Factors Associated with the Use of Hyaluronic Acid and Corticosteroid Injections among Patients with Radiographically Confirmed Knee Osteoarthritis: A Retrospective Data Analysis.

PURPOSE: Despite the rapid proliferation of hyaluronate (HA) and corticosteroid (CO) injections and clinical guidelines regarding their use in osteoarthritis (OA), information on the characteristics of people receiving these injections is scarce. We describe the use of injections among adults with radiographically confirmed knee OA and identify factors associated with injection use.

METHODS: We used publicly available data from the Osteoarthritis Initiative (OAI), an international collaboration sponsored by the National Institutes of Health, and included participants with ≥1 radiographically confirmed knee OA (Kellgren-Lawrence grade ≥2 [definite osteophytes and possible joint space narrowing (JSN) on anteroposterior weight-bearing radiograph]) at baseline. We matched 415 participants who received at least 1 HA and/or CO injection during the 6-month interval before 1 of the first 7 annual follow-up assessments to 1841 injection nonusers by randomly selecting a study visit to match the distribution observed in the injection users. Multinomial logistic regression models were used for identifying factors associated with injection use, including sociodemographic and clinical/functional factors.

FINDINGS: Eighteen percent of the 2256 patients identified as having knee OA had received at least 1 injection (years 1-7, 16.9%, 13.7%, 16.6%, 13.5%, 15.9%, 13.5%, and 9.9%, respectively), most commonly with CO (68.4%). HA and CO were more commonly injected in those with a higher annual household income (adjusted odds ratio [aOR] [95% CI] with HA, US ≥$50,000 vs <$25,000, 3.63; [1.20-10.99]) and less commonly in black patients (HA, 0.19 [0.06-0.55]). Greater Kellgren-Lawrence grade (grade 4 vs 2) was associated with an increased likelihood (aOR [95% CI]) of having received HA (4.79 [2.47-9.30]), CO (1.56 [1.04-2.34]), or both (4.94 [1.99-12.27]).

IMPLICATIONS: The receipt of HA or CO injection may be associated with higher socioeconomic positioning and indicators of greater disease severity in patients with knee OA.