The impact of COPD case finding on clinical care: a prospective analysis of the TargetCOPD trial
COPD is vastly underdiagnosed and a large number of studies have evaluated the effectiveness of case finding in terms of the number of new diagnoses made in primary care. However, few studies have evaluated the impact of case finding on subsequent clinical care.
This was a prospective analysis of the TargetCOPD trial, which was a pragmatic cluster RCT based in primary care in the West Midlands, UK. It evaluated the effectiveness of COPD case finding against usual care. Following the trial, additional data on COPD-related care were extracted from electronic healthcare records (EHR) for a subset with newly diagnosed COPD. In addition, a subset of participants with case-found COPD were provided questionnaires that included questions about clinical care. The primary outcome was addition to a COPD disease register by the end of the TargetCOPD trial. The secondary outcome was a clinical management score formed by summing the number of COPD-related clinical assessments and interventions received. Multilevel logistic regression was used to assess for associations between participant characteristics and the likelihood of being added to a COPD register. Multilevel linear regression was used to assess for associations between participant characteristics and the clinical management score.
The primary analysis included 857 patients identified with COPD by case finding and 764 by usual care. Only 21.2% of case-found patients had been added to a COPD register, compared to 92.7% of patients diagnosed by usual care. Factors associated with a higher likelihood of being added to a COPD register were current and former smoking (adjusted OR 8.68, 95% CI 2.53 to 29.8, and aOR 6.32, 95% CI 1.88 to 21.3, respectively), and lower percentage of predicted FEV1 (aOR 0.96, 95% CI 0.95 to 0.98). Among participants with additional EHR data (n=532), factors associated with a higher clinical management score were being on a COPD register (adjusted β 5.06, 95% CI 4.36 to 5.75), and having a higher number of comorbidities (aβ 0.38, 95% CI 0.11 to 0.65). Among participants with additional questionnaire data (n=375), factors associated with a higher clinical management score were being on a COPD register (aβ 3.48, 95% CI 2.81 to 4.15), higher CAT score (aβ 0.05, 95% CI 0.01 to 0.08), and lower percentage of predicted FEV1 (aβ -0.03, 95% CI -0.03 to -0.01).
Only 1 in 5 case-found patients had been added to a COPD disease register by the end of the TargetCOPD trial. Smokers and those with lower lung function were more likely to be formally registered with COPD by their GP. Being on a COPD register was associated with receiving a significantly higher level of clinical care.