Objective and subjective measures of sleep quality in patients with end stage kidney disease: A cross-sectional study

In a survey of patients with end stage kidney disease treated (ESKD), improvement in sleep was one of the most desired outcomes of an exercise program. In participants with ESKD enrolled in an exercise study, our objectives included: 1) assess sleep quality using objective and subjective measures, 2) determine variables associated with poor sleep and 3) determine correlation between the objective and subjective measures.

In this cross-sectional study, adult patients with ESKD at 4 academic Canadian hospitals completed objective and subjective sleep using 2 weeks of Fitbit data and the Pittsburgh Sleep Quality Index (PSQI) respectively. Poor sleep was defined as: 1) total sleep <360 min or sleep efficiency <80% with the Fitbit or 2) PSQI >5. Percentage of participants with poor sleep was calculated; variables associated with poor sleep were determined using logistic regression. Correlations between the Fitbit and PSQI for select variables was determined using Pearson correlation coefficients.

Ninety-one of 131 patients screened were included in the final analysis. Participants had a mean age of 62.0 (±13.4) years, 48% female. Sixty-eight percent and 66% of the population were considered poor sleepers by Fitbit and PSQI respectively. Male sex was associated with poor sleep with the Fitbit; BMI was associated with poor sleep by PSQI. The correlation between sleep efficiency and hours of true sleep from the Fitbit and PSQI was 0.06 (p = 0.61) and 0.44 (p < 0.0001) respectively.

Most patients with ESKD experienced poor sleep. Consistent with other populations, the objective and subjective measures of sleep were weakly correlated suggesting instrument choice should align with the specific outcome of interest. Further research is required in the ESKD population is required.