Prevalence, Timing and Mutual Relationships of Acute and Chronic Respiratory Failure in People with Chronic Obstructive Pulmonary Disease.

Background and aim: Prevalence, time to first diagnosis of acute (ARF) and chronic (CRF) respiratory failure in people with chronic obstructive pulmonary disease (COPD) are still unclear and were assessed in this 15-year, retrospective, observational, real-world data study. Methods: Our study examined one cohort (Cohort C1) of people older than 40 years diagnosed with COPD without any previous diagnosis of ARF. To assess the temporal relationship between ARF and CRF, two more cohorts of individuals were created: Cohort C2 included people with COPD subsequently diagnosed with CRF, without any previous diagnosis of ARF. Cohort C3 consisted of COPD people subsequently diagnosed with ARF, without any previous diagnosis of CRF. Adjusted hazard risk of and timing to first diagnosis were estimated for: i-ARF and CRF in Cohort C1; ii-ARF in Cohort C2; iii-CRF in Cohort C3. Results: Participants in Cohort C1 were equally distributed by gender, with a mean age of 66.9 ± 12.2 years and BMI 28.1 ± 7.72 kg/m2. After 15 years since COPD diagnosis, participants in Cohort C1 showed 45.25% (75th percentile reached after 7.2 years) and 21.86% (80th percentile after 13.7 years) probabilities for ARF and CRF, respectively. Participants in Cohort C2 showed an 86.78% ARF (acute-on-chronic) probability (1.7 years median time to ARF since CRF diagnosis). Individuals in Cohort C3 showed a 41.52% CRF probability (75th percentile after 3.3 years since first ARF diagnosis). Conclusions: COPD individuals reported different prevalence of and times to ARF or CRF diagnoses. Time since CRF diagnosis to first acute-on-chronic respiratory failure is shorter than time to post-ARF chronic respiratory failure. Our findings provide useful insights into periods of increased vulnerability following COPD diagnosis and respiratory failure events, which may have implications for patient monitoring and preventive strategies.