Surfactant protein D, a clinical biomarker for chronic obstructive pulmonary disease with excellent discriminant values

Abstract

Biological markers can help to better identify a disease or refine its diagnosis. In the present study, the association between surfactant protein D (SP-D) and chronic obstructive pulmonary disease (COPD) was studied among subjects consulting for respiratory diseases or symptoms and was compared with C-reactive protein (CRP) and fibrinogen. A further aim of this study was to identify the optimal cut-off point of SP-D able to discriminate COPD patients. A case-control study including 90 COPD patients, 124 asthma patients and 180 controls was conducted. Standardized questionnaires were administered and lung function tests were performed. Biological markers were measured in blood samples according to standardized procedures. The association between SP-D and COPD was investigated using logistic regression models. Receiver-operating characteristic curves were used for threshold identification. SP-D levels above the median value were positively associated with COPD [adjusted odds ratio (OR)=3.86, 95% confidence interval (CI): 1.51–9.85, P=0.005). No associations with COPD or asthma were found for CRP or fibrinogen levels. Scores for COPD diagnosis in all COPD patients or ever-smoker COPD patients were identified (sensitivity, 76.4 and 77.8%; specificity, 89.3 and 88.5%, respectively). The results indicate that SP-D can differentiate COPD from other respiratory symptoms or diseases. Used with socio-demographic characteristics and respiratory symptoms, SP-D is able to discriminate COPD patients from controls, particularly among smokers.

The relation between serum surfactant protein-d level and chronic obstructive pulmonary disease severity

“…Akiki et al measured serum SP-D, CRP, and fibrinogen levels in patients with COPD. In their study, SP-D levels were found significantly and positively associated with COPD, whereas serum CRP and plasma fibrinogen levels were not [32].…”

Surfactant protein D multimerization and gene polymorphism in COPD and asthma

“…In COPD, serum SP‐D was found to be associated with the BODE index of severity and to mortality . However, serum SP‐D levels were not found to be associated with COPD disease severity in the ECLIPSE study as well as in other additional smaller studies …”

“…During the period from June 2011 to April 2013, 90 COPD and 123 asthmatic patients were recruited from the outpatient clinics of the Pulmonology Department of the Saint George Hospital University Medical Center, Beirut, Lebanon. In addition, a total of 223 controls were recruited from the general population . All participants were 18 years old or above.…”

“…Patients were subjected to baseline spirometry measurements by a trained physician . Peripheral blood samples were collected by venipuncture from all study participants into ethylenediaminetetraacetic acid (EDTA) vacutainer or dry tubes for leukocytes and serum collection, respectively.…”

Effect of Pingchuan Guben decoction on patients with chronic obstructive pulmonary disease: Results from a randomized comparative effectiveness research trial

“…SP-D is positively asso ciated with the severity of COPD, and SP-D may successfully differentiate COPD from other respiratory symptoms or diseases (36). Serum SP-D levels are remarkably increased in acute exacerbations of patients with COPD, and are negatively correlated with the lung function in COPD patients (37).…”