Comorbidities in patients with polymyalgia rheumatica prior to and following diagnosis: A case control and cohort study.

Objectives: To determine the burden of comorbidities, including glucocorticoid (GC) related adverse effects, in patients with polymyalgia rheumatica (PMR) before and after diagnosis.

Methods: We extracted anonymised electronic medical records of patients over the age of 40 years from the Clinical Practice Research Datalink from 1990-2016. Patients with PMR were individually matched on age, sex and registered General Practice to between three and five controls. The prevalence, cumulative probability and likelihood of a range of comorbidities was estimated. Odds ratios (ORs) and hazard ratios (HRs) were calculated using conditional logistic regression and Cox proportional hazards regression respectively, adjusted for a wide range of covariates.

Results: 31,984 patients with PMR were matched to 149,436 controls. PMR was prospectively associated with vascular disease (adjusted HR 1.23 [95% confidence interval (CI) 1.19, 1.28]), as well as respiratory (HR 1.25 [1.18, 1.32]), renal (HR 1.34 [1.30, 1.39]), and autoimmune diseases (HR 4.68 [4.35, 5.03]). Conversely, before PMR diagnosis, the risk of cancer (adjusted OR [OR] 0.89 [0.86, 0.93]) and neurological disease (OR 0.36 [0.33, 0.40]) was significantly lower. Patients with PMR had an increased risk of comorbidities associated with glucocorticoid (GC) use.

Conclusions: Patients with PMR have a high comorbidity burden, both before and after diagnosis. Whilst further work is needed to more fully understand these associations, clinicians should be aware of the high prevalence of comorbid conditions in this group and the impact that treatment with glucocorticoids may have on comorbidity.