THE NATIONAL MEDICAL JOURNAL OF INDIA VOL. 11, NO.1, 1998

Original Articles5

Prevalence of Helicobacter pylori infection in disorders of theupper gastrointestinal tract in south India

V. KATE, N. ANANTHAKRISHNAN, S. BADRINATH, C. RATNAKAR

ABSTRACTBackground. Helicobacter pylori (H. pylon) .is the most

common human infection. Though most individuals areasymptomatic, H. pylori plays a key role in the aetiology ofmany upper gastrointestinal disorders. The prevalence ofduodenal ulcer in south India is high but there are very fewreports regarding the prevalence of H. pylori infection invarious upper gastrointestinal disorders in south Indians.Therefore, we studied the prevalence of H. pylori infection inupper gastrointestinal disorders in south Indians.

Methods. Three hundred and thirty-five patients with vari-ous upper gastrointestinal disorders were included in thestudy. Seventy-five patients with no gastrointestinal diseasebased on symptoms and endoscopy were taken as controls.The H. pylori status was determined by the urease test,serology and histology and the prevalence compared betweenvarious upper gastrointestinal disorders, with controls and withone another.

Results. The prevalence of H.pylori was high in the patientsand controls. Duodenal ulcer patients had a significantly higherprevalence compared to controls (p<O.001) and those withother upper alimentary disorders. There was no significantdifference between patients with other disorders and controlsnor between each other (p>O.05).

Conclusion. The prevalence of H. pylori infection is high insouth India. It is closely associated with duodenal ulcer. Morepopulation-based studies are required to evaluate the relation-ship of H. pylori with other disorders of the upper gastrointes-tinal tract.Natl Med J India 1998;11:5-8

INTRODUCTIONHelicobacter pylori (H. pylori) is possibly the most commonhuman infection. While most individuals are asymptomatic, in-fection acts as a co-factor to produce gastrointestinal disease in asmall but significant minority. It has been strongly linked aetio-logically to chronic gastritis and duodenal ulcer disease but itsrole in non-ulcer dyspepsia, gastric ulcer disease and gastriccarcinoma has been less well established. I Higher H. pylori

lawaharlal Institute of Postgraduate Medical Education and Research,Pondicherry 605006, India

V. KATE, N. ANANTHAKRISHNAN Department of SurgeryS. BADRINA TH Department of MicrobiologyC. RATNAKAR Department of Pathology

Correspondence to N. ANANTHAKRISHNAN

© The National Medical Journal of India 1998

infection rates have been reported with increasing age from allover the world and certain ethnic groups are at higher risk thanothers. African and Hispanic Americans have higher infectionrates compared with Caucasian Americans.i-' However, regard-less of the ethnic background, people in developing countriesacquire infection earlier than those in developed countries.

The epidemiology of H. pylori in India differs from thatobserved in developed countries. Exposure occurs in the earlyyears and almost all adults have evidence of previous exposure.More than half the population has active colonization by the ageof 20 years.' However, data concerning the prevalence of H.pylori infection in south India are scanty. The present study wasundertaken to determine the prevalence and relationship betweenH.pylori infection in patients with different upper gastrointestinaldisorders and the asymptomatic population using urease test,serology and histology.

PATIENTS AND METHODSPatientsThree hundred and thirty-five patients having disorders of theupper gastrointestinal tract with a clinical diagnosis of duodenalulcer, gastric ulcer, carcinoma stomach, non-ulcer dyspepsia,chronic gastritis, and stomal ulcer were studied from January1995 to December 1996. The diagnosis was con finned by video-endoscopy and histology for gastric ulcer, carcinoma stomach andchronic gastritis. Patients with peptic ulcer type of pain but anormal endoscopic appearance were classified as non-ulcerdyspepsia (NUD). Others who had oedema or redness of thegastric mucosa which was histologically confirmed as gastritiswere included in the chronic gastritis group. Seventy-five patientsadmitted to the surgical wards without gastrointestinal disorderswere included as controls. Informed consent and ethical clearancefrom the institute's ethics committee were obtained. An uppergastrointestinal endoscopy was done in all the patients andcontrols to rule out asymptomatic peptic ulcers or other uppergastrointestinal disorders. Patients who had taken antibiotics, H2blockers or proton pump inhibitors in the month preceding pre-sentation were excluded.

MethodsThe presence of H. pylori was determined by the urease test,serology and histology. Any two of the three tests, if positive,were considered positive for H. pylori infection. Serology wasused as one of the methods as some patients might have takendrugs such as metronidazole (unknowingly) which are known toproduce suppression of H. pylori and a false-negative urease test.However, the serology of H. pylori would not be affected as it is

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a chronic infection that does not resolve spontaneously. ElevatedIgG titres indicate active infection, unless the patient is known tohave been treated for H pylori in the recent past.'

Urease test

This was done using a urea solution prepared and standardized inour institution. It contained 250 mg urea, 400 JlI of gentamicin (40mg/ml) and 400 JlI of phenol red in 15 ml of distilled water. Oneml of this solution was then put in a sterile 5 ml screw-cappedbottle. The sensitivity and specificity of this urea solution wasmore than 90% compared to histology. The change of colour fromyellow to pink read up to 24 hours at room temperature afterinoculating two endoscopic biopsies from the gastric antrum wasconsidered positive.

SerologyThe serum assay used for the detection of IgG antibodies to Hpylori was a validated second-generation Microwell ELISA assayusing purified solid phase antigens (UBI Magiwell Helicobacterpylori IgG quantitative IA-60I Microwell ELISA supplied byUnited Biotech Inc., CA, USA). Blood (5 ml) was collected fromeach patient by standard venepuncture and centrifuged to collectthe sera which was stored at -20°C till use. The test was consid-ered valid if it met the given criteria. This commercial kit had asensitivity of 96% and specificity of 90% compared with breathtest, histology and Campylobacter-Iike organism (CLO) test(information supplied by the manufacturer). This has been vali-dated at our centre and found to have a sensitivity of 91% andspecificity of 84% compared to urease and histology. The resultsofthe optical density (OD value) were converted to ELISA unitsper ml (EU/ml) by the given formula. All equivocal and positivetests were repeated to confirm the result.

HistologyTwo endoscopic biopsies taken from the pyloric antrum close tothe pylorus were fixed in 10% formalin. Paraffin-embeddedhistological sections were stained with Giemsa for identificationof H pylori.

The results were analysed by the Chi-square test with Yates'correction. The prevalence of H pylori infection in various uppergastrointestinal disorders was compared with controls and witheach other. A calculated alpha value ofless than 5% was consid-ered significant.

RESULTSThree hundred and thirty-five patients with various upper gas-trointestinal disorders were included in the study. Seventy-fivepatients were taken as controls. None of the patients taken as

THE NATIONAL MEDICAL JOURNAL OF INDIA VOL. 11, NO.1, 1998

controls had a silent peptic ulcer. The patients and controls werecomparable with respect to age, sex and socio-economic status.All patients who had a stomal ulcer previously had a truncalvagotomy and gastrojejunostomy for chronic duodenal ulcer.

The prevalence of H pylori in various disorders is shown inTable I. H pylori infection in duodenal ulcer patients was signifi-cantly more than that in controls (p<O.OOI). A similar highprevalence was seen in patients with stomal ulcer. However, thiswas not statistically significant compared to the controls (p>0.05;Table I). There was no significant difference in the prevalence ofH pylori in patients with other disorders and controls. Compari-son between the prevalence of H pylori in different upper gastro-intestinal disorders showed a significantly higher prevalence ofH pylori infection in duodenal ulcer patients than those withcarcinoma stomach, non-ulcer dyspepisa, gastric ulcer and chronicgastritis (p<0.05). However, there was no difference in preva-lence between duodenal ulcer and stomal ulcer patients. Compari-son of H pylori prevalence in other groups of patients did notshow any significant difference between one another (p>0.05;Table II).

DISCUSSIONNumerous epidemiological studies have shown considerable dif-ferences in the prevalence of H pylori infection in the populationstudied." The infection rate is generally higher and begins at anearlier age in developing as compared to developed countries,indicating an important role of socio-economic milieu in itstransmission. For detection of H pylori infection in patients withdyspepsia, an indirect test such as serology along with a direct onesuch as urease or histology might be more useful, as such acombination will detect the organisms as well as the antibodies.Hence, there would be a lesser possibility of getting a false-negative test even in patients who are continuously or intermit-tently on antibiotics, H2blockers or proton pump inhibitors.

