Prevalence of Insomnia in an Oncology Patient Population: An Irish Tertiary Referral Center Experience

Abstract

Background: The NCCN Guidelines for Survivorship recommend dedicated sleep assessment. Reported insomnia prevalence in the general Irish population is 6% to 15%. Reported insomnia prevalence internationally among new/recently diagnosed patients with cancer varies from 30.9% to 54.3%. Insomnia prevalence has not been previously quantified in an Irish oncology cohort. Methods: A 40-item questionnaire was prospectively administered to ambulatory patients with cancer aged ≥18 years. Prespecified criteria to define insomnia syndrome combined those of the International Classification of Sleep Disorders, version 1, and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The Hospital Anxiety and Depression Scale-Depression/Anxiety (HADS-D/A) was used to screen for potential confounding variables. Results: The response rate to the questionnaire was 87% (294/337). The predominant respondent age group was 55 to 64 years (26%; 77/294), 70.7% were female (208/294), and the most common cancer subtypes were breast (37.4%), colorectal (12.9%), and lung (12.2%). A total of 62% (183/294) of patients reported sleep disturbance after diagnosis, 63% (115/183) reported moderate/severe distress related to this disturbance, and 37% (61/183) reported a significant impact on physical function. Although 33% (98/294) met insomnia syndrome criteria, only 34% (33/98) of these patients had a preexisting history of sleep disturbance. Female sex, age <65 years, cancer subtype, alcohol consumption, and HADS-D/A ≥11 were associated with statistically significant higher odds ratios (OR) of insomnia syndrome. Multivariate analysis identified breast cancer (OR, 3.17; P=.01), age <65 years (OR, 1.8; P=.03), and alcohol consumption (OR, 2.3; P=.005) as independent predictors of insomnia syndrome. Conclusions: Insomnia syndrome prevalence in this cohort is comparable to that reported previously and supports dedicated sleep assessment. This study identifies potentially modifiable risk factors for insomnia and demonstrates additional utility of the HADS score in identifying patients at risk.