Cost-effectiveness Analysis of Intra-articular Injection of Plasma Rich in Growth Factors for Knee Osteoarthritis in the Aging Population Who Failed Conservative Treatment

Abstract

Purpose: As Thailand moves toward an aging society in the future, knee osteoarthritis is becoming an important public-health problem. This study aimed to perform a cost-effectiveness analysis (CEA) of plasma rich in growth factors (PRGF) injection compared with standard treatment using non-steroidal anti-inflammatory drugs (NSAIDs) and celecoxib for knee osteoarthritis in older Thai patients and to study the incidence of total knee arthroplasty (TKA) surgery in the group treated with PRGF after conservative treatment had failed.

Methods: This retrospective single-cohort study included Thai patients (age, ≥55 years) with Kellgren–Lawrence grade II–IV knee osteoarthritis who did not respond to standard conservative treatment and required TKA surgery who were treated between January 2022 and December 2024 at Priest Hospital. The Western Ontario and McMaster Universities Osteoarthritis Index score (obtained at baseline, 1 month, 6 month, and 12 months), which was used to measure clinical outcomes, was converted into a utility score using the Barton mapping algorithm. The cost analysis used the payer perspective, calculated from direct medical costs, which included physician examination fees, radiology fees, procedure fees, the cost of treating gastrointestinal complications, and the cost of TKA surgery.

Results: The mean utility score increased from 0.5957 at baseline to 0.7252 at month 6 (utility gain, 0.1295), which was the period of peak effectiveness, before decreasing to 0.6660 at month 12. The total cost was 6,000 Thai baht (THB) for a PRGF injection, whereas those of NSAIDs and celecoxib were 3,762.64 and 7,719.78 THB, respectively. The average cost of TKA surgery in Priest Hospital was 105,213.30 THB/case. During the 12-month follow-up, a low rate of surgical conversion was observed, with only 19 (9.64%) of 197 patients undergoing TKA. At month 6, PRGF had an incremental cost-effectiveness ratio (ICER) of 41,059.01 THB per 6-month utility gain relative to NSAIDs. Compared with celecoxib, PRGF had a negative ICER (-36,212.45 THB per 6-month utility gain), showing an economically dominant status by providing greater utility gains at a lower total direct cost.

Conclusions: PRGF was associated with favorable short-term economic outcomes compared with externally derived estimates for conventional NSAIDs and celecoxib.