Mid-term outcomes after corticosteroid injection for adhesive capsulitis in patients with type-2 diabetes: a retrospective cohort study.

Abstract

The mid-term clinical course after intra-articular corticosteroid injection for adhesive capsulitis ("frozen shoulder") in patients with type-2 diabetes mellitus (T2DM) remains unclear. Therefore, we evaluated coded shoulder-related outcomes and selected coded complications after such injections in patients with T2DM. This retrospective TriNetX Research Network study identified patients with T2DM and first-time adhesive capsulitis (2004-2024). Patients receiving a coded intra-articular corticosteroid injection within 6 months after diagnosis were compared with patients without a coded injection during that period (3,820 vs. 55,234). After propensity matching, 3,819 patients remained per group. Outcomes from 6 to 12 months after diagnosis included subsequent shoulder procedures, infection, pain, stiffness, and neurologic complications (P<.05). The injection cohort had a higher incidence of new shoulder pain within 6-12 months after diagnosis (11%) compared with the no-injection cohort (5%) (relative risk [RR] 2.4, P<.0001). The incidence of subsequent arthrocentesis, aspiration, or injection procedures was also higher in the injection cohort (12%) than in the no-injection cohort (5%) (RR 2.4, P<.0001). The injection cohort had a higher incidence of shoulder arthroscopy (2%) than the no-injection cohort (1%) (RR 2.2, P=.0001). Despite these higher intervention rates, no differences were observed in coded infection rates, persistent shoulder stiffness, or neurologic complications. In patients with T2DM and adhesive capsulitis, receipt of a coded intra-articular corticosteroid injection within 6 months after diagnosis was associated with higher incidence of subsequent shoulder procedures and persistent joint pain at mid-term follow-up. These findings may reflect confounding by indication and a more complex disease course among patients selected for injection rather than a direct adverse effect of corticosteroid therapy. Tailored treatment strategies for adhesive capsulitis in patients with T2DM should account for distinct metabolic and inflammatory factors that may influence treatment response and recovery. III.