Incidence and prevalence of obstructive sleep apnoea and narcolepsy in the UK: a population-based descriptive study

BACKGROUND: Obstructive sleep apnoea (OSA) and narcolepsy are estimated to affect approximately 4.8% and 0.047% of the UK population, respectively. We do not know how many people have been diagnosed or how this varies over time and by demographic factors. METHODS: We, therefore, conducted a historical population-based descriptive study estimating prevalence and incidence of diagnosed OSA and narcolepsy in England from 2000 to 2019 stratified by demographic factors, and compared estimates to Scotland, Wales and Northern Ireland. Data were from Clinical Practice Research Datalink (CPRD) primary care records linked to Hospital Episode Statistics (HES) admissions. The study population included people with ≥90 days follow-up between 1 January 2000 and 31 December 2019, no prior record of primary or central sleep apnoea, and aged ≥18 years (OSA only). Diagnoses were defined using the first coded record for each condition in CPRD or HES data. Annual prevalence was estimated at mid-year and directly age/sex-standardised to the national population. Incidence was estimated by dividing new diagnoses by total person-time at risk. RESULTS: In England, 2019 adult standardised diagnosed OSA prevalence was 1.40% (95% CI 1.40% to 1.41%) representing approximately 622 528 people; standardised narcolepsy prevalence was 0.020% (95% CI 0.019% to 0.021%) representing approximately 11 307 people. Despite increases over time, diagnosed incidence and prevalence remained substantially lower than published estimates of symptomatic frequency. Rates varied by age, sex, ethnicity and UK nation for both conditions, and urban-rural living, area-based deprivation and practice size for OSA. CONCLUSION: Our results call for high-quality research to drive initiatives that increase diagnosis rates and address variation.