Hospital volume, mitral repair rates, and mortality in mitral valve surgery in the elderly: An analysis of US hospitals treating Medicare fee-for-service patients

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 149; no. 3; pp. 762 - 768.e1
• Main Authors: Vassileva, Christina M., MD, McNeely, Christian, BS, Spertus, John, MD, Markwell, Stephen, MA, Hazelrigg, Stephen, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2015
• Subjects: Age Factors; Aged; Cardiac Surgical Procedures - adverse effects; Cardiac Surgical Procedures - mortality; Cardiac Surgical Procedures - trends; Cardiothoracic Surgery; Chi-Square Distribution; Comorbidity; Fee-for-Service Plans - trends; Female; Heart Valve Diseases - diagnosis; Heart Valve Diseases - mortality; Heart Valve Diseases - physiopathology; Heart Valve Diseases - surgery; Hospital Mortality; hospital volume; Hospitals, High-Volume - trends; Hospitals, Low-Volume - trends; Humans; Logistic Models; Male; Medicare - trends; mitral valve; Mitral Valve - physiopathology; Mitral Valve - surgery; Odds Ratio; outcome research; Proportional Hazards Models; Quality Indicators, Health Care - trends; Risk Assessment; Risk Factors; surgery; Time Factors; Treatment Outcome; United States; United States; OR; MEDPAR; Nationwide Inpatient Sample; CI; CMS; HR; 35.4.2; odds ratio; 35.4.1; BASF; Centers for Medicare and Medicaid Services; STS; hospital volume; Medicare Provider Analysis and Review; Beneficiary Annual Summary Files; hazard ratio; Society of Thoracic Surgeons; NIS; mitral valve; confidence interval; outcome research; 35.4; surgery
• DOI: 10.1016/j.jtcvs.2014.08.084
• ISSN: 0022-5223

Abstract Background The volume-outcome relationship has been suggested as a quality metric in mitral valve surgery and would be particularly relevant in the elderly because of their greater burden of comorbidities and higher perioperative risk. Methods and Results The study included 1239 hospitals performing mitral valve surgery on Medicare beneficiaries from 2000 through 2009. Only 9% of hospitals performed more than 40 mitral operations per year, 29% performed 5 or less, and 51% performed 10 or less. Mitral repair rates were low; 22.7% of hospitals performed 1 or less, 65.1% performed 5 or less, and only 5.6% performed more than 20 mitral repairs per year in those aged 65 years or more. Repair rates increased with increasing volume of mitral operations per year: 5 or less, 30.5%; 6 to 10, 32.9%; 11 to 20, 34.9%; 21 to 40, 38.8%; and more than 40, 42.0% ( P  = .0001). Hospitals with lower volume had significantly higher adjusted operative mortality compared with hospitals performing more than 40 cases per year: 5 or less cases per year, odds ratio (OR) 1.58 (95% confidence interval [CI], 1.40-1.78); 6 to 10 cases per year, OR 1.29 (95% CI, 1.17-1.43); 11 to 20 cases per year, OR 1.17 (95% CI, 1.07-1.28); 21 to 40 cases per year, OR 1.15 (95% CI, 1.05-1.26). Hospitals with lower mitral repair rates had an increased likelihood of operative mortality relative to the top quartile: lowest quartile, OR 1.31 (95% CI, 1.20-1.44); second quartile, OR 1.18 (95% CI, 1.09-1.29); and third quartile, OR 1.14 (95% CI, 1.05-1.24). Long-term mortality beyond 6 months was also higher in low-volume hospitals: 5 or less cases year, hazard ratio (HR) 1.11 (95% CI, 1.06-1.18); 6 to 10 cases per year, OR 1.06 (95% CI, 1.02-1.10) compared with hospitals performing more than 40 cases per year. Conclusions Most hospitals perform few mitral valve operations on elderly patients. Greater volume of mitral procedures was associated with higher repair rates. Both greater volume of mitral procedures and increasing mitral repair rates were associated with decreased mortality.