Exploring the impact of varying definitions of exacerbations of chronic obstructive pulmonary disease in routinely collected electronic medical records

• Published in: PloS one 2023-11, Vol.18 (11), p.e0292876-e0292876
• Main Authors: Whittaker, Hannah, Rothnie, Kieran J, Quint, Jennifer K
• Format: Article
• Language: English
• Subjects: Accuracy; Algorithms; Antibiotics; Asthma; Biology and Life Sciences; Care and treatment; Chronic obstructive pulmonary disease; Clinical medicine; Codes; Computer and Information Sciences; Confidence intervals; Congestive heart failure; Data collection; Data entry; Diagnosis; Electronic health records; Electronic medical records; Electronic records; Family medicine; Heart failure; Lung diseases; Lung diseases, Obstructive; Management; Medical records; Medicine and Health Sciences; Patients; Population; Primary care; Robustness; Statistical analysis; Steroids
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0292876

Validity of exposure and outcome measures in electronic medical records is vital to ensure robust, comparable study findings however, despite validation studies, definitions of variables used often differ. Using exacerbations of chronic obstructive pulmonary disease (COPD) as an example, we investigated the impact of potential misclassification of different definitions commonly used in publications on study findings. A retrospective cohort study was performed. English primary care data from the Clinical Practice Research Datalink Aurum database with linked secondary care data were used to define a population of COPD patients [greater than or equal to]40 years old registered at a general practice. Index date was the date eligibility criteria were met and end of follow-up was 30/12/19, death or end of data collection. Exacerbations were defined using 6 algorithms based on definitions commonly used in the literature, including one validated definition. For each algorithm, the proportion of frequent exacerbators ([greater than or equal to]2 exacerbations/year) and exacerbation rates were described. Cox proportional hazard regression was used to investigate each algorithm on the association between heart failure and risk of COPD exacerbation. A total of 315,184 patients were included. Baseline proportion of frequent exacerbators varied from 2.7% to 15.3% depending on the algorithm. Rates of exacerbations over follow-up varied from 19.3 to 66.6 events/100 person-years. The adjusted hazard ratio for the association between heart failure and exacerbation varied from 1.45, 95% confidence intervals 1.42-1.49, to 1.01, 0.98-1.04.