CD4(+) T cells related to disease severity in elderly and frailty community‐acquired pneumonia patients: A retrospective cohort study

BACKGROUNDS: Elderly and frailty individuals show a more senescent immune system, which may relate to worse outcome in community‐acquired pneumonia (CAP). This study aimed to explore prognostic factors related to immune. METHODS: Sixty of elderly (≥65 years) and frailty (clinical frailty scale ≥5 scores) nonsevere CAP patients and 60 severe CAP (SCAP) patients were recruited at our center. Clinical and laboratory data, and several assessment scores were collected. RESULTS: Compared with nonsevere CAP group, the elderly and frailty SCAP patients showed higher level of BMI, PaCO2 and lactate in arterial blood‐gas, CURB‐65 score, ICU admission, mechanical ventilation, shock accidence, and longer hospital stay using two‐tailed t test. The SCAP group also showed increased CRP, IL‐6, and PCT, and decreased CD3(+) T cells, CD4(+) T cells, and CD8(+) T cells. Logistic regression analysis showed that CD4(+) T cells, IL‐6 and PCT were independent prognostic factors for SCAP. The area under the receiver operating characteristic (ROC) curve for CD4(+) T cells combined with PCT was 0.771 (95% CI 0.683–0.859), and the sensitivity and specificity were both 76.7%. Paired t test analysis showed that low CD4(+) T cells in SCAP patients increased after treatment. CONCLUSIONS: CD4(+) T cells decreased in elderly and frailty SCAP patients, and CD4(+) T cells combined with PCT were relatively accurate in the prediction of elderly and frailty SCAP.