Impact of Laboratory-Derived Frailty Index on Clinical Outcomes in Critical Care Patients with COPD: A Retrospective Analysis Using the MIMIC-IV Database.

Background and objective: Chronic obstructive pulmonary disease (COPD) is associated with high mortality and morbidity worldwide. Notably, 20% of COPD patients are admitted to the ICU, and among them, there is a 25% mortality rate. Therefore, identifying novel risk factors for effective intervention is crucial for managing COPD. This research aims to investigate the relationship between the physiological and laboratory - based frailty index (FI - Lab) and mortality among critical care patients with COPD.

Methods: The FI-Lab was constructed using 33 items. This index was used to quantify the frailty level of critically ill patients with COPD in the ICU. We analyzed data from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Our study group consisted of 6825 COPD patients with an average age of 65.8 ± 14.8 years, and 52.2% of them were male. The primary outcomes were 30-day and 90-day mortality rates. Multivariable Cox regression was used for statistical analysis. Propensity score matching (PSM) was applied to ensure robustness.

Results: In total, 6825 patients were included in the study, and the PSM cohort had 1282 patients. Both continuous and categorical increases in the FI-Lab were significantly associated with higher mortality (P < 0.001). These results were further validated by PSM. Subgroup analyses corroborated these findings. Restricted cubic splines illustrated a linear relationship between the FI-Lab and mortality. Kaplan-Meier analysis revealed significantly reduced 90-day survival with increasing FI-Lab (Log rank test, P < 0.001).

Conclusion: Elevated FI-Lab is an independent predictor of increased mortality in critical care patients with COPD. Further randomized controlled trials are required to confirm these results and refine patient management strategies.