A 3-year longitudinal study of sleep disordered breathing 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 3-yr period in a community-based sample of elderly subjects. From the initial cohort of 854 healthy subjects aged mean ± SD 68.4 ± 0.8 yrs, 519 untreated subjects accepted clinical and instrumental follow-up 3.6 ± 1.6 yrs later. SDB was defined as a respiratory disturbance index (RDI) >15 events · h(-1). At baseline, 202 (39%) subjects had an RDI ≤ 15 events · h(-1) and 317 (61%) had an RDI >15 events · h(-1). 3 yrs later, 280 (54%) subjects were non-SDB and 239 (46%) had SDB. Between evaluations, the RDI decreased from 22.3 ± 16.2 to 16.4 ± 13.0 events · h(-1), with a greater decrease in the number of cases with an RDI >30 events · h(-1) that in those with RDI ≥ 30 events · h(-1). In the non-SDB group, 81% had a stable RDI and 19% increased their RDI by a mean of 13.7 events · h(-1). In the SDB group, the RDI decreased to values ≤ 15 events · h(-1) 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 toward natural worsening, some cases having improvement or a remission independent of weight changes. These findings also suggest that in the elderly, natural SDB progression is still hypothetical.