Insomnia-related comorbidities and economic costs among a commercially insured population in the United States.

OBJECTIVE: To describe the association between insomnia and comorbid conditions, and subsequent effects on total health costs and work productivity in a large managed-care setting.
METHODS: Administrative claims data from a large commercially insured population were reviewed for patients with a prescription claim for an insomnia medication or an insomnia-related medical diagnosis, between 1/1/2001 and 12/30/2003. A control group of patients having no insomnia-related medical or prescription claim was identified within this same time period. Propensity score matching methods were used to reduce observed biases between cohorts. Economic costs and comorbidities were evaluated using t-tests for bivariate comparisons, negative-binomial regression to assess the degree of comorbidity, Wilcoxon-Mann-Whitney test for cost outcomes and generalized linear models for multivariate cost comparisons.
RESULTS: Among both unmatched and matched cohorts, insomnia patients had statistically higher rates of depression, anxiety/phobia, stress, and head pain compared to the controls. After adjusting for patient covariates, insomnia patients had higher predicted healthcare and productivity costs than a cohort of matched control patients ($4434 vs. $3576; p < 0.001).
CONCLUSION: Though identified patients were required to have enrollment in both medical and productivity databases, and the presence of insomnia could not be verified through medical records, these results suggest a significant link between insomnia and higher rates of comorbid conditions, healthcare expenditures and productivity losses. Payers and employers should consider insomnia as a factor in disease-related case-management initiatives.