Rationale: Current chronic obstructive pulmonary disease (COPD) exacerbation risk prediction models are based on clinical data not easily accessible to national quality-of-care organizations and payers. Models developed from data sources available to these organizations are needed.
Objectives: This study aimed to validate a risk measure constructed using pharmacy claims in patients with COPD. Administrative claims data were used to construct a risk model to test and validate the ratio of controller (maintenance) medications to total COPD medications (CTR) as an independent risk measure for COPD exacerbations. The ability of the CTR to predict the risk of COPD exacerbations was also assessed.
Methods: This was a retrospective study using health insurance claims data from the Truven MarketScan database (2006-2011), whereby exacerbation risk factors of patients with COPD were observed over a 12-month period and exacerbations monitored in the following year. Exacerbations were defined as moderate (emergency department or outpatient treatment with oral corticosteroid dispensings within 7 d) or severe (hospital admission) on the basis of diagnosis codes. Models were developed and validated using split-sample data from the MarketScan database and further validated using the Reliant Medical Group database. The performance of prediction models was evaluated using C-statistics.
Measurements and main results: A total of 258,668 patients with COPD from the MarketScan database were included. A CTR of greater than or equal to 0.3 was significantly associated with a reduced risk for any (adjusted odds ratio [OR], 0.91; 95% confidence interval [CI], 0.85-0.97); moderate (OR, 0.93; 95% CI, 0.87-1.00), or severe (OR, 0.87; 95% CI, 0.80-0.95) exacerbation. The CTR, at a ratio of greater than or equal to 0.3, was predictive in various subpopulations, including those without a history of asthma and those with or without a history of moderate/severe exacerbations. The C-statistics ranged from 0.750 to 0.761 for the development set and 0.714 to 0.761 in the validation sets, indicating the CTR performed well in predicting exacerbation risk.
Conclusions: The ratio of controller to total medications dispensed for COPD is a measure that can easily be calculated using only pharmacy claims data. A CTR of greater than or equal to 0.3 can potentially be used as a quality-of-care measurement for prevention of exacerbations.
Keywords: chronic obstructive pulmonary disease; exacerbation; health insurance claims; risk assessment.