Fibrinogen: Possible New Marker for Polymyalgia Rheumatica

Plasma fibrinogen appears at least as accurate as C-reactive protein (CRP) and erythrocyte sedimentation rates (ESR) as a biomarker of disease activity in polymyalgia rheumatica – and more specific in confirming response to treatment, according to Irish researchers.

In a pilot study, 60 patients (the majority women, mean age 71) were divided into groups by active and inactive PMR status based on clinical features and CRP and ESR levels. The 25 untreated, newly-diagnosed PMR patients were given 15 mg of prednisone at baseline; the 35 with inactive PMR already taking 0-15 mg. Both groups were assessed for fibrinogen, CRP, and ESR levels at baseline and 6 weeks, with disease activity recorded during all visits.

Between weeks 1 and 6, disease activity scores improved in both active and inactive groups, with no significant differences between groups.

In terms of biomarkers, however, there were significant differences, with abnormal fibrinogen showing the best performance in assessing disease activity compared with abnormal ESR and CRP. Fibrinogen was significantly superior at 6 weeks at detecting response to treatment.

The researchers conclude that fibrinogen is at least as useful as ESR and CRP for identifying disease activity in PMR, and more specific at confirming remission. They suggest it as an adjunct to the other tests, to enhance diagnosis and guide therapy.