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Correspondence to: Masahiko Inamori, MD, PhD, Gastroenterology Division, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. pj.ca.uc-amahokoy.dem@miromani
Telephone: +81-45-7872640 Fax: +81-45-7843546
AIM: To clarify the gender differences about the clinical features and risk factors of low-dose aspirin (LDA) (81-100 mg daily)-associated peptic ulcer in Japanese patients.
METHODS: There were 453 patients under treatment with LDA (298 males, 155 females) who underwent esophagogastroduodenoscopy at the Department of Gastroenterology and Hepatology of Hiratsuka City Hospital between January 2003 and December 2007. They had kept taking the LDA or started treatment during the study period and kept taking LDA during the whole period of observation. Of these, 119 patients (87 males, 32 females) were diagnosed as having LDA-associated peptic ulcer. We examined the clinical factors associated with LDA-associated peptic ulcer in both sexes.
RESULTS: A history of peptic ulcer was found to be the risk factor for LDA-associated peptic ulcer common to both sexes. In female patients, age greater than 70 years (prevalence ORs 8.441, 95% CI: 1.797-33.649, P = 0.0069) was found to be another significant risk factor, and the time to diagnosis as having LDA-associated peptic ulcer by endoscopy was significantly shorter than that in the male patients (P = 0.0050).
CONCLUSION: We demonstrated gender differences about the clinical features and risk factors of LDA-associated peptic ulcer. Special attention should be paid to aged female patients taking LDA.
Low-dose aspirin (LDA) is one of the main agents used for the prevention of thromboembolic vascular events, and has the advantages of both low cost and a prolonged duration of antiplatelet action; however, it is associated with a doubling of the risk of gastrointestinal bleeding, even at doses as low as 75 mg daily[2,3]. The gender differences in the clinical manifestations of LDA-associated gastroduodenal mucosal injury have not been well studied. The aim of this study was to clarify the clinical features and risk factors of LDA-associated gastroduodenal mucosal injury in both sexes.
There were 453 patients under treatment with LDA (298 males; median age, 71 years; age range, 43-93 years and 155 females; median age, 73 years; age range, 47-95 years) who underwent esophagogastroduodenoscopy (EGD) at the Department of Gastroenterology and Hepatology of Hiratsuka City Hospital between January 2003 and December 2007. The study was conducted in accordance with the Declaration of Helsinki and the study protocol was approved by the Ethics Committee of Hiratsuka City Hospital. The exclusion criteria were: patients who were taking LDA for less than 7 d, patients who had been previously diagnosed or treated for LDA-associated gastroduodenal mucosal injury in the past, patients with gastric or duodenal cancer, history of gastric or esophageal surgery and any current active cancer. Detailed information about the drug treatment and other risk factors were obtained from the medical records and also from interviews with the patients when they underwent medical examination. Concomitant use of anti-ulcer drugs (proton-pump inhibitors (PPIs), Histamine type 2 receptor antagonists (H2RAs), muco-protective agents, anticoagulants and/or antiplatelets and antithrombotic agents was defined as starting with LDA or taken for more than 4 wk before receiving endoscopy.
Endoscopic examinations were performed in each patient. Only ulcers with whitish exudate that were over 5 mm in size and had perceptible depth were included in the determination of the ulcer, with ulcer scars being excluded.
The patients diagnosed to have ulcer were checked for Helicobacter pylori (H. pylori) infection using the H. pylori serum antibody assay, urea breath test, rapid urease test and H. pylori culture of two biopsy specimens obtained from the gastric body and antrum. If one of the tests was positive, the patient was labeled as H. pylori-positive, and if more than two of the tests were negative, the patient was labeled as H. pylori-negative.
Statistical evaluation was carried out using Fisher’s exact test, t-test or Mann-Whitney U-test and these variables were also evaluated by multivariate logistic regression model using a Wald statistic forward stepwise selection. The level of significance was set at P < 0.05. Statistical analyses were performed with Stat View software (SAS Institute, Cary, NC).
