Use of home sleep studies for diagnosis of the sleep apnoea/hypopnoea syndrome

Background - A study was undertaken to test the hypothesis that unsupervised domiciliary limited sleep studies do not impair the accuracy of diagnosis when used to investigate the sleep apnoea/hypopnoea syndrome (SAHS) and can be cheaper than laboratory polysomnography. Methods - For validation, 23 subjects with suspected SAHS underwent laboratory polysomnography and a home study (EdenTec 3711) on successive nights. All subjects with >15 apnoeas+hypopnoeas (A+H)/hour on polysomnography showed >30 A+H/hour on their home study. Thereafter, in a prospective trial 150 subjects had a home study as the initial investigation and studies showing >30 events/hour were regarded as diagnostic of SAHS. Those showing fewer events were investigated with polysomnography if necessary. Time to treatment, outcome, and costs of this protocol were compared with those of 75 patients investigated initially with polysomnography. Results - Of the prospective trial subjects, 29% had >30 A+H/hour and proceeded directly from home study to treatment; 15% without daytime sleepiness were not investigated further. Polysomnography was undertaken to establish a diagnosis in 56% of cases, including 18% whose home studies were unsuccessful. Compared with the 75 control patients, this protocol gave a diagnosis faster (median 18 (range 0-221) versus 47 (0-227) days, p<0.001) and more cheaply (mean (SD) pound 164 (104) versus pound 210 (0), p<0.001). The proportions offered CPAP (61% versus 67%) and subsequent objective CPAP usage (mean 4.7 (2.4) versus 5.0 (2.4) hours/night) were not different. Conclusions - Use of home sleep studies has benefits in time and cost. For diagnostic reliability a further sleep study was required in 56% of cases.