Frank K. Friedenberg, MD, MS (Epi)
Professor of Medicine
Temple University Hospital
G&H What have studies reported to date regarding the prevalence of gastroesophageal reflux disease in minority populations? Do these rates differ from the prevalence of this condition in the general population?
FF The prevalence of gastroesophageal reflux disease (GERD) in the black population appears to be 25–35%, which is similar to the prevalence of GERD in white populations, as reported by the Mayo Clinic, for example. One limitation in comparing the true prevalence of GERD in differing populations is the inconsistent definitions used for this condition.
Two comparative studies of GERD prevalence have been performed. A recent study by Yuen and colleagues included over 1,000 subjects presenting at local civic events in Philadelphia, Pennsylvania and found that 50% of Hispanic subjects experienced heartburn at least monthly, compared with 37% of white subjects and 31% of black subjects. In 2004, El-Serag and colleagues examined a convenience sample of hospital employees and found that the weekly rate of GERD symptoms was 27% in black subjects and 23% in white subjects. A study from Kaiser Permanente found that the prevalence of recent GERD (asked categorically as “yes/no”) was higher in black subjects than white subjects (16% vs 12%). Other studies have used endoscopic databases such as the Clinical Outcomes Research Initiative (CORI), which do not provide population-level data. Of note, there are no population-based studies describing the prevalence of GERD in African countries.
G&H Why has there been limited research conducted to date evaluating minority populations with GERD?
FF Administrative databases are commonly used to ascertain population prevalence rates. Potentially biased disease rates may exist in black subjects due to relatively low rates of health insurance, access to medical care, and willingness/ability to participate in surveys. In a study we recently conducted, 75.2% of black subjects with GERD had insurance (primarily public assistance) and only 31.6% [au: of these subjects?] with daily symptoms stated that they had discussed GERD with their doctor.
G&H Do you foresee an increase in research in this area in the future?
FF It will be interesting to see the effect that President Obama’s healthcare plan has on this issue. Currently, 25% of the black population in Philadelphia, Pennsylvania has no health insurance; presumably, these individuals will have some form of coverage beginning in 2014 under the new healthcare plan. Therefore, we may see increasing numbers of minorities presenting with reflux to gastroenterologists and primary care physicians. As previously mentioned, studies based upon physician encounter data have noted a relative disparity in access to healthcare for African Americans; thus, these studies have often included a low number of African American subjects. This trend of underrepresentation may change if more African Americans have access to healthcare.
G&H Has there been research examining risk factors in minority patients with GERD?
FF My colleagues and I recently conducted a cross‑sectional study of 503 African Americans in the North Philadelphia community. We surveyed a convenience sample of subjects at a local retail pharmacy and measured body weight, waist circumference, and height in order to calculate body mass index and waist-to-hip ratio. We queried numerous confounders, including dietary habits and use of alcohol and tobacco. In addition to active tobacco use, we found that an increasing waist circumference, rather than body mass index, was associated with reflux; this finding has been found previously in primarily white populations. In previous studies, central obesity has been associated with Barrett esophagus in white populations; however, our study did not include endoscopy.
G&H Has there been any research conducted specifically on Hispanic patients with GERD?
FF There have been very little North American data on the prevalence and risk factors for GERD in Hispanic patients. This patient population will be an important area of research, as Hispanics comprise the fastest-growing segment of the US population.
Some data exist from South America and Spain. For example, a population-based study from Argentina assessed GERD in 1,000 residents. The overall prevalence of reflux experienced at least once in the previous year was 61.2%; less than once a month 20.5%; approximately once a month 16.8%; approximately once a week 10.3%; several times a week 9.6%; and daily 3.1%. A Brazilian study that was conducted in 22 cities and enrolled 13,959 adults reported a prevalence of 11.9% for at least weekly symptoms. In a population-based study, Diaz-Rubio reported the prevalence of reflux symptoms in a representative sample population of Spain. Using a validated questionnaire, a telephone survey of 2,500 subjects was performed. The annual prevalence of reflux symptoms was 31.6% and 9.8% for at least weekly symptoms. Obesity, higher psychosomatic symptom scores, and a family history of reflux symptoms were identified as the risk factors.
