Most people who seek medical care for upper abdominal pain are diagnosed with either gastroesophageal reflux disease (GERD) or functional dyspepsia. Both conditions are common in the general population and have similar symptoms, so distinguishing between them can be challenging. Yet in the past two decades, diagnoses of GERD have far exceeded those of functional dyspepsia, leading G. Richard Locke III, M.D., of Mayo Clinic in Minnesota, to question whether observer bias might contribute to the dramatic rise in GERD-related doctor visits and hospitalizations.
"We wondered whether we were really seeing something different or whether all upper GI pain was being labeled GERD," he says. "There is a great deal of concern about Helicobacter pylori, so the conversation tends to focus on GERD and reflux rather than on functional dyspepsia. We felt that this might influence diagnosis."
To assess whether observer bias exists in the evaluation of GERD, Dr. Locke and colleagues undertook a three-part study.
First, they compared GERD and functional dyspepsia diagnoses in Olmsted County, Minn., between 1985 and 2009. They also assessed upper-GI symptom reporting from community-based surveys over the past 20 years. And, in a separate analysis, they retrospectively reviewed medical charts for upper-GI diagnoses in randomly-selected survey respondents and compared those diagnoses with patient-reported symptoms.
"We had a great opportunity in Olmsted County because we had been following a group of patients over time," Dr. Locke explains. We could look at symptoms not through the lens of the physician but through the lens of the patient. And what we found is that people were getting a reflux diagnosis even when they didn't have reflux symptoms."
In fact, between 1985 and 2009, GERD diagnoses increased from 325 to 1,866 per 100,000 patients, even though GERD symptoms decreased from 12 percent between 1988 and 1994 to 7.6 percent between 2008 and 2009.
Functional dyspepsia diagnoses rose from 45 in 1985 to 964 in 1999, but fell to 452 between 1999 and 2009, while reported functional dyspepsia symptoms remained stable, at around 5 percent.
What's more, the chance that patients reporting GERD symptoms would receive a GERD diagnosis was 63 percent, whereas the chance that patients with functional dyspepsia symptoms would be diagnosed accurately was just 12.5 percent.
"These results confirm that people with functional dyspepsia are being diagnosed with GERD," Dr. Locke says. "This is a reminder to physicians to keep an open mind when patients complain of upper GI pain. Most people need further evaluation and testing and shouldn't be diagnosed on the basis of symptoms or response to acid blockers alone."
He adds, "We need to step back and discover what a patient really has before resorting to fundoplication or other treatments that are inappropriate for functional GI disorders."
Dr. Locke says that there is great interest in functional dyspepsia at Mayo Clinic, particularly the pathogenesis of the disease.
"Functional dyspepsia and irritable bowel syndrome are similar," he says. Visceral hypersensitivity, abnormal motility and autonomic dysfunction seem to play a role in both. We're engaged in ongoing studies in an effort to understand the exact nature of these disorders."