Comparison between olfactory training and curcumin therapy in improving olfactory dysfunction in patients with chronic kidney disease

OBJECTIVE: Olfactory dysfunction can be seen in chronic kidney disease (CKD) patients. We aimed to investigate the effects of olfactory training and curcumin on olfactory dysfunction in CKD patients and compare their impact with a placebo. METHODS: We conducted a double-blind, randomized, placebo-controlled trial in CKD patients, 2021–2022. We enrolled 60 participants in our study into three groups (curcumin, training, and control). Participants were randomized into trials and control groups and assessed using the Iran-smell identification test (Iran-SIT), a questionnaire of olfactory disorders (QOD), and a self-assessment tool. P-value < 0.05 was considered statistically significant. RESULTS: We gathered 58 participants (mean age of 56.1 ± 2.5, 56.9% men). All the tests showed that curcumin improved olfactory function after the trial, though it was significant in QOD (17.5 ± 11.8 vs. 13.1 ± 9.7, p = 0.045) and self-assessment results (8.5 ± 3.1 vs. 9.5 ± 4.0, p = 0.047). Moreover, compared to baseline, training patients experienced an increase in their olfactory function in Iran-SIT (15.3 ± 4.9 vs. 18.8 ± 2.7, p = 0.001), QOD (19.0 ± 10.4 vs. 12.2 ± 9.9, p = 0.003), and self-assessment tools (6.8 ± 1.8 vs. 8.2 ± 3.1, p = 0.027). In contrast, the olfactory function was unchanged in control in all the tests (p > 0.05). Also, the improved change of Iran-SIT and QOD scores during the trial was more significant in training compared to the curcumin group (p < 0.002). CONCLUSION: The findings of this study indicate that olfactory training, even more than curcumin, can improve olfactory function in CKD patients. This information may help manage olfactory dysfunction in the CKD population.