# Device-assessed sleep health among older patients with heart failure: a cross-sectional study using actigraphy

## TL;DR

This study used actigraphy to assess sleep in older heart failure patients and found that poor sleep is linked to worse heart health and physical function.

## Contribution

The study provides new insights into the relationship between sleep health and clinical outcomes in older adults with heart failure using actigraphy.

## Key findings

- 42% of patients had inefficient sleep, defined as sleep efficiency <80%.
- Lower sleep efficiency was associated with higher NT-proBNP levels and worse functional dependence and frailty.
- Sleep irregularity was linked to worse heart failure symptoms, functional performance, and quality of life.

## Abstract

Poor sleep is common among patients with heart failure (HF) and is associated with adverse cardiovascular outcomes. The utility of actigraphy in sleep assessment, especially among older adults, remains underexplored. This study aimed to assess sleep health among older adults with HF using actigraphy and explore associations between sleep parameters and cardiac biomarkers, functional performance and quality of life (QoL).

A cross-sectional study.

The study was conducted at an outpatient HF clinic within a tertiary cardiology service in a National Health Service hospital in the UK between March and October 2023.

A total of 150 older adults aged ≥65 years with a diagnosis of HF were enrolled.

Participants were given a wrist-accelerometer to wear for 7 days. On Day 0, patients completed a 4-metre walk test (4MWT), handgrip strength test (HGST), Timed Up and Go test (TUGT), Barthel Index (BI), Kansas City Cardiomyopathy Questionnaire (KCCQ-12) and frailty assessment (Clinical Frailty Scale, CFS). Subsequently, they were fitted with an accelerometer, with the device configured to start recording the following day (Day 1). Sleep outcomes were calculated after a 7-day wear period and averaged across valid nights (minimum 3 nights of recording, noon-to-noon with ≥16 hours wear-time). Sleep parameters studied include average sleep efficiency, sleep period time window, sleep duration, sleep onset and wake up time, wake after sleep onset (WASO), sleep interruptions and Sleep Regularity Index (SRI). Inefficient sleep was defined as sleep efficiency <80%. Regression analysis was used to examine associations between sleep parameters and the previously stated tests and assessments, adjusting for age, gender and comorbidities.

The primary outcome measure was sleep efficiency; all other sleep parameters were classified as secondary or exploratory outcomes.

Accelerometry data from 145 participants were analysed; 42% had inefficient sleep based on average sleep efficiency across valid nights. These patients had significantly higher plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels (p=0.044). No statistically significant difference was noted in 4MWT, HGST, TUGT, BI, KCCQ-12 and CFS between patients with sleep efficiency <80% and those with sleep efficiency ≥80%. Lower sleep efficiency was associated with lower BI scores (adjusted β=0.271, p=0.016) and worse frailty (adjusted β=−0.017, p=0.014). Lower SRI was associated with worse New York Heart Association class (adjusted β=−0.009, p=0.007), BI scores (adjusted β=0.310, p<0.001), frailty (adjusted β=−0.017, p<0.001) and QoL (adjusted β=0.344, p=0.001); longer WASO was associated with slower gait speed (adjusted β=−0.039, p=0.040).

Older adults with HF who had inefficient sleep had significantly higher NT-proBNP levels. Lower sleep efficiency was associated with higher functional dependence and frailty. Sleep irregularity was linked to HF symptom load, frailty, functional performance and QoL, while sleep fragmentation was associated with impaired gait speed.