Effect of Body Mass Index and Psychosocial Traits on Total Knee Replacement Costs in Patients with Osteoarthritis
Christian A Waimann1, Rodrigo J Fernandez-Mazarambroz1, Scott B Cantor1
1From the Hospital Municipal Dr. Héctor M. Cura, Buenos Aires, Argentina; University of Texas MD Anderson Cancer Center; St. Luke's Episcopal Health System, Houston, Texas, USA.C.A. Waimann, MD, Hospital Municipal Dr. Héctor M Cura; R.J. Fernandez-Mazarambroz, BBA, University of Texas MD Anderson Cancer Center; S.B. Cantor, PhD, University of Texas MD Anderson Cancer Center; M.A. Lopez-Olivo, MD, PhD, University of Texas MD Anderson Cancer Center; A.G. Barbo, MS, University of Texas MD Anderson Cancer Center; G.C. Landon, MD, St. Luke's Episcopal Health System; S.J. Siff, MD, St. Luke's Episcopal Health System; H. Lin, PhD, University of Texas MD Anderson Cancer Center; M.E. Suarez-Almazor, MD, PhD, University of Texas MD Anderson Cancer Center.
Objective:
Clinical and psychosocial attributes are associated with clinical outcomes after total knee replacement (TKR) surgery in patients with osteoarthritis (OA), but their relationship with TKR-related costs is less clear. Our objective was to evaluate the effect of clinical and psychosocial attributes on TKR costs.
Methods:
We conducted a 6-month prospective cohort study of patients with knee OA who underwent TKR. We examined baseline demographic, clinical [body mass index (BMI) and comorbidities], and psychosocial attributes (social support, locus of control, coping, depression, anxiety, stress, and self-efficacy); baseline and 6-month OA clinical outcomes [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function]; and 6-month direct and indirect TKR-related costs. Multiple regression was performed to identify determinants of TKR-related costs.
Results:
We included 212 patients; 66% were women, 71% were white, and the mean age was 65.2 years. The mean baseline WOMAC pain score was 55 (SD 19) and WOMAC function score was 54 (SD 20). Mean total TKR-related costs were US$30,831 (SD $9893). Multivariate regression analyses showed that increasing BMI and anxiety levels and decreasing levels of positive social interactions were associated with increased costs. A lower cost scenario with a lower range of normal BMI (19.5), highest positive social interaction, and no anxiety predicted TKR costs to be $22,247. Predicted costs in obese patients (BMI 36) with lowest positive social interaction and highest anxiety were $58,447.
Conclusion:
Increased baseline BMI, anxiety, and poor social support lead to higher TKR-related costs in patients with knee OA. Preoperative interventions targeting these factors may reduce TKR-related costs, and therefore be cost-effective.
