American society of anesthesiologists grade and association with joint specific outcome, health-related quality of life, readmission and mortality risk after hip and knee arthroplasty.

Abstract

The aims were to assess whether American Society of Anesthesiologists (ASA) grade influenced improvement in joint-specific outcomes (JSO), health-related quality of life (HRQoL), length of stay (LOS), readmission, or mortality after knee (KA) or total hip arthroplasty (THA). This retrospective study was conducted over a 6-year period and included 7644 KA and 7745 THA. Patient demographics, ASA grade, LOS, 30-day readmission and postoperative mortality were recorded from National electronic medical records. Preoperative and 1-year postoperative Oxford knee/hip scores (OKS/OHS), EQ-5D and EQ-VAS scores were obtained from a local arthroplasty register, which had postoperative data for 6272 KA and 6182 THA. For both KA and THA cohorts, increasing ASA grade was associated with female gender (p < 0.001), older age (p < 0.001), and worse preoperative Oxford (p < 0.001), EQ-5D (p < 0.001), and EQ-VAS (p < 0.001) scores. Unadjusted improvements in OKS (p = 0.866), EQ-5D (p = 0.574) or EQ-VAS (p = 0.714) were not significantly influenced by ASA grade after KA. In contrast, those with a worse ASA grade had significantly (p < 0.001) greater improvements in the OHS and EQ-5D. A higher ASA grade was associated with an increased risk of readmission (KA p = 0.020, THA p < 0.001). When adjusting for confounding factors ASA grades 3 and 4 were associated with an increased risk of mortality relative to ASA 1 following KA and THA. ASA 3 (KA + 0.9 days, p < 0.001) and 4 (KA + 2.0 days, p < 0.001, THA + 3.0 days p < 0.001) were also independently associated with an increased length of stay relative to grade 1. Increasing ASA grade did not have a clinically meaningful association with improvement in JSO or HRQoL following KA and THA, but was associated with an increased LOS, 30-day readmission and postoperative mortality risks. Retrospective study, Level III.