A three - year longitudinal study of sleep disordered breathing in the elderly

Running title: Sleep disordered breathing evolution in the elderly. Abstract Limited and controversial data exist on the natural evolution of sleep disordered breathing (SDB) in untreated individuals. This study examines the evolution of SDB over a three-year period in a community-based elderly sample. From the initial cohort of 854 healthy subjects aged 68.40.8 yr, 519 untreated subjects accepted clinical and instrumental follow-up 3.6+1.6 yr later. SDB was defined as a respiratory disturbance index (RDI)>15. At baseline, 202 subjects (39%) had an RDI<15 and 317 (61%) an RDI>15. Three years later, 280 subjects (54%) were non-SDB and 239 (46%) were SDB. Between evaluations, the RDI decreased from 22.3 16.2 to 16.4  13.0, with a greater fall in RDI>30 cases. In the non-SDB group, 81% had a stable RDI and 19% increased their RDI by a mean of 13.7. In the SDB group, the RDI decreased to values <15 in 36.6% of cases, 63.4% still having SDB. The RDI changes did not depend on weight changes. In healthy elderly subjects the prevalence and severity of SDB did not show a tendency to natural worsening, some cases having improvement or a remission independent of weight changes. These findings also suggest that in the elderly the natural SDB progression is still hypothetical.