The ASA physical status score predicted 6-month mortality and functional status, while ASA class 1 was associated with a higher rate of early revision after hip arthroplasty compared to ASA class 3 (HR 1.39; 95% CI 1.04-1.95; P=0.015).
Cohort (n=41,034)
Yes
Does a higher ASA physical status rating predict increased mortality, early revision, and poorer clinical outcomes in patients undergoing total hip or knee arthroplasty?
The ASA physical status score is a significant predictor of postoperative mortality, functional status, and early revision following total hip and knee arthroplasty.
Hazard Ratio: 1.39 (95% CI 1.04–1.95)
p-value: p=0.015
BACKGROUND: The purpose of this study was to review the results of the first four years of use of the American Society of Anesthesiologists (ASA) physical status rating system in the New Zealand Joint Registry. Our hypothesis was that patients with a higher ASA score would have an increased mortality rate, an increased early revision arthroplasty rate, and poorer clinical outcomes at six months after total hip or knee arthroplasty. METHODS: We prospectively evaluated the preoperative ASA classes for all patients in the registry who underwent primary total hip or knee arthroplasty from 2005 to 2008 with regard to the six-month mortality rate and the Oxford Hip and Knee Scores at six months. Survival curves were constructed with use of revision joint replacement as the end point. RESULTS: Twenty-two thousand six hundred patients who underwent total hip arthroplasties and 18,434 patients who underwent total knee arthroplasties were recorded in the New Zealand Joint Registry. The six-month mortality rate was 0.77% following hip arthroplasty and 0.40% following knee arthroplasty. Significant differences were observed in the mortality rate between all ASA classes following hip arthroplasty (p < 0.001). Similarly, significant differences were observed in the mortality rate between ASA classes after knee arthroplasty, except between ASA classes 1 and 2 and between ASA classes 3 and 4. The mortality rate was significantly higher (p < 0.001) following hip arthroplasty compared with knee arthroplasty. A significant difference (p < 0.001) in Oxford scores was observed when ASA class 1 and ASA class 2 were compared with ASA class 3 and ASA class 4, independent of age and sex, following both hip or knee arthroplasty. A significant difference was observed in the rate of early revision (revision less than two years after the index procedure) following total hip arthroplasty when ASA class 1 (hazard ratio, 1.39 95% confidence interval (CI), 1.04 to 1.95; p = 0.015) and ASA class 2 (hazard ratio, 1.24 95% CI, 1.02 to 1.55; p = 0.030) were compared with ASA class 3, which was independent of age and sex. No significant difference was observed in the rate of early revision after total knee arthroplasty. CONCLUSIONS: The ASA physical status score can be used as a predictor of postoperative mortality and functional status following both hip and knee arthroplasty and may predict early failure of total hip arthroplasty necessitating revision. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.
Hooper et al. (Wed,) conducted a cohort in Total hip or knee arthroplasty (n=41,034). American Society of Anesthesiologists (ASA) physical status rating vs. Different ASA classes (e.g., ASA class 3) was evaluated on Early revision (less than two years after the index procedure) following total hip arthroplasty (ASA class 1 vs ASA class 3) (HR 1.39, 95% CI 1.04-1.95, p=0.015). The ASA physical status score predicted 6-month mortality and functional status, while ASA class 1 was associated with a higher rate of early revision after hip arthroplasty compared to ASA class 3 (HR 1.39; 95% CI 1.04-1.95; P=0.015).