USA: Patients with severe obesity (BMI of 40 kg/m2 or greater) and end-stage osteoarthritis (OA) have high rates of complications post total knee replacement (TKR) surgery due to which surgeons often hesitate to perform the surgery. Now, a recent study published in the journal Annals of Internal Medicine, has found TKR surgery to be cost-effective in these patients.
Patients with obesity are at increased risk for knee osteoarthritis, more than 14 million people in the US are said to be obese. A growing proportion of patients who receive TKR are obese (BMI of 30 kg/m2 or higher).
TKR is shown to be very effective and cost-effective in non-obese patients with end-stage knee OA but it is not known if TKR is cost-effective in population with obesity and end-stage knee OA. Considering this, Elena Losina, Boston University School of Public Health, Boston, Massachusetts, and colleagues aimed to assess the value of TKR in recipients with a BMI of 40 kg/m2 or greater using a cost-effectiveness analysis.
The researchers used Osteoarthritis Policy Model for assessing long-term clinical benefits, costs, and cost-effectiveness of TKR in patients with a BMI of 40 kg/m2 or greater. Total knee replacement parameters were obtained from longitudinal studies and published literature, and costs from Medicare Physician Fee Schedules, the Healthcare Cost and Utilization Project, and published data.
It included people who were recipients of TKR with a BMI of 40 kg/m2 or greater in the United States. Outcome measures included cost, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs), discounted at 3% annually.
Key findings include:
Total knee replacement increased QALYs by 0.71 year and lifetime medical costs by $25 200 among patients aged 50 to 65 years with a BMI of 40 kg/m2or greater, resulting in an ICER of $35 200.
Total knee replacement in patients older than 65 years with a BMI of 40 kg/m2 or greater increased QALYs by 0.39 year and costs by $21 100, resulting in an ICER of $54 100.
In TKR recipients with a BMI of 40 kg/m2 or greater and diabetes and cardiovascular disease, ICERs were below $75 000 per QALY.
Results were most sensitive to complication rates and preoperative pain levels.
In the probabilistic sensitivity analysis, at a $55 000-per-QALY willingness-to-pay threshold, TKR had a 100% and 90% likelihood of being a cost-effective strategy for patients aged 50 to 65 years and patients older than 65 years, respectively.
"From a cost-effectiveness perspective, TKR offers good value in patients with a BMI of 40 kg/m2 or greater, including those with multiple comorbidities," concluded the authors.
Reference:
The study titled, "The Value of Total Knee Replacement in Patients With Knee Osteoarthritis and a Body Mass Index of 40 kg/m2 or Greater: A Cost-Effectiveness Analysis," is published in the journal Annals of Internal Medicine.
DOI: https://www.acpjournals.org/doi/10.7326/M20-4722