Direct and indirect costs of osteoarthritis in Singapore: a comparative study among multiethnic Asian patients with osteoarthritis

OBJECTIVE:
To estimate and compare the direct and indirect costs of osteoarthritis (OA) in multiethnic Asian patients with OA in Singapore.

METHODS:
The study was a retrospective and cross-sectional design. Patients were stratified according to ethnicity and presence or absence of joint surgery. Direct costs were estimated from both a societal and a patient perspective using the Singapore General Hospital database; indirect costs were estimated using the human capital approach. All costs were expressed as mean costs per patient per annum in 2003 Singapore dollars.

RESULTS:
A total of 1179 patients (83.6% Chinese, 7.2% Malay, 3.5% Indian, 5.7% others) were included in estimating direct costs, of which 513 (43.5%) had total knee replacement (TKR) and 92 (7.8%) total hip replacement (THR), while 105 patients (71.4% Chinese, 14.3% Malay, 14.3% Indian) were included in estimating indirect costs. Direct costs to patients ranged from 1460 dollars to 7477 dollars for Chinese, 1362 dollars-7211 dollars for Malays, 1688 dollars-6226 dollars for Indians, and 1437 dollars-12,140 dollars for other ethnic patients; direct costs to society ranged from 3351 dollars to 15,799 dollars for Chinese, 2939 dollars-15,436 dollars for Malays, 3150 dollars-10,990 dollars for Indians, and 2597 dollars-17,879 dollars for other ethnic patients. In contrast, the indirect costs ranged from 1215 dollars to 3834 dollars for Chinese, 1138 dollars-6116 dollars for Malays, and 1371 dollars-5292 dollars for Indians. However, most ethnic variations were not statistically significant.

CONCLUSION:
The economic burden of OA to society and patients increased by 3-fold or more in the patients with TKR/THR compared to those without. The ethnic differences in health resources consumed were more apparent when the disease progressed.