Association between geriatric nutritional risk index and remimazolam dose requirements for gastrointestinal endoscopy sedation in older adults: a prospective dose-finding study

Nutritional risk may influence sedative requirements in older adults, but the association between the geriatric nutritional risk index (GNRI) and remimazolam dose requirement during gastrointestinal endoscopy sedation remains unclear. This study compared the median effective dose (ED50) and 95% effective dose (ED95) of remimazolam between older patients with low and high GNRI. In this single-center prospective dose-finding clinical study, 54 evaluable patients aged ≥65 years undergoing elective painless gastrointestinal endoscopy were included in the final analysis, with 27 patients in each GNRI group. All patients received remifentanil, and remimazolam was administered using a modified Dixon up-and-down method with an initial dose of 0.20 mg/kg and a dose interval of 0.02 mg/kg. Effective sedation was defined as completion of the procedure without body movement or other interfering responses. ED50 was calculated using the modified Dixon method, and ED50 and ED95 were estimated using probit regression. Using the modified Dixon method, the ED50 of remimazolam was significantly lower in the low-GNRI group than in the high-GNRI group (0.125 mg/kg, 95% CI 0.116–0.134 vs 0.173 mg/kg, 95% CI 0.162–0.184; P < 0.001). Probit regression showed similar ED50 values of 0.127 mg/kg and 0.170 mg/kg, respectively. The corresponding ED95 values were 0.154 mg/kg and 0.227 mg/kg, although the confidence interval for the latter was wide and should be interpreted cautiously; the dose-response curve was shifted leftward in the low-GNRI group. Older patients with low GNRI required a lower dose of remimazolam for effective gastrointestinal endoscopy sedation. GNRI may help individualize remimazolam dosing in older adults. Chinese Clinical Trial Registry, ChiCTR2600126218; registration date: June 5, 2026.