Factors associated with inadequate diagnosis of COPD: On-Sint cohort analysis

BACKGROUND: The purpose of this study was to evaluate the frequency of inadequate diagnosis and factors predictive of this in patients with chronic obstructive pulmonary disease (COPD) participating in the On-Sint study. METHODS: The On-Sint cohort was recruited for a multicenter observational study in which 356 physicians (71.6% from primary care) included adult patients who had been diagnosed with COPD. Patients’ clinical and functional information since diagnosis and details for the recruiting physicians were collected from patient files and at the inclusion visit. We performed a multivariate analysis to evaluate the influence of these variables on diagnostic inadequacy (absence of postbronchodilator forced expiratory volume in one second/forced vital capacity [FEV(1)/FVC] <0.70 or, if this value was missing, prebronchodilator FEV(1)/FVC <0.70). RESULTS: In total, 1,214 patients were included in the study. The patients had a mean age of 66.4±9.7 years and 78.8% were male. In total, 51.3% of patients did not have an obstructive spirometry performed, and 21.4% had a normal or non-obstructive spirometry pattern. Patient-related factors associated with inadequate diagnosis were: years since diagnosis (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01–1.05), number of exacerbations in the previous year (OR 1.01, 95% CI 1.01–1.02), comorbidities (OR 1.05, 95% CI 1.01–1.015), and obesity (OR 1.06, 95% CI 1.02–1.10 per kg/m(2) of body mass index), while a longer smoking history (OR 0.98, 95% CI 0.97–0.99 for each pack/year) and short-acting or long-acting bronchodilator therapy (OR 0.61, 95% CI 0.44–0.76 and OR 0.46, 95% CI 0.27–0.76, respectively) were inversely related. With regard to physician-related variables, being followed up by primary care physicians (OR 3.0, 95% CI 2.11–4.34) and in rural centers (OR 1.63, 95% CI 1.12–2.38) were positively associated with an inadequate diagnosis, while having regular follow-ups in the most severe cases (OR 0.66, 95% CI 0.46–0.93) and use of quality of life questionnaires (OR 0.55, 95% CI 0.40–0.76) were negatively associated. CONCLUSION: Diagnosis of COPD was inadequate in half of the patients from the On-Sint cohort. There were multiple factors, both patient-related and physician-related, associated with this misdiagnosis.