Distribution and Drivers of Average Direct Cost of Osteoarthritis in Canada From 2003 to 2010.

OBJECTIVE: To estimate the distribution and drivers of the average direct cost of osteoarthritis (OA) in Canada using a population-based health microsimulation model of OA from 2003 to 2010.

METHODS: We used a previously published microsimulation model to estimate the distribution of average cost of OA across different cost components and OA stages. OA stages were defined according to the patient flow within the health care system. Cost components associated with pharmacologic and nonpharmacologic treatments, physician visits, and hospitalization were included. Scenario analysis was performed to evaluate average cost drivers from 2003 to 2010.

RESULTS: During the study period, the OA population size grew from 2.9 to 3.6 million, while the average cost increased from $577 to $811 (Canadian) per patient per year. The highest increase in share of cost components was for total joint replacement (TJR) surgery (24% to 32%). The highest average cost was incurred by patients in stage 4 (during and after revision surgery), while around 80% of OA patients were in stage 1 (OA diagnosed but has not visited an orthopedic surgeon). Increase in the proportion of OA patients receiving TJR surgeries (34%) and price inflation (29%) were the most significant drivers of average cost.

CONCLUSION: The average cost of OA has been increasing during the study period mostly due to an increase in the proportion of patients receiving TJR surgeries and price inflation. The distribution of average cost of OA across disease stages needs to be considered when designing policies targeting specific aspects of OA care.