Abstract

Rapid urease test for the detection of Helicobacter pylori infection was carried out in 97 symptomatic patients referred for gastro-intestinal segment endoscopy. Sixty seven were found positive. H. pylori was detected in 100% of patients with gastric cancer, gastric ulcer and reflux esophagitis, in 83% with duodenal ulcer, in 74% with gastritis, and in 50% with antritis and non ulcer dyspepsia cases. H. pylori was similarly frequent in all age groups, suggesting that infection occurred within childhood and/or adolescence. Duration of symptoms of epigastric disorder as well as socio-economic factors correlated with H. pylori presence in the antral mucosa. High prevalence in Seychelles of H. pylori in some gastro-intestinal disorders points to the need to establish relevant diagnostic and therapeutic approaches to this infection. (SMDJ, 1999;6:24-26.)

Introduction

Since its discovery in 1983 by Warren and Marshal (1), Helicobacter pylori, a Gram-negative bacterium, has been the subject of many studies that contributed to a better understanding of its epidemiology and its clinical importance in the pathology of the upper gastro-intestinal segment. In 1993, the National Institutes of Health Consensus Conference declared H. pylori infection an important cause of duodenal and gastric ulcers (2) and in 1994 the International Agency for Research on Cancer classified H. pylori as a carcinogen of the group I, a definite cause of gastric adenocarcinoma in humans (3).

No data on H. pylori were previously available in Seychelles. In this tropical country, the prevalence of H. pylori might be expected to be similarly high as in other developing countries. Low incidence of stomach cancer and atrophic gastritis in Seychelles (4) could question the role of H. pylori infection in disorders of the upper gastro-intestinal segment.

This study was undertaken to evaluate the prevalence of H. pylori infection in patients with gastro-duodenal disorders, and to discuss the therapeutic implications of these findings for the Seychellois patients.

Subjects and methods

From December 1996 to May 1997, 97 patients with symptoms of non ulcer dyspepsia (NUD) or other upper gastro intestinal segment disorders were referred for endoscopy to Victoria Hospital. NUD refers to functional gastric disorder lasting more than four weeks and with no evident pathology. Ninety of the 97 patients were referred from the primary health services because of upper gastro-intestinal symptoms for an elective gastroscopy and the remaining 7 were referred from the inpatient Victoria Hospital services for an urgent gastroscopy. All 97 referred patients underwent gastroscopy and had a gastric mucosa biopsy.

Prior to gastroscopy information was collected with regards to age, sex, origin, household size (open), duration of symptoms (number of months and years), previous recent treatment for dyspepsia (yes or no), recent treatment with metronidazole (yes or no), alcohol drinking (yes or no), use of treated/untreated water at home (yes or no), taste for spicy food (yes or no), ownership of pets or/and animals at home (yes or no).

Gastroscopy was performed in the endoscopy unit of Victoria Hospital with a GIF Q30 Olympus gastroscope under standard condition (4).

A single biopsy of stomach antral mucosa along the greater curvature was routinely taken in every patient. Gastric mucosa specimens were examined by a rapid urease test for H. pylori infection. After the insertion of the mucosa specimen into the plate (Helicobacter Test - Institute of Immunology and Virology Torlak. Belgrade), the slide was kept warm at 37 degree Celsius and the result was read after three and 24 hours. The sensitivity of this test is 90-95% and its specificity 98%.

Results

The prevalence of H. Pylori across categories of selected variables is shown in Table 1. Of the 97 patients, 37 were females and 60 males. The average age was 44.5 years (range:18-81, median 42). The duration of symptoms varied from one month to 10 years. Referrals for endoscopy were due to NUD symptoms in the majority of patients (74.2%) and for other upper gastrointestinal segment diseases in 26.8%. In 75 patients, the following treatments had been used before the urease test: antacids in 27, antacides and cimetidine in 27, cimetidine alone in 8, methoclopramide in 1, metronidazole in 11. None was on anti-H. pylori treatment. Twenty two patients had no treatment at all.

The average number of family members living in the same house was 5,5. Alcohol consumption was negative in 35% of patients and positive in 65%. Spicy food was consumed by 84,5% of patients and treated water by 78,3%. Fourteen patients had a pre-existing chronic disease: 1 had allergy, 3 had diabetes, 1 had liver cirrhosis and 9 had arterial hypertension.

The urease test was positive for H. pylori in 67 out of the 97 (69%) patients. The test was more frequently positive in patients with ulcer and cancer of the stomach and less frequently positive in patients with NUD (Figure 1). The frequency of positive tests was similar in both sexes (men: 71.6% and women: 64.9%) and did not vary substantially with age (Figure 2).

