Medical comorbidity in narcolepsy: findings from the Burden of Narcolepsy Disease (BOND) study

The objective of this study was to evaluate medical comorbidity patterns in patients with a narcolepsy diagnosis in the United States.

This was a retrospective medical claims data analysis. Truven Health Analytics MarketScan® Research Databases were accessed to identify individuals ≥18 years of age with ≥1 diagnosis code for narcolepsy (International Classification of Diseases (ICD)-9, 347.0, 347.00, 347.01, 347.1, 347.10, or 347.11) continuously insured between 2006 and 2010, and controls without narcolepsy matched 5:1 on age, gender, region, and payer. Narcolepsy and control subjects were compared for frequency of comorbid conditions, identified by the appearance of >1 diagnosis code(s) mapped to a Clinical Classification System (CCS) level 1 category any time during the study period, and on specific subcategories, including recognized narcolepsy comorbidities of obstructive sleep apnea (OSA) and depression.

The final study group included 9312 subjects with narcolepsy and 46,559 controls (each group: average age, 46.1 years; 59% female). As compared with controls, patients with narcolepsy showed a statistically significant excess prevalence in all the CCS multilevel categories, the only exceptions being conditions originating in the perinatal period and pregnancy/childbirth complications. The greatest excess prevalence in the narcolepsy cohort was seen for mental illness (31.1% excess prevalence; odds ratio (OR) 3.8, 95% confidence interval (CI) 3.6, 4.0), followed by diseases of the digestive system (21.4% excess prevalence; OR 2.7, 95% CI 2.5, 2.8) and nervous system/sense organs (excluding narcolepsy; 20.7% excess prevalence; OR 3.7, 95% CI 3.4, 3.9).

In this claims analysis, a narcolepsy diagnosis was associated with a wide range of comorbid medical illness claims, at significantly higher rates than matched controls.