Psychometric validation of the insomnia severity index in adults with sickle cell disease

Background. The Insomnia Severity Index (ISI) is an instrument to evaluate insomnia symptoms. The psychometric properties have not been established in adults (18 years of age or older) with sickle cell disease (SCD). Objective. Evaluate the reliability and validity of the ISI among adults with SCD. Methods. Analysis included psychometric evaluation with exploratory factor analysis. Results. Our 263 participants had a mean age of 35.6 years and primarily were female (54.8%) with HbSS genotype (69.2%). Almost 41% were classified as clinical insomnia cases (ISI ≥14) using the traditional scoring approach. Two factors, Insomnia Symptoms and Insomnia Impact, emerged during factor analysis. Reliability of both factor- scales was good and each correlated with pain severity and depressive symptomatology (r = 0.38 to 0.66, p<.01). Conclusion. The ISI demonstrated construct validity and reliability for evaluating insomnia symptomatology among adults with SCD and can be used in research and clinical practice.