Decreased Olfactory Function Is Associated With Mortality in Patients Undergoing Hemodialysis

Several studies have suggested that hemodialysis (HD) patients with olfactory impairment are associated with poor quality of life and malnutrition. However, to date, the association of olfactory impairment with mortality has not yet been studied. The aim of the present study was to evaluate the factors affecting olfactory function, inflammatory and nutritional parameters, and mortality in HD patients.

A total of 102 HD patients were assessed for olfactory function using the Sniffin' Sticks test, alongside demographic, nutritional, and inflammatory parameters. Patients were divided into 2 groups based on odor scores: impaired group (severe olfactory dysfunction, ≤6 odors) and nonimpaired group (mild-moderate/normal olfactory function, ≥7 odors). Patients were followed for 1 year.

Impaired group, comprising patients with severe olfactory dysfunction, exhibited significantly lower albumin levels (P = .021) and higher C-reactive protein levels (P < .001) compared to nonimpaired group. Nutritional status, as measured by Subjective Global Assessment, was also poorer in the impaired group (P = .010). Over a 1-year follow-up period, mortality was higher in the impaired group, with 12 deaths, compared to 6 deaths in the nonimpaired group. In the multivariate analysis, total olfactory score emerged as an independent predictor of mortality (odds ratio = 0.73; P = .032). Kaplan-Meier survival curves showed a survival advantage for the nonimpaired group, and the log-rank test confirmed that this difference was statistically significant (P < .009).

The findings suggest that olfactory dysfunction in HD patients is closely linked to malnutrition, inflammation, and increased mortality. These results highlight the potential of olfactory function as a prognostic marker in HD patients.