Functional dyspepsia (FD) is a common disorder characterized by symptoms that are often described as indigestion; unpleasant sensations in the middle of the abdomen, uncomfortable fullness after eating, and sometimes inability to eat normal-size meals. FD is a much-researched disorder, but surprisingly, no nationwide studies have been done in the U.S. to evaluate what proportion of adults actually meet formal criteria for FD as defined by the current Rome III diagnostic criteria. Moreover, little is known about how rates of dyspepsia differ among race or ethnic groups or between different age group in the American population.
Today (May 3, 2014) I presented in poster format at Digestive Disease Week 2014 in Chicago the results of statistical analyses that our research team carried out to estimate how common FD is in American adults. We used for this purpose data from the Rome Normative Gastrointestinal Symptom Survey that we conducted last year, and which was sponsored by the Rome Foundation. In this secure online survey, we obtained responses from a large group of adults across every state in the U.S. The survey included questions about the responders’ demographics, health history, and the whole Rome III Diagnostic Questionnaire that diagnoses all functional gastrointestinal disorders. To minimize bias due to the possibility that people with GI symptoms might be more interested than others in participating and therefore be over-represented in our sample, invitations to participate described the study as a physical symptoms survey but did not mention gastrointestinal symptoms. We also controlled how many participants in different demographic categories could participate, in order to ensure equal gender proportions and get enough minority participation for our sample to be similar to the U.S. population.
A total of 1,665 individuals ranging in age from 18-94 years completed our survey, but we then eliminated from our analysis dataset people who showed evidence of inconsistent survey answers (we included three repeat questions in the survey for quality-check purposes), leaving us with responses from 1,277 people suitable for analysis. We have used that sample to estimate how common different functional gastrointestinal disorders are in the U.S. population and whether they have different frequency in various subgroups of the population (like males vs. females or older individuals versus young). In today’s presentation we only reported such findings for FD, but we will also be presenting our results for IBS and fecal incontinence separately here at DDW on Tuesday. We found that 11.4% of the people who completed our survey met Rome III criteria for FD. However, to get a more accurate estimate of the national dyspepsia prevalence, we statistically adjusted (weighted) our calculations to make the sample match the national adult age, gender and race/ethnicity distribution in the 2010 U.S. Census. Doing this only altered our numbers slightly, resulting in an estimated overall national U.S. FD rate of 11.9%.
We also found that functional dyspepsia tended to be more common in women than men (13.0% versus 9.9%) but this actually did not quite reach statistical significance, so we cannot be confident about the sexes really being different in this regard. In both sexes, FD rates were lowest in the youngest and oldest age groups, and significantly higher at mid-life; see the Figure below. Dyspepsia prevalence was not significantly different in white (12.3%) hispanic (12.9%) and black (9.6%) respondents in our survey.
There are presently two recognized subtypes of FD, separated by difference in the symptom pattern. A surprising finding in our survey was that only 3 individuals in our whole sample (a mere 0.2%) met criteria for one of those sub-types, which is called Epigastric Pain Syndrome (defined primarily by pain in the upper gut, above the stomach). In contrast, most of the people (87%) in our survey who qualified for FD diagnosis based on their responses fit into the other subgroup, called Postprandial Distress Syndrome (meaning that they mostly have uncomfortable fullness after eating).
In summary, our analyses of responses to the FD diagnostic questions in this large nationwide survey give a clear picture for the first time of the prevalence of this disorder overall in the U.S. and in population subgroups, as it is defined by current Rome symptom criteria. Our results indicate that about 12% of American adults have this disorder, which makes it one of the most common of all gastrointestinal problems in the U.S.
Sa1335. Olafur S. Palsson, Miranda A. Van Tilburg, Brennan M. Spiegel, Jan F. Tack, Robin C. Spiller, Lynn S. Walker, Yunsheng Yang, William E. Whitehead. Uninvestigated Dyspepsia in the U.S. General Population: Results From the ROME Normative Gastrointestinal Symptoms Survey (RNGSS). Center for Functional GI and Motility Disorders, University of North Carolina, Chapel Hill, NC; Digestive Diseases, VA/UCLA, Los Angeles, CA; TARGID, University Hospitals of Gasthuisberg, Leuven, Belgium; Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, United Kingdom; Adolescent Medicine, Vanderbilt Children’s Hospital, Nashville, TN; Department of Gastroenterology and Hepatology, Chinese PLA General Hospital, Beijing, China.