Hospital volume and surgical outcomes after elective hip/knee arthroplasty: A risk adjusted analysis of a large regional database
Jasvinder A. Singh, MBBS, MPH,1 C. Kent Kwoh, MD,2 Robert M. Boudreau, PhD,2 Gwo-Chin Lee, MD,3 and Said A. Ibrahim, MD, MPH2,3Hip Knee
Objective
Examine the relationship between hospital procedure volume and surgical outcomes following primary elective total hip or total knee arthroplasty (THA/TKA).
Methods
Using the Pennsylvania Health Care Cost Containment Council database, we identified all patients who underwent primary elective THA/TKA in Pennsylvania. Hospitals were categorized by annual procedure volume of THA/TKA into: ≤25, 26–100, 101–200 and >200. Logistic regression models assessed 30-day complications and 30-day and 1-year mortality, adjusted for age, gender, race, insurance type, hospital region, 3M™ All Patient Refined-Diagnosis Related Group Risk of Mortality score, hospital teaching status and bed count.
Results
THA and TKA cohorts had mean age of 69 years each with 42.8% (n=10,187) and 35% men (n=19,418), respectively. Compared to high-volume hospitals (>200/year), patients who underwent elective primary THA at low-volume hospitals (≤25, 26–100, and 101–200 annually) had higher multivariable-adjusted odds ratios (95% confidence interval) for: venous thromboembolism: 2.0(0.2–16.0), 3.4(1.4–8.0) and 1.1(0.3–3.7), respectively, (p=0.02) (respective events were 3/814, 24/4,163, 7/2,246, 9/2,964); and one-year mortality: 2.1(1.2–3.6) -2.0(1.4–2.9) and 1.0(0.7–1.5) (respective events were 32/814, 147/4,163, 50/2,246, 25/2,964), respectively, (p<0.01). Patients ≥65 who underwent elective primary TKA at low-volume hospitals had significantly higher odds ratios (95% confidence interval) for one-year mortality: 0.6(0.2–2.1), 1.6(1.0–2.4) and 0.9(0.6–1.3), respectively, (p=0.02), compared to high volume hospitals (respective events were 3/309, 58/2,462, 59/3,966, 83/5,750).
Conclusions
A low hospital surgery volume was associated with higher risk of venous thromboembolism and mortality after primary elective THA/TKA. Confounding due to unmeasured variables is possible. Modifiable system-based factors/processes should be targeted to reduce complications.
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