title: The association of serum procalcitonin and high-sensitivity C-reactive protein with pneumonia in elderly multimorbid patients with respiratory symptoms: retrospective cohort study.
abstract: BACKGROUND
  Serum procalcitonin and high-sensitivity C-reactive protein (hs-CRP) elevations have been associated with pneumonia in adults. Our aim was to establish their diagnostic usefulness in a cohort of hospitalized multimorbid patients ≥65 years old admitted to hospital with acute respiratory symptoms.
  
  
  METHODS
  With a retrospective cohort study design, all multimorbid patients ≥65 years-old with acute respiratory symptoms admitted to an internal medicine hospital ward in Italy from January to August 2013 were evaluated. Pneumonia diagnosis, comorbidities expressed through Cumulative Illness Rating Scale (CIRS), setting of living, length of stay, serum hs-CRP and procalcitonin at admission were collected for each patient. Data were analyzed with Mann-Whitney's U test and multivariate Cox logistic regression analysis. A Receiver Operating Characteristic (ROC) curve was used to verify each biomarker's association with pneumonia diagnosis.
  
  
  RESULTS
  Four hundred fifty five patients (227 M) were included in the study, of whom 239 with pneumonia (138 M, mean age 80 ± 13) and 216 without pneumonia (89 M, mean age 80 ± 14). After adjustment for age and sex, median levels of hs-CRP were significantly higher in patients with pneumonia (116 mg/L, IQR 46.5-179.0, vs 22.5 mg/dl, IQR 6.9-84.4, p < 0.0001), while procalcitonin median levels were not (0.22 ng/ml IQR 0.12-0.87, vs 0.15 ng/ml, IQR 0.10-0.35, p = 0.08). The ROC analysis showed that, unlike procalcitonin, hs-CRP values were predictive of pneumonia (AUC 0.76, 95% CI 0.72-0.79, p < 0.0001, cut-off value 61 mg/L), even after adjustment for possible confounders including nursing home residence and dementia. Serum hs-CRP levels >61 mg/L were independently associated with a 3.59-fold increased risk of pneumonia (OR 3.59, 95% CI 2.35-5.48, p < 0.0001).
  
  
  CONCLUSIONS
  In elderly multimorbid patients who require hospital admission for respiratory symptoms, serum hs-CRP testing seems to be more useful than procalcitonin for guiding the diagnostic process when clinical suspicion of pneumonia is present. Procalcitonin testing might hence be not recommended in this setting.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy. antonio.nouvenne@alice.it.|Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy. antonio.nouvenne@alice.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Nouvenne
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.|Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ticinesi
authors.affiliation: INAIL-CERT Research Center at University of Parma, Parma, Italy.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Folesani
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.|Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Cerundolo
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Prati
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Morelli
authors.affiliation: Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Guida
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.|Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Lauretani
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Maggio
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, Parma University Hospital, Parma, Italy.
authors.forename: Rosalia
authors.initials: R
authors.lastname: Aloe
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, Parma University Hospital, Parma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lippi
authors.affiliation: Department of Clinical and Experimental Medicine, University of Parma, Parma, Italy.|Internal Medicine and Critical Subacute Care Unit, Geriatric-Rehabilitation Department, Parma University Hospital, Parma, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Meschi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006760:Hospitalization; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D011014:Pneumonia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D011498:Protein Precursors / Q000097:blood*; D012372:ROC Curve; D012189:Retrospective Studies; D013223:Statistics as Topic; D063189:Symptom Assessment / Q000379:methods
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide