IntroductionPRISMA statement was published in 2009 in order to set standards in the reporting of systematic reviews and meta-analyses. Our aim was to evaluate the impact of PRISMA endorsement on the quality of reporting and methodological quality of systematic reviews and meta-analyses, published in journals in the field of gastroenterology and hepatology (GH).MethodsQuality of reporting and methodological quality were evaluated by assessing the adherence of papers to PRISMA checklist and AMSTAR quality scale. After identifying the GH journals which endorsed PRISMA in instructions for authors (IA), we appraised: 15 papers published in 2012 explicitly mentioning PRISMA in the full text (Group A); 15 papers from the same journals published in 2012 not explicitly mentioning PRISMA in the full text (Group B); 30 papers published the year preceding PRISMA endorsement from the same journals as above (Group C); 30 papers published in 2012 on the 10 highest impact factor journals in GH which not endorsed PRISMA (Group D).ResultsPRISMA statement was referred in the IA in 9 out of 70 GH journals (12.9%). We found significant increase in overall adherence to PRISMA checklist (Group A, 90.1%; Group C, 83.1%; p = 0.003) and compliance to AMSTAR scale (Group A, 85.0%; Group C, 74.6%; p = 0.002), following the PRISMA endorsement from the nine GH journals. Explicit referencing of PRISMA in manuscript was not associated with increase in quality of reporting and methodological quality (Group A vs. B, p = 0.651, p = 0.900, respectively). Adherence to PRISMA checklist, and the compliance with AMSTAR were significantly higher in journals endorsing PRISMA compared to those not (Groups A+B vs. D; p = 0.003 and p = 0.016, respectively).ConclusionThe endorsement of PRISMA resulted in increase of both quality of reporting and methodological quality. It is advised that an increasing number of medical journals include PRISMA in the instructions for authors.

No abstract

Introduction: PRISMA statement was published in 2009 in order to set standards in the reporting of systematic reviews and meta-analyses. Our aim was to evaluate the impact of PRISMA endorsement on the quality of reporting and methodological quality of systematic reviews and meta-analyses, published in journals in the field of gastroenterology and hepatology (GH).

Conjoined twins (CT) are a very rare developmental accident of uncertain etiology. Prevalence has been previously estimated to be 1 in 50,000 to 1 in 100,000 births. The process by which monozygotic twins do not fully separate but form CT is not well understood. The purpose of the present study was to analyze diverse epidemiological aspects of CT, including the different variables listed in the Introduction Section of this issue of the Journal. The study was made possible using the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR) structure. This multicenter worldwide research includes the largest sample of CT ever studied. A total of 383 carefully reviewed sets of CT obtained from 26,138,837 births reported by 21 Clearinghouse Surveillance Programs (SP) were included in the analysis. Total prevalence was 1.47 per 100,000 births (95% CI: 1.32-1.62). Salient findings including an evident variation in prevalence among SPs: a marked variation in the type of pregnancy outcome, a similarity in the proportion of CT types among programs: a significant female predominance in CT: particularly of the thoracopagus type and a significant male predominance in parapagus and parasitic types: significant differences in prevalence by ethnicity and an apparent increasing prevalence trend in South American countries. No genetic, environmental or demographic significant associated factors were identified. Further work in epidemiology and molecular research is necessary to understand the etiology and pathogenesis involved in the development of this fascinating phenomenon of nature.

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre-established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10-15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia-acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies.

BACKGROUND Genetic and environmental factors interact in determining the risk of venous thromboembolism (VTE). The risk associated with the polymorphic variants G1691A of factor V (Factor V Leiden,FVL), G20210A of prothrombin (PT20210A) and C677T of methylentetrahydrofolate reductase (C677T MTHFR) genes has been investigated in many studies. METHODS We performed a pooled analysis of case-control and cohort studies investigating in adults the association between each variant and VTE, published on Pubmed, Embase or Google through January 2010. Authors of eligible papers, were invited to provide all available individual data for the pooling. The Odds Ratio (OR) for first VTE associated with each variant, individually and combined with the others, were calculated with a random effect model, in heterozygotes and homozygotes (dominant model for FVL and PT20210A; recessive for C677T MTHFR). RESULTS We analysed 31 databases, including 11,239 cases and 21,521 controls. No significant association with VTE was found for homozygous C677T MTHFR (OR: 1.38; 95% confidence intervals [CI]: 0.98–1.93), whereas the risk was increased in carriers of either heterozygous FVL or PT20210 (OR=4.22; 95% CI: 3.35–5.32; and OR=2.79;95% CI: 2.25–3.46, respectively), in double hterozygotes (OR=3.42; 95%CI 1.64-7.13), and in homozygous FVL or PT20210A (OR=11.45; 95%CI: 6.79-19.29; and OR: 2.79; 95%CI: 2.25 – 3.46, respectively). The stratified analyses showed a stronger effect of FVL on individuals ≤45 years (p-value for interaction = 0.036) and of PT20210A in women using oral contraceptives (p-value for interaction = 0.045). CONCLUSIONS In this large pooled analysis, inclusive of large studies like MEGA, no effect was found for C677T MTHFR on VTE; FVL and PT20210A were confirmed to be moderate risk factors. Notably, double carriers of the two genetic variants produced an impact on VTE risk significantly increased but weaker than previously thought.

Background There are few published studies on microtia-anotia frequency. Methods Using data from birth defects surveillance programs around the world, we conducted a systematic review on the frequency of microtia-anotia to further explore the differences in prevalence across countries. Ninety-two birth defects surveillance programs were evaluated with a total of 8,917 cases of microtia-anotia. We computed the prevalence per 10,000 births for each surveillance program for total cases of microtia-anotia (microtia types I to IV), microtia (types I to III), and anotia (type IV). Prevalence ratios were calculated by large geographical areas, race/ethnicity, and by surveillance methodologies. Results The overall prevalence were for microtia-anotia 2.06 (CI: 2.02–2.10), for microtia 1.55 (CI: 1.50–1.60), and for anotia 0.36 (CI: 0.34–0.38). Higher prevalence was observed in the Americas, Northern Europe and Asia, among Hispanics and Asians, and among active ascertainment and hospital-based surveillance programs. Conclusions We observed marked variation in the prevalence of microtia-anotia across surveillance programs and within countries. These results must be interpreted cautiously as this variability may be explained mainly by differences in surveillance methods. However, given the magnitude of some of the differences, other factors may also be involved. This study contributes to the knowledge on the prevalence of microtia-anotia by providing a critical analysis of the existing data. In addition, it supports the need for a coding system that allows complete phenotype characterization of microtia-anotia, including severity and laterality; as well as further studies on the variation of its frequency related to race and ethnicity.

No abstract