Therapeutic strategies for olfactory impairment in patients with chronic kidney disease: a systematic review.

BACKGROUND: Olfactory impairment is often considered a minor complication of chronic kidney disease (CKD), carrying important consequences for nutrition, safety, and overall quality of life. While several therapeutic strategies have been introduced in other populations, their effectiveness in the context of CKD remains poorly understood. This systematic review aimed to evaluate current evidence on the treatment of olfactory impairment in CKD patients, including those undergoing dialysis or kidney transplantation (KT). METHODS: A comprehensive literature search was conducted across PubMed, Scopus, and Web of Science. Studies were included if they assessed therapeutic interventions targeting olfactory impairment in CKD patients. Data on study design, population, olfactory assessments, interventions, and outcomes were extracted and quality-assessed using the Effective Public Health Practice Project (EPHPP) tool. RESULTS: Eight studies, published from 1987 to 2023, involving 469 CKD patients were included, spanning pre-dialysis, hemodialysis (HD), peritoneal dialysis (PD), and KT populations. Olfactory impairment was highly prevalent across all groups, affecting odor identification and discrimination. While KT offered the most complete recovery, dialysis had mixed effects, with limited improvement in olfactory thresholds. Among treatments, intranasal theophylline and curcumin showed partial efficacy, while olfactory training demonstrated the most consistent improvements in subjective and objective measures. CONCLUSION: Olfactory impairment in CKD is a complex complication. Among available approaches, olfactory training stands out as a promising, non-pharmacologic option. Future clinical trials are essential to validate and refine treatment strategies tailored to the distinct metabolic and neurological challenges of CKD.Incorporating routine screening and targeted mannagement of olfactory impairment into nephrology practice may enhance overall patient care, nutritional status, and quality of life. CLINICAL TRIAL NUMBER: Not applicable.