Abstract: Objective To examine the association between sleep quality and frailty among the oldest old (≥80 years) residing in integrated medical and long-term care institution, and to inform frailty prevention and management. Methods In a cross-sectional study conducted in Jiangsu Province Zhongshan Sanatorium from January to April 2024, 130 residents aged ≥80 years were surveyed using convenience sampling. Sleep quality was assessed subjectively using the Pittsburgh Sleep Quality Index (PSQI) and objectively via a wrist-worn smart band, which captured various sleep parameters.Frailty was screened using the FRAIL Scale. Multivariable logistic regression was applied to evaluate associations between sleep-related variables and frailty. Results The prevalence rates of sleep disturbance and frailty were 56.9%(74/130) and 40.8%(53/130), respectively.Among 74 participants with sleep disturbances, 39 individuals presented with frailty. Univariate analysis demonstrated that frailty group exhibited shorter nocturnal sleep duration, increased light sleep duration, and a higher frequency of daytime napping compared to non-frail group (P<0.05).Multivariable logistic regression analysis revealed that higher PSQI score (PSQI≥5) (OR=1.392, 95%CI: 1.151-1.680), longer total sleep time (OR=2.431, 95%CI: 1.202-4.911), longer light sleep duration (OR=1.123, 95%CI: 1.013-1.252), and greater number of daytime naps (OR=1.680, 95%CI:1.050-2.671) were independent risk factors for frailty. Conversely, longer nighttime sleep duration (OR=0.359, 95%CI: 0.178-0.731) was a protective factor. Conclusions Frailty among oldest old in integrated medical and long-term care institution is closely associated with poor sleep quality, impaired sleep structure and fragmented circadian rhythms, exhibiting characteristics of poor quality and fragmentation. Targeted intervention strategies need to be developed to improve sleep quality in order to mitigate the risk of frailty.

Key words: integrated medical and long-term care facility, advanced aged, sleep quality, frailty