Representativeness and response rates from the Domestic/International Gastroenterology Surveillance Study (DIGEST)

Systematic review of the epidemiology of gastroesophageal reflux disease in Japan

BACKGROUND

Epidemiological studies of gastroesophageal reflux disease (GERD) in Japan vary in design. This systematic review examines the prevalence of GERD in Japan, distinguishing between study methodologies, and reports on changes over time and factors potentially associated with GERD.

METHODS

PubMed and Embase searches identified studies reporting the prevalence of GERD in the general population, primary care patients, and individuals undergoing routine health checks.

RESULTS

Of the twenty eligible studies, half excluded individuals taking acid-suppressive medication, so these studies would have been likely to have underestimated the prevalence by 2-3%. Nine studies reported the prevalence of at least weekly reflux symptoms (the definition closest to the Montreal definition): in seven studies this was 6.5-9.5%, but in two studies that included individuals who underwent upper gastrointestinal endoscopy the prevalence was 19.0 and 21.8%. Eight studies used symptom scores: prevalence estimates ranged from 10.2 to 29.0% in five studies using the Carlsson-Dent self-administered questionnaire (QUEST), and from 27.0 to 37.6% in three studies using the frequency scale for the symptoms of GERD. Prevalence estimates were 15.1-24.3% in three studies that reported the presence of reflux symptoms of undefined frequency. Six studies reported the prevalence of reflux esophagitis as 4.9-8.2%. Changes in prevalence over time and factors associated with reflux symptoms were inconsistent.

CONCLUSIONS

Few studies have reported the prevalence of GERD in Japan using standardized criteria. Thus, prevalence estimates vary substantially, reflecting differences in study populations and GERD definitions. However, seven studies reported that the prevalence of at least weekly symptoms was 6.5-9.5%, a finding which approaches that reported in Western populations (10-20%).

Methods and representativeness of a European survey in children and adolescents: the KIDSCREEN study

BACKGROUND

The objective of the present study was to compare three different sampling and questionnaire administration methods used in the international KIDSCREEN study in terms of participation, response rates, and external validity.

METHODS

Children and adolescents aged 8-18 years were surveyed in 13 European countries using either telephone sampling and mail administration, random sampling of school listings followed by classroom or mail administration, or multistage random sampling of communities and households with self-administration of the survey materials at home. Cooperation, completion, and response rates were compared across countries and survey methods. Data on non-respondents was collected in 8 countries. The population fraction (PF, respondents in each sex-age, or educational level category, divided by the population in the same category from Eurostat census data) and population fraction ratio (PFR, ratio of PF) and their corresponding 95% confidence intervals were used to analyze differences by country between the KIDSCREEN samples and a reference Eurostat population.

RESULTS

Response rates by country ranged from 18.9% to 91.2%. Response rates were highest in the school-based surveys (69.0%-91.2%). Sample proportions by age and gender were similar to the reference Eurostat population in most countries, although boys and adolescents were slightly underrepresented (PFR <1). Parents in lower educational categories were less likely to participate (PFR <1 in 5 countries). Parents in higher educational categories were overrepresented when the school and household sampling strategies were used (PFR = 1.78-2.97).

CONCLUSION

School-based sampling achieved the highest overall response rates but also produced slightly more biased samples than the other methods. The results suggest that the samples were sufficiently representative to provide reference population values for the KIDSCREEN instrument.

Demographic determinants of acute gastrointestinal illness in Canada: a population study

Background

Gastrointestinal illness is an important global public health issue, even in developed countries, where the morbidity and economic impact are significant. Our objective was to evaluate the demographic determinants of acute gastrointestinal illness in Canadians.

Methods

We used data from two population-based studies conducted in select communities between 2001 and 2003. Together, the studies comprised 8,108 randomly selected respondents; proxies were used for all respondents under 12 years and for respondents under 19 years at the discretion of the parent or guardian. Using univariate and multivariate logistic regression, we evaluated the following demographic determinants: age, gender, cultural group, and urban/rural status of the respondent, highest education level of the respondent or proxy, number of people in the household, and total annual household income. Two-way interaction terms were included in the multivariate analyses. The final multivariate model included income, age, gender, and the interaction between income and gender.

