Double- vs single-blind peer review effect on acceptance rates: a systematic review and meta-analysis of randomized trials.

OBJECTIVE: This study aimed to assess the changes in the acceptance rates between double- and single-blind peer review systems. DATA SOURCES: The search was conducted using Medline, Embase, and ClinicalTrials.gov databases as electronic databases from the inception of each database to June 2021. No restriction for language or geographic location was applied. STUDY ELIGIBILITY CRITERIA: The selection criteria included randomized controlled trials comparing the double-blind peer review process vs the single-blind peer review process. METHODS: The primary outcome was manuscripts acceptance rates. The summary measures were reported as relative risk with 95% confidence intervals using the random-effects model meta-analyses. Between-study heterogeneity was explored using the I2 statistic. RESULTS: A total of 11 randomized controlled trials, including 3477 reviewers and 3784 manuscripts, were identified. The manuscript acceptance rates were significantly lower in the double-blind (200/1413 [14.2%]) peer review processes than in the single-blind (194/1019 [19.0%]) peer review processes (relative risk, 0.82; 95% confidence interval, 0.70-0.97; n=5 randomized controlled trials). Only 1 randomized controlled trial assessed the authors' and/or institutions' prestige on acceptance rates with results not statistically significant. Only 2 randomized controlled trials assessed the manuscript origin (US or non-US) effect on acceptance rates with results not statistically significant. Gender of the manuscript authors was assessed by only 1 randomized controlled trial, and although blinding or not female author names made no statistical difference, blinding of male author names was associated with a significant decrease in acceptance rate (139/1266 [11.0%] vs 190/1266 [15.0%]; relative risk, 0.73; 95% confidence interval, 0.59-0.90). Double-blind peer review was deemed successful by reviewers in only approximately 52% of the cases (n=5 randomized controlled trials). CONCLUSION: The double-blind peer review process seemed to be associated with an 18% lower manuscript acceptance rate than the single-blind peer review process. However, given the large heterogeneity among the included studies, more research is needed to confirm these findings and elucidate those factors that can affect the acceptance rate in double- and single-blind peer reviews.

Ultrasound evaluation