COPD overdiagnosis in primary care: a UK observational study of consistency of airflow obstruction
Josephs L, Cullifor D, Johnson M, et al.
npj Prim Care Respir Med 2019;29:2–19
Persistent airflow obstruction (AFO) is fundamental to the diagnosis of chronic obstructive pulmonary disease (COPD). While many patients go undiagnosed, overdiagnosis of the condition is also likely to be a problem.
In this retrospective observational study, patient anonymised individual data from the Care and Health Information Analytics (CHIA) database were analysed. Additionally, the authors assessed the consistency of AFO from initial diagnosis, as well as the factors associated with absent or inconsistent AFO.
A COPD cohort was identified in primary care records and categorised into three groups according to the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) measurements from their initial COPD diagnosis. If all their measurements were <70%, they were placed in the ‘persistent’ group, while patients with some or no measurements <70% were categorised as ‘variable’ or ‘absent’ respectively. Respiratory prescriptions between 2011 and 2013 were also analysed by multivariable logistic regression to estimate the likelihood of absent or variable AFO and potential predictors.
14,378 patients with a diagnosis of COPD were identified (mean ± standard deviation [SD] age 68.8 ± 10.7 years), with a median (interquartile range [IQR]) time since COPD diagnosis of 60 (25,103) months. 12,491 (86.9%) patients had recorded FEV1/FVC, with a median (IQR) of 5 (3,7) measurements per person. 6,550 (52.4%) had persistent AFO, 4,507 (36.1%) variable and 1,434 (11.5%) absent AFO. The results of the multivariable logistic regression analysis found that being female, never smoking, higher body mass index (BMI) or having comorbidities significantly predicted having absent and variable AFO. Patients with absent AFO were prescribed less medication, but 57.3% still received long-acting bronchodilators and 60.1% still received inhaled corticosteroids. This dropped to 50% and 49% respectively when patients with asthma were excluded. 13.1% of patients with COPD had no recorded FEV1/FVC and 11.5% had absent AFO on repeated measurements, but many still received inhaled pharmacotherapy.
The study suggests many patients may be receiving inhaled medications inappropriately and the true cause of their symptoms may have been missed. Patients without AFO require clinical assessment, as their medications are potentially harmful and costly and a correct diagnosis should be established.