Daylight saving time and acute myocardial infarction: a meta-analysis

Background The current evidence on the effects of daylight saving time (DST) transitions on major cardiovascular diseases is limited, and available results are conflicting. We carried out the first meta-analysis aimed at evaluating the risk of acute myocardial infarction (AMI) following DST transitions. Methods We searched MedLine and Scopus up to December 31, 2018, with no language restriction, to retrieve cohort or case-control studies evaluating AMI incidence among adults (≥18y) in the week following spring and/or autumn DST shifts versus control periods. A summary relative risk of AMI was computed after: (1) spring, (2) autumn, (3) both transitions considered together versus control weeks. Stratified analyses were performed by gender and age. Data were combined using a generic inverse-variance approach. Results Seven studies (>115,000 subjects) were included in the analyses. A significantly higher risk of AMI (Odds Ratio: 1.03; 95% CI: 1.01-1.06) was observed in the two weeks following spring or winter DST transitions. The risk increase was however significant only after the spring shift (OR: 1.05; 1.02-1.07), while AMI incidence in the week after winter DST transition was comparable to control periods (OR 1.01; 0.98-1.04). No substantial differences by age or gender emerged. Conclusions The risk of AMI increases modestly but significantly following DST transitions, supporting the proposal of DST shifts discontinuation. Additional studies fully adjusting for potential confounders are required to confirm the present findings

Weight discordance and perinatal mortality in twin pregnancy: systematic review and meta‐analysis

Objectives The primary aim of this systematic review was to explore the strength of association between birth‐weight (BW) discordance and perinatal mortality in twin pregnancy. The secondary aim was to ascertain the contribution of gestational age and growth restriction in predicting mortality in growth‐discordant twins. Methods MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched. Only studies reporting on the risk of mortality in twin pregnancies affected compared with those not affected by BW discordance were included. The primary outcomes explored were incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death. Outcome was assessed separately for monochorionic (MC) and dichorionic (DC) twin pregnancies. Analyses were stratified according to BW discordance cut‐off (≥ 15%, ≥ 20%, ≥ 25% and ≥ 30%) and selected gestational characteristics, including incidence of IUD or NND before and after 34 weeks' gestation, presence of at least one small‐for‐gestational age (SGA) fetus in the twin pair and both twins being appropriate‐for‐gestational age. Risk of mortality in the larger vs smaller twin was also assessed. Meta‐analyses using individual data random‐effects logistic regression and meta‐analyses of proportion were used to analyze the data. Results Twenty‐two studies (10 877 twin pregnancies) were included in the analysis. In DC pregnancies, a higher risk of IUD, but not of NND, was observed in twins with BW discordance ≥ 15% (odds ratio (OR) 9.8, 95% CI, 3.9–29.4), ≥ 20% (OR 7.0, 95% CI, 4.15–11.8), ≥ 25% (OR 17.4, 95% CI, 8.3–36.7) and ≥ 30% (OR 22.9, 95% CI, 10.2–51.6) compared with those without weight discordance. For each cut‐off of BW discordance explored in DC pregnancies, the smaller twin was at higher risk of mortality compared with the larger one. In MC twin pregnancies, excluding cases affected by twin–twin transfusion syndrome, twins with BW discordance ≥ 20% (OR 2.8, 95% CI, 1.3–5.8) or ≥ 25% (OR 3.2, 95% CI, 1.5–6.7) were at higher risk of IUD, compared with controls. MC pregnancies with ≥ 25% weight discordance were also at increased risk of NND (OR 4.66, 95% CI, 1.8–12.4) compared with those with concordant weight. The risk of IUD was higher when considering discordant pregnancies involving at least one SGA fetus. The overall risk of mortality in MC pregnancies was similar between the smaller and larger twin, except in those with BW discordance ≥ 20%. Conclusion DC and MC twin pregnancies discordant for fetal growth are at higher risk of IUD but not of NND compared with pregnancies with concordant BW. The risk of IUD in BW‐discordant DC and MC twins is higher when at least one fetus is SGA

Risk factors for abnormally invasive placenta: a systematic review and meta-analysis.