Results

After adjusting for income, gender, and their interaction, children under 10 years had the highest risk of acute gastrointestinal illness, followed by young adults aged 20 to 24 years. For males, the risk of acute gastrointestinal illness was similar across all income levels, but for females the risk was much higher in the lowest income category. Specifically, in those with total annual household incomes of less than $20,000, the odds of acute gastrointestinal illness were 2.46 times higher in females than in males.

Conclusion

Understanding the demographic determinants of acute gastrointestinal illness is essential in order to identify vulnerable groups to which intervention and prevention efforts can be targeted.

The burden of acute gastrointestinal illness in Ontario, Canada, 2005-2006

A retrospective, cross-sectional telephone survey (n=2090) was conducted in Ontario, Canada, between May 2005 and April 2006, to determine the burden of acute gastrointestinal illness in the population. The 4-week prevalence was 8.56% (95% CI 7.36-9.76); in households with more than one resident, 35% of cases reported someone else in their household had similar symptoms at the same time. The annual adjusted incidence rate was 1.17 (95% CI 0.99-1.35) episodes per person-year, with higher rates in females, rural residents, and in the winter and spring. Health care was sought by 22% of cases, of which 33% were asked to provide a stool sample. Interestingly, 2.2% of cases who did not visit a health-care provider reported self-administering antibiotics. Overall, acute gastrointestinal illness appears to pose a significant burden in the Ontario population. Further research into the specific aetiologies and risk factors is now needed to better target intervention strategies.

A systematic review of the efficacy of cesarean section in the preservation of anal continence

PURPOSE

Elective primary cesarean section is performed largely to avoid maternal pelvic trauma that may result in anal incontinence, although its efficacy in this regard has not been thoroughly assessed. We perform a systematic review of published reports that compare anal incontinence risk by mode of delivery.

METHODS

PubMed was searched from 1966 through August 2005. Authors were contacted for missing data or analyses. Both randomized and nonrandomized reports were included. Eligible studies included females having vaginal delivery or cesarean section, fecal and/or flatal incontinence was reported as an outcome, and risk was calculable from the reported data. Crude data were extracted from the reports, as well as reported odds ratios and confidence intervals. In the nonrandomized studies, adjusted odds ratios also were extracted and additional data obtained from authors to adjust risks for age and parity if not originally done. Sensitivity analyses were performed using quality indicators: age and parity adjustment, time to continence assessment, and mode of previous delivery.

RESULTS

Fifteen studies were found eligible, encompassing 3,010 cesarean sections and 11,440 vaginal deliveries. The summary relative risk for fecal incontinence was 0.91 (95 percent confidence interval, 0.74-1.14). For flatus the relative risk was 0.98 (range, 0.86-1.13). The number needed to treat by cesarean section was 167 to prevent a single case of fecal incontinence. Five studies were judged to be of high quality. In these studies, the summary relative risk was 0.94 (range, 0.72-1.22) and number needed to treat was 198.

CONCLUSIONS

The best evidence to assess the efficacy of cesarean section in the prevention of anal incontinence would be in randomized trials of average-risk pregnancies with few crossovers. In the absence of such trials and based on this review, cesarean section does not prevent anal incontinence. This implies that incontinence associated with delivery may be more likely incontinence caused by pregnancy.

Gastroesophageal reflux symptoms and well-being in a random sample of the general population of a Swedish community

OBJECTIVES

There is limited information on the relationship between gastroesophageal reflux symptoms and well-being in the general population. This study aimed to investigate this relationship and determine the severity threshold at which reflux symptoms meaningfully affect patients' well-being.

METHODS

A random sample of the population of Malmö, Sweden (n = 4,624), was sent the Gastrointestinal Symptom Rating Scale, the Subjective Symptom Assessment Profile, and the Psychological General Well-Being Index. The relationship between well-being and the severity of heartburn, acid regurgitation, stomach pain, and abdominal pain was investigated by analysis of covariance (ANCOVA).

