Prevalence, Comorbidities of Idiopathic Hypersomnia Revealed in New Posters

Idiopathic hypersomnia (IH) has been found to be prevalent in adults, and those with IH experience a significant burden of psychiatric and medical comorbidities, according to findings in posters presented at SLEEP 2023.

IH is a neurological disorder that can cause excessive daytime sleepiness, prolonged nighttime sleep, severe sleep inertia, cognitive dysfunction, and long and unrefreshing naps. Limited research has looked into the prevalence of IH and its comorbidities, but these newly published posters looked into both areas of interest.

A poster¹ evaluating the prevalence of IH analyzed Symphony Integrated Dataverse administrative claims from November 2015 to December 2021. Patients were eligible if they were 18 years and older and had 1 medical or prescription claim from 2019, 2020, or 2021 and in the year prior. Any IH cases that were observed by the participant through the last day of the year of interest acted as diagnosed prevalence. Cases of IH were defined by patients who had 1 or more medical claims that contained a diagnosis code for IH in any position before or during the years 2019, 2020, or 2021. Prevalence was reported per 100,000 persons. Prevalence estimates that were adjusted by age and sex were calculated with 2019 US Census Bureau data.

The study found eligible patients in each year of 2019, 2020, and 2021; 158 million were eligible for 2019, 168 million for 2020, and 187 million for 2021. The unweighted diagnosed prevalence of IH was found to be 32.12 per 100,000 persons (95% CI, 31.84-32.40) in 2019, 35.71 per 100,000 persons (95% CI, 35.43-36.00) in 2020, and 37.03 per 100,000 persons (95% CI, 36.75-37.30) in 2021.

The standardized number of adults diagnosed with IH in the United States was estimated at 80,603 (95% CI, 80,048-81,161) in 2019; 89,539 (95% CI, 88,954-90,127) in 2020; and 92,139 (95% CI, 91,545-92,736) in 2021.

The researchers acknowledged that a proportion of IH cases may remain undiagnosed, as the condition is underrecognized, there is a low utilization of sleep testing, and there are concerns with the reliability of latency testing.

“I think something that we need to consider is definitely additional research around the prevalence of [IH],” said Marisa Whalen, PharmD, coauthor of both studies. “We know it’s a rare disease and awareness around the disorder is low…but I think this gives a lot of great insight into the number of diagnosed patients that are out there.”

The clinical burden for patients with IH was also examined, as those with this disorder tend to experience comorbidities. Researchers for this poster² analyzed MarketScan administrative claims from December 2013 to February 2020. Patients who were eligible to be in the study were 18 years and older with 365 days of continuous medical coverage, although gaps of less than 30 days were allowed. The first medical claim that contained a diagnosis of IH was when the patient was entered into the cohort. Controls were matched 5:1 to patients with IH based on age, sex, payer type, cohort entry date, and region. Logistic regression models were used to compare the cohorts’ prevalence estimates of the Clinical Classification System Multilevel (CCSM) categories and comorbid conditions during the study period.

There were 11,428 patients with IH and 57,138 controls who were included in the study; 65% of the patients were female and the median age was 45 years. A higher prevalence of all CCSM categories were found in patients with IH compared with the controls. Sleep apnea (odds ratio [OR], 26.1; 95% CI, 24.8-27.6), mood disorders (OR, 3.7; 95% CI, 3.6-3.9), and headache/migraine (OR, 2.9; 95% CI, 2.7-3.0) were some of the conditions that had higher prevalence in patients with IH.

Cardiovascular disease (OR, 2.2; 95% CI, 2.1-2.4), stroke (OR, 2.2; 95% CI, 2.0-2.4), major adverse cardiovascular events (OR, 2.2; 95% CI, 2.0-2.4), hypertension diagnosis (OR, 2.0; 95% CI, 2.0-2.1), and heart failure (OR, 2.0; 95% CI, 1.8-2.3) were also found to be more prevalent in patients diagnosed with IH.

Similar to other sleep disorders like narcolepsy, patients with IH were found to have a significant burden of comorbidities, including chronic cardiovascular diseases. The 2 posters’ findings indicate that increased awareness of IH is important, not only for more accurate diagnoses but also to help treat those who have IH for potential comorbidities.

References

1. Saad R, Black J, Bogan R, et al. Diagnosed prevalence of idiopathic hypersomnia among adults in the United States. Presented at: SLEEP 2023; June 3-June 7, 2023; Indianapolis, IN. Abstract 0838.
2. Lillaney P, Saad R, Profant D, et al. Real-world idiopathic hypersomnia total health model (RHYTHM): clinical burden of patients diagnosed with idiopathic hypersomnia. Presented at: SLEEP 2023; June 3-June 7, 2023; Indianapolis, IN. Abstract 0847.