Development and internal validation of the elderly COPD diagnostic score (ECDS): a multidimensional diagnostic tool for moderate-to-severe chronic obstructive pulmonary disease

Background Accurate diagnosis of chronic obstructive pulmonary disease (COPD) among elderly individuals (≥65 years) presents considerable clinical difficulties. Age-associated physiological alterations, frequent multimorbidity, and atypical symptom manifestations complicate the diagnostic process. The conventional fixed FEV₁/FVC threshold of 0.70 may not be optimally suited for this population. This study aimed to construct and validate a novel multidimensional diagnostic tool that integrates both clinical and functional parameters. Methods We conducted a single-center retrospective diagnostic accuracy study involving 976 symptomatic elderly patients (mean age 73.0 ± 6.7 years) who underwent comprehensive post-bronchodilator spirometry between February 2023 and March 2025. A blinded multidisciplinary expert panel established final diagnoses (moderate/severe COPD versus non-COPD) based on GOLD 2023 criteria and comprehensive clinical assessment. Using a temporal split approach, patients were allocated to either a Derivation Cohort ( n = 650, February–December 2023) or an independent Internal Validation Cohort ( n = 326, January 2024–March 2025). Within the Derivation Cohort, we developed the Elderly COPD Diagnostic Score (ECDS) through multivariable logistic regression and established age-specific FEV₁/FVC diagnostic thresholds. The finalized ECDS formula and threshold values were subsequently applied to the Validation Cohort without modification. Diagnostic performance was evaluated using ROC-AUC analysis, sensitivity and specificity calculations, and decision curve analysis (DCA). Results The ECDS incorporates five weighted components: (100 - FEV₁/FVC), age 65 years, Charlson Comorbidity Index, mMRC dyspnea scale score, and COPD Assessment Test score. In the Derivation Cohort, the ECDS demonstrated excellent discriminative ability with an AUC of 0.972 (95% CI: 0.962–0.982), significantly outperforming FEV₁/FVC alone (AUC 0.942, p 0.05). At the optimal cutoff of ≥2.8, sensitivity reached 96.4% with specificity of 93.2%. In the independent Validation Cohort, the ECDS maintained robust performance with an AUC of 0.968, sensitivity of 95.1%, and specificity of 90.8%. DCA confirmed superior net clinical benefit across relevant threshold probabilities compared to alternative diagnostic strategies. Age-stratified FEV₁/FVC cutoffs (e.g., 64.5% for age ≥80) proved more accurate than the fixed 70% threshold. Notably, diagnostic accuracy of standard FEV₁/FVC measurement significantly diminished among patients with high comorbidity burden (CCI ≥ 5). Conclusion The Elderly COPD Diagnostic Score (ECDS), which synthesizes spirometric data, clinical parameters, and comorbidity information, demonstrated excellent and validated diagnostic accuracy for moderate-to-severe COPD in elderly patients, surpassing the performance of conventional FEV₁/FVC criteria. Implementation of age-specific spirometric thresholds further refines diagnostic precision. The ECDS represents a practical, superior tool for diagnosing COPD in the complex geriatric patient population. While the ECDS offers a superior diagnostic tool for moderate-to-severe COPD in older adults, its performance in mild disease requires further validation.