To determine the frequency and clinical characteristics of polymyalgia rheumatica (PMR) with low erythrocyte sedimentation rate (ESR) at diagnosis in a community based cohort of 232 patients.
A retrospective review of medical records of all the patients with a diagnosis of PMR in Olmsted County, Minnesota, seen and followed over a 22 year period, from 1970 through 1991.
Seventeen (7.3%) patients had ESR < 40 mm/h at diagnosis. The findings and outcome in these patients were compared with the others in the group. There was no difference in sex or age between the 2 groups. Both groups had the same delay to diagnosis, typical gradual onset of the disease, the same frequency of both proximal and distal stiffness/pain, and the same frequency of synovitis. Systemic features were less frequent in the low ESR group than in the high ESR group (59 vs 81%, p = 0.05). Mean ESR in the low ESR group was 26+/-9 mm/h versus 74+/-24 mm/h in the high ESR group. The mean hemoglobin concentration was significantly lower (p = 0.0015) in the high compared to the low ESR group (12.2+/-1.4 g/dl versus 13.3+/-1.3 g/dl). The frequency of positive temporal artery biopsy and of diagnosed giant cell arteritis was the same in the 2 groups. Initial response to therapy, frequency of relapses, number of patients going into remission, time to remission, and daily dose of steroids were the same in both groups.
Other than more frequent systemic symptoms, our population of patients with PMR and low ESR at diagnosis had similar clinical characteristics and course of disease as patients with high ESR at diagnosis.