Peptic ulcer is a localized loss of mucosa in the gastric and/or duodenal wall, reaching deep into the muscularis . It results from an imbalance between aggressive and protective factors of the gastroduodenal wall [1] - [3] . Of the several etiologies of PUD, the most frequent is chronic H. pylori infection, as shown by the study of Marshall and Warren [4] . However, H. pylori seems to decrease with the level of industrialization of the country [5] [6] and highlights the African paradox where the prevalence of H. pylori, estimated at 80% by the World Health Organization (WHO), is not associated with a higher frequency of peptic ulcer [7] [8] . It is in this light that we question the impact of H. pylori on the occurrence of PUD in Libreville.

The aim of this study was to establish the epidemiological and etiological profile of patients with PUD and investigate the relationship between H. pylori and PUD in Libreville.

This is a prospective cross-sectional study carried out in the Hepato-Gastro-Enterology (HGE) Department of the Libreville University Teaching Hospital. The study was conducted between 1 January 2017 and 31 December 2019. The study population involved all patients undergoing oesogastroduodenal endoscopy (OGDE). We included patients with gastric and/or duodenal ulcers who gave their consent and had undergone at least two antral and two fundic biopsies for H. pylori, and for whom we had pathological results. We excluded patients who had previously received antibiotic therapy less than 1 month and those who had received a proton pump inhibitor (PPI) less than 2 weeks previously. Using a standardized form, we collected epidemiological data (age, sex, socio-economic level), clinical data (pain characteristics), indication for OGDE, personal history (PUD, notion of H. pylori gastritis, upper digestive hemorrhage, gastro-esophageal reflux disease (GORD), stroke, diabetes, sickle cell anemia, HIV infection, hepatitis B, hepatitis C, cirrhosis), family history (history of PUD, history of stomach cancer), history of taking gastrotoxic substances (anti-inflammatories, anti-platelet aggregates, anti-coagulants, traditional concoctions, tobacco, alcohol), notion of stress, results of OGDE (number of PUD, location and site, Forrest classification, associated endoscopic lesions), anatomopathological results of biopsies (presence or absence of H. pylori, acute gastritis, chronic gastritis, dysplasia, metaplasia, cancer). Data were entered and analyzed using Epi Info 7.2 statistical software. Qualitative variables were expressed as percentages and quantitative variables as means and standard deviation. Comparisons or associations between categorical variables were analyzed using Pearson’s chi-square test corrected according to Yates and Fisher to account for the number of patients. Confidence intervals were expressed at the alpha error threshold equal to 0.05. Variables whose association with the expected event had a p-value of less than 0.05 were considered statistically significant.

Study limitations

The fact that immunohistochemistry is not routinely used to detect H. pylori infection means that the incidence of this condition may be underestimated. However, pathological analysis remains the gold standard for diagnosing H. pylori infection [9] .

Epidemiology

The hospital incidence of PUD was 16.1% in upper GI endoscopy at the Libreville University Teaching Hospital. This frequency, similar to that found in Togo (15.53%) and Cameroon (17.1%), was higher than that reported by Perret et al. in Gabon (8.75%) and Diouf et al. in Senegal [10] - [13] . These differences support the observation by Archampong et al. in Ghana that the development of digestive endoscopy in Africa has led to a significant increase in the number of cases in recent publications [14] . The mean age was 48.7 ± 17.3 years, similar to that found in all African countries [10] - [15] . However, it remains lower than in studies conducted in the Western countries, where it is 15 years to 20 years higher [16] [17] . The male predominance of patients with PUD (52.7%) is consistent with the literature [10] - [18] . Analysis of the socioeconomic profile reveals a predominance of the disease in participants with low socioeconomic status (65.9%). This same observation was made in Cameroon, including 64.9% of patients with PUD by Ankouane et al. . Diagnosis Clinically, the typical ulcer syndrome was present in 71.3% of patients. It was also observed in 64.3% of patients in Congo by Ontsira et al. and in 64.52% of patients in Togo by Lawson et al. [10] [19] . The most common location of the ulcer was gastric (55.1%), whereas it was duodenal in the other African studies [10] [11] [13] - [15] . This gastric location of PUD in Gabon was already highlighted by Perret et al. more than 30 years ago [12] .

In terms of etiology, H. pylori infection was present in 79.6% of patients. Although this prevalence is close to that found in Cameroon (72.5%), Congo (72%), Togo (70.41%), and Senegal (83.6%), it contrasts with previous Gabonese data which found a prevalence of H pylori of 37.5% in endoscopy and 62% in pediatrics [10] - [13] [15] [21] - [23] . This difference with previous Gabonese data is probably a consequence of methodological differences. We excluded patients who had taken antibiotics and PPIs, which was not the case in previous studies. In addition, comparative analysis of other known risk factors for PUD revealed a statistically significant difference between the absence of H. pylori infection and the use of NSAIDs (p = 0.00014), as well as alcohol consumption (p = 0.0242) and occupational stress (p = 0.003). These other risk factors, although poorly identified in African studies, are among the most common causes of PUD in the West [10] - [20] . Similarly, the predominant gastric location of positive H. pylori PUD and the predominant duodenal location of PUD without H. pylori, reveals a decrease in gastric protective factors during H. pylori infection and an increase in aggressive factors when taking NSAIDs, alcohol, and occupational stress [16] - [18] .

PUD is a frequent pathology in upper digestive endoscopy in Libreville, preferentially affecting men of low socioeconomic status aged under 50. It is revealed by a typical PUD syndrome with a common endoscopic site in the stomach. H. pylori infection is the main etiology, although the use of NSAIDs, alcohol, and occupational stress are risk factors that need to be clarified in our context.