What is the prevalence of gastroesophageal reflux disease and of reflux esophagitis?
R.C. Heading (Edinburgh)
To determine prevalence values for reflux disease and for reflux esophagitis in the population it is necessary to: 1) define the two conditions; and 2) undertake studies
in the community to identify the occurrence of the conditions so defined. There are formidable difficulties in meeting these two requirements and in consequence no truly satisfactory prevalence data are yet available which compare directly the occurrence of reflux disease and esophagitis. Nevertheless, some inferences may be drawn from the data which do exist.
Prevalence of symptomatic reflux disease
Reflux disease may be defined as the occurrence of symptoms, tissue damage or both, attributable to gastroesophageal reflux. Although this definition is broadly satisfactory for patients coming under the care of physicians, the label "reflux disease" seems inappropriate for individuals who suffer only very mild or infrequent symptoms. This in turn implies that some threshold of symptom frequency or severity, or of patient distress, should be set to justify application of the term "reflux disease", but because any such threshold is necessarily arbitrary, the definition of "reflux disease" is thereby rendered less robust. Prevalence data based on the definition are then correspondingly less certain.
Simple enquiry about dyspeptic symptoms has produced broadly similar data in the United Kingdom and the United States. The 6 month prevalence in the United Kingdom is reported to be 41%, with just over half of symptomatic individuals experiencing both upper abdominal symptoms and heartburn, and heartburn alone in about one fifth . Only one quarter of the sufferers had sought medical advice for their symptoms. In a Gallup poll conducted in the United States, 44% of respondents described suffering heartburn at least once a month and approximately one third of symptomatic individuals had never discussed their complaint with a doctor. In a well known study of hospital staff , Nebel and colleagues found 7% of individuals suffering heartburn on a daily basis, 14% weekly and 15% approximately monthly . Thomson and Heaton reported figures of 4 and 10% for the proportion of the population suffering daily and weekly heartburn respectively .
The principal difficulty in interpreting these data to estimate the prevalence of reflux disease centres on the inadequacy of heartburn as an indicator of symptomatic reflux. Klauser and colleagues have shown that when heartburn is a dominant symptom, it serves as a relatively specific (though insensitive) predictor of reflux disease. In contrast, simple enquiry about the presence or absence of heartburn is not reliable as an indicator of the presence or absence of reflux disease . Among individuals with proven reflux disease, the most common symptom pattern seems to be a complex dyspepsia which is not a basis for specific clinical diagnosis. These data therefore indicate that it is not possible to identify reflux disease reliably on the basis of symptom questionnaires alone. The published literature concerning the occurrence and frequency of so called reflux symptoms in the population must be interpreted in this context.
Prevalence of esophagitis
In comparison with symptomatic reflux, more accurate information about the prevalence of esophagitis might reasonably be expected but difficulties of definition arise here also, especially with mild forms of the disease. There is much observer variation in the endoscopic recognition of mild esophagitis and because mild disease is more common than severe disease, estimates of the incidence of abnormality among any population may be more variable than endoscopists would wish. Nevertheless, there is a measure of agreement around a figure of 20% for the presence of esophagitis in patients undergoing endoscopy for upper gastrointestinal symptoms [6,7]. An interesting study from Norway suggests that among individuals in the community who admit to dyspeptic symptoms on enquiry, approximately 12% have esophagitis at endoscopy whereas in a matched group of controls, who deny dyspeptic symptoms, approximately 8% have esophagitis .
For the reasons given above, figures which claim to represent the prevalence of reflux disease and esophagitis must be accepted with caution. Nevertheless, numbers can be useful as broad indicators of the occurrence of the condition in the population. Reflux symptoms are reported by approximately 10% of the adult population with a frequency or severity which would seem to justify the term "reflux disease". It seems likely, however, that an additional group of individuals, perhaps almost as numerous, suffers dyspeptic symptoms which are not obviously of reflux type but are in fact caused by gastroesophageal reflux. Esophagitis is found in approximately 20% of patients with upper gastrointestinal symptoms coming to gastroenterologists. For every two patients with such symptoms found to have esophagitis, a further one patient with similar symptoms but without esophagitis, can be shown to have abnormal 24-h esophageal pH monitoring . The prevalence of reflux disease among symptomatic individuals is thus approximately 1.5 times the prevalence of esophagitis.