Prevalence of COPD overdiagnosis in ambulatory care and associated factors: cross-sectional study

<bold>Introduction:</bold> COPD overdiagnosis increases patients’ emotional burden, healthcare expenses, medication side effects, and missed diagnostic opportunities. We aimed to determine the prevalence of COPD overdiagnosis in non-hospitalized patients, with a secondary objective to assess associated factors. <bold>Methods:</bold> Cross-sectional study at a tertiary-level hospital in Argentina, from January 1st, 2015, to December 31st, 2019. Simple random sampling was performed and data were recorded through electronic health records. Overdiagnosis was defined as the absence of spirometry, no post-bronchodilator measurement, or a post-bronchodilator spirometry with a FEV1/FVC ratio ≥ 0.7 at the time of COPD diagnosis. Multivariate logistic regressión was performed to determine factors associated to overdiagnosis. <bold>Results:</bold> The study included 380 patients, 51.1% being females, mean age at diagnosis of 71.1 years (SD 8.7). Prevalence of COPD overdiagnosis was 32.9% (95% CI 28.2%-37.6%). Of these, 35.2% lacked pre-diagnosis spirometry, 29.6% had unacceptable spirometries, and 35.2% (N=44) had spirometries with interpretive errors. OR for overdiagnosis was 2.4 for diabetes mellitus, 3.9 for heart failure and 9.5 if performed by a non-pulmonologist. <bold>Conclusions:</bold> The prevalence of COPD overdiagnosis was high (32.9%), although lower than reported in some studies. Misinterpretation of spirometry or its absence were the main causes of overdiagnosis. Specialist Pulmonologist diagnosis is independently associated with lower overdiagnosis risk.