Purpose of the article. To explore the strength of association between different maternal and pregnancy characteristics and the occurrence of abnormally invasive placenta (AIP). MATERIALS AND METHODS: Pubmed, Embase, CINAHL databases were searched. The risk factors for AIP explored were: obesity, age > 35 years, smoking before or during pregnancy, placenta previa, prior cesarean section (CS), placenta previa and prior CS, prior uterine surgery, abortion and uterine curettage, in vitro fertilization (IVF) pregnancy and interval between a previous CS and a subsequent pregnancy. Random-effect head-to-head meta-analyses were used to analyze the data. RESULTS: Forty-six were included in the systematic review. Maternal obesity (Odd ratio, OR: 1.4, 95% CI 1.0-1.8), advanced maternal age (OR: 3.1, 95% CI 1.4-7.0) and parity (OR: 2.5, 95% CI 1.7-3.6), but not smoking were associated with a higher risk of AIP. The presence of placenta previa in women with at least a prior CS was associated with a higher risk of AIP compared to controls, with an OR of 12.0, 95% CI 1.6-88.0. Furthermore, the risk of AIP increased with the number of prior CS (OR of 2.6, 95% CI 1.6-4.4 and 5.4, 95% CI 1.7-17.4 for two and three prior CS respectively). Finally, IVF pregnancies were associated with a high risk of AIP, with an OR of 2.8 (95% CI 1.2-6.8). CONCLUSION: A prior CS and placenta previa are among the strongest risk factors for the occurrence of AIP

Risk of fetal loss following amniocentesis or chorionic villus sampling in twin pregnancy: systematic review and meta‐analysis

Objective To assess the rate of fetal loss following amniocentesis or chorionic villus sampling (CVS) in twin pregnancy. Methods MEDLINE, EMBASE and Cochrane databases were searched for studies reporting procedure‐related complications following amniocentesis or CVS in twin pregnancy. The primary outcome was the rate of procedure‐related fetal loss. The secondary outcomes were fetal loss occurring before 24 weeks of gestation and fetal loss occurring within 4 weeks after the procedure. Head‐to‐head meta‐analyses were used to compare directly each outcome, between women undergoing amniocentesis and those not undergoing amniocentesis and between women undergoing CVS and those not undergoing CVS, and to compute pooled risk differences (RD) between women exposed and those not exposed to each invasive procedure. Additionally, meta‐analyses of proportions were used to estimate the pooled rates of each of the three outcomes in women undergoing amniocentesis or CVS and in controls. Results Sixteen studies (3419 twin pregnancies undergoing and 2517 not undergoing an invasive procedure) were included. Head‐to‐head meta‐analyses comparing directly twin pregnancies undergoing and those not undergoing amniocentesis showed a higher risk for overall fetal loss in those undergoing amniocentesis (odds ratio (OR), 1.46 (P = 0.04); RD, 0.013 (P = 0.04)), while there was no difference in the risk of either fetal loss before 24 weeks of gestation (OR, 1.59 (P = 0.06); RD, 0.010 (P = 0.11)) or fetal loss within 4 weeks after the procedure (OR, 1.38 (P = 0.3); RD, 0.003 (P = 0.8)). Overall, the pooled rate of fetal loss was 2.4% (95% CI, 1.4–3.6%) in twin pregnancies undergoing amniocentesis compared with 2.4% (95% CI, 0.9–4.6%) in those not undergoing amniocentesis. Head‐to‐head meta‐analyses directly comparing twin pregnancies undergoing and those not undergoing CVS showed no significant difference in either overall fetal loss (OR, 1.61 (P = 0.5); RD, 0.003 (P = 0.8)) or fetal loss before 24 weeks of gestation (OR, 1.61 (P = 0.5); RD, 0.003 (P = 0.8)). Overall, the pooled rate of fetal loss was 2.0% (95% CI, 0.0–6.5%) in twin pregnancies undergoing CVS compared with 1.8% (95% CI, 0.3–4.2%) in those not undergoing CVS. Conclusion The risk of fetal loss following amniocentesis and CVS in twins is lower than reported previously and the rate of fetal loss before 24 weeks of gestation, or within 4 weeks after the procedure, did not differ from the background risk in twin pregnancy not undergoing invasive prenatal testing. These data can guide prenatal counseling for twin pregnancies undergoing invasive procedures

Outcome of twin–twin transfusion syndrome according to Quintero stage of disease: systematic review and meta‐analysis

