Background: Delayed diagnosis of Chronic Obstructive Pulmonary Disease (COPD) in primary care is common and contributes to preventable morbidity. A deeper understanding of pre-diagnostic patterns is needed to develop targeted detection strategies. We aimed to characterize diagnostic delay and missed diagnostic opportunities (MDOs) and identify high-risk clinical profiles. Methods: We conducted a retrospective cohort study of 167 patients newly diagnosed with COPD in primary care centers in Madrid, Spain. Healthcare utilization in the 12 months preceding diagnosis was analyzed. Multivariable logistic regression was used to identify predictors of MDOs, and K-means clustering was used to identify patient phenotypes. Results: Diagnostic delay (>30 days) was present in 45.5% of patients, and MDOs in 47.3%. MDO-positive patients had significantly worse lung function (mean FEV₁: 1577 vs. 1898 mL, p = 0.008), greater symptom burden (CAT score ≥ 10: 79.7% vs. 59.1%, p = 0.003), and more frequent pre-diagnostic exacerbations (mean: 1.24 vs. 0.71, p = 0.032). After multivariable adjustment, diagnostic delay remained a powerful independent predictor of MDOs (OR 10.25, 95% CI 4.39–24.88; p < 0.001). Cluster analysis identified three distinct clinical phenotypes: ‘Paucisymptomatic–Preserved’, ‘Frequent Attenders/High-Risk’, and ‘Silent Decliners’. Conclusions: The pre-diagnostic period in COPD is a dynamic window of detectable, and potentially preventable, clinical deterioration driven by diagnostic inertia. The identification of distinct patient phenotypes suggests that a proactive, stratified, and personalized approach, rather than a one-size-fits-all strategy, is required to improve early diagnosis in primary care.

Atrial fibrillation (AF) and obstructive sleep apnea (OSA) frequently coexist, worsening cardiovascular outcomes. The aim of this study was to describe the clinical profile and outcomes of patients referred from Cardiology with suspected OSA, with a particular focus on those with AF. Methods: This retrospective study included adults with suspected OSA evaluated between Nov 2022 and Sept 2024. Patients with obesity hypoventilation syndrome or neuromuscular diseases were excluded. Demographic data, respiratory polygraphy (RP), ECG Holter monitoring, and echocardiographic findings were analyzed. Results: A total of 91 patients were included (57.1% male, mean age 63 ± 12 years, BMI 31.5 ± 4.4 kg/m²). Hypertension was the most common comorbidity (85.7%). The prevalence of AF was 25.3% (n = 23), and 60.8% of these patients had severe or very severe OSA. CPAP therapy was initiated in 95.7% of patients with AF, with a mean adherence of 4.3 ± 2.5 hours/night at 6 months. Conclusions: OSA, particularly severe forms, is highly prevalent among patients with AF. Respiratory polygraphy is an effective diagnostic tool in this population. The high rates of CPAP initiation and adherence support its role in the comprehensive management of cardiovascular risk erj;68/suppl_70/PA3658/F1 F1 F1 erj;68/suppl_70/PA3658/F2 F2 F2