Sleep Patterns and Associated Clinical Correlates Amongst Ghanaian Individuals with Sickle Cell Disease

Background: Sickle cell disease (SCD) is the most commonly inherited blood disorder that affects 1 in 500 individuals of African descent worldwide and 70,000-80,000 individuals in the United States. While the molecular basis and progression of this condition has been well established, the association between sleep, stress and frequency of complications such as pain crises has not been well studied. In this study, we investigate how sleep behavioral patterns are associated with the severity and incidence of sickle cell crises amongst patients with SCD.

Methods: Adult individuals with SCD were recruited from the Korle Bu Teaching Hospital in Accra, Ghana as participants for this study. No compensation was provided. Participants completed a questionnaire that assessed SCD disease severity such as frequency of pain crises and need for hospitalization. Self-reported sleep habits, including average hours of sleep both at baseline and during pain crisis were also evaluated. Medical records for each participant were also obtained to establish demographic and genotype information.

Results: A total of 308 individuals with SCD were enrolled in the study. Patients were classified according to SCD genotype with 68.6% of individuals with severe genotype (hemoglobin SS or sickle/beta thalassemia), and 31% had mild genotype (hemoglobin SC, sickle/beta plus thalassemia disease). Regarding average sleep per night, 2.4% reported 0-2 hours, 14.4% reported 3-4 hours, 38.8% reported 5-6 hours, 36.8 reported 7-9 hours, and 7.7% reported 10 hours or more. During pain crises, 48% reported 0-2 hours of sleep and 91.1% reported 0-4 hours of sleep per night. A paired sample t-test of average hours of sleep at baseline versus sleep during pain crisis showed a significant decrease in hours of sleep while in pain crisis (t=20.16, p < 0.001). Furthermore, female gender was associated with decreased sleep during pain crises (p = 0.008) compared to their male counterparts. An analysis of all SCD Genotypes revealed average sleep per night at baseline was not associated with frequency of crises per year, pain crises requiring ER/doctor visits nor per pain crises per year requiring hospitalizations. However, within the mild genotype group alone, average hours of sleep during a pain crisis was significantly associated with number of crises per year (r = 0.299, p = 0.04), number of crises/year requiring ER/doctor visit (r = 0.256, p = 0.013), and crises/year requiring hospitalization per year (r = 0.246, p = 0.018). Sleep patterns and pain crises/year measures did not correlate amongst patients with severe genotype.

Discussion: Per patient self-report, individuals with SCD experience significant disruption with sleep due to pain crises. Most of the individuals report a significant reduction in average amount of sleep during a pain crisis, suggesting that pain crisis likely plays a crucial role in quality of life amongst patients with SCD. In patient with milder genotypes, worse outcomes (frequent ER/doctor visits, frequent crises, and frequent hospitalizations) are associated with less sleep during a pain crisis. This association suggests that amongst those with mild genotypes, sleep amount likely reflects SCD morbidity. The lack of associated pain crises patterns and sleep within the severe genotype suggests most adult patient regardless of severity report a severe lack of sleep during painful crises. Leg ulcer associated with less sleep during painful crises may reflect the impact of leg ulcers on sleep patterns. A limitation of this study was that data was obtained from a single site which may not reflective of sleep patterns amongst individuals with SCD elsewhere. Future areas of exploration could include evaluation of sleep habits with a validated sleep questionnaire and compared with end organ complications of sickle cell disease.