Tracking the journey: Gastrointestinal transit and intraluminal pH dynamics in aging populations using wireless...

Gastrointestinal (GI) changes may alter drug absorption, potentially impacting both efficacy and safety of oral pharmacotherapy. However, the GI physiology is rarely studied in the aging population. This study aimed to explore GI transit time and pH in geriatric inpatients and older adults, and compare these findings with those from young volunteers.

A prospective study was performed in geriatric inpatients and community-dwelling adults aged ≥ 75 years. GI transit and intraluminal pH were assessed by using a wireless motility capsule system. Participants' data were pooled with those from a previous study in healthy young volunteers (n = 11). Multivariable linear regression models were developed to identify explanatory variables for GI transit time and pH value.

We recruited 30 subjects (median age 80 [interquartile range (IQR) = 77-83] years). When compared to young volunteers (median age 21 [20-33]) years), geriatric inpatients (N = 8) exhibited prolonged gastric emptying times (median = 0.63 h [IQR = 0.32-0.86 h] vs median = 2.98 h [IQR = 1.50-20.35 h], p < 0.01). Community-dwelling older adults (N = 22) did not demonstrate delayed gastric emptying (median = 0.42 h [IQR = 0.36-0.53 h]; p = 0.85. Proton pump inhibitors (PPI) use was associated with increased gastric pH (median pH = 3.75 [IQR = 1.69-4.96] vs. non-PPI median pH = 1.28[IQR = 1.01-1.70]; p < 0.01) in the pooled analysis. The total older cohort had significantly lower small intestine pH compared to young group (median pH = 6.8 vs. 7.2; p < 0.01).

Older age did not necessarily alter GI physiology with respect to gastric emptying time and luminal pH values. Only geriatric inpatients exhibited delayed gastric emptying of the motility capsule as compared to young volunteers, while community-dwelling older adults did not. Prevalent PPI use in the aging population led to higher gastric pH levels, with substantial intersubject variability.