Indigestion Common With Joint Hypermobility Syndrome for Reasons Unknown

Joint hypermobility syndrome, including hypermobile Ehlers–Danlos syndrome (hEDS), is present in a large proportion of people with functional dyspepsia — a common gastrointestinal disorder also known as indigestion without an underlying cause, a study showed.

The presence of joint hypermobility, however, does not significantly prevent the digestive system from working as it should. Reasons that might explain why indigestion is common in this disorder are also not clear, its researchers said.

The study, “Impact of joint hypermobility syndrome on gastric accommodation and nutrient tolerance in functional dyspepsia,” was published in Neurogastroenterology & Motility as a collaborative effort between researchers with KU Leuven in Belgium, and Queen Mary University of London.

Previous studies have shown that gastrointestinal symptoms — such as reflux, constipation, bloating, and food intolerances — are common in patients with joint hypermobility syndrome. But “the association between [functional dyspepsia] and [joint hypermobility syndrome], and the underlying pathophysiological alterations are poorly understood,” the researchers wrote.

The researchers investigated the prevalence of joint hypermobility syndrome in people with functional dyspepsia, and if this syndrome affected gastric motility (digestive system’s movement, and the transit of its contents), satiation, nutrient tolerance, and symptoms of dyspepsia.

Their study (NCT04279990) enrolled 39 functional dyspepsia patients and 15 people with no gastrointestinal disorders. Patients with functional dyspepsia were older (mean age, 41.2) than the healthy group (mean age, 27.3), but both had a similar body mass index (a measure of body fat based on height and weight).

Joint hypermobility syndrome was found in 22 (56%) people with functional dyspepsia, and in one (7%) person in the healthy group.

Of note, joint hypermobility syndrome was reclassified in 2017 as hEDS in those meeting the strict criteria, and as hypermobility spectrum disorder in those satisfying some but not all criteria for hEDS. Since the study was conducted in 2016, before the 2017 international diagnostic criteria were defined, joint hypermobility syndrome was diagnosed based on the old criteria.

When researchers compared the set of gastrointestinal symptoms, such as bloating and fullness after eating, and the occurrence of symptoms of dyspepsia in daily life between patients with joint hypermobility syndrome and those without it, no significant differences were found.

The team then assessed gastric motility by measuring intragastric pressure.

Patients were infused with a commercially available nutritional drink until maximal satiation. Results showed a drop in intragastric pressure, as expected. This drop, used as a measure of gastric accommodation, was similar between people with joint hypermobility syndrome and those without.

In addition, the amount of nutritional drink tolerated during the test — a measure of satiation — was similar between the two groups.

“Nutrient drink tolerance was not significantly different in [joint hypermobility syndrome] patients compared with healthy subjects,” the researchers wrote.

Bloating after the nutritional drink, however, was less common in people with joint hypermobility syndrome than in those without.

“In conclusion, [joint hypermobility syndrome] is strongly associated with [functional dyspepsia], but our findings do not support the hypothesis that [gastric accommodation] would be affected and cause [gastrointestinal] symptoms in” joint hypermobility syndrome, the researchers wrote.

According to the team, the impact of and underlying reasons for the high prevalence of joint hypermobility syndrome in people with functional dyspepsia requires further research.