Functional Comorbidity Index and health-related quality of life in patients with obstructive sleep apnea.

Introduction: The role of comorbidities in determining health-related quality of life (HRQL) in obstructive sleep apnea (OSA) pa-tients has not been thoroughly investigated. Commonly used comorbidity tools, such as Charlson Comorbidity Index (CCI), have been designed with mortality as the outcome variable. A new tool, the Functional Comorbidity Index (FCI), has been especially developed to assess the effect of comorbidities on the "physical functioning" subscale of the Medical Outcomes Short Form-36 Health Survey (SF-36).