TABLE I. Prevalence of Helicobacter pylori infection in variousupper gastrointestinal tract disorders and controls

Disorder n Helicobacter pylori status p value"Positive Negative

Duodenalulcer 145 132 (91) 13 (9) <0.001Gastriculcer 50 38 (76) 12 (24) nsCarcinomastomach 51 33 (65) 18 (35) nsNon-ulcerdyspepsia 43 32 (74) 11 (26) nsChronicgastritis 30 23 (77) 7 (23) nsStomalulcer 16 15 (94) 1 (6) nsControls 75 45 (60) 30 (40)

• Comparison of Helicobacterpyloripositive patients with controlsFigures in parentheses are percentages ns not significant

TABLE II. Comparison of Helicobacter pylori prevalence between various disorders of upper gastrointestinal tract using theChi-square test for analysis

Disorder Duodenalulcer GastricuI cer Carcinomastomach Non-ulcerdyspepsia Chronicgastritis StomalulcerX' value p value X' value p value X' value p value X' value p value X' value p value x' value p value

Duodenalulcer 7.55 <0.01 19.5 <0.001 8.2 <0.01 5.18 <0.05 o .008 nsGastriculcer 7.55 <0.01 1.63 ns 0.037 ns 0.003 ns 1.35 nsCarcinomastomach 19.5 <0.001 1.63 ns 1.06 ns 1.31 ns 3.029 nsNon-ulcerdyspepsia8.2 <0.01 0.37 ns 1.06 ns 0.048 ns 1.54 nsChronicgastritis 5.18 <0.05 0.003 ns 1.31 ns 0.48 ns 1.13 nsStomalulcer 0.0086 ns 1.35 ns 3.029 ns 1.54 ns 1.13 ns

ns not significant At one degree freedom, the )(' value of more than 3.48 was interpreted as significant at 5% level

KATEet al. : PREVALENCEOFHelicobacter pylori IN SOUTHINDIA 7

TABLEIII. Results of studies on the prevalence of Helicobacter pylori infection in upper gastrointestinal tract disorders

Author(year) n Method % Prevalenceof H. pyloriDuodenalulcer Gastriculcer Chronicgastritis Carcinomastomach Non-ulcerdyspepsia Controls

Dore? (1997) 50 B 82Dayal' (1997) 60 UH 95Sivaprakash"(1996) 70 US 63 47Bhargava'? (1994) 49 H 76Prasad" (1994) 206 H 93 81 71 83Satoskar'!(1994) 109 H 50PrabhuIJ (1995) 100 H 38 68our- (1993) 608 UH 65 46Laine" (1996) 207 H 65 56Goh16 (1997) 1060 H 91 74 31HU'7(1995) 1006 H 99 100Lin" (1994) 639 S 87 76 56 59Uyub'9 (1994) 1136 HS 50 5 9 5Joshi'? (1997) 104 UH 66 100 * 48 100 * 44Presentstudy (1997) 335 UHS 91 76 77 65 74 60

The prevalence of Helicobacter pylori in stomal ulcers in the present study was found to be 94% U urease test H histology S serologyB 13 C urea breath test All figures have been rounded off to whole numbers * Only 2 patients in this group

The prevalence of H. pylori infection in duodenal ulcer pa-tients has consistently been found to be between 95% and 100%.6In the present study too it was 91% and significantly morecompared to the other gastrointestinal disorders and controls(Tables I and II). The prevalence of H. pylori seen in other Indianand non-Indian series is shown in Table IIJ.1-20Prasad et al. alsoreported a high prevalence of H. pylori infection in patients withduodenal ulcer from south India." In spite of the close associationof H. pylori with duodenal ulcer, evidence for a definite directcausal relationship does not exist as yet. Only a minority ofindividuals harbouring H. pylori develop duodenal ulcer disease(lifetime prevalence approximately 10%).21Thus, H. pylori prob-ably plays the role ofa risk factor, albeit a dominant one, becausesustained eradication cures the disease. Patients with non-ulcerdyspepsia" have been reported to have H pylori infection (43o/n-87%).13-25Uyub et al. reported a very low prevalence (9%) of Hpylori infection in north-eastern peninsular Malaysia in patientswith non-ulcer dyspepsia as well as those with duodenal (50%)and gastric ulcer (5%).19In our study, the prevalence was 74% inpatients with non-ulcer dyspepsia; relatively higher compared toother Indian reports." There was no significant difference incolonization rates in other gastrointestinal disorders compared tocontrols.