Objectives To report the outcome of pregnancies complicated by twin–twin transfusion syndrome (TTTS) according to Quintero stage. Methods MEDLINE, EMBASE and CINAHL databases were searched for studies reporting the outcome of pregnancies complicated by TTTS stratified according to Quintero stage (I–V). The primary outcome was fetal survival rate according to Quintero stage. Secondary outcomes were gestational age at birth, preterm birth (PTB) before 34, 32 and 28 weeks' gestation and neonatal morbidity. Outcomes are reported according to the different management options (expectant management, laser therapy or amnioreduction) for pregnancies with Stage‐I TTTS. Only cases treated with laser therapy were considered for those with Stages‐II–IV TTTS and only cases managed expectantly were considered for those with Stage‐V TTTS. Random‐effects head‐to‐head meta‐analysis was used to analyze the extracted data. Results Twenty‐six studies (2699 twin pregnancies) were included. Overall, 610 (22.6%) pregnancies were diagnosed with Quintero stage‐I TTTS, 692 (25.6%) were Stage II, 1146 (42.5%) were Stage III, 247 (9.2%) were Stage IV and four (0.1%) were Stage V. Survival of at least one twin occurred in 86.9% (95% CI, 84.0–89.7%) (456/552) of pregnancies with Stage‐I, in 85% (95% CI, 79.1–90.1%) (514/590) of those with Stage‐II, in 81.5% (95% CI, 76.6–86.0%) (875/1040) of those with Stage‐III, in 82.8% (95% CI, 73.6–90.4%) (172/205) of those with Stage‐IV and in 54.6% (95% CI, 24.8–82.6%) (5/9) of those with Stage‐V TTTS. The rate of a pregnancy with no survivor was 11.8% (95% CI, 8.4–15.8%) (69/564) in those with Stage‐I, 15.0% (95% CI, 9.9–20.9%) (76/590) in those with Stage‐II, 18.6% (95% CI, 14.2–23.4%) (165/1040) in those with Stage‐III, 17.2% (95% CI, 9.6–26.4%) (33/205) in those with Stage‐IV and in 45.4% (95% CI, 17.4–75.2%) (4/9) in those with Stage‐V TTTS. Gestational age at birth was similar in pregnancies with Stages‐I–III TTTS, and gradually decreased in those with Stages‐IV and ‐V TTTS. Overall, the incidence of PTB and neonatal morbidity increased as the severity of TTTS increased, but data on these two outcomes were limited by the small sample size of the included studies. When stratifying the analysis of pregnancies with Stage‐I TTTS according to the type of intervention, the rate of fetal survival of at least one twin was 84.9% (95% CI, 70.4–95.1%) (94/112) in cases managed expectantly, 86.7% (95% CI, 82.6–90.4%) (249/285) in those undergoing laser therapy and 92.2% (95% CI, 84.2–97.6%) (56/60) in those after amnioreduction, while the rate of double survival was 67.9% (95% CI, 57.0–77.9%) (73/108), 69.7% (95% CI, 61.6–77.1%) (203/285) and 80.8% (95% CI, 62.0–94.2%) (49/60), respectively. Conclusions Overall survival in monochorionic diamniotic pregnancies affected by TTTS is higher for earlier Quintero stages (I and II), but fetal survival rates are moderately high even in those with Stage‐III or ‐IV TTTS when treated with laser therapy. Gestational age at birth was similar in pregnancies with Stages‐I–III TTTS, and gradually decreased in those with Stages‐IV and ‐V TTTS treated with laser and expectant management, respectively. In pregnancies affected by Stage‐I TTTS, amnioreduction was associated with slightly higher survival compared with laser therapy and expectant management, although these findings may be confirmed only by future head‐to‐head randomized trials

Bounds and Decays of New Heavy Vector-like Top Partners

We study the phenomenology of new heavy vector-like fermions that couple to the third generation quarks via Yukawa interactions, covering all the allowed representations under the standard model gauge groups. We first review tree and loop level bounds on these states. We then discuss tree level decays and loop-induced decays to photon or gluon plus top. The main decays at tree level are to W b and/or Z and Higgs plus top via the new Yukawa couplings. The radiative loop decays turn out to be quite close to the naive estimate: in all cases, in the allowed perturbative parameter space, the branching ratios are mildly sensitive on the new Yukawa couplings and small. We therefore conclude that the new states can be observed at the LHC and that the tree level decays can allow to distinguish the different representations. Moreover, the observation of the radiative decays at the LHC would suggest a large Yukawa coupling in the non-perturbative regime.Comment: 32 pages, 2 tables, 10 figure

Integration of first-trimester assessment in the ultrasound staging of placenta accreta spectrum disorders.

