Cost-Effectiveness of Interventions for OA
Primary Interventions
Despite clear evidence of an association of OA with obesity and of a reduction in symptoms and progression of the disease with weight reduction, no formal studies of the cost-effectiveness of this intervention are available.
Secondary Interventions
Patient education programs, exercise programs, medications, and synovial fluid replacement have demonstrated varying levels of cost-effectiveness.
Education Programs
Lord and others (1999) evaluated the cost-effectiveness of a nurse-led education program for patients with OA of the knee in the United Kingdom, using usual care as the comparator. They found that the costs for the intervention group were greater than for the control group, but that the outcomes for the two groups were not statistically different.
The cost-effectiveness of education programs for OA patients in the developing countries is unknown. Education programs will be subject to diminishing returns, and their marginal effectiveness may depend directly on the basic level of education of those targeted. Though the scant evidence presented here suggests that education programs may not be cost-effective, further research on their effectiveness and cost-effectiveness in developing countries is required.
Exercise Programs
Patrick and others (2001) analyzed the cost-effectiveness of an aquatic exercise program for the management of OA and compare it with usual care. The study involved a 20-week randomized trial of aquatic classes for 249 adults age 55 to 75 with a confirmed diagnosis of OA. The results were generally unfavorable. In many cases (24 percent of the bootstrapped estimates), the exercise program was dominated by usual care, and the 95 percent confidence interval ranged from dominated to US$498,700 per QALY gained.
Evidence of the cost-effectiveness of exercise programs for established OA is currently meager. Nevertheless, as part of a diversified portfolio, low-cost exercise programs may still play a useful role in the aging populations of developing regions and confer some benefit on those with established OA, particularly if they are associated with weight reduction.
Nonselective NSAIDs
In a U.K. study, McCabe and others (1998) consider the cost-effectiveness of the use of five different NSAIDs (nabumetone, diclofenac, ibuprofen, piroxicam, and naproxen) in RA and OA. Taking the least and most expensive of the five NSAIDs—namely, ibuprofen and nabumetone, which were also at the high- and low-risk ends of the spectrum in terms of adverse gastrointestinal events—the authors conclude that nabumetone is not a cost-saving prescription.
Gastroprotective Agents
The most common side effects of NSAIDs are gastrointestinal; therefore, evaluating therapies to reduce these events is important. Van Dieten and others (2000) review the literature on the cost-effectiveness of misoprostol in reducing adverse gastrointestinal events in OA and RA patients who take NSAIDs. Unfortunately, the reviewed studies evidently reported CERs based on such nongeneralizable measures as cost per patient ratios. Nevertheless, van Dieten and others (2000) argue that strong evidence exists that gastroprotection is cost-effective for OA and RA patients taking NSAID therapy. This finding appears to be true in relation to several of the reviewed studies, which produced estimates of cost savings derived from prophylaxis. However, van Dieten and others' (2000) study is at variance with that of Gabriel, Campion, and O'Fallon (1994), who conclude that misoprostol was generally dominant in that it provided no greater quality-of-life improvement and cost more.
Synovial Fluid Replacement
In a Canadian study, Torrance and others (2002) analyzed the cost-effectiveness of synovial fluid replacement in a randomized, one-year, multicenter trial of 255 patients with OA of the knee. Patients were randomized to appropriate care with hylan G-F 20 or to appropriate care without hylan G-F 20. The mean QALY gain in the intervention group was 0.071, and the resulting ICER was US$5,233 per QALY (with similar results from sensitivity analyses). However, the relevant incremental comparators in developing regions are likely to be quite different from those used by the foregoing study. Also, the relative price of this product is likely to be higher. Thus, we cannot find strong grounds for recommending that developing regions adopt this intervention.
Tertiary Interventions
Total joint replacement for arthritis is one of the most commonly performed and cost-effective operations in developed countries. In developing countries, however, the availability of this intervention is constrained by the availability of surgeons able to perform the operation. If the surgical expertise is available, the cost-effectiveness of total joint replacement is likely to be as good as in Australia, Europe, and North America.
Total Hip Arthroplasty
Chang, Pellissier, and Hazen (1996) assess the cost-effectiveness of total hip arthroplasty in various age groups compared with nonsurgical management. Their analyses suggest that, in 60-year-old white women, total hip arthroplasty is dominant compared with nonsurgical management. For 85-year-old men, the cost per QALY is US$6,893. Generally, their results suggest that, when total hip arthroplasty is used as a treatment for OA of the hip with significant functional limitation, it is cost-effective.
Knee Replacement
Segal and others (2004) review a number of interventions for OA and suggest a cost per QALY of US$5,407 for knee replacement in Australia.
