Association between adhesive capsulitis and thyroid disease: a meta-analysis

Adhesive capsulitis (AC) is a common clinical condition of the shoulders without a clear pathophysiology or etiology. Although thyroid disease has been linked to AC, an appropriate understanding of the disease and its epidemiological evidence are lacking. This metaanalysis investigated the association of AC with thyroid disease and identified which manifestations of thyroid disease contribute to the risk of AC. The databases of PubMed, Embase, and Scopus were searched for literature retrieval up to September 20, 2022. Articles evaluating the association between AC and any type of thyroid disease were enrolled. Data from studies reporting the prevalence and its 95% confidence interval (CI) were pooled. Subgroup analysis was performed on the different manifestations of thyroid disease. We explored heterogeneity with sensitivity analyses and publication bias with funnel plots and Egger's tests. A trim and fill analysis was conducted if publication bias was found. Results: In total, 10 case-control studies comprising a total of 127,967 patients were included. The prevalence of thyroid disease was significantly higher in patients with AC (odds ratio [OR] = 1.87, 95% CI: 1.37-2.57, P <.0001) than in patients without AC. The results of subgroup analysis indicated significantly higher rates of hypothyroidism (OR = 1.92, 95% CI: 1.09-3.39, P =.02) and subclinical hypothyroidism (OR = 2.56, 95% CI: 1.81-3.63, P <.00001), but not hyperthyroidism (OR = 1.42, 95% CI: 0.63-3.22, P =.40), among patients with AC than among those without AC. Our meta-analysis demonstrated that thyroid disease, especially when presenting as hypothyroidism or subclinical hypothyroidism, is associated with an increased risk of AC. Evidence for an association between hyperthyroidism and AC was not found, although this may be due to the lack of related studies. Further research on the pathogeneses of and relationship between these two diseases is warranted.