Researchers investigated the association between odor identification ability and nutritional status in patients with advanced chronic kidney disease, including those undergoing maintenance hemodialysis.
Their findings, published in the Journal of Renal Nutrition, underscore the complex relationship between olfactory dysfunction and malnutrition in patients with CKD.
The study, which involved 139 participants (including 34 healthy controls, 50 patients with stage 3 to 4 chronic kidney disease [CKD], and 55 patients on maintenance hemodialysis [MHD]), aimed to assess how changes in olfactory function might contribute to protein-energy wasting (PEW). The researchers utilized the Sniffin’ Sticks odor identification test, which contains 12 different smells, to evaluate the participants' ability to identify odors.
"Patients with CKD had higher C-reactive protein and lower serum albumin concentrations compared to healthy individuals," wrote first study author Ragibe Gulsah Dilaver, MD, of Vanderbilt University Medical Center's Division of Nephrology and Hypertension, and colleagues.
The group of patients on MHD exhibited the most significant impairment in odor identification, scoring the lowest on the odor test. In contrast, healthy controls scored the highest. The mean total odor identification score for patients on MHD was notably lower than that of patients with CKD, with the latter group also showing a higher frequency of severe olfactory dysfunction, defined as identifying six or fewer correct odors.
Additionally, the malnutrition inflammation score (MIS) used to assess PEW was similarly worse in patients on MHD. However, despite a clear difference in olfactory function and nutritional status, the study found no statistically significant inverse correlation between odor identification scores and the MIS (r = −0.124, P = .21).
While the study did not establish a direct statistical link between olfactory dysfunction and PEW, its findings highlight the potential role of sensory changes in the progression of nutritional challenges in patients with CKD. The researchers suggest that olfactory dysfunction may contribute to anorexia in those with CKD, which could exacerbate malnutrition and worsen the overall health status of patients. However, further research is needed to explore this relationship in more detail.
The study’s cross-sectional design and lack of a clear correlation between odor scores and malnutrition emphasize the need for longitudinal research to confirm olfactory dysfunction's role in PEW development in patients with CKD. Further exploration of sensory function factors could enhance patient care strategies.
No conflicts of interest were mentioned in the study.
