Assessment of pancreatic exocrine insufficiency and pancreatic enzyme dose-response using the 13C-Mixed triglyceride breath test.

INTRODUCTION

Faecal elastase-1 testing is the most commonly used method for diagnosing pancreatic exocrine insufficiency (PEI), but has poor diagnostic precision and cannot guide titration of pancreatic enzyme replacement therapy (PERT). An alternative is 13C-mixed triglyceride breath test. We investigated concordance between breath test and faecal elastase-1, and response to bicarbonate-buffered enzymes.

METHODS

In this prospective study, adults with faecal elastase <100 µg/g using PERT performed a baseline breath test without enzyme treatment. Participants with normal baseline exhalation (≥29%) were enrolled in Substudy I, where they discontinued pancreatic enzyme replacement therapy (PERT) and were clinically reassessed after 6 months. Participants with abnormal exhalation (<29%) were enrolled in Substudy II, a three-arm crossover study where breath test was repeated on three separate days while receiving 24,000, 48,000, and 72,000 IU PERT, in random order. Primary outcomes were PERT reinstatement at follow-up (substudy I) and differences in cumulative 13CO2 exhalation (substudy II).

RESULTS

Baseline tests where performed in 25 participants. Thirteen participants had normal breath test, 11 agreed to pause PERT, but only five participants did not reinitiate treatment (substudy I). 12 participants were included in substudy II (mean age 65, all males). All had significant breath test improvements on lowest enzyme dose (24,000 IU) versus baseline (mean difference 21.5%, p < 0.001), yet higher enzyme doses did not improve results significantly.

DISCUSSION: About half of participants previously categorised with PEI had normal 13C-mixed triglyceride breath test, questioning diagnosis. Most participants demonstrated normal breath test with lowest enzyme dose during standardised test meal. However, this finding may not generalise to habitual meals.