The 453 patients under treatment with LDA who underwent EGD were included in this investigation. The baseline characteristics of the study population are summarized in Table Table1.1. One hundred and nineteen (26.3%, 87 males, 32 females) of the 453 patients receiving LDA were diagnosed as having LDA-associated peptic ulcer, consisting of 92 patients with LDA-associated gastric ulcer (71 males, 21 females), 20 patients with duodenal ulcer (14 males, 6 females) and 7 patients with gastric and duodenal ulcers (2 males, 5 females).
The age of female patients with ulcer was greater than that of without ulcer (P = 0.0338). The most common indication for LDA was secondary prevention of ischemic heart disease (62.3%, 282/453). There were no significant differences in the distribution of underlying diseases between patients with ulcer and without ulcer (P = 0.8380). There were no significant differences in the presence of the gastrointestinal (GI) symptoms, defined as abdominal pain, nausea, reflux symptoms and/or the indigestion syndrome, between the patients with ulcer and without ulcer (P = 0.0761). Forty-six patients presented with melena and/or hematemesis and bleeding source in the stomach or duodenum identified by endoscopy were excluded from GI symptoms in this analysis. Moreover, even in patients with peptic ulcer, about half were asymptomatic.
Univariate analyses to identify predicted factors of LDA-associated gastroduodenal ulcer in both sexes were shown in Table Table2.2. A history of peptic ulcer was found to be the only significant risk factor common to both sexes (male, P = 0.0109, female P = 0.0030), and age greater than 70 years was another risk factor in female patients (P = 0.0443). As shown in Table Table3,3, there were no significant differences in the prevalence of LDA-associated peptic ulcer among age brackets in either sex (male, P = 0.3137, female P = 0.3612).
The H. pylori infection status was determined in 69 patients (58.0%, 69/119), but remained unknown in the remaining 50 patients who were therefore not included in the statistical analysis of this parameter. Of the 69 patients, 62.3% (43/69) were H. pylori-positive [gastric ulcer, 69.1% (38/55); duodenal ulcer, 25.0% (2/8); gastric and duodenal ulcer, 50.0% (3/6)] and 26 (37.7%) were H. pylori-negative. There were no significant differences in the H. pylori infection rate between both sexes [male: 66.7% (30/45), female: 54.2% (13/24)] (P = 0.4344). The H. pylori infection rate was significantly lower in patients with LDA-associated ulcer as compared with that in patients with non-LDA-associated ulcer [including other nonsteroidal anti-inflammatory drugs (NSAIDs) associated ulcer] (77.0%, 419/544) diagnosed in the same study period (data are not shown in Tables) (P = 0.0112).
As shown in Table Table4,4, we investigated the time from the start of LDA administration to the diagnosis as having LDA-associated peptic ulcer by endoscopy in 106 of the 119 patients (89.1%). LDA-associated peptic ulcer was diagnosed within the first month in 6 cases (5.7%) within the first 12 mo in 28 cases (26.4%), and within 5 years in 74 cases (69.8%). In female patients, the duration was significantly shorter than in male patients (P = 0.0050) (male: mean 42.0 mo; range, 1-223 mo, female: mean, 25.5 mo; range, 1-130 mo). The incidence of LDA-associated peptic ulcer seemed almost constant and did not decrease with time, at least over the follow-up period of 72 mo in this study.
Table Table55 shows the results of multivariate analyses to identify the risk factors of LDA-associated peptic ulcer in both sexes. In male patients, a history of peptic ulcer (prevalence ORs 3.745, 95% CI: 1.734-8.088, P = 0.0008) was found to be associated with an increase in the risk, and a history of PPIs (prevalence ORs 0.069, 95% CI: 0.009-0.555, P = 0.0120) and/or H2RAs (prevalence ORs 0.498, 95% CI: 0.256-0.967, P = 0.0396) use was found to be associated with a decrease in the risk. In female patients, a history of peptic ulcer (prevalence ORs 6.439, 95% CI: 1.874-22.131, P = 0.0031) and age greater than 70 years (prevalence ORs 8.441, 95% CI: 1.797-33.649, P = 0.0069) were associated with an increase in the risk. Statistical analysis with respect to the use of PPIs could not be performed in female patients, because there was no female patient taking PPIs who was diagnosed as having LDA-associated peptic ulcer.