G&H You recently received a National Institutes of Health grant to investigate GERD in African Americans. Could you discuss the design of your study?
FF The study that my colleagues and I conducted on risk factors of minorities with GERD using convenience sampling provided the preliminary data needed to power this study. We are performing a population‑based cross‑sectional survey that is aided by geographical mapping. In this way, we hope to obtain an unbiased sample of individuals living in the community surrounding our institution. Invited subjects complete a standardized electronic survey that looks at a variety of environmental factors that could contribute to GERD and functional bowel disease (as defined by Rome III criteria). The control population will be comprised of white subjects in another area of Philadelphia. The first pieces of our data will be presented in several abstracts at the upcoming American College of Gastroenterology meeting.
G&H How prevalent is Barrett esophagus in minority populations with GERD?
FF In previous studies, the prevalence of Barrett esophagus in minority populations with GERD has been very low—in fact, much lower than in white populations. According to Wang and colleagues, who used the CORI database, the suspected prevalence in whites, blacks, and Hispanics was 5.0%, 1.5%, and 2.9%, respectively. Obviously, many unmeasured confounders may be influencing this rate discordance. It is important to know the rate of Barrett esophagus in black patients; if the rate is much higher than previously reported, this could influence screening strategies, although this is a very controversial area in general.
The prevalence of Barrett esophagus will be examined in our study. Subjects with GERD will undergo pH and manometry studies as well as an upper endoscopy.
G&H Are there differences in the knowledge or care patterns of GERD in minority patients?
FF The study published by Yuen and others discusses this issue in great detail. Surprisingly, there are few differences between minority patients (black and Hispanic) and white patients with respect to their understanding of the complications of GERD and avenues to seek treatment. White subjects were found to be more likely to use the Internet and family members to find out more information. White subjects with severe heartburn were least likely to see a primary care or specialist doctor.
G&H Has there been any research on whether proton pump inhibitors or other treatments for GERD have the same efficacy in different ethnicities or races?
FF To my knowledge, no studies have examined this issue, but it is an interesting subject to pursue.
G&H What are the most important research needs in this patient population?
FF In my opinion, the most important area of research involves identification of modifiable risk factors for GERD in minority populations. If our cross‑sectional study confirms that central obesity is a risk factor in minorities with GERD, this finding will have important implications. Previously uninvestigated risks in black patients may include post-traumatic stress disorder, substance abuse, and other understudied factors. Once potentially modifiable risk factors are identified, we can go back to the black community to present our findings as well as our recommendations for reducing the prevalence of GERD.
G&H Do you know of any specific upcoming or ongoing studies in this area?
FF My colleagues and I have received funding to examine the relationship between weight loss (through a prescription diet) and its effects on GERD and esophageal physiology. In this study, which will start next summer, obese blacks with GERD will enter a 6-month weight loss program in our Center for Obesity Research.
Friedenberg FK, Rai J, Vanar V, et al. Prevalence and risk factors for gastroesophageal reflux disease in an impoverished minority population. Obes Res Clin Pract. 2010;4:e261-e269.
Yuen E, Romney M, Toner RW, et al. Prevalence, knowledge and care patterns for gastro-oesophageal reflux disease in United States minority populations. Aliment Pharmacol Ther. 2010;32:645-654.
El-Serag HB, Petersen NJ, Carter J, et al. Gastroesophageal reflux among different racial groups in the United States. Gastroenterology. 2004;126:1692-1699.
Friedenberg FK, Hanlon A, Vanar V, et al. Trends in gastroesophageal reflux disease as measured by the National Ambulatory Medical Care Survey. Dig Dis Sci. 2010;55:1911-1917.
Sharma P, Wani S, Romero Y, Johnson D, Hamilton F. Racial and geographic issues in gastroesophageal reflux disease. Am J Gastroenterol. 2008;103:2669-2680.