Abstract
OBJECTIVE: To determine if severity of osteoarthritis-related knee pain is associated with a willingness to undergo total knee replacement (TKR) and whether this association is confounded or modified by components of socioeconomic status and health care coverage. METHODS: Cross-sectional analysis was conducted among 3,530 Osteoarthritis Initiative study participants. Logistic regression models were used to assess the effect of knee pain severity (where 0 = none, 1-3 = mild, 4-7 = moderate, and 8-10 = severe) on willingness to undergo TKR. Stratified analyses were conducted to evaluate whether socioeconomic status and health care coverage modify the effect of knee pain severity on willingness. RESULTS: Participants with severe knee pain, compared to participants without pain, were less willing to undergo TKR (odds ratio [OR] 0.73, 95% confidence interval [95% CI] 0.57-0.93). This association was attenuated when adjusted for age, sex, comorbidity, depression, health insurance coverage, prescription medicine coverage, health care source, education, income, employment, race, and marital status (adjusted OR 0.92, 95% CI 0.68-1.24). The odds of willingness to undergo TKR were significantly lower in those with the highest level of pain, compared to those without pain, among participants without health insurance (adjusted OR 0.08, 95% CI 0.01-0.56), but not among those with health insurance (adjusted OR 1.03, 95% CI 0.73-1.38), when adjusted for demographic, clinical, health care access, and socioeconomic factors (P = 0.015). However, <5% of participants were without health insurance. CONCLUSION: Among participants without health insurance, severe knee pain was paradoxically associated with less willingness to undergo TKR. Policies that improve access to quality health care may affect patient preferences and increase utilization of TKR surgery among vulnerable populations.