@phdthesis{discovery1528622, school = {UCL (University College London)}, title = {Sleep in children with sickle cell disease}, year = {2016}, month = {November}, booktitle = {UCL (University College London)}, note = {Unpublished}, author = {Gavlak, JCD}, url = {https://discovery.ucl.ac.uk/id/eprint/1528622/}, abstract = {BACKGROUND: Sickle Cell Anaemia (SCA) or homozygosity for the sickle haemoglobin gene (HbSS) is the most common genetic condition in the UK. A high prevalence of Sleep Disordered Breathing (SDB) in SCA is widely accepted but there is a lack of unselected population based studies. As Polysomnography (PSG) is expensive, screening for SDB using a robust tool, e.g. the Delta 12 ({\ensuremath{\Delta}}12) index and 3\% Oxygen Desaturation Indices (ODI) calculated from home pulse oximetry, should be validated. Elevated Cerebral Blood Flow Velocity (CBFV) is a predictor of stroke in SCA, and may be associated with SDB. METHODS AND RESULTS: Prevalence of OSA was assessed and compared with the general paediatric population from Polysomnography (SCA n=195) analysed using the American Academy of Sleep Medicine (AASM) criteria. Interobserver reliability between two observers was excellent. At all ages, the prevalence of OSA was higher in SCA. OSA prevalence was highest in young children, with 50\% of 4-6 year olds having an obstructive apnoea hyopnoea index (OAHI) of {\ensuremath{>}}1. A zero inflated model was fitted for prediction of OAHI from {\ensuremath{\Delta}}12 or ODI; for predicting OAHI zero or {\ensuremath{>}}1, 3\% ODI alone had the best fit. In 83 London patients, OSA was associated with elevated CBFV. Mean SpO2, ODI and CAI were predictors of basilar velocity independent of age. In the final model, mean SpO2 remained a predictor (B-3.1, beta -0.41, t -4.2, p{\ensuremath{<}}0.0005) independent of age (B- 2.9, beta -0,453, t -4.7, p{\ensuremath{<}}0.0005). CONCLUSION: Despite the difficulties in comparing across populations, there is a higher prevalence of OSA in unselected children with SCA than in typically developing children with no SDB symptoms, screening with overnight pulse oximetry to select those with OAHI{\ensuremath{>}}1 is feasible, and this may be important as there is an association between OSA and basilar CBFV in this population.} }