Oral Frailty and Health-related Quality of Life in Japanese hemodialysis patients: A Cross-Sectional Analysis from the Fukushima Dialysis Cohort Study.

Oral frailty, defined as a decline in oral function and feeding ability, has been increasingly recognized as a geriatric syndrome associated with disability and mortality in older adults. However, evidence on its impact on health-related quality of life (HRQOL) among patients undergoing maintenance hemodialysis remains limited. This study aimed to examine the association between oral frailty and HRQOL assessed by the EQ-5D-5L score and to explore whether nutritional status, assessed by the Geriatric Nutritional Risk Index (GNRI), mediates this relationship.

We analyzed cross-sectional data from 264 participants enrolled in the newly established Fukushima Dialysis Cohort Study, which included patients from four dialysis facilities in Fukushima Prefecture, Japan. The primary outcome was the EQ-5D-5L utility score (logit-transformed to stabilize variance). The main explanatory variable was the presence of oral frailty, assessed using the Oral Frailty Index-8 (OFI-8), and participants with a score of 4 or higher were classified as having oral frailty. Multiple linear regression analysis was performed to examine the independent association between oral frailty and EQ-5D-5L, adjusting for potential confounders: age, sex, smoking history, diabetes, hypertension, dyslipidemia, cardiovascular disease (CVD), C-reactive protein (CRP), hemoglobin, Kt/V, and GNRI. Potential mediation through GNRI, representing the pathway from oral frailty to reduced nutritional status and subsequent decline in QOL, was further evaluated using a regression-based mediation analysis. Mediation analysis was performed using cases with complete data (n = 214).

The median age of participants was 68 years; 32% were female. Oral frailty was present in 51.5% of participants. The EQ-5D-5L utility scores calculated using the Japanese value set ranged from 0.18 to 0.94 with a median of 0.87 (IQR, 0.74–0.94). Oral frailty was significantly associated with lower EQ-5D-5L scores after multivariable adjustment (β = -0.43, 95% CI; -0.70 to -0.17, p = 0.002). GNRI showed a weak positive association with EQ-5D-5L (β = 0.02, 95% CI; 0.004 to 0.04, p = 0.019). In the mediation analysis, the average causal mediation effect (ACME) via GNRI was not statistically significant (-0.023, 95% CI; -0.08 to 0.02), and the average direct effect (ADE) of oral frailty on EQ-5D-5L was significant (-0.43, 95% CI; -0.69 to -0.18). The total effect of oral frailty on EQ-5D-5L was -0.46 (95% CI; -0.71 to -0.19), with only 5.0% of the total effect mediated through GNRI.

In this cross-sectional study of hemodialysis patients, oral frailty was independently associated with reduced HRQOL measured by the EQ-5D-5L, even after adjustment for age, comorbidities, inflammation, smoking, dialysis adequacy, and nutritional status. The absence of mediation via GNRI suggests that oral function impairment may deteriorate quality of life through psychosocial or functional mechanisms rather than nutritional decline. Assessment and intervention of oral function may improve patient-centered outcomes beyond nutritional and dialysis adequacy measures.