Symptom Severity and Glucocorticoid Dosing in Patients With Polymyalgia Rheumatica and Obesity

Polymyalgia rheumatica (PMR) is an inflammatory disorder of the elderly characterized by girdle pain and stiffness. Obesity has an influence on disease activity and outcome in rheumatic diseases like osteoarthritis and rheumatoid arthritis. We aimed to investigate the relationship between high BMI and the severity and outcome of PMR, which is incompletely understood.

In a post hoc analysis, 83 patients with recent-onset PMR were studied over 6 months using clinical examination, laboratory evaluation, and girdle ultrasound (US). The modified Health Assessment Questionnaire (mHAQ), 36-item Short Form Health Survey (SF-36), and PMR visual analog scale (VAS) scores, as well as prednisone therapy data, were recorded. Patients were grouped according to their BMI.

At baseline, the 12 patients with obesity had significantly more shoulder pain (P = 0.03), global pain (P = 0.03), PMR VAS (P < 0.01), and fatigue (P = 0.03); higher mHAQ (P = 0.01); and lower SF-36 physical component summary (P = 0.048) and SF-36 pain index (P < 0.001). The mean initial prednisone dose was similar among groups, but patients with obesity received a lower dose/kg (1.9 [SD 0.7] mg vs 2.2 [SD 0.7] mg; P < 0.01). At 6 months, patients with obesity were being treated with higher mean daily prednisone doses (8.5 [SD 3.2] mg/d vs 6.2 [SD 5.2] mg/d; P = 0.02), and 40% of them were receiving higher daily prednisone doses than the standard protocol compared with 14% patients without obesity (P = 0.048). Clinical features, laboratory results, and US results were similar between patients with and without obesity.

Obesity affects both symptom severity and prednisone utilization in patients with PMR. The reason for this may relate to different subjective pain perception rather than increased inflammation in patients with obesity. BMI should be considered when interpreting symptoms in patients with PMR and deciding their prednisone doses.