volume hospitals for both ACS and HF as follows: 77.9%, 81.3%, and 76.3% (P<0.001), and 18.0%, 16.3%, and 13.0% (P<0.001), respectively. Compared to low-volume units, critical care patients with ACS and HF admitted to high-volume hospitals had shorter mean critical care stays (56.6 versus 95.6 hours, P<0.001), more critical care procedures (1.9 versus 1.2 per patient, <0.001), and higher resource-intensive weighting (2.8 versus 1.5, P<0.001). No differences in in-hospital mortality (5.5% versus 6.2%, adjusted odds ratio 0.93; 95% CI, 0.61 to 1.41) were observed between high- and low-volume hospitals; however, 30-day cardiovascular readmissions (4.6% versus 6.8%, odds ratio 0.77; 95% CI, 0.60 to 0.99) and cardiovascular emergency-room visits (6.6% versus 9.5%, odds ratio 0.80; 95% CI, 0.69 to 0.94) were lower in high-volume compared to low-volume hospitals. Outcomes stratified by ACS or HF admission diagnosis were similar.


CONCLUSIONS
Cardiac patients hospitalized in low-volume hospitals were more frequently admitted to critical care units and had longer hospitals stays despite lower resource-intensive weighting. These findings may provide opportunities to standardize critical care utilization for ACS and HF patients across high- and low-volume hospitals.
Divisions of Critical Care and Cardiology, University of Alberta, Edmonton, Alberta, Canada (S.D.) Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.).
Sean
S
van Diepen
Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.).
Jeffrey A
JA
Bakal
Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.).
Meng
M
Lin
Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.) Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (P.K., J.A.E.).
Padma
P
Kaul
Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.) Division of General Internal Medicine, Department of Medicine, University of Alberta, Edmonton, Canada (F.A.M.A.).
Finlay A
FA
McAlister
Canadian Vigour Center, University of Alberta, Edmonton, Alberta, Canada (S.D., J.A.B., M.L., P.K., F.A.M.A., J.A.E.) Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada (P.K., J.A.E.).
Justin A
JA
Ezekowitz
D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta; D016507:Cardiology Service, Hospital / Q000706:statistics & numerical data / Q000639:trends; D016009:Chi-Square Distribution; D003422:Critical Care / Q000639:trends*; D016208:Databases, Factual; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data / Q000639:trends; D005260:Female; D019538:Health Care Surveys; D006295:Health Resources / Q000706:statistics & numerical data / Q000639:trends; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D017052:Hospital Mortality / Q000639:trends; D061847:Hospitals, High-Volume / Q000639:trends*; D061846:Hospitals, Low-Volume / Q000639:trends*; D006801:Humans; D007902:Length of Stay / Q000639:trends; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010343:Patient Admission / Q000639:trends*; D010359:Patient Readmission / Q000639:trends; D010818:Practice Patterns, Physicians' / Q000639:trends*; D017064:Process Assessment, Health Care / Q000639:trends*; D019984:Quality Indicators, Health Care / Q000639:trends; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
acute coronary syndrome; critical care; heart failure; hospital variation