RESULTS

Complete data were obtained from 1,476 subjects (43% male; mean age [standard deviation], 49.9 [14.2] yr). The mean Psychological General Well-Being Index score was 102 (95% CI: 101-103). Increasing symptom severity was associated with a decrease in well-being, and correlations between Psychological General Well-Being Index score and symptom severity ratings were statistically significant. At least mild symptoms of heartburn or abdominal pain (a mean Gastrointestinal Symptom Rating Scale score of > or =3) were associated with a clinically meaningful reduction in well-being (a Psychological General Well-Being Index score of less than 98).

CONCLUSIONS

Reflux symptoms are associated with impaired well-being in the general population. Individuals with symptoms that are mild or more severe report a meaningful reduction in well-being similar to that seen in other diseases. This may represent an appropriate threshold for patient selection in trials of GERD therapy and for more detailed evaluation of patients consulting with reflux symptoms in clinical practice.

Symptom-based outcome measures for dyspepsia and GERD trials: a systematic review

BACKGROUND

Symptom assessment using questionnaires has been recommended as the primary outcome measure in clinical gastroesophageal reflux and dyspepsia trials. Questionnaires should have proven reliability, validity, and responsiveness, and may assess the frequency and/or severity of dyspepsia symptoms. Although a number of measures have been developed, it remains unclear which of these should be used in new trials.

OBJECTIVE

To describe existing questionnaire outcome measures that assess symptoms of gastroesophageal reflux dyspepsia for use in clinical trials.

METHODS

Studies were identified from Medline, Embase, the Cochrane library, and reference lists. The inclusion criterion was that the study assessed a questionnaire, which measured the frequency or severity of dyspepsia or gastroesophageal reflux symptoms, in a sample of patients.

RESULTS

No direct comparison between questionnaires was possible due to methodological heterogeneity. Thirty-seven studies describing 26 questionnaires met the inclusion criteria. Twelve were unidimensional (assessed symptoms only) and 14 were multidimensional (also assessed quality of life). Eleven questionnaires assessed both frequency and severity of dyspepsia, and 10 had proven reliability, validity, and responsiveness. No studies compared different questionnaires.

CONCLUSIONS

Future gastroesophageal reflux and dyspepsia clinical trials should use unidimensional or multidimensional outcome measures that assess both the frequency and severity of symptoms, and have proven reliability, validity, and responsiveness. Further research is necessary to compare existing outcome measures to determine which are the most reliable, valid, and responsive instruments.

Three-month prevalence rates of gastrointestinal symptoms and the influence of demographic factors: results from the Domestic/International Gastroenterology Surveillance Study (DIGEST)

BACKGROUND

This paper reports the 3-month prevalence rates of gastrointestinal (GI) symptoms from the Domestic/International Gastroenterology Surveillance Study (DIGEST), and their relationship with demographic factors; namely age, gender and body mass index (BMI).

METHODS

Subjects were recruited from 10 international sites by a total of 5581 face-to-face interviews conducted with randomly selected members of the general population aged 18 years and over (50.6% female; mean age 44 years). The sample was divided according to whether subjects reported 1 or more of 14 GI symptoms, or no GI symptoms. Those with any of 11 upper GI symptoms were then subdivided according to their most bothersome symptom: gastro-oesophageal reflux (GORD)-like symptoms, ulcer-like symptoms or dysmotility-like symptoms. Symptoms were classified as relevant if they were of at least moderate severity and/or occurred at least once a week.

RESULTS

A mean of 46.4% of subjects reported experiencing one or more of the 14 GI symptoms, with 28.1% experiencing upper GI symptoms classified as relevant. Significant differences between the prevalences of relevant symptoms were evident between sampling sites. The estimated prevalence of GORD-like symptoms for the pooled sample was 7.7%. For ulcer-like symptoms, prevalence was 4.1%, and for dysmotility-like symptoms 15.5%. Significant differences were observed in the prevalence rates of symptom groups between countries. Women were significantly more likely than men to experience relevant symptoms, with gender differences also observed in the rates of GORD-like and dysmotility-like symptoms. The proportion of those with relevant symptoms experiencing GORD-like symptoms increased significantly with age; ulcer-like symptoms showed no significant relationship with age; and dysmotility-like symptoms decreased significantly with age. The prevalence of relevant symptoms increased with increasing BMI.

CONCLUSIONS

In conclusion, the DIGEST has provided valuable data on the cross-country prevalence of upper GI symptoms, and their association with biological factors.