The association of serum procalcitonin and high-sensitivity C-reactive protein with pneumonia in elderly multimorbid patients with respiratory symptoms: retrospective cohort study

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).CONCLUSION: 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

Exhaled breath condensate in subjects exposed to environmental pollutants: acidity and biomarkers of inflammation

La misura del pH nel condensato dell’aria espirata (CAE) è ad oggi il modo migliore e non invasivo per valutare il ruolo dell’acidificazione del fluido di rivestimento broncoalveolare (lining fluid, LF) nelle patologie respiratorie da inquinanti ambientali. Le misure di pH nel CAE, fluido acquoso ottenuto dalla condensazione ex vivo di sostanze sia volatili che non volatili provenienti dal polmone, forniscono informazioni indirette, ma difficilmente ottenibili mediante misure in vivo, sull’omeostasi nel LF. In questa Tesi sono discusse le variazioni di pH nel CAE associate a modificazioni della funzionalità polmonare ed a fenomeni di flogosi sia in patologie respiratorie che in esposizioni accidentali a sostanze pneumotossiche. I dati riportati dimostrano l’utilità degli indicatori di flogosi e del pH nel follow-up di un gruppo di bambini acutamente intossicati da cloro durante attività sportiva in piscina e nello studio dell’asma, patologia associabile all’esposizione ad inquinanti ambientali ed occupazionali. Attraverso la caratterizzazione dell’equilibrio acido-base nel CAE di bambini con fibrosi cistica è stato possibile dimostrare che l’acidificazione del CAE e delle vie aeree in generale è, almeno in parte, funzione di un processo infiammatorio, suggerendo così l’impiego del pH come indicatore di flogosi.The measurement of pH in exhaled breath condensate (EBC) is currently the best and not invasive way to evaluate the role of acidification of pulmonary lining fluid (LF) in respiratory diseases associated with environmental pollutants. EBC is an ex vivo aqueous matrix obtained by condensation of volatile and not volatile substances arising from the lung. Since repeated in vivo measurements of LF pH are ethically unacceptable, the determination of pH in EBC may provide indirect information on the homeostasis in LF. Changes in the EBC pH value associated with impairment in the lung function and inflammation processes are discussed in this Thesis, both in the case of respiratory diseases and accidental exposures to pneumotoxic substances. Data show that biomarkers of inflammation and pH are useful in the follow-up of a group of children acutely intoxicated by chlorine and in the study of asthma, a disease associated with exposure to environmental or occupational pollutants. The characterization of acid-base equilibria in EBC of children with cystic fibrosis demonstrated that both CAE and airways acidification may be, at least in part, determined by inflammation, thus suggesting the use of pH as a simple and inexpensive indicator of inflammation