Effect of a lubricating jelly paste on swallowing pills in patients with subjective swallowing difficulty: a pilot randomised controlled trial

Background: Pill-swallowing difficulty is common yet under-recognised, and patients rarely seek or receive support from healthcare professionals. Lubricating jelly pastes are widely available in Japan, yet evidence for their effectiveness in pill administration remains limited. The PILL-5 enables validated, self-reported screening of clinically relevant pill-swallowing difficulty. Aim: This study aimed to explore whether a lubricating jelly paste reduced self-reported pill-swallowing difficulties using the Japanese version of the PILL-5 questionnaire. Method: In a pilot randomised, parallel-group trial, 24 participants with PILL-5 scores ≥2 were stratified and randomised 1:1 to one-week pill intake using a lubricating jelly paste (IDDSI Level 4) (intervention group) or pill intake as usual (control group). The PILL-5 was administered at baseline, Day 1, and Day 7. The primary outcome was change in total PILL-5; between-group differences were tested with the exact Mann–Whitney U test. Ethical approval was granted by the Ethics Review Committee of Fujita Health University (Reference no: HM20-076; HM20-619) and the study conforms with the Declaration of Helsinki. Informed consent was obtained from all participants via the distribution of project information and completion of written consent forms. The study was registered in the UMIN Clinical Trials Registry (UMIN-CTR) (Registration ID: UMIN000057324). Results: The median PILL-5 scores at baseline were 4.5 and 5.5 for the intervention and control groups, respectively (p = 0.525). At Day 1, median scores were 3.0 and 4.5 in the intervention group and control group, respectively and on Day 7, median scores were 3.0 and 4.0 in the intervention and control groups, respectively. From baseline to Day 1, the between-group median difference in change (intervention minus control) was 2 (95% confidence interval [CI] 0–2, p = 0.037), indicating a greater reduction in the intervention group. On Day 7, the between-group difference was 1 (95% CI 0–2, p = 0.119) and not significant. Conclusion: Lubricating jelly paste use was associated with an early, self-reported reduction in PILL-5 scores at Day 1, with a significant between-group difference. By Day 7, the between-group difference was not significant, likely due to floor effects from low baseline severity. Future studies with stricter inclusion criteria and larger sample sizes are warranted to further clarify the potential benefits.