PD-1⁺ T lymphocyte proportions and hospitalized exacerbation of COPD: a prospective cohort study

To evaluate the predictive value of PD-1 expression in T lymphocytes for rehospitalization due to acute exacerbations of COPD (AECOPD) in discharged patients.

115 participants hospitalized with COPD (average age 71.8 ± 6.0 years) were recruited at Fujian Provincial Hospital. PD1⁺T lymphocytes proportions (PD1⁺T%), baseline demographics and clinical data were recorded at hospital discharge. AECOPD re-admission were collected at 1-year follow-up. Kaplan-Meier analysis compared the time to AECOPD readmissions among groups stratified by PD1⁺T%. Multivariable Cox proportional hazards regression and stratified analysis determined the correlation between PD1⁺T%, potential confounders, and AECOPD re-admission. ROC and DCA evaluated PD1⁺T% in enhancing the clinical predictive values of Cox models, BODE and CODEX.

68 participants (59.1%) were AECOPD readmitted, those with AECOPD readmission exhibited significantly elevated baseline PD-1⁺CD4⁺T/CD4⁺T% and PD-1⁺CD8 + T/CD8 + T% compared to non-readmitted counterparts. PD1⁺ T lymphocyte levels statistically correlated with BODE and CODEX indices. Kaplan-Meier analysis demonstrated that those in Higher PD1⁺ T lymphocyte proportions had reduced time to AECOPD readmission (logRank p < 0.05). Cox analysis identified high PD1⁺CD4⁺T and PD1⁺CD8⁺T ratios as risk factors of AECOPD readmission, with hazard ratios of 1.384(95%CI [1.043-1.725]) and 1.401(95%CI [1.013-1.789]), respectively. Notably, in patients aged < 70 years and with fewer than twice AECOPD episodes in the previous year, high PD1⁺T lymphocyte counts significantly increased risk for AECOPD readmission(p < 0.05). The AECOPD readmission predictive model, incorporating PD1⁺T% exhibited superior discrimination to the Cox model, BODE index and CODEX index, AUC of ROC were 0.763(95%CI [0.633-0.893]) and 0.734(95%CI [0.570-0.899]) (DeLong's test p < 0.05).The DCA illustrates that integrating PD1⁺T% into models significantly enhances the utility in aiding clinical decision-making.

Evaluation of PD1⁺ lymphocyte proportions offer a novel perspective for identifying high-risk COPD patients, potentially providing insights for COPD management.

Chinese Clinical Trial Registry (ChiCTR, URL: www.chictr.org.cn/ ), Registration number: ChiCTR2200055611 Date of Registration: 2022-01-14.