It is widely accepted that colonization of the-gastric surfaceepithelium by H pylori is commonly associated with type Bchronic gastritis. Characteristically, H. pylori gastritis predomi-nantly affects the antrum. In the present study, all patients ofchronic gastritis were type B. Biopsy showed evidence of gastritisand endoscopically marked congestion was present in the antrum.The prevalence of H pylori in subjects with type B antral gastritisapproaches 100% but lesser prevalence rates have also beenreported.":" H. pylori infection was seen in 77% of cases of ourpatients with gastritis. Though previous reports show an almostequal prevalence in duodenal ulcer and gastritis, we found asignificant difference between them (p<0.05). The need for treat-ment of H pylori infection in gastritis is controversial. Someinvestigators advise treatment to prevent progression to duodenalulcer and rarely gastric cancer. The National Institutes of Healthstudy has not given any clear guidelines for this condition."

H. pylori is directly linked with chronic non-specific andduodenal ulcer disease. It may also be indirectly linked to gastric

ulceration through its association with gastric atrophy. A moredirect association has not yet been proved. Langenberg et al.reported an H pylori prevalence of 80% in patients with gastriculcer." A study which showed decreased gastric ulcer recurrenceusing triple antibiotic and ranitidine compared with ranitidinealone has provided evidence for a direct role of H. pylori in thepathogenesis of gastric ulcers."

The prevalence of H pylori infection in patients taking non-steroidal anti-inflammatory drugs (NSAIDs) has been reported torange from 22% to 63%.32.33Since factors such as age, ethnicbackground and socio-economic status are important in determin-ing the background prevalence of H pylori infection, a matchedcontrol group is mandatory to determine whether H. pylori preva-lence is similar in NSAID users and non-users. Most studies haveshown no significant difference."

In the present study the prevalence of H pylori in gastric ulcerswas 76% which was significantly less than that seen in duodenalulcer patients (p<O.OI) but there was no significant differencebetween gastric ulcer and controls. The current recommendationis that patients with H pylori-associated gastric ulcer should betreated to eradicate H. pylori infection." As the prevalence is lowin NSAID-associated gastric ulcer, more patients are likely to beH. pylori negative in this subset of patients. No specific treatmentagainst H. pylori is necessary in them.

Two cancers are associated with H pylori-gastric carcinomaand lymphoma ofthe mucosa-associated lymphoid tissue (MALT).The intestinal type of adenocarcinoma is strongly associated withH. pylori. In an extensive review of gastric cancer and H. pylori,the EUROGAST Study Group determined that presence of H.pylori confers an approximately 6-fold risk of gastric cancer,accounting for about half of all gastric cancers." Cross-sectionalstudies reveal infection rates between 50% and 100% in peoplewith adenocarcinoma.v-" The present study showed the preva-lence of H. pylori to be only 65% which was not significantlyhigher than that in controls. In our study, there was no significantdifference in H. pylori prevalence between benign and malignantulcers of the stomach (p>0.05) but a significant difference wasseen in comparison to duodenal ulcer patients (p<O.OOl).Most ofour patients had the intestinal type of gastric adenocarcinoma. Huet al. reported that those who develop gastric cancer have asignificantly higher prevalence of H pylori infection (92.2%) as

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diagnosed by serology than that found in an age/sex-matchedcontrol population."

MALT lymphomas are associated with H. pylori in 90% ofcases." In a recent abstract, the German MALT Lymphoma StudyGroup reported that apparent cure of MALT lymphoma occurredin half the patients in whom H. pylori was eradicated." In future,H. pylori therapy may be the initial step in the treatment of provenor suspected gastric lymphoma. In India, no study has beenreported regarding MALT lymphoma and H. pylori. We, too,have not come across a case of MALT lymphoma.

In our study, the prevalence of H. pylori in stomal ulcers washigh (94%). However, this was not statistically different fromcontrols, probably due to the small number of patients. Eradica-tion of H. pylori in patients with stomal ulcer and completevagotomy should reduce the incidence of relapse of these ulcersand prevent complications such as perforation and gastro-jejunocolic fistula.

We conclude that H. pylori infection is very common in thesouth Indian population. A high prevalence is seen in all gas-troduodenal diseases and more than half the population withoutany abdominal symptoms was colonized by the bacterium. Theprevalence of duodenal ulcer is high in south India and the highprevalence of H. pylori infection might suggest an important rolein its pathogenesis. More population-based studies are required toevaluate its role in other gastrointestinal disorders in this region.

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