GERD in British and south‐east Asian dyspeptic patients

Abstract

Sirs, Mahadeva et al.’s1 paper on the correlation between British and south-east Asian patients and dyspepsia raises a number of fundamental issues. We are sceptical about the findings as we feel there are problems with the sampling and methodology in general. All hospital-based patient studies run the risk of not being representative of the population they are derived from. This bias is further exacerbated when patients from two different health systems and cultures as well as differing attitudes to health care are compared. We were surprised that only British Caucasian dyspeptics were recruited for the study whereas all Malaysians of a generic background were included and lumped together as south-east Asians (a term which also applies to the ethnically diverse inhabitants of Brunei, Burma, Cambodia, Indonesia, Laos, Singapore, Thailand and Vietnam). It would have been more appropriate for British dyspeptics, irrespective of race or at least of Asian origin, to have been included in the study, particularly as south Asian (Indian) descent has been shown to be a risk factor for gastro-oesophageal reflux disease (GERD) in a British community study.2 Moreover, both Britain and Malaysia have multiethnic and multicultural populations, some of whom are of east and south Asian origin. Hence, the inherent differences in the referral patterns and selection of patients between the two systems (which we are both acutely aware of having also worked in the UK) could alone account for the differences in findings between British and Malaysian patients. We feel that selective referencing has been used to convey the message that GERD is not common in the east. Relatively recent papers from Hong Kong and Malaysia (not mentioned in the article) revealed monthly reflux prevalence figures of 9.9% and 9.7% respectively.3, 4 Moreover, our endoscopy unit in a major teaching hospital reported a prevalence rate of 1.6% of histologically proven long segment Barrett's oesophagus and 4.6% short segment Barrett.5 These figures obtained from a study in which endoscopies were performed/supervised by a single consultant endoscopist (SR) between 1997 and 2000 contrast sharply with the 0.9% columnar-lined oesophagus diagnosed in south-east Asians by endoscopy personnel in various stages of training as reported by Mahadeva et al.’s1 group. This is especially so as there were a disproportionately high number of Indians (who have been shown to have the highest prevalence of Barrett's oesophagus in Malaysia5) in their study group (as was the case in SR's study), i.e. 31.2% when compared with the Federal Territory of Kuala Lumpur (research location) Indian population distribution of 10.6%.6 In our unit, trainees have great difficulty in diagnosing columnar-lined oesophagus endoscopically. Reasons include the belief that the accentuated or serrated squamo-columnar junctions are a normal variant and difficulty in identifying the gastro-oesophageal junction in complicated GERD.7 Almost a third of dyspeptic Malaysian patients in Mahadeva et al.’s1 study were on antisecretory therapy as opposed to none in their British counterparts. Surely this fact could account for at least partially, if not all, the observed differences in reflux symptoms and oesophagitis between Asian and Caucasian patients. In the study published from our endoscopy unit, all dyspeptic patients were off antisecretory therapy for a month prior to endoscopy.5 Not surprisingly, 77.7% of our patients with oesophagitis had reflux symptoms5 as opposed to 58.6% of Malaysian patients and 80.6% of British study subjects as reported by Mahadeva et al.’s1 group. Moreover, it is well known that there is no equivalent term for ‘heartburn’ (itself, a rather non-descript and inappropriate term for the retrosternal burning sensation arising from the epigastrium and moving up towards the neck) in the various languages and dialects spoken in Asia.7 In Malaysia, word descriptors such as ‘upwardly rising wind’, ‘acidic stomach’, ‘excessive burping’, ‘burning chest’ and ‘chest irritation’ are common expressions amongst Malay, Chinese and Indian patients to describe reflux symptoms,7 and these terms should be included in any locally validated questionnaire. Otherwise, low symptom reporting leads to reduced doctor referral for endoscopic examination. Moreover, there is data on ethnic differences in the perception of symptoms in other diseases as well.8 The authors have also stated that the western lifestyle is more sedentary than the east and may account for the apparent GERD differences; this, we believe, is pure speculation, as lifestyle was not one of the risk factors in their analysis, or was body mass index. Thus, for all the above reasons, we find it difficult to accept the authors’ conclusion that the perceived GERD variation between a monoethnic dyspeptic British patient population and a multiracial Malaysian dyspeptic cohort (who are not necessarily typical of other south-east Asians) is probably due to a combination of intrinsic ethnic differences and environmental influences. In short, weaknesses in study method could explain the differences and the findings should be interpreted cautiously.