Is there any correlation between high sensitive CRP and disease activity in systemic lupus erythematosus?

The role of C-reactive protein (CRP) in systemic lupus erythematosus (SLE) as an inflammatory marker is still controversial. Recently, more sensitive methods, such as high sensitive CRP (hs-CRP) have been used to detect micro-inflammation. The role of hs-CRP in lupus flare has not been documented well. We conducted this study to examine the correlation between hs-CRP serum concentrations and disease activity in lupus. Ninety-two SLE patients and 49 healthy controls contributed to our study. Most confounding factors influencing the hs-CRP values were excluded. Disease activity was estimated using the SLE Disease Activity Index (SLEDAI-2K). hs-CRP values were determined using an enzyme-linked immunosorbent assay (ELISA) kit. Serum values of hs-CRP were significantly higher (p < 0.001, z = 3.29) in patients compared with healthy controls. The cutoff point for hs-CRP between patients and controls was 0.93 mg/L (Youden’s Index = 0.39). There was no correlation between hs-CRP serum levels and disease activity. Furthermore, hs-CRP values did not correlate with any of the laboratory parameters, except for C3 (p = 0.003, r_s = −0.2) and C4 (p = 0.02, r_s = −0.1). Although hs-CRP serum levels were significantly higher in lupus patients compared with healthy controls, it seems that this marker is not a good indicator for disease activity.