The present study demonstrated gender differences in the clinical features of LDA-associated gastroduodenal ulcer in Japanese patients. Previous reports have indicated age greater than 65 years, previous history of peptic ulcer[4,5], use of other NSAIDs and H. pylori infection as some of the risk factors of LDA-associated peptic ulcer, and the concomitant use of antisecretory drugs as a factor reducing the risk of LDA-associated peptic ulcer[5,8,9]. In this study, a history of peptic ulcer was found to be the risk factor of LDA-associated peptic ulcer common to both sexes. In female patients, advanced age or aging was found to be another significant factor. In elderly patients, gastric mucosal defenses are impaired because of the reduced mucus and bicarbonate secretion, and also the significant decrease in gastric mucosal perfusion. The reduced gastric mucosal defenses coupled with a reduced gastric prostaglandin biosynthesis may account for the higher susceptibility of the mucosa to damage-inducing agents. In general, female subjects are at a relatively reduced risk of developing gastric ulcers. In animal experimental models, female sex hormones have been demonstrated to show significant antiulcer activity and to promote healing of drug-associated ulcers (aspirin, indomethacin)[12,13]. Estrogen has also been reported to reduce the incidence of H. pylori-associated gastric mucosal injuries, despite having no effect on the H. pylori infection status. Female sex hormones may exert a protective effect against LDA-associated mucosal injury. In female patients of advanced age, the gradual decrease in the serum levels of female sex hormones after menopause and with advancing age, coupled with the reduced gastric mucosal defenses may be responsible for the increase in the risk of LDA-associated peptic ulcer.
In addition, time from the start of LDA until the diagnosis of LDA-associated peptic ulcer by endoscopy was shorter in the female patients. This gender difference, akin to the significantly higher relative risk and short time-to-onset of alcohol-related liver disease in women as compared to men for any given level of alcohol intake, is yet to be well elucidated. The incidence of peptic ulcer seemed almost constant and does not decrease with time, at least over the follow-up period of 72 mo in this study (Table (Table3).3). It has been suggested that NSAID-associated gastrointestinal bleeding occurs mainly within the first few weeks of treatment, which is a shorter period than that reported in LDA users. We should recognize that LDA-associated peptic ulcer may not occur for several years; therefore, it is important to continue antisecretory therapy, especially in high-risk patients. Future prospective cohort studies are needed to confirm this assumption.
The gender differences in the clinical manifestations of low-dose aspirin (LDA)-associated gastroduodenal mucosal injury have not been well-studied.
The authors hypothesized that there were gender differences in clinical features of LDA-associated peptic ulcer, and it might be useful to identify the risk factors of LDA associated ulcer in both sexes.
In female patients, age greater than 70 years was found to be a significant risk factor of LDA associated peptic ulcer in addition to a history of peptic ulcer, and the time to diagnosis as having LDA-associated peptic ulcer by endoscopy was significantly shorter than that in the male patients.
By understanding the gender differences in clinical features of LDA-associated ulcer, this study may represent a future strategy for the prevention of LDA-associated peptic ulcer.
Special attention should be paid to aged female patients taking LDA. People should also recognize that LDA-associated peptic ulcer may not occur for several years; therefore, it is important to continue antisecretory therapy, especially in high-risk patients.
This study is adequately designed and performed. It means a contribution in a topic of high relevance.
Peer reviewers: Dr. Philip Abraham, Professor, Consultant Gastroenterologist & Hepatologist, P. D. Hinduja National Hospital & Medical Research Centre, Veer Savarkar Marg, Mahim, Mumbai 400 016, India; Julio H Carri, Professor, Internal Medicine - Gastroenterology, Universidad Nacional de Córdoba, Av.Estrada 160-P 5-Department D, Córdoba 5000, Argentina
S- Editor Tian L L- Editor O'Neill M E- Editor Lin YP