Cost-of-illness of knee osteoarthritis: potential cost savings by not undergoing arthroplasty within the first 2 years

Abstract

Purpose

Although knee arthroplasty (KA) is the largest source of hospitalization costs for knee osteoarthritis (OA), some studies have suggested reducing the use of “low-value” interventions, such as intra-articular hyaluronic acid (HA), to lower health care costs. However, those studies fail to consider that HA has demonstrated benefits in extending time to more costly KA or avoiding KA altogether. We evaluated 1) the overall knee OA costs (direct) within a 2-year period; 2) the relative contribution of HA and KA costs; 3) the direct cost savings from HA patients not undergoing KA.

Patients and methods

Knee OA patients were identified from the Optum Clinformatics data set, which includes physician, facility, and pharmacy claims data from privately insured patients of all ages. Patients were stratified in the no HA, non-hylan G-F 20, and hylan G-F 20 cohorts. The cumulative costs (payer perspective) were evaluated for all knee OA-related claims (adjusted to Consumer Price Index Jan 2017$) for patients who had at least 2 years follow-up. Costs were stratified into various clinical categories.

Results

The study cohort included 2,030,497 knee OA patients, of which 65,144 patients (3.2%) underwent KA. The cost of treating knee OA within the 2-year follow-up period was estimated to be $4.99 billion (B). The majority of the costs (69%) were attributed to KA patients (3.2% of patients). In all, 15.9% of the HA patients underwent KA within 2 years, but HA only contributed 1.7% to the total costs for these patients. The remaining 84.1% of HA patients did not undergo KA, which saved an estimated total of $1.54B (average $20,740 per patient) or 83.9%, after accounting for their non-KA therapies.

Conclusion

Our study estimated substantial cost savings through a large percentage of HA patients not undergoing KA. Although a fraction of patients moved on from their conservative therapy to undergo KA within the 2-year period, HA attributed to <2% of their total treatment costs.

Keywords:

• hyaluronic acid
• knee arthroplasty
• intra-articular injections
• health care expenditures

Acknowledgments

This study was supported by Sanofi US.

Disclosure

KLO, MR, and EL are employees of Exponent, Inc, a scientific and engineering consulting firm. Exponent, Inc received funding from Sanofi US for this study. Exponent, Inc has been paid fees by companies and suppliers for KLO’s consulting services on behalf of the following companies and suppliers: Stryker Orthopaedics, Zimmer Biomet, Ethicon, Ferring Pharmaceuticals, Paradigm Spine, Medtronic, Pacira Pharmaceuticals, DJO, and Ossur. RDA has been a paid consultant for Ferring Pharmaceuticals, Novartis, Pfizer and an unpaid consultant for Sanofi-Aventis. The authors report no other conflicts of interest in this work.