From the Guidelines
C-reactive protein (CRP) is a crucial inflammatory marker in polymyalgia rheumatica (PMR) that should be monitored regularly throughout the disease course, as recommended by the 2015 European League Against Rheumatism/American College of Rheumatology collaborative initiative 1.
Importance of CRP Monitoring
Most PMR patients present with significantly elevated CRP levels (typically >10 mg/L and often >30-40 mg/L) at diagnosis, which correlates with disease activity.
- CRP should be measured at baseline before starting treatment, then every 4-8 weeks during initial therapy, and every 3-6 months during maintenance and tapering phases.
- A normal CRP is not required for diagnosis, as approximately 10-20% of PMR patients may have normal inflammatory markers despite typical symptoms.
Treatment Response and CRP
When monitoring treatment response, expect CRP to normalize within 1-2 weeks of starting glucocorticoid therapy (typically prednisolone 15-20 mg daily) 1.
- Persistent elevation suggests inadequate treatment, poor adherence, or an alternative diagnosis.
- During glucocorticoid tapering, rising CRP often precedes clinical relapse and may indicate the need to slow the tapering schedule or temporarily increase the dose.
CRP Monitoring and Clinical Decision-Making
CRP monitoring is particularly useful because it's more specific than ESR for inflammation and isn't affected by age, gender, or anemia.
- However, clinical symptoms should always guide treatment decisions, as CRP may occasionally normalize despite ongoing disease activity.
- The 2015 recommendations for the management of PMR emphasize the importance of individualized patient care and shared decision-making between patients and healthcare providers 1.
Research Agenda and Future Directions
Future studies in PMR should investigate the optimal strategies for CRP monitoring, treatment response, and disease management, including the use of biomarkers and imaging techniques 1.
- The research agenda should prioritize the development of personalized treatment approaches and the identification of biomarkers that can predict disease outcomes and treatment response.
From the Research
CRP in PMR
- C-reactive protein (CRP) is a marker of inflammation that is often elevated in patients with polymyalgia rheumatica (PMR) 2.
- CRP values are elevated in over 90% of patients with PMR, making it a useful diagnostic tool 3.
- Studies have shown that CRP levels can be used to assess disease activity and severity in PMR, with higher levels indicating more severe disease 2.
- CRP levels have also been shown to decrease with treatment, particularly with glucocorticoids, and can be used to monitor response to therapy 4.
Comparison with ESR
- Erythrocyte sedimentation rate (ESR) is another marker of inflammation that is often used in conjunction with CRP to diagnose and monitor PMR 2.
- While ESR is a superior predictor of relapse, CRP is a more sensitive indicator of current disease activity 2.
- Studies have shown that CRP and ESR can be used together to assess disease activity and severity, with both markers providing valuable information 2.
Clinical Significance
- Elevated CRP levels have been associated with an increased risk of relapse and recurrence in PMR 2.
- CRP levels can be used to guide treatment decisions, with higher levels indicating a need for more aggressive therapy 4.
- The use of CRP as a diagnostic and monitoring tool can help to improve outcomes in patients with PMR, particularly in those with elevated levels of inflammation 5.