Total knee replacement offers good value in obese patients with knee OA

Obese patients with knee osteoarthritis (OA), including those with multiple comorbidities, tend to benefit more from total knee replacement (TKR) from a cost-effectiveness perspective, a recent study has shown.

The investigators assessed long-term clinical benefits, costs, and cost-effectiveness of TKR in patients with a body mass index (BMI) of ≥40 kg/m². They evaluated TKR parameters from longitudinal studies and published literature and costs from Medicare Physician Fee Schedules, the Healthcare Cost and Utilization Project, and published data.

In a base-case analysis, TKR increased quality-adjusted life-years (QALYs) by 0.71 year and lifetime medical costs by $25,200 among patients aged 50–65 years with a BMI of ≥40 kg/m², resulting in an incremental cost-effectiveness ratio (ICER) of $35,200. In patients aged >65 years with a BMI ≥40 kg/m², TKR increased QALYs by 0.39 year and costs by $21,000, resulting in an ICER of $54,100.

Sensitivity analysis revealed ICERs in TKR recipients with a BMI of ≥40 kg/m² and diabetes and cardiovascular disease of <$75,000 per QALY. Results were most sensitive to complication rates and preoperative pain levels.

In the probabilistic sensitivity analysis, TKR tended to be a cost-effective strategy for 100 percent of patients aged 50–65 years and for 90 percent of those older than 65 years at a $55,000-per-QALY willingness-to-pay threshold.

One limitation of this study was that data were derived from several sources.

“TKR is an effective and cost-effective strategy for treating end-stage knee OA,” the investigators said. “Greater risk for complications among TKR recipients with a BMI of 40 kg/m² or greater has raised concerns about the value of TKR in this population.”