The validity of using ICD-9 codes and pharmacy records to identify patients with chronic obstructive pulmonary disease

Abstract

BackgroundAdministrative data is often used to identify patients with chronic obstructive pulmonary disease (COPD), yet the validity of this approach is unclear. We sought to develop a predictive model utilizing administrative data to accurately identify patients with COPD.MethodsSequential logistic regression models were constructed using 9573 patients with postbronchodilator spirometry at two Veterans Affairs medical centers (2003-2007). COPD was defined as: 1) FEV1/FVC <0.70, and 2) FEV1/FVC < lower limits of normal. Model inputs included age, outpatient or inpatient COPD-related ICD-9 codes, and the number of metered does inhalers (MDI) prescribed over the one year prior to and one year post spirometry. Model performance was assessed using standard criteria.Results4564 of 9573 patients (47.7%) had an FEV1/FVC < 0.70. The presence of ≥1 outpatient COPD visit had a sensitivity of 76% and specificity of 67%; the AUC was 0.75 (95% CI 0.74-0.76). Adding the use of albuterol MDI increased the AUC of this model to 0.76 (95% CI 0.75-0.77) while the addition of ipratropium bromide MDI increased the AUC to 0.77 (95% CI 0.76-0.78). The best performing model included: ≥6 albuterol MDI, ≥3 ipratropium MDI, ≥1 outpatient ICD-9 code, ≥1 inpatient ICD-9 code, and age, achieving an AUC of 0.79 (95% CI 0.78-0.80).ConclusionCommonly used definitions of COPD in observational studies misclassify the majority of patients as having COPD. Using multiple diagnostic codes in combination with pharmacy data improves the ability to accurately identify patients with COPD.

An Internet-Mediated Pedometer-Based Program Improves Health-Related Quality-of-Life Domains and Daily Step Counts in COPD

“…Our method of using the ICD-9-CM code to identify COPD has been previously shown to have diagnostic accuracy. 49 Furthermore, our baseline mean SGRQ-TS of 46 Ϯ 15 is strikingly similar to the baseline mean SGRQ-TS of 46 Ϯ 17 in UPLIFT, 49 Ϯ 17 in TORCH, and 50 Ϯ 20 in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study, arguing against any signifi cant error in the COPD diagnosis. 34,36,50 We did not ascertain information about acute exacerbations prior to study entry that may impact HRQL and daily step counts.…”

Long‐term oral mesalazine adherence and the risk of disease flare in ulcerative colitis: nationwide 10‐year retrospective cohort from the veterans affairs healthcare system

“…This increased the captured diagnosis specificity as shown in previous work in other chronic diseases as hypertension 18,41 and chronic obstructive pulmonary disease. 42 Lastly, we were able to capture the high-dose steroid filling, but we cannot ensure that the intention for the prescribed drug was for acute exacerbation of UC. Other diseases are treated with oral corticosteroids, such as rheumatoid arthritis and systemic lupus.…”

COPD and risk of venous thromboembolism and mortality in a general population

“…In these studies the exposure (COPD) and outcome (VTE) were defined according to International Classification of Diseases codes and treatment with COPD medications. Previous studies have reported low validity of COPD diagnoses obtained from administrative databases [15,16]. Similarly, a validation of VTE diagnoses in the Danish National Patient Registry reported positive predictive values for VTE diagnoses from emergency departments and hospitals of 44% and 67-77%, respectively [17].…”