Tampa, FL—Current guidelines for the management of knee osteoarthritis (OA) from the American Academy of Orthopaedic Surgeons do not recommend intra-articular hyaluronic acid (IAHA) injection (ie, viscosupplementation) for patients with symptomatic OA because of the lack of data indicating that its use reduces pain. However, researchers at the 2014 Academy of Managed Care Pharmacy found that the mean time-to-total knee replacement (TKR) after starting IAHA was 2.5 years.
“Today, a growing number of physicians and patients are utilizing viscosupplementation for OA as a means to delay or avoid knee replacement procedures (which are invasive and carry an average cost of $49,000-$57,000),” according to study author Taha Khan, PharmD, Horizon Blue Cross Blue Shield of New Jersey, Newark, and colleagues.
In a retrospective analysis of medical claims data, the investigators assessed the effectiveness of IAHA in managing OA and delaying TKR. Study participants were eligible for inclusion if they were Horizon Blue Cross Blue Shield of New Jersey members with both medical and pharmacy benefits between January 1, 2008, and October 30, 2013, and aged ≥18 years. In addition, patients had to be diagnosed with OA based on the International Classification of Diseases, Ninth Revision (ICD-9) codes.
Among approximately 30,000 patients, 2326 (7.8%) were eligible for study inclusion. Of these patients, approximately 75% underwent TKR after 1 year of receiving their first IAHA injection and 37% of the patients within the first year of starting viscosupplementation. The mean time-to-TKR in patients who received 1 through 9 courses of therapy (duration, ≤41.5 months) was 29.65 months; 58.1% of patients received only 1 course of IAHA therapy before undergoing TKR. Because the severity of OA most likely increased with courses of therapy, the investigators noted, the time from end of IAHA therapy to TKR trended downward from patients who received 1 course of therapy to those who received 9 courses of therapy.
Synvisc-One and Synvisc had the highest utilization in both groups of patients (IAHA only and IAHA plus TKR) and the average cost for 1 hyaluronic acid injection, including administration fees, was $668.
Data from the analysis indicated that decreases in mean age and time-to-TKR were directly proportional, suggesting that it might work best in younger patients. “Viscosupplementation continues to be an option for treatment of OA in the knee for patients who have failed or are intolerant to conventional treatment such as analgesics, but the benefit of IAHA must be weighed against possible adverse events and long-term cost implications in this growing population,” according to Dr Khan and colleagues.