External Validation of a COPD Risk Measure in a Commercial and Medicare Population: The COPD Treatment Ratio

BACKGROUND: Chronic obstructive pulmonary disease (COPD) exacerbations can accelerate disease progression and lead to higher health care costs. To improve patient survival and reduce cost, risk assessment measures should be developed to identify patients at risk for exacerbations and prevent future exacerbations. OBJECTIVES: To (a) externally validate the COPD treatment ratio (CTR) as a measure of COPD exacerbation risk based on predictive models previously tested and (b) assess the measure’s capability to assess risk using only pharmacy claims for use in Medicare Part D programs. METHODS: This was a retrospective observational study conducted using the Humana research datasets. Separate assessments were performed using pharmacy-only models that excluded risk factors derived from medical claims. Patients were aged ≥ 40 years, with ≥ 1 inpatient hospitalization or ≥ 2 physician’s office, emergency department, or urgent care visits with a COPD diagnosis. Using logistic regression models, risk factors (age, ...