Model of Nocturnal Polyuria in Older Japanese Adults Receiving Enteral Nutrition in Medical Long-Term Care Hospitals: An Exploratory Cross-Sectional Study.

OBJECTIVE

Nocturnal polyuria (NP) with urinary incontinence increases the risk of sleep disturbance, incontinence-associated dermatitis, and urinary tract infection. Factors associated with NP in older adults receiving enteral nutrition (EN) have not been clearly identified. This study aimed to evaluate the direct and indirect associations between NP and related factors in older adults receiving EN in medical long-term care hospitals (MLTCHs).

METHODS

This cross-sectional observational study enrolled men and women aged 65 years or older, hospitalized at MLTCHs, and receiving EN. Participants underwent 72-h urine monitoring and multiple clinical assessments, including body composition. Structural equation modeling was used to explore associations with nocturnal urinary volume (NUV), with extensive model modifications based on data patterns.

RESULTS

In total, 101 participants (43 men) with a median age of 86 years were included. The NP model showed an excellent fit (CFI = 1.00, RMSEA = 0.00, SRMR = 0.09) and explained 29% of the variance in NUV; however, this was not statistically significant (p = 0.16). Significant direct associations with NUV were observed for fluid and salt intake, sex, serum sodium, fat-free mass, and diuretic use. Estimated glomerular filtration rate, body mass index, age, and the change in extracellular water volume from night to morning also showed non-significant but theoretically relevant direct associations. Indirect associations were observed for nocturnal systolic blood pressure, protein intake, and fasting blood glucose.

CONCLUSIONS

NUV in older adults receiving EN in an MLTCH was complexly associated with multiple factors. This study suggests future research directions for comprehensive evaluation indices of NP.