OBJECTIVE: To explore the role of early first trimester ultrasound at 5-7 postmenstrual weeks of gestation in predicting sonographic staging of placenta accreta spectrum (PAS) and to elucidate whether integrating first trimester assessment with ultrasound staging of PAS can predict surgical outcome in women at risk for PAS. METHODS: Secondary analysis of prospectively collected data of women who had at least one previous caesarean delivery (CD) or uterine surgery and placenta previa for whom early (5-7 weeks of gestation) ultrasound images could be retrieved. The relationship between gestational sac position and prior CD scar was assessed using classifications by Cali et al. (cross-over COS), Kaelin Agten et al. ("on the scar" vs "in the niche" implantation) and Timor-Tritsch et al. ("above the line" vs "below the line" implantation) by two different examiners blinded to the final diagnosis and clinical outcome. Primary aim of the study was to explore the strength of association and predictive accuracy of first trimester ultrasound in predicting PAS stage. Secondary aim was to elucidate whether integration of first trimester ultrasound with PAS staging can predict surgical outcome. Logistic regression and area under the curve analyses were used to analyse the data. RESULTS: One hundred and eighty-seven women were included. Of these ,79.6% (95% CI 67.1-88.2) had COS1, 94.4% (95% CI 84.9-98.1) "in the niche" and 92.6% (95% CI 82.4-97.1) "below the line" implantation confirmed to be affected by PAS3 in the third trimester of pregnancy. On multivariate logistic regression analysis, COS1 (OR: 7.9 (95% CI 4.0-15.5; p<0.001), "in the niche" (OR: 29.1, 95% CI 8.1-104; p<0.001) and "below the line" (OR: 38.1, 95% CI 12.1-121; p<0.001) implantations, however, neither parity (p= 0.4), nor the number of prior CDs (p= 0.5) were independently associated with PAS3. When translating these figures in a diagnostic model, either COS1 (AUC: 0.94, 95% CI 0.91-0.97), or implantation "in the niche" (AUC: 0.92, 95% CI 0.89-0.96) or "below the line" (AUC: 0.92, 95% CI 0.88-0.96) had a high predictive accuracy for PAS3. Adverse surgical outcome was more common in women with COS1 (p<0.001), implantation "in the niche" (p<0.001) and "below the line" (p<0.001) then those without them.) On multivariate logistic regression analysis, ultrasound diagnosis of PAS3 (OR: 4.3, 95% CI 2.1-17.3), COS1 (OR: 7.9, 95% CI 4.0-15.5; p<0.001), "in the niche" (OR: 29.1, 95% CI 8.1-104; p<0.001) and "below the line" (OR: 7.9, 95% CI 4.0-15.5; p<0.001) implantations were independently associated with adverse surgical outcome. When combining the three imaging methods, we identified, an area we call "high-risk-for-PAS Triangle" which may enable an easy visual perception and application of the three methods to prognosticate the risk for CSP and PAS, although it requires validation in further large prospective studies. CONCLUSION: Early first trimester sonographic assessment of pregnancies after CDs can reliably predict ultrasound staging of possible PAS. Integrating first with second and third trimester ultrasound can stratify surgical risk of women affected by PAS. This article is protected by copyright. All rights reserved

Composite GUTs: models and expectations at the LHC

We investigate grand unified theories (GUTs) in scenarios where electroweak (EW) symmetry breaking is triggered by a light composite Higgs, arising as a Nambu-Goldstone boson from a strongly interacting sector. The evolution of the standard model (SM) gauge couplings can be predicted at leading order, if the global symmetry of the composite sector is a simple group G that contains the SM gauge group. It was noticed that, if the right-handed top quark is also composite, precision gauge unification can be achieved. We build minimal consistent models for a composite sector with these properties, thus demonstrating how composite GUTs may represent an alternative to supersymmetric GUTs. Taking into account the new contributions to the EW precision parameters, we compute the Higgs effective potential and prove that it realizes consistently EW symmetry breaking with little fine-tuning. The G group structure and the requirement of proton stability determine the nature of the light composite states accompanying the Higgs and the top quark: a coloured triplet scalar and several vector-like fermions with exotic quantum numbers. We analyse the signatures of these composite partners at hadron colliders: distinctive final states contain multiple top and bottom quarks, either alone or accompanied by a heavy stable charged particle, or by missing transverse energy.Comment: 55 pages, 13 figures, final version to be published in JHE

The influence of the team in conducting a systematic review

There is an increasing body of research documenting flaws in many published systematic reviews' methodological and reporting conduct. When good systematic review practice is questioned, attention is rarely turned to the composition of the team that conducted the systematic review. This commentary highlights a number of relevant articles indicating how the composition of the review team could jeopardise the integrity of the systematic review study and its conclusions. Key biases require closer attention such as sponsorship bias and researcher allegiance, but there may also be less obvious affiliations in teams conducting secondary evidence-syntheses. The importance of transparency and disclosure are now firmly on the agenda for clinical trials and primary research, but the meta-biases that systematic reviews may be at risk from now require further scrutiny

Non-inferiority is almost certain with lenient non-inferiority margins

We thank Dr. Soonawala et al. for their interesting comment [1] to our article on the sponsorship of head-tohead randomized trials [2]. Our proportion of noninferiority trials with ‘‘desirable favorable results’’ (97%) was higher than the one reported by Soonawala (84%, if we only consider the 165 trials with a sample larger than 100, that was one of our study selection criteria) [2,3]...