TY - JOUR T1 - Sleep disordered breathing and the outcome of stroke JF - Thorax JO - Thorax SP - 361 LP - 363 DO - 10.1136/thx.2003.020040 VL - 59 IS - 5 AU - G J Gibson Y1 - 2004/05/01 UR - http://thorax.bmj.com/content/59/5/361.1.abstract N2 - Patients with OSA not only have an increased risk of stroke, but also a higher mortality and greater disability after stroke Interest in abnormal breathing after stroke has a long history dating back at least to the observations of John Cheyne in 1818.1 In recent years this interest has been reawakened by a number of publications on the relations between sleep disordered breathing (SDB) and stroke. These studies have been of two main types—those investigating the possible increased risk of stroke in individuals with obstructive sleep apnoea (OSA) and those reporting a high prevalence of SDB after stroke and its possible effects on residual disability and mortality. Unravelling the direction of causality—that is, whether OSA causes stroke or stroke causes OSA—has proved challenging.2–5 Most of the evidence on the risk of stroke associated with OSA is circumstantial and is based on case-control studies in which a history of snoring, with or without other features suggestive of OSA, is compared in patients with stroke and matched controls.6–11 Such studies lack objective confirmation of pre-stroke OSA, are critically dependent on the validity of the control population, and are subject to recall bias. Moreover, most studies have included subjects who had previously had a stroke where, inevitably, the direction of causality is uncertain. In studies where account has been taken of potential confounding factors such as obesity, smoking and hypertension, the estimated risk of stroke is reduced. Of the possible “confounders”, hypertension is of particular relevance as the contribution of OSA to systemic hypertension has been demonstrated beyond reasonable doubt and clearly it offers a potential causal link with stroke. Even after statistical adjustment for hypertension, however, several studies still support an association between OSA and stroke. Various alternative mechanisms related to demonstrated abnormalities in patients with OSA … ER -