The prevalence of insomnia syndrome was more than 2-fold higher in a cohort of ambulatory patients with cancer compared with historical controls for the general population, according to results of a prospective, survey-based study reported in the Journal of the National Comprehensive Cancer Network.1
According to results reported by the Irish Sleep Apnea Trust, insomnia is experienced by 6% to 15% of the general Irish population.2 However, compared with the general population, previous studies have revealed that insomnia is more commonly experienced by those with cancer or other medical conditions.
Nevertheless, the study investigators noted, with respect to the cancer setting, “Data regarding exact prevalence of insomnia syndrome distinct from sleep disturbance are more limited.”
In this study, a nonblinded, self-report questionnaire was administered to ambulatory, adult patients with cancer between June and December 2014 who were receiving outpatient services at a single tertiary cancer center located in Ireland. The questionnaire included 40 items covering demographic and clinical information, as well as questions related to functional status, sleep-related practices and disturbances, and a screen for depression and anxiety.
The primary study endpoint was assessment of the prevalence of insomnia syndrome, defined as “diﬃculty initiating sleep or diﬃculty maintaining sleep, sleep disturbance occurring [3 or more] nights per week, sleep disturbance causing signiﬁcant impairment of daytime functioning or severe distress, and sleep disturbance present [at least once a] month.”
Of the 337 patients invited to participate in the study, the acceptance rate was 87% (n=294).
Baseline characteristics of the study cohort, most of whom had solid tumor cancers, included female sex (70.7%), an Eastern Cooperative Oncology Group (ECOG) performance status of 0/1 (81.3%), active receipt of chemotherapy (83.3%), prior cancer surgery (56.6%), and hospitalization within the past month (17%). Approximately two-thirds of patients were younger than 65.
A key study finding was that 33% of patients met criteria consistent with a diagnosis of insomnia syndrome. Furthermore, only one-third of the patients with insomnia syndrome reported a previous history of a sleep disorder.
“One-third of our patient cohort met criteria for insomnia syndrome and most had no preexisting history of sleep disorder, suggesting causality with both their diagnosis and treatment,” the study investigators noted.
On multivariate analysis, only a breast cancer diagnosis (odds ratio [OR], 3.17; P =.01), alcohol consumption (OR, 2.3; P =.005), and age younger than 65 (OR, 1.8; P =.03) were independently associated with insomnia syndrome in this patient cohort.
In their concluding remarks, the study authors noted, “it is essential that the long-term goal of research on sleep disturbances in patients with cancer focuses on treatment approaches that will improve quality of life both during treatment and after completion.”
1. Harrold EC, Idris AF, Keegan NM, et al. Prevalence of insomnia in an oncology patient population: an Irish tertiary referral center experience. J Natl Compr Canc Netw. 2020;18(12):1623-1630. doi:10.6004/jnccn.2020.7611
2. Chevalier H, Los F, Boichut D, et al. Evaluation of severe insomnia in the general population: results of a European multinational survey. J Psychopharmacol. 1999;13(4 Suppl 1):S21–S24. doi:10.1177/026988119901304S04