Three months of regular gum chewing neither alleviates xerostomia nor reduces overhydration in chronic hemodialysis patients.
INTRODUCTION AND AIMS
Gum chewing has been known to be a part of adjunctive medical therapy for cancer-related xerostomia. Nonadherence to fluid restriction in hemodialysis (HD) patients brought about by unrestricted thirst and xerostomia leads to excessive interdialytic weight gain (IWG). The effectiveness of gum chewing in reducing thirst in HD patients has till recently been evaluated by only a single study with short 2-week intervention period. The aim of the present study was to assess the effect of 3 months of regular use of sugar-free chewing gum on xerostomia, thirst, and hydration and nutritional status in HD patients.


METHODS
A prospective pre/post (3 + 1 month[s]) study including 38 chronic HD patients (14 women, 17 men; mean age, 59 ± 10 years; time on dialysis, 48 ± 45 months) with mean mid-week IWG of >1 kg, persistent xerostomia, and/or thirst was conducted. Seven patients did not complete the study including 3 because of suspected side effects of gum chewing (diarrhea or paradoxically increased thirst). After a 2-week run-in period, the subjects received a specified number of packs of low-tack, sugar-free chewing gum and specially designed diaries. Basic biochemistry and multifrequency electric bioimpedance were performed a total of 8 times, that is, at baseline and after each month of the intervention period, both before and after dialysis. Questionnaires related to xerostomia and thirst were filled in by the patients at baseline, at the end of the intervention period, and 1 month later. Body weight (for IWG assessment) and blood pressure were measured at the start of each dialysis for the whole duration of the study.


RESULTS
The mean number of chewing gum pellets used during the first and the third month of the study was 137 ± 56 and 139 ± 59, respectively. The patients did not report experiencing any changes in the intensity of xerostomia and thirst during the study. Total body water content assessed with bioimpedance did not decrease (41.9 ± 8.9 kg at baseline vs. 42.7 ± 9.1 kg at the end of the intervention period). Moreover, no changes in extracellular mass (31.9 ± 6.4 kg vs. 32.6 ± 6.6 kg), extracellular water (18.0 ± 5.2 kg vs. 18.3 ± 5.0 kg), and phase angle (4.6 ± 0.8 vs. 4.6 ± 0.8) were observed. Mean IWG between 2 mid-weekly HD sessions also did not change (2.3 ± 0.8 kg at baseline vs. 2.3 ± 0.9 kg at the end of the intervention period). No significant changes in thirst and xerostomia were observed 4 weeks after the end of the intervention period; however, mean IWG between 2 mid-weekly HD sessions increased to 2.8 ± 1.0 kg (P < .001).


CONCLUSIONS
Regular gum chewing is known to be well tolerated by most HD patients; however, it does not lead to the alleviation of xerostomia or excessive thirst and does not reduce IWG or improve hydration status.