Table 1. Prevalence of H. pylori across categories of selected variables
 

Variable	Group	HP+	HP-	% Pos	P
Gender	M	43	17	71.7
	F	24	13	64.9	0.505
Age	<30	11	7	61.1
	30-50	35	10	77.8
	>50	21	13	61.8	0.225
Household size	<2	17	12	58.6
	3-5	35	12	74.5
	>5	15	6	71.4	0.337
Duration (yrs)	<1	32	19	62.7
	1+	35	11	76.1	0.191
Previous treatment	Yes	55	20	73.3
	No	12	10	54.5	0.118
Rx with metronidazole.	Yes	14	20	41.1
	No	53	10	84.1	0.000
Drinks alcohol	Yes	42	6	87.5
	No	25	24	51.0	0.000
Drinks treated water	Yes	54	21	72.0
	No	13	9	59.1	0.068
Eats spicy food	Yes	58	21	73.4
	No	9	9	50.0	0.397
Pets/animals at home	Yes	42	24	63.6
	No	25	6	80.6	0.105

 

Figure 1. Prevalence of HP infection by category of gastrointestinal disease

H. pylori prevalence was similar in drinkers and non-drinkers (respectively 67.5% and 65.0%). H. pylori tended to be less frequent in households with fewer persons (5.6 relatives per household in patients with H. pylori compared to 4.4 in patients without H. pylori). Groups with or without H. pylori did not differ as regards water treatment, food and spices consumption, and animals and pets at home. Patients with less than two years of symptoms before gastroscopy had less often H. pylori than those with symptoms for more than two years (respectively 64.1% [34/53] and 75.1% [33/44]). Patients who were on previous treatment were positive in 73.3% while those who had no treatment were positive in 54.5%.

Figure 2. Distribution of HP prevalence by age

Discussion

A previous review of gastroscopy outcomes in Seychelles from 1990 to 1994 showed (4) high prevalence of gastric pathologies and this study demonstrates that these pathologies are frequently associated with H. pylori. This association is consistent with evidence found in other countries (5,6,7). These findings are relevant to Seychelles where tests to detect H. pylori (e.g. rapid urease test) are not routinely available locally and the national drug formulary does not include antibiotherapy for this indication.

Although the use of gastroscopy and biopsy is an invasive method resulting in some discomfort for the patient, this procedure provides clinicians with concrete proof of active H. pylori infection in the patients' stomach mucosa (8,9). For clinical purposes, with a patient displaying serious symptoms, the invasive approach including gastroscopy, biopsy and rapid urease test from the mucosa specimen (8) is indicated as the method has high specificity and sensitivity. It can be done easily with rapid results, without need for laboratory services.

Data in this study are based on a clinically selected group of patients and findings cannot therefore be inferred to the general population. For population purposes, the methods of choice would involve a non-invasive, serological screening (10).

Acknowledging that one single site biopsy may not be optimal to assess the infection of the gastric mucosa, we chose the antrum mucosa site alongside the greater curvature of the stomach, which is known to be the most common site for H. pylori colonization (10).

While our study may underestimate the prevalence of H. pylori colonization, our results suggest that at least 69% of the symptomatic patients were infected. The prevalence might be further underestimated as the results found in the remaining 31% of negative cases included totally negative as well as weak and late positive cases (i.e. test response after 24 hours). Late positive results are probably due to other bacterial infections or other Helicobacter strains with a low urease production or activity (11,12). Furthermore, we may have underestimated the true prevalence in our series by taking only one specimen from the antrum (10). It is known that H. pylori may be present in other areas of the stomach mucosa and that one negative biopsy is not sufficient to rule out H. pylori infection.

All patients were symptomatic at the time of the test. The higher H. pylori prevalence among treated (73,3%) patients than untreated (54,5%) patients suggests that the treatments failed to relieve symptoms or eradicate H. pylori.

We found similar prevalence of positive tests across various categories of several variables in agreement with findings in other studies (13-15). Higher prevalence of the infection among the members of the larger families is consistent with other studies (16). This suggests that the infection is acquired in closed social contacts, most probably in early childhood or adolescence (16).

In 1994, the International Agency for Research on Cancer classified H. pylori as a group I carcinogen, a definite cause of gastric adenocarcinoma in humans. This study and a previous one (4) suggest low incidence of atrophic gastritis, stomach cancer and stomach ulcer in Seychelles. Our findings of high prevalence of H. pylori and low prevalence of gastric cancer do therefore not suggest that H. pylori is strongly associated with cancer, as suggested by other studies (17-20). It may be speculated that H. pylori strains found in Seychelles have low pathogenic potential (11) and cause only benign stomach conditions. Whether different H. pylori strains do produce different clinical outcomes is yet to be clarified. However, it must be acknowledged that the study design and the limited number of cases in the studies from Seychelles do not permit to draw definitive conclusions to be drawn. Thus, further research is needed to investigate H. pylori strains in Seychelles and the apparent paradox of high prevalence of H. pylori and low incidence of gastric cancer and atrophic gastritis.

Findings suggest that two out of every three patients with recurrent symptoms might require treatment for H. pylori. Uncritical use of antibiotics, especially those which are known to select resistant strains of H. pylori (metronidazole), may have influenced our results and compromised the future efficacy of treatment (21-23). One-week regimens including omeprazole in combination with either clarithromycin or amoxycillin and a nitroimidazole have been shown to be cost-effective (24). Although H. pylori eradication initially results in higher costs than the alternative therapies, it reduces the risk of recurrence and, for most patients avoids future costs. The National Drug Formulary should be amended to include drugs for H. pylori eradication.

Acknowledgment

The author acknowledges the support of the Rotary Club of Victoria Seychelles in providing the test for this study.

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