Background Total knee arthroplasty (TKA) relieves pain and improves quality of life for persons with advanced knee osteoarthritis. However, to our knowledge, the cost-effectiveness of TKA and the influences of hospital volume and patient risk on TKA cost-effectiveness have not been investigated in the United States. Methods We developed a Markov, state-transition, computer simulation model and populated it with Medicare claims data and cost and outcomes data from national and multinational sources. We projected lifetime costs and quality-adjusted life expectancy (QALE) for different risk populations and varied TKA intervention and hospital volume. Cost-effectiveness of TKA was estimated across all patient risk and hospital volume permutations. Finally, we conducted sensitivity analyses to determine various parameters’ influences on cost-effectiveness. Results Overall, TKA increased QALE from 6.822 to 7.957 quality-adjusted life years (QALYs). Lifetime costs rose from $37 100 (no TKA) to $57 900 after TKA, resulting in an incremental cost-effectiveness ratio of $18 300 per QALY. For high-risk patients, TKA increased QALE from 5.713 to 6.594 QALY, yielding a cost-effectiveness ratio of $28 100 per QALY. At all risk levels, TKA was more costly and less effective in low-volume centers than in high-volume centers. Results were insensitive to variations of key input parameters within policy-relevant, clinically plausible ranges. The greatest variations were seen for the quality of life gain after TKA and the cost of TKA. Conclusions Total knee arthroplasty appears to be cost-effective in the US Medicare-aged population, as currently practiced across all risk groups. Policy decisions should be made on the basis of available local options for TKA. However, when a high-volume hospital is available, TKAs performed in a high-volume hospital confer even greater value per dollar spent than TKAs performed in low-volume centers.

Objective The prevalence of symptomatic knee osteoarthritis (OA) has been increasing over the past several decades in the United States concurrent with an aging population and the growing obesity epidemic. We quantify the impact of these factors on the number of persons with symptomatic knee OA in the first decades of 21st century. Methods We calculated prevalence of clinically diagnosed symptomatic knee OA from the National Health Interview Survey 2007–08 and derived the proportion with advanced disease (Kellgren-Lawrence grades 3–4) using the Osteoarthritis Policy Model, a validated simulation model of knee OA. Incorporating contemporary obesity rates and population estimates, we calculated the number of persons living with symptomatic knee OA. Results We estimate that about fourteen million persons had symptomatic knee OA, with advanced OA comprising over half of those cases. This includes over three million African American, Hispanic, and other racial/ethnic minorities. Adults under 45 years of age represented nearly two million cases of symptomatic knee OA and individuals between 45 and 65 years of age six million more. Conclusion Over half of all persons with symptomatic knee OA are younger than 65 years of age. As many of these younger persons will live for three decades or more, there is substantially more time for greater disability to occur and policymakers should anticipate healthcare utilization for knee OA to increase further in upcoming decades. These data emphasize the need for the deployment of innovative prevention and treatment strategies for knee OA, especially among younger persons.

OBJECTIVE To update estimates of cancer risk in SLE relative to the general population. METHODS A multisite international SLE cohort was linked with regional tumor registries. Standardized incidence ratios (SIRs) were calculated as the ratio of observed to expected cancers. RESULTS Across 30 centres, 16,409 patients were observed for 121,283 (average 7.4) person-years. In total, 644 cancers occurred. Some cancers, notably hematologic malignancies, were substantially increased (SIR 3.02, 95% confidence interval, CI, 2.48, 3.63), particularly non-Hodgkin’s lymphoma, NHL (SIR 4.39, 95% CI 3.46, 5.49) and leukemia. In addition, increased risks of cancer of the vulva (SIR 3.78, 95% CI 1.52, 7.78), lung (SIR 1.30, 95% CI 1.04, 1.60), thyroid (SIR 1.76, 95% CI 1.13, 2.61) and possibly liver (SIR 1.87, 95% CI 0.97, 3.27) were suggested. However, a decreased risk was estimated for breast (SIR 0.73, 95% CI 0.61–0.88), endometrial (SIR 0.44, 95% CI 0.23–0.77), and possibly ovarian cancers (0.64, 95% CI 0.34–1.10). The variability of comparative rates across different cancers meant that only a small increased risk was estimated across all cancers (SIR 1.14, 95% CI 1.05, 1.23). CONCLUSION These data estimate only a small increased risk in SLE (versus the general population) for cancer over-all. However, there is clearly an increased risk of NHL, and cancers of the vulva, lung, thyroid, and possibly liver. It remains unclear to what extent the association with NHL is mediated by innate versus exogenous factors. Similarly, the etiology of the decreased breast, endometrial, and possibly ovarian cancer risk is uncertain, though investigations are ongoing.

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