Erythrocyte Sedimentation Rate and C-reactive Protein in the Evaluation of Disease Activity and Severity in Polymyalgia Rheumatica: A Prospective Follow-Up Study

Semin Arthritis Rheum. 2000 Aug;30(1):17-24. doi: 10.1053/sarh.2000.8366.

Abstract

Objective: To determine the frequency and clinical features of patients with polymyalgia rheumatica (PMR) and normal erythrocyte sedimentation rate (ESR) at diagnosis or during relapse/recurrence. To evaluate the usefulness of C-reactive protein (CRP) and ESR in the assessment of PMR activity.

Methods: A prospective follow-up study on 177 consecutive patients meeting the criteria for PMR diagnosed over a 5-year period was conducted in two Italian secondary referral centers of rheumatology. At diagnosis and during follow-up, ESR (Westergren method) and CRP (nephelometry) were measured in all patients. Phenotypic analysis of lymphocyte subpopulations was performed on 78 PMR patients at diagnosis. A two-color technique using the association of specific monoclonal antibodies was applied. A control group consisting of 18 healthy adults older than 60 years was matched for age and sex with the PMR patients.

Results: Ten of 177 (6%) patients had normal ESR values at diagnosis (< or = 30 mm/h). Patients with normal ESR were predominantly men and had lower CRP levels; systemic signs and symptoms were more frequent in patients with higher ESR. The percentages of circulating CD8+ cells were similar in the two groups. CRP values at diagnosis were normal in only 2 of 177 (1%) patients. CRP values were elevated in 9 of 10 patients with normal ESR at diagnosis. Twenty-five episodes of relapse/recurrence with normal ESR occurred in 17 patients. CRP was high in 62% of these episodes. Results of univariate analysis indicated that the 10th percentile for ESR (40 mm/h) and the 70th percentile for CRP (7.8 mg/dL) values at diagnosis were the best cutoff points that discriminate between patients with and without relapse/recurrence. Cox proportional hazards modeling showed that ESR greater than 40 mm/h and CRP greater than 7.8 mg/dL at diagnosis were the two variables that independently increased the risk of relapse/recurrence. However, the relative risk related to ESR was twice than that related to CRP (4.9 vs 2.1).

Conclusion: PMR with a normal ESR at diagnosis was infrequent in our study compared with previous studies. ESR was a superior predictor of relapse than CRP. However, CRP was a more sensitive indicator of current disease activity.

MeSH terms

  • Aged
  • Blood Sedimentation*
  • C-Reactive Protein / analysis*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Polymyalgia Rheumatica / blood
  • Polymyalgia Rheumatica / diagnosis*
  • Polymyalgia Rheumatica / physiopathology*
  • Prospective Studies
  • Recurrence
  • Risk Factors
  • Severity of Illness Index

Substances

  • C-Reactive Protein