180 Different Time Course of PDS Versus EPS Functional Dyspepsia Symptoms After Ingestion of a Meal

Abstract

Background: According to the Rome III consensus, functional dyspepsia (FD), is subcategorized into Postprandial Distress Syndrome (PDS) and Epigastric Pain Syndrome (EPS). Relationship to ingestion of a meal has been proposed as a distinguishing feature of PDS (comprising early satiation and postprandial fullness) and not of EPS (comprising epigastric pain and burning). The aim of the present study was to study the time-course of different FD symptoms after ingestion of a standardized meal. FD patients underwent a 13C-octanoic acid gastric emptying breath test during which they were asked to score the severity (0-4) of 6 symptoms (pain, fullness, bloating, nausea, epigastric burning and belching) at each sampling point (every 15 min for 4 hrs postprandially). For each symptom, a meal-related severity score was obtained by adding scores at all time-points. Different curve models were evaluated for goodness of fit of the time after the meal vs. symptom intensity based on the lowest sum of squared errors (SSE). Results: 218 consecutive FD patients (149 women, age 39±1) participated in the study. Meal ingestion was associated with a significant increase in intensity of each symptom at 15 min, and this remained significant throughout the 4 study hours. Meal-related symptom score was highest for fullness (23.2±1.3) and bloating (18.8±1.2), followed by belching (14.8±1.0) and epigastric pain (14.4±1.2) and lowest for nausea (13.0±1.1) and epigastric burning (9.7±1.0). Curve fitting revealed two different patterns. For postprandial fullness, a power law curve with exponential cutoff (y=C*x(T)*e(-x/K)+d) provided the best fit (SSE 0.005, C=0.383; T=-0.336; K=139.937; d=0.647). The same curve type also provided the best fit for bloating (SSE 0.002, C=0.217; T=-0.455; K=112.917; d=0.535), for nausea (SSE 0.008, C=0.042; T=-0.685; K=99.842; d=0.497), and for belching (SSE 0.005, C=0.233; T=-0.404; K=108.262; d=0.403). For epigastric pain, a sigmoid curve (y=a/(1.0+e(-(x-b)/c))+d) provided the best fit (SSE 0.037, a=-0.846; b= 7.029; c=-8.730; d=1.040). The same curve type also provided the best fit for epigastric burning (SSE 0.026, a=-0.646; b=2.938, c=-15.215, d=0.613). Conclusion: In FD patients, epigastric pain and burning follow a different pattern and time course after a standardized meal compared to fullness, bloating, nausea and belching. The different types of curve that best approximate these respective time courses do not depend on symptom intensity, and suggest different underlying pathophysiological mechanisms. The observations and curve fitting support the Rome III subdivision of FD into EPS versus PDS.