OBJECTIVE To investigate the expression levels of peripheral blood ratio of helper T lymphocytes 17 (Th17) to regulatory T lymphocytes (Treg), soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and insulin-like growth factor 1 (IGF-1) in the elderly patients with type 2 diabetes mellitus (T2DM) and analyze the predictive values.

METHODS A total of 57 elderly T2DM patients who were complicated with pulmonary infection and were treated in the First Affiliated Hospital of Jinzhou Medical University from Jan 2021 to Apr 2023 were assigned as the infection group, 61 patients who were not complicated with pulmonary infection were chosen as the non-infection group. The expression levels of peripheral blood Th17/Treg, sTREM-1 and IGF-1 were detected, and the clinical values of the indexes in prediction of pulmonary infection in the T2DM patients were analyzed by means of receiver operating characteristic (ROC) curves.

RESULTS The expression levels of Th17/Treg and sTREM-1 of the infection group were significantly higher than those of the non-infection group(P < 0.05), the expression level of IGF-1 of the infection group was significantly lower than that of the non-infection group(P < 0.05). The areas under curves (AUCs) of Th17/Treg, sTREM-1 and IGF-1 were respectively 0.764, 0.784 and 0.779 in prediction of pulmonary infection in the elderly patients with T2DM, the AUC of the joint detection of the three indexes was 0.846.

CONCLUSION The pulmonary infection in the elderly T2DM patients may lead to the abnormal expressions of Th17/Treg, sTREM-1 and IGF-1. The joint detection of the three indexes has higher value in prediction of the pulmonary infection in the elderly patients with T2DM.