title: Diagnostic accuracies of procalcitonin and C-reactive protein for bacterial infection in patients with systemic rheumatic diseases: a meta-analysis.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Korea University College of Medicine, Hanyang University Medical Centre, Seoul, Korea.
authors.forename: Gwan Gyu
authors.initials: GG
authors.lastname: Song
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The Hospital for Rheumatic Diseases, Hanyang University Medical Centre, Seoul, Korea.
authors.forename: Sang-Cheol
authors.initials: SC
authors.lastname: Bae
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Korea University College of Medicine, Hanyang University Medical Centre, Seoul, Korea.
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Lee
mesh_terms: D001424:Bacterial Infections / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D016009:Chi-Square Distribution; D006801:Humans; D011237:Predictive Value of Tests; D011498:Protein Precursors / Q000097:blood*; D012216:Rheumatic Diseases / Q000097:blood / Q000150:complications* / Q000276:immunology; D012307:Risk Factors
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide