The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies

Reporting of systematic reviews of micronutrients and health: a critical appraisal

BACKGROUND

The quality of nutrition-related systematic reviews (SRs) is an unstudied but important factor affecting their usefulness.

OBJECTIVES

The objectives were to evaluate the reporting quality of published SRs and to identify areas of improvement.

DESIGN

Descriptive and exploratory analyses of the reporting quality (7 nutrition items and 28 SR reporting items) of all English-language SRs published through July 2007 linking micronutrients and health outcomes in humans were conducted. Factors that may be associated with reporting quality were also evaluated.

RESULTS

We identified 141 eligible SRs of 21 micronutrients. Ninety SRs that included only interventional studies met a higher proportion of our reporting criteria (median: 62%; interquartile range: 51%, 72%) than did 31 SRs with only observational studies (median: 53%; interquartile range: 47%, 60%) or 20 SRs with both study designs (median: 47%; interquartile range: 39%, 52%) (P < 0.001). SRs published after consensus reporting standards (since 2003) met a higher proportion of the reporting criteria than did earlier SRs (median: 59% compared with 50%; P = 0.01); however, the reporting of nutrition variables remained unchanged (median: 38% compared with 33%; P = 0.7). The least-reported nutrition criteria were baseline nutrient exposures (28%) and effects of measurement errors from nutrition exposures (24%). Only 58 SRs (41%) used quality scales or checklists to assess the methodologic quality of the primary studies included.

CONCLUSIONS

The reporting quality of SRs has improved 3 y after publication of SR reporting standards, but the reporting of nutrition variables has not. Improved adherence to consensus methods and reporting standards should improve the utility of nutrition SRs.

Types of study in medical research: part 3 of a series on evaluation of scientific publications

BACKGROUND

The choice of study type is an important aspect of the design of medical studies. The study design and consequent study type are major determinants of a study's scientific quality and clinical value.

METHODS

This article describes the structured classification of studies into two types, primary and secondary, as well as a further subclassification of studies of primary type. This is done on the basis of a selective literature search concerning study types in medical research, in addition to the authors' own experience.

RESULTS

Three main areas of medical research can be distinguished by study type: basic (experimental), clinical, and epidemiological research. Furthermore, clinical and epidemiological studies can be further subclassified as either interventional or noninterventional.

CONCLUSIONS

The study type that can best answer the particular research question at hand must be determined not only on a purely scientific basis, but also in view of the available financial resources, staffing, and practical feasibility (organization, medical prerequisites, number of patients, etc.).

The Tachikawa cohort of motor vehicle accident study investigating psychological distress: design, methods and cohort profiles

BACKGROUND

The Tachikawa cohort of motor vehicle accident (TCOM) Study has been carried out in Tokyo since 2004. This study examined the association of medical and psychosocial variables evaluated shortly after admission to the acute critical care center with long-term psychiatric morbidity risk in patients with accidental injuries.

METHODS

Between May 2004 and January 2008, patients with accidental injury consecutively admitted were recruited to the TCOM Study. Psychiatric morbidity as a primary endpoint was measured using a structured clinical interview at 1, 6, 18 and 36 months after involvement in a motor vehicle accident (MVA). The baseline investigation consisted of self-administered questionnaires concerning acute psychological responses and personality. Medical information was obtained from patients' medical charts. Various socio-demographic data, health-related habits and psychosocial factors were assessed by interview. To examine potential biomarkers of psychological distress, blood samples were collected.

RESULTS

Out of 344 patients who were asked to participate in this study, 300 (87%) patients with MVA-related injury were enrolled. Corresponding rates for the questionnaires on psychological responses and blood sampling were 98-99 and 79%, respectively. The cohort sample was composed of 78% men; the median age was 34 years; and 45% of the participants were motorcycle drivers.

CONCLUSIONS

The TCOM Study should prove useful for researchers examining the association between bio-psychosocial variables and psychological distress and may contribute to the formation of a framework for providing care for patients with MVA-related injury.

Prevalence of hereditary ataxia and spastic paraplegia in southeast Norway: a population-based study

A population-based, cross-sectional study was performed in southeast Norway, between January 2002 and February 2008, to identify subjects with hereditary ataxia and hereditary spastic paraplegia, and to estimate the prevalence of these disorders. Patients were recruited through colleagues, families, searches in computerized hospital archives and the National Patients' Association for Hereditary Ataxia and Spastic Paraplegia. Strict criteria were used for inclusion of familial and isolated subjects. A project neurologist examined all index subjects and clinical and genetic data were registered. The source population on January 1, 2008 was 2.63 million and the prevalence day was set as February 1, 2008. One hundred seventy-one subjects from 87 unrelated families with hereditary ataxia and 194 subjects from 65 unrelated families with hereditary spastic paraplegia were included. The total prevalence was estimated at 13.9/100 000. Hereditary ataxia prevalence in the region was estimated at 6.5/100 000: 4.2/100 000 for autosomal-dominant and 2.3/100 000 for autosomal recessive, 0.15/100 000 for Friedreich's ataxia and 0.4/100 000 for ataxia telangiectasia. Hereditary spastic paraplegia prevalence was 7.4/100 000: 5.5/100 000 for autosomal dominant-hereditary spastic paraplegia, 0.6/100 000 for autosomal recessive-hereditary spastic paraplegia and 1.3/100 000 for isolated subjects. Marked differences were found in the frequencies of hereditary ataxia subtypes compared with other countries, while those of the most common autosomal dominant-hereditary spastic paraplegia genotypes, SPG4, SPG3 and SPG31, were similar to those previously reported. Clear variations between age groups and counties were observed, but no gender differences. Mean age on prevalence day was 48 years, mean age at onset was 24 years. We present the largest population study performed on hereditary ataxia and hereditary spastic paraplegia prevalence and report a higher prevalence than expected. Better inclusion criteria and multiple search strategies may explain the observed differences.

The effect of alcohol advertising, marketing and portrayal on drinking behaviour in young people: systematic review of prospective cohort studies

Background

The effect of alcohol portrayals and advertising on the drinking behaviour of young people is a matter of much debate. We evaluated the relationship between exposure to alcohol advertising, marketing and portrayal on subsequent drinking behaviour in young people by systematic review of cohort (longitudinal) studies.

Methods

studies were identified in October 2006 by searches of electronic databases, with no date restriction, supplemented with hand searches of reference lists of retrieved articles. Cohort studies that evaluated exposure to advertising or marketing or alcohol portrayals and drinking at baseline and assessed drinking behaviour at follow-up in young people were selected and reviewed.

Results

seven cohort studies that followed up more than 13,000 young people aged 10 to 26 years old were reviewed. The studies evaluated a range of different alcohol advertisement and marketing exposures including print and broadcast media. Two studies measured the hours of TV and music video viewing. All measured drinking behaviour using a variety of outcome measures. Two studies evaluated drinkers and non-drinkers separately. Baseline non-drinkers were significantly more likely to have become a drinker at follow-up with greater exposure to alcohol advertisements. There was little difference in drinking frequency at follow-up in baseline drinkers. In studies that included drinkers and non-drinkers, increased exposure at baseline led to significant increased risk of drinking at follow-up. The strength of the relationship varied between studies but effect sizes were generally modest. All studies controlled for age and gender, however potential confounding factors adjusted for in analyses varied from study to study. Important risk factors such as peer drinking and parental attitudes and behaviour were not adequately accounted for in some studies.

Conclusion

data from prospective cohort studies suggest there is an association between exposure to alcohol advertising or promotional activity and subsequent alcohol consumption in young people. Inferences about the modest effect sizes found are limited by the potential influence of residual or unmeasured confounding.

Abnormal glucose regulation in patients with acute ST- elevation myocardial infarction-a cohort study on 224 patients

Background

A high prevalence of impaired glucose tolerance and unknown type 2-diabetes in patients with coronary heart disease and no previous diagnosis of diabetes have been reported. The aims of the present study were to investigate the prevalence of abnormal glucose regulation (AGR) 3 months after an acute ST-elevation myocardial infarction (STEMI) in patients without known glucometabolic disturbance, to evaluate the reliability of a 75-g oral glucose tolerance test (OGTT) performed very early after an acute STEMI to predict the presence of AGR at 3 months, and to study other potential predictors measured in-hospital for AGR at 3 months.

Methods

This was an observational cohort study prospectively enrolling 224 STEMI patients treated with primary PCI. An OGTT was performed very early after an acute STEMI and was repeated in 200 patients after 3 months. We summarised the exact agreement observed, and assessed the observed reproducibility of the OGTTs performed in-hospital and at follow up. The patients were classified into glucometabolic categories defined according to the World Health Organisation criteria. AGR was defined as the sum of impaired fasting glucose, impaired glucose tolerance and type 2-diabetes.

Results

The prevalence of AGR at three months was 24.9% (95% CI 19.1, 31.4%), reduced from 46.9% (95% CI 40.2, 53.6) when measured in-hospital. Only, 108 of 201 (54%) patients remained in the same glucometabolic category after a repeated OGTT. High levels of HbA1c and admission plasma glucose in-hospital significantly predicted AGR at 3 months (p < 0.001, p = 0.040, respectively), and fasting plasma glucose was predictive when patients with large myocardial infarction were excluded (p < 0.001).

Conclusion

The prevalence of AGR in STEMI patients was lower than expected. HbA1c, admission plasma glucose and fasting plasma glucose measured in-hospital seem to be useful as early markers of longstanding glucometabolic disturbance. An OGTT performed very early after a STEMI did not provide reliable information on long-term glucometabolic state and should probably not be recommended.

Prediction of treatment outcomes after global endometrial ablation

OBJECTIVE

To report rates of amenorrhea and treatment failure after global endometrial ablation and to estimate the association between patient factors and these outcomes by developing and validating prediction models.

METHODS

From January 1998 through December 2005, 816 women underwent global endometrial ablation with either a thermal balloon ablation or radio frequency ablation device; 455 were included in a population-derived cohort (for model development), and 361 were included in a referral-derived cohort (for model validation). Amenorrhea was defined as cessation of bleeding from immediately after ablation through at least 12 months after the procedure. Treatment failure was defined as hysterectomy or reablation for patients with bleeding or pain. Logistic and Cox proportional hazard regression models were used in model development and validation of potential predictors of outcomes.

RESULTS

The amenorrhea rate was 23% (95% confidence interval [CI] 19-28%) and the 5-year cumulative failure rate was 16% (95% CI 10-20%). Predictors of amenorrhea were age 45 years or older (adjusted odds ratio [aOR] 2.6, 95% CI 1.6-4.3); uterine length less than 9 cm (aOR 1.8, 95% CI 1.1-3.1); endometrial thickness less than 4 mm (aOR 2.7, 95% CI 1.2-6.3); and use of radio-frequency ablation instead of thermal balloon ablation (aOR 2.8, 95% CI 1.7-4.9). Predictors of treatment failure included age younger than 45 years (adjusted hazard ratio [aHR] 2.6, 95% CI 1.3-5.1); parity of 5 or greater (aHR 6.0, 95% CI 2.5-14.8); prior tubal ligation (aHR 2.2, 95% CI 1.2-4.0); and history of dysmenorrhea (aHR 3.7, 95% CI 1.6-8.5). After global endometrial ablation, 23 women (5.1%, 95% CI 3.2-7.5%) had pelvic pain, three (0.7%, 95% CI 0.1-1.9%) were pregnant, and none (95% CI 0-0.8%) had endometrial cancer.

CONCLUSION

Population-derived rates and predictors of treatment outcomes after global endometrial ablation may help physicians offer optimal preprocedural patient counseling.

LEVEL OF EVIDENCE

II.

Applying the CONSORT and STROBE statements to evaluate the reporting quality of neovascular age-related macular degeneration studies

PURPOSE

To evaluate the quality of reporting in the neovascular age-related macular degeneration (nvAMD) literature by applying the Consolidated Standards for Reporting Trials (CONSORT) and Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement writing standards.

DESIGN

CONSORT and STROBE impact analysis; literature review.

PARTICIPANTS

Phase III randomized controlled trials (RCTs) of verteporfin photodynamic therapy, pegaptanib, and ranibizumab, and interventional case studies of bevacizumab for nvAMD.

METHODS

A literature search identified eligible articles published before October 31, 2007. We assessed the report quality of Phase III RCTs using the CONSORT statement and case series publications using the STROBE statement, both with indicators relevant to nvAMD.

MAIN OUTCOME MEASURES

Presence or absence of CONSORT or STROBE statement indicators.

RESULTS

Seven publications of Phase III RCTs and 29 publications on bevacizumab interventional case studies for nvAMD met our inclusion criteria. Of 37 possible CONSORT writing guideline items, the mean report quality for RCTs was 30.6 (83%), with a range from 23 to 35 (65%-95%). Of 35 possible STROBE writing guideline items, the mean report quality grade for intravitreal bevacizumab case series was 23 (70%), with a range from 16 to 31 (46%-94%). Among the bevacizumab studies, more than 90% reported scientific background, drug dose and administration, baseline characteristics, unadjusted results, and adverse events. Fewer than 20% reported study size calculations, handling of missing data, or a discussion of bias.

CONCLUSIONS

Since the adoption of the CONSORT standards by Ophthalmology and other journals in 1996, the reporting quality for RCTs has further improved among this cohort of nvAMD articles. On the other hand, no reporting standards for case series have existed until the recent publication of the STROBE statement. In this first application of the STROBE standards to ophthalmology, we found that the small interventional studies in our series had an average reporting score lower than the RCTs, but also that some individual scores were higher than the RCTs. This outcome demonstrates that good, useful articles can be written about small studies. Although not a direct measure of the quality of a study, good reporting allows a reader to assess the validity and applicability of the study's findings.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Quality of Life, Exercise Capacity and Comorbidity in Old Patients with Permanent Atrial Fibrillation

Background: The impact of atrial fibrillation (AF) on quality of life (QoL) differs with the AF population studied and is influenced by comorbidity. In hospital-based studies younger and highly symptomatic patients may be overrepresented. We performed an observational cross sectional study in two municipalities, comparing 75 year-old patients with and without permanent atrial fibrillation, with respect to health-related QoL and exercise capacity, with adjustment for the effects of confounders. Methods: Maximal treadmill exercise testing provided peak oxygen uptake (VO2 peak). Health-related QoL was assessed by self-completed SF-36 questionnaires. The lowest quartile identified poor outcomes.

RESULTS

27 subjects with permanent AF and 71 subjects in sinus rhythm participated. AF patients had higher prevalence of compensated chronic heart failure (p < 0.001), valvular heart disease (p < 0.001), lower mean VO2 peak (22.7 ± 5.5 vs. 28.6 ± 6.3 ml/kg/min; p < 0.001), and more often poor VO2 peak; crude OR 5.3 (95%CI 1.8, 15.3), adjusted OR 7.5 (2.0, 28.3). Median Physical Component Summary score (with 25th and 75th percentile) was 41 (31, 51) in AF vs. 52 (45, 55) in controls (p < 0.001). Furthermore, the AF group had higher odds for poor physical QoL scores; crude OR 5.0 (1.8, 13.7), adjusted OR 4.3 (1.5, 12.4). Median Mental Component Summary score was 56 (42, 61) in the AF group vs. 57 (51, 60) in controls (p=0.565). The AF group had non-significantly increased odds for poor mental QoL scores; crude OR 2.3 (0.8, 6.2), adjusted OR 2.8 (1.0, 8.4). Conclusion: Also after adjustment for confounders, older patients with permanent AF had higher odds for poor exercise capacity and poor physical QoL compared to subjects in sinus rhythm.

Diabetes and obesity-related risks for pelvic reconstructive surgery in a cohort of Swedish twins

OBJECTIVE

To determine the diabetes- and obesity-related risks for surgically managed stress urinary incontinence and pelvic organ prolapse.

RESEARCH DESIGN AND METHODS

This twin cohort study used the Swedish Twin Register to identify 8,443 female twin pairs born from 1926 through 1958. The association between diabetes and pelvic floor surgery was estimated while taking into account the correlated (twin) structure of the data.

RESULTS

For type 1 and type 2 diabetes, no significant associations were observed for stress urinary incontinence (odds ratio [OR] 1.0 [95% CI 0.1-9.2] and 2.0 [1.0-4.0], respectively). There were no cases of prolapse surgery in type 1 diabetic subjects, and for type 2 diabetes the risk estimate was nonsignificant (1.6 [1.0-2.7]). BMI >25 kg/m(2), age >or=60 years, and childbirth were the strongest risk factors for having incontinence surgery.

CONCLUSIONS

Our data suggest that diabetes is not associated with stress urinary incontinence or pelvic organ prolapse surgery.

Prevalence of pulmonary embolism in acute exacerbations of COPD: a systematic review and metaanalysis

BACKGROUND

Nearly 30% of all exacerbations of COPD do not have a clear etiology. Although pulmonary embolism (PE) can exacerbate respiratory symptoms such as dyspnea and chest pain, and COPD patients are at a high risk for PE due to a variety of factors including limited mobility, inflammation, and comorbidities, the prevalence of PE during exacerbations is uncertain.

METHODS

A systematic review of the literature was performed to determine the reported prevalence of PE in acute exacerbations of COPD in patients who did and did not require hospitalization. The literature search was performed using MEDLINE, CINAHL, and EMBASE, and complemented by hand searches of bibliographies. Only cross-sectional or prospective studies that used CT scanning or pulmonary angiography for PE diagnosis were included.

RESULTS

Of the 2,407 articles identified, 5 met the inclusion criteria (sample size, 550 patients). Overall, the prevalence of PE was 19.9% (95% confidence interval [CI], 6.7 to 33.0%; p = 0.014). In hospitalized patients, the prevalence was higher at 24.7% (95% CI, 17.9 to 31.4%; p = 0.001) than those who were evaluated in the emergency department (3.3%). Presenting symptoms and signs were similar between patients who did and did not have PE.

CONCLUSIONS

One of four COPD patients who require hospitalization for an acute exacerbation may have PE. A diagnosis of PE should be considered in patients with exacerbation severe enough to warrant hospitalization, especially in those with an intermediate-to-high pretest probability of PE.

Rapid molecular detection of rifampicin resistance facilitates early diagnosis and treatment of multi-drug resistant tuberculosis: case control study

BACKGROUND

Multi-drug resistant tuberculosis (MDR-TB) is a major public health concern since diagnosis is often delayed, increasing the risk of spread to the community and health care workers. Treatment is prolonged, and the total cost of treating a single case is high. Diagnosis has traditionally relied upon clinical suspicion, based on risk factors and culture with sensitivity testing, a process that can take weeks or months. Rapid diagnostic molecular techniques have the potential to shorten the time to commencing appropriate therapy, but have not been put to the test under field conditions.

METHODOLOGY/PRINCIPAL FINDINGS

This retrospective case-control study aimed to identify risk factors for MDR-TB, and analyse the impact of testing for rifampicin resistance using RNA polymerase B (rpoB) mutations as a surrogate for MDR-TB. Forty two MDR-TB cases and 84 fully sensitive TB controls were matched by date of diagnosis; and factors including demographics, clinical presentation, microbiology findings, management and outcome were analysed using their medical records. Conventionally recognised risk factors for MDR-TB were absent in almost half (43%) of the cases, and 15% of cases were asymptomatic. A significant number of MDR-TB cases were identified in new entrants to the country. Using rpoB mutation testing, the time to diagnosis of MDR-TB was dramatically shortened by a median of 6 weeks, allowing patients to be commenced on appropriate therapy a median of 51days earlier than those diagnosed by conventional culture and sensitivity testing.

CONCLUSIONS/SIGNIFICANCE

MDR-TB is frequently an unexpected finding, may be asymptomatic, and is particularly prevalent among TB infected new entrants to the country. Molecular resistance testing of all acid fast bacilli positive specimens has the potential to rapidly identify MDR-TB patients and commence them on appropriate therapy significantly earlier than by conventional methods.

Treating TTP/HUS with plasma exchange: a single centre's 25-year experience

Thrombotic thrombocytopenic purpura/Haemolytic uremic syndrome (TTP/HUS) is a thrombotic microangiopathy with a 6-month mortality rate of 16-29%. The present study described the clinical features, treatment regime and 6-month all-cause mortality rate of TTP/HUS patients at the London Health Sciences Centre (LHSC), Canada. Data for this retrospective cohort study were obtained from inpatient and outpatient records for all patients referred for plasma exchange therapy at LHSC, Canada between 1981 and 2006. Patients (n = 110) were categorized as: idiopathic primary (38%) or relapsed (16%), and secondary responsive (30%) or non-responsive (16%). Mortality data were available for all but three patients. The all-cause 6-month mortality rate was 19% overall and was 12% and 26% among idiopathic and secondary TTP/HUS patients, respectively. No mortality events occurred among the 17 idiopathic patients who relapsed. Relapsed patients had the least severe presenting characteristics, the fastest response time, and experienced significant improvement in the severity of clinical features between the first and final presentation. These findings suggest an excellent outcome for relapsed TTP/HUS patients. Patient education, surveillance, and aggressive plasma exchange therapy are hypothesized to improve the likelihood of survival: these hypotheses should be tested in a randomized controlled trial.

Using respondent-driven sampling methodology for HIV biological and behavioral surveillance in international settings: a systematic review

To determine operational and analytical characteristics of respondent-driven sampling (RDS) in international settings and to explore factors that may affect recruitment of most-at-risk populations using RDS, we reviewed HIV biological and behavioral surveillance studies that used this method outside of the United States. We identified 123 eligible studies, 59 from Europe, 40 from Asia and the Pacific, 14 from Latin America, seven from Africa and three from Oceania. Studies collectively recruited 32,298 participants between 2003 and 2007; 53% of studies were conducted among injecting drug users, which generally had faster recruitment compared with studies among sex workers. All but 13 studies reached > or = 90% of their intended sample size, and six studies failed to reach equilibrium for key variables. This review has shown that RDS is an effective technique, when designed and implemented appropriately, to sample most-at-risk populations for HIV biological and behavioral surveys.

Genome-wide association studies for complex traits: consensus, uncertainty and challenges

The past year has witnessed substantial advances in understanding the genetic basis of many common phenotypes of biomedical importance. These advances have been the result of systematic, well-powered, genome-wide surveys exploring the relationships between common sequence variation and disease predisposition. This approach has revealed over 50 disease-susceptibility loci and has provided insights into the allelic architecture of multifactorial traits. At the same time, much has been learned about the successful prosecution of association studies on such a scale. This Review highlights the knowledge gained, defines areas of emerging consensus, and describes the challenges that remain as researchers seek to obtain more complete descriptions of the susceptibility architecture of biomedical traits of interest and to translate the information gathered into improvements in clinical management.

How much of the data published in observational studies of the association between diet and prostate or bladder cancer is usable for meta-analysis?

Epidemiologic investigations often report dose-response associations, which may be combined in meta-analyses. The authors examined how often the log odds, risk, or hazard ratio per unit increase in exposure, and its standard error, can be estimated from results reported from observational studies of diet and prostate or bladder cancer so that results are usable in meta-analyses estimating dose-response associations. Eight electronic databases were searched for studies reporting on the association of diet, nutrition, or physical activity with these cancers. A total of 767 papers reported 3,284 results; 1,999 (61%) results, reported in 545 (71%) papers, were usable in dose-response meta-analyses. The most important reason that results were not usable was the absence of sufficient information on exposure levels in the different groups. The proportion of results usable in "high-low" meta-analyses (comparisons of extreme categories) was similar (62%). Results that showed evidence of an association were more likely to be usable than results that found no such evidence. Insufficient detail in reporting of results of observational studies can lead to exclusion of these results from meta-analyses and is an important threat to the validity of systematic reviews of such research. Results providing evidence of associations may be overrepresented in meta-analyses of observational studies.