Obesity Increases Risk of Failure to Achieve the 1-Year PROMIS PF-10a Minimal Clinically Important Difference Following Total Joint Arthroplasty

Introduction: The aims of this study were to determine if increasing body mass index (BMI) is a risk factor for failure to attain the 1-year Patient Reported Outcomes Measurement Information System Physical Function (PROMIS PF-10a) minimal clinically important difference (MCID) following total joint arthroplasty (TJA) and to determine a possible BMI threshold beyond which this risk increases significantly. Methods: This retrospective study was performed using 3506 TJAs sourced from a regional-based registry. An anchor-based MCID threshold of 7.9 was chosen. PROMIS PF-10a scores were collected at the preoperative and 1-year postoperative timepoints, and the change was used to determine failure to achieve the 1-year MCID. Demographic and surgical variables were also collected. The association between BMI and failure to achieve 1-year PROMIS PF-10 MCID was then evaluated using logistic regression. A BMI threshold was determined using receiver operating characteristic (ROC) curve analysis. Results: Increasing BMI assessed continuously was a significant risk factor for failure to achieve the MCID (P <.001). Obese Class I (30-35 kg/m(2)), Obese Class II (35-40 kg/m(2)), and Obese Class III (>40 kg/m(2)) subgroups compared to Normal BMI (<25 kg/m(2)) were significantly associated (P <.05) with this adverse outcome as well. Conclusion: Our study showed that increasing BMI is a risk factor for failure to achieve the 1-year PROMIS PF-10a MCID following TJA. Among our patients, an increase in 1 kg/m(2) increased the risk of failure to achieve the MCID by 2%. With these findings, surgeons will be better equipped to preoperatively advise patients with elevated BMIs considering TJA. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

Increasing BMI is a significant risk factor for failure to achieve the 1-year PROMIS PF-10a MCID following TJA, with obese patients at higher risk of this adverse outcome. Surgeons should consider advising patients with elevated BMIs accordingly.