COPD overdiagnosis in primary care: a UK observational study of consistency of airflow obstruction

Abstract

Chronic obstructive pulmonary disease (COPD) is heterogeneous, but persistent airflow obstruction (AFO) is fundamental to diagnosis. We studied AFO consistency from initial diagnosis and explored factors associated with absent or inconsistent AFO. This was a retrospective observational study using patient-anonymised routine individual data in Care and Health Information Analytics (CHIA) database. Identifying a prevalent COPD cohort based on diagnostic codes in primary care records, we used serial ratios of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC%) from time of initial COPD diagnosis to assign patients to one of three AFO categories, according to whether all (persistent), some (variable) or none (absent) were <70%. We described respiratory prescriptions over 3 years (2011–2013) and used multivariable logistic regression to estimate odds of absent or variable AFO and potential predictors. We identified 14,378 patients with diagnosed COPD (mean ± SD age 68.8 ± 10.7 years), median (IQR) COPD duration of 60 (25,103) months. FEV1/FVC% was recorded in 12,491 (86.9%) patients: median (IQR) 5 (3, 7) measurements. Six thousand five hundred and fifty (52.4%) had persistent AFO, 4507 (36.1%) variable AFO and 1434 (11.5%) absent AFO. Being female, never smoking, having higher BMI or more comorbidities significantly predicted absent and variable AFO. Despite absent AFO, 57% received long-acting bronchodilators and 60% inhaled corticosteroids (50% and 49%, respectively, in those without asthma). In all, 13.1% of patients diagnosed with COPD had unrecorded FEV1/FVC%; 11.5% had absent AFO on repeated measurements, yet many received inhalers likely to be ineffective. Such prescribing is not evidence based and the true cause of symptoms may have been missed.

Prevalence and burden of COPD misclassification in the Canadian Longitudinal Study on Aging (CLSA)

“…Despite the label of COPD and high rates of respiratory symptoms, this group reported lower rates of bronchodilator inhaler use. Therefore, our data do not support prior concerns regarding inappropriately higher use of inhaler therapies in over-diagnosed COPD 23. Furthermore, recent evidence has highlighted the heterogeneity in COPD phenotypes, some of which (ie, emphysema, early COPD and smaller airways disease) may not exhibit spirometry AO as defined by the FEV 1 /FVC ratio <LLN or 0.7 24.…”

“…Therefore, our data do not support prior concerns regarding inappropriately higher use of inhaler therapies in over-diagnosed COPD. 23 Furthermore, recent evidence has highlighted the heterogeneity in COPD phenotypes, some of which (ie, emphysema, early COPD and smaller airways disease) may not exhibit spirometry AO as defined by the FEV 1 /FVC ratio <LLN or 0.7. 24 Lastly, the mechanical restriction imposed by obesity that is prevalent in this group, may obscure the finding of reduced FEV 1 /FVC ratio.…”

Implications of using the GLI-2012, GOLD and Australian COPD-X recommendations in assessing the severity of airflow limitation on spirometry among an Indigenous population with COPD: an Indigenous Australians perspective study

“…Although there is continued debate regarding which reference norms to use in specific populations, [45][46][47] in the Australian context it is recommended to use GLI-2012 'others/mixed' reference norms for the adult Indigenous population. 23 This study has demonstrated the potential effects of using these recommendations [23][24][25][26] for the classification of [48][49][50][51] In this study, we observed that the agreement between clinical diagnosis of COPD as per medical records entry Open access against spirometry criteria was only about 54%. It is not clear, given the fact that Indigenous patients have a higher prevalence of smoking and respiratory conditions, 7 8 if health practitioners may have a preconceived perception that any or all Indigenous patients presenting with respiratory symptoms will have COPD.…”

Lung function in adults and future burden of obstructive lung diseases in a long-term follow-up

“…A variety of approaches to identify lung diseases in primary care setting had been investigated 7,8,[16][17][18][19] . Clinicians favoured the fixed ratio due to simplicity and the GOLD recommendations 20 , whereas a claim for accuracy was used among some pulmonary physiologists and researchers arguing for the lower limit of normal 7,8,[16][17][18][19]21,22 . As the case finding take place in primary care, we favour the fixed ratio.…”