Using a discrete choice experiment to elicit patients' preferences and willingness-to-pay for knee osteoarthritis treatments in Thailand.

Osteoarthritis is the most common type of joint disease among elderly patients around the world. In response to the need for patient-centered care, patients' and physicians' preferences for knee osteoarthritis treatments have been studied in multiple countries, but not in Thailand. The objective of this study was to investigate Thai patients' preferences and their willingness to pay (WTP) for knee osteoarthritis treatments by using a discrete choice experiment (DCE). Six knee osteoarthritis treatment attributes, including pain relief, delayed disease progression, gastrointestinal side effects, kidney side effects, cardiovascular side effects, and cost, were used to develop a paper-based, DCE questionnaire survey. Patients with knee osteoarthritis, who were at least 18 years old and who provided written informed consent, were recruited from the orthopedic department in a tertiary care hospital in Thailand via convenience sampling. The conditional logit model was used to determine patients' preferences and WTP. The Institutional Review Board at Chulalongkorn University approved this study before it started. A total of 232 patients were collected and analyzed in this study. Patients preferred treatments with a higher efficacy (pain relief and delayed disease progression), a lower probability of side effects (gastrointestinal, kidney, and cardiovascular side effects), and a lower cost. Regarding efficacy and side effects, the patients weighted the importance of a 1% change in cardiovascular side effects (- 0.08) more heavily than 1% changes in kidney (- 0.07) and gastrointestinal (- 0.02) side effects, delayed disease progression (0.02), and pain relief (0.01). Patients were willing to pay 29.56 Thai Baht (THB) and 41.84 THB per month for every 1% increase in pain relief and delayed disease progression, respectively. Conversely, patients were willing to pay 52.04 THB, 145.18 THB and 164.23 THB per month for every 1% decrease in gastrointestinal, kidney, and cardiovascular side effects, respectively. In conclusion, pain relief, delayed disease progression, gastrointestinal side effects, kidney side effects, cardiovascular side effects, and the cost of treatment were significant factors among patients undergoing knee osteoarthritis treatment. Additionally, patients had a higher WTP for delayed disease progression than pain relief and a higher WTP for a reduced probability of cardiovascular side effects than gastrointestinal and kidney side effects. These findings could be used to support treatment decisions for knee osteoarthritis patients in Thailand.