ASA class is associated with early revision and reoperation after total hip arthroplasty: an analysis of the Geneva and Swedish Hip Arthroplasty Registries

Background and purpose - Data from several joint replacement registries suggest that the rate of early revision surgery after primary total hip arthroplasty (THA) is increasing. The ASA class, now widely recorded in arthroplasty registries, may predict early revision. We investigated the influence of ASA class on the risk of revision and other reoperation within 3 months and within 5 years of primary THA. Patients and methods - We used data from the Geneva and Swedish Hip Arthroplasty Registries, on primary elective THAs performed in 1996-2016 and 2008-2016, respectively. 5,319 and 122,241 THAs were included, respectively. Outcomes were all-cause revision and other reoperations evaluated using Kaplan-Meier survival and Cox regression analyses. Results - Within 3 months after surgery, higher ASA class was associated with greater risk of revision and other reoperation. 3-month cumulative incidences of revision by ASA class I, II, and III-IV respectively, were 0.6%, 0.7%, and 2.3% in Geneva and 0.5%, 0.8%, and 1.6% in Sweden. 3-month cumulative incidences of other reoperation were 0.4%, 0.7%, and 0.9% in Geneva and 0.2%, 0.4%, and 0.7% in Sweden. Adjusted hazard ratios (ASA III-IV vs. I) for revision within 3 months were 2.7 (95% CI 1.2-5.9) in Geneva and 3.3 (CI 2.6-4.0) in Sweden. Interpretation - Assessment of ASA class of patients prior to THA will facilitate risk stratification. Targeted risk-reduction strategies may be appropriate during the very early postoperative period for patients identified as at higher risk. Systematically recording ASA class in arthroplasty registries will permit risk adjustment and facilitate comparison of revision rates internationally.

Summary statistics for Patient-reported Outcome Measures: the improvement ratio

Rationale, aims and objective: Patient-reported outcomes measures (PROMs) can facilitate objective comparisons of alternative treatments and can aid clinicians, researchers, decision-makers and members of the general public in gauging different healthcare providers’ performance. However, this assumes an easy to use and understand summary measure. Methods: Using PROMs (EQ-5D index, EQ VAS and VAS Pain) from 1799 patients in 7 Swedish hospitals with at least 200 hip arthroplasty surgeries in 2009, we illustrated the possibility of summarizing pre- and post-treatment PROM values with the help of a simple index. This index expressed the attained improvement as a percentage of the total possible improvement. Change score, Cohen’s effect size and Standardized Response Means served as alternative measures. Results: The Improvement Ratio index proved capable of offering a vivid and easy to understand summary of healthcare providers’ performance. The alternative measures indicated similar patterns as the Improvement Index. The routines of statistical inference made possible null-hypothesis testing of the improvement in different groups or testing for trends. Conclusions: This simple improvement index gives an easy to understand summary measure that appeals not only to researchers, but also to laymen for consulting healthcare provider comparisons or countrywide white papers. We recommend using the Improvement Ratio index to summarize the PROMs outcome of elective surgeries.