Abstract:Objective To explore the predictive value of body plethysmography combined with serum levels of monocyte chemoattractant protein-1 (MCP-1) for asthma in patients with acute lower respiratory tract infection.Methods The medical records of 188 patients with acute lower respiratory tract infection admitted to Qinghai Provincial People's Hospital from June 2019 to December 2022 were retrospectively analyzed. According to whether the patients were complicated with asthma during hospitalization, they were divided into the combined group (48 cases) and the non-combined group (140 cases). The demographic data and laboratory indicators, including parameters measured via body plethysmography such as total lung capacity (TLC), residual volume (RV) and RV/TLC ratio as well as the serum level of MCP-1, of all subjects were collected and sorted out. The differences in the clinical data were compared between the two groups of patients, and the correlations of TLC and RV with the functional residual capacity (FRC) and the serum level of MCP-1 were analyzed. In addition, relevant factors affecting the occurrence of asthma in patients with acute lower respiratory tract infection and the predictive value of FRC combined with the serum level of MCP-1 for asthma in patients with acute lower respiratory tract infection were determined.Results The FRC, TLC, RV, RV/TLC ratio and the serum level of MCP-1 in the combined group were higher than those in the non-combined group (P < 0.05). FRC was positively correlated with TLC and RV (r =0.681 and 0.671, both P =0.001), while the serum level of MCP-1 was positively correlated with TLC and RV (r =0.669 and 0.654, both P =0.001). The results of multivariable Logistic regression analysis showed that high FRC [O^R = 2.450 (95% CI: 1.239, 4.840) ] and serum level of MCP-1 [O^R = 2.995 (95% CI: 1.516, 5.918) ] were risk factors for asthma in patients with acute lower respiratory tract infection (P < 0.05). The receiver operating characteristic curve analysis demonstrated that the sensitivities of FRC, the serum level of MCP-1 and their combination in predicting asthma in patients with acute lower respiratory tract infection were 72.92% (95% CI: 0.579, 0.842), 83.33% (95% CI: 0.692, 0.920) and 79.17% (95% CI: 0.645, 0.890), with the specificities being 81.43% (95% CI: 0.737, 0.873), 70.71% (95% CI: 0.623, 0.779) and 81.43% (95% CI: 0.737, 0.873).Conclusions Body plethysmography and the serum level of MCP-1 can be used to evaluate the lung function of patients with acute lower respiratory tract infection. Serum MCP-1 and FRC measured via body plethysmography exhibit great predictive efficacy for asthma in patients with acute lower respiratory tract infection.