Authors' Reply: The Role of Malnutrition and Psychiatric Illnesses in Olfactory Dysfunction Post-Kidney Transplantation

We found the letter to the editor by Dr. Chao1 on our article in JASN, "Changes in Olfactory and Cognitive Function after Kidney Transplantation,"2 insightful. Olfactory dysfunction in CKD is indeed multifactorial and associated with malnutrition, gustatory dysfunction, and psychiatric illnesses including depression. Depression is common in patients with CKD but improves with kidney transplantation.3 In response to this letter, we analyzed the Beck Depression Inventory scores in the 24 participants in our study2 and noted a significant improvement in depression after transplantation. The mean Beck Depression Inventory score pretransplant was 12.0±7.8, which improved to 5.5±5.7 after transplant (P value for change in score = 0.004). Similar to depression, malnutrition is also common in patients with CKD and in those on the transplant list awaiting transplant and improves after transplantation.4 Some patients may have malnutrition and weight loss after transplantation, often due to post-transplant complications, but most experience improved appetite and gain weight. While we did not assess gustatory function or nutritional status in our study, we did assess post-transplant graft function and changes in weight. All participants had a functioning allograft at the 3-month post-transplant visit with a mean post-transplant eGFR of 45±16 ml/min per 1.73 m2. In addition, most patients gained weight after transplant, and only a third of the patients experienced weight loss. We however acknowledge that change in weight is not an accurate measurement of change in nutritional status in this population, with large changes in volume status before and after transplantation. In summary, these data on depression, allograft function, and body weight suggest that these factors do not explain the lack of improvement in olfactory function after transplantation. Future studies on olfactory function in CKD should include assessment of psychiatric illnesses, gustatory function, and nutritional status.