The purpose of this study was to compare the diagnostic performance of procalcitonin and C-reactive protein (CRP) for bacterial infection in patients with systemic rheumatic diseases.
We searched Medline, Embase, and the Cochran library, and performed two meta-analyses on the diagnostic accuracy of procalcitonin and CRP for bacterial infection in systemic rheumatic disease patients.
A total of eight studies including 668 patients in whom the patients with bacterial infection were 208 were available for the meta-analysis. The pooled sensitivity and specificity of procalcitonin were 66.8% (95% confidence interval [CI] 60.0-73.2) and 89.8% (86.6-92.4), respectively, and those of CRP were 81.3% (75.3-86.3) and 63.0% (58.5-67.5). Procalcitonin PLR, NLR, and DOR were 5.930 (3.593-9.786), 0.352 (0.229-0.539), and 19.33 (10.25-36.45), respectively, and those for CRP were 2.228 (1.376-3.608), 0.367 (0.252-0.534), and 7.066 (3.559-14.03), respectively. The AUC of procalcitonin was 0.884 and the Q* index was 0.814, while the AUC of CRP was 0.789 and the Q* index was 0.726, which indicated that the diagnostic accuracy of procalcitonin in patients with systemic rheumatic diseases is higher than that of CRP (difference of AUC 0.095, 95% CI 0.004-0.185, p=0.039). When the data were limited to SLE, the specificity of procalcitonin was also significantly higher than that of CRP (difference 0.219, 95% CI 0.127-0.310, p<0.0001).
Our meta-analysis of published studies demonstrates that procalcitonin is more specific and has better diagnostic accuracy than CRP for bacterial infection in systemic rheumatic diseases.