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

Abstract

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

Patients/methods: 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.

Results: 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).

Conclusions: 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.

Keywords: Claims data; Comorbidity; Narcolepsy; Retrospective.