C - reactive protein (CRP) is associated with high disease activity in systemic sclerosis: results from the Canadian Scleroderma Research Group (CSRG)
Arthritis Care & Research , 05/16/2012
Muangchan C et al. – CRP is elevated in approximately one quarter of SSc patients, especially early disease. It is correlated with disease activity, severity and poor pulmonary functionand shorter survival.Methods
- The Canadian Scleroderma Research Group (CSRG) data was used to study the frequency of elevated CRP and ESR and their relationships to clinical parameters, scleroderma disease activity score (SDAS), scleroderma disease severity score (SDSS), health assessment and changes between annual follow up.
- Statistical comparisons were made for CRP ≤ 8 mg/L vs. > 8 mg/L, in early (<3 years from 1st non–RP symptom) vs. late SSc, diffuse cutaneous SSc (dcSSc) vs. limited cutaneous (lcSSc).
- A survival analysis was analyzed between normal vs. elevated CRP patients.
- 1,043patients aged 55.4 ± 12.1 years, female predominant (86.1%), and disease duration of 11.0 ± 9.5 years were analyzed; 38% had dcSSc, 62% had lcSSc and 10.6% were early dcSSc.
- Elevation of CRP occurred in 25.7% and ESR (>20 mm/hr) 38.2%.
- Baseline CRP in dcSSc (11.98 ± 25.41 mg/L) was higher than in lcSSc (8.15 ± 16.09 mg/L); p = 0.016. SSc with disease duration ≤ 3 years had higher CRP (12.89 ± 28.13 mg/L) than that with disease duration > 3 years (8.60 ± 17.06 mg/L); p = 0.041.
- Though not consistent in all subsets, CRP was significantly associated (p<0.01) in the overall group with ESR, mRSS, worse TLC < 80%, FVC < 80%, DLCO< 75%, disease activity (SDAS), damage (SDSS) and HAQ.
- In early dcSSc, frequency of elevated CRP and ESR was 41.5% and 44.2%respectively. CRP seemed to normalize in many SSc patients over time. Adding or withdrawing prednisone did not significantly change CRP.
- Total lung capacity (TLC) <80% predicted, modified Rodnan skin score, and serum creatinine were predictors of elevated CRP in SSc with OR (95% CI) of 2.76 (1.73–4.40), p = 0.0001; 1.03 (1.01–1.05), p = 0.005; 1.005 (1.001–1.010), p = 0.02, respectively.
- Survival (from onset of 1st non Raynaud's symptoms) for elevated CRP patients was less than normal CRP patients, p = 0.001.