ABSTRACT
Objective:To investigate the correlation between sputum culture results and serum levels of C-reactive protein, amyloid A, and procalcitonin in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD).Methods:The clinical data of 131 older adult patients with AECOPD who received treatment in the Affiliated Hospital of Shaoxing University between January 2019 and January 2021 were retrospectively analyzed. According to sputum culture results, these patients were divided into a sputum culture positive group ( n = 52) and a sputum culture negative group ( n = 79). The sputum of patients was collected aseptically for isolation and identification of pathogens. The general data [age, gender, history of smoking, underlying diseases (hypertension, diabetes mellitus, coronary heart disease), albumin level, mechanical ventilation, method of sputum suction, duration of antibiotics medication, length of hospital stay] were recorded for each group. The risk factors for positive sputum culture were analyzed using binary logistic regression techniques. The efficiency of serum levels of C-reactive protein, amyloid A, and procalcitonin for predicting positive sputum culture was analyzed using the receiver operating characteristic curve. Results:There were 67 strains of pathogens isolated from 52 older adult patients with positive sputum culture of AECOPD. The main pathogens were Gram-negative bacteria (67.16%) [Klebsiella pneumonia (31.34%)], followed by Gram-positive bacteria (25.37%) and fungi (7.47%). Logistic regression analysis showed that mechanical ventilation ( OR = 2.75, P = 0.020), usage of broad-spectrum antibiotics ( OR = 2.95, P = 0.012), serum C-reactive protein level ≥ 20.96 mg/L ( OR = 2.44, P = 0.007), serum amyloid A level ≥ 18.03 mg/L ( OR = 2.67, P = 0.016) and serum procalcitonin level ≥ 2.08 μg/L ( OR = 2.51, P = 0.013) were independent risk factors of positive sputum culture in older adult patients with AECOPD. The receiver operating characteristic curve analysis showed that the area under the receiver operating characteristic curve depicting serum levels of C-reactive protein, amyloid A, and procalcitonin in combination for predicting AECOPD was 0.896, which is of predictive efficiency for positive sputum culture ( P < 0.05). Conclusion:The sputum culture pathogens in older adult patients with AECOPD are mainly Gram-negative bacteria. Increased serum levels of C-reactive protein, amyloid A, and procalcitonin are independent risk factors for Gram-positive bacteria. Combined detection of serum levels of C-reactive protein, amyloid A, and procalcitonin is highly efficient in the diagnosis of AECOPD and can be used to evaluate the sputum culture results in older adult patients with AECOPD.