Association of frailty with clinical outcomes in chronic obstructive pulmonary disease: A retrospective longitudinal cohort study.

Background: Frailty is a clinical syndrome and common phenomenon in the elderly, particularly when it coexists with chronic obstructive pulmonary disease (COPD). However, the relationship between frailty and its prognosis in COPD patients has not been clearly elucidated.

Methods: We collected electronic data of inpatients who were diagnosed with COPD in the First Affiliated Hospital with Nanjing Medical University (NJMU) from January 2018 to December 2020. In further, we divided them into different groups based on Frailty Index Common Laboratory Tests (FI-LAB). Binary logistic regression was performed to analyze the risk factors associated with COPD. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were applied to validate FI-LAB's value in prognosis. Primary clinical outcomes contained 30-day mortality and readmission. Moreover, we also compared the prognositic value of FI-LAB with Hospital Frailty Risk Score (HRS) by ROC curve, significance was set at P < 0·05.

Findings: The final study included 826 COPD patients, among of them, 30-day mortality and readmission of frailty group was 11·2%, 25·9%, the robust group was 4·3%, 16·0%, and p value was 0·001, 0·004 respectively. Multivariate analysis revealed that smoking, CCI≥3, oral drug≥5, pneumonia, abnormal lymphocyte, abnormal haemoglobin were independent risk factors with frailty. As for the prediction of FI-LAB about frailty in 30-day mortality, the AUC was 0·832, and 30-day readmission was 0·661. As for the prognositic value, FI-LAB and HRS showed no difference in predicting clinical outcomes.

Interpretation: COPD individuals have a higher rate of frailty and pre-frailty. There exists a strong correlation between frailty and 30-day mortality in COPD patients, and FI-LAB has good prognostic value in clinical outcomes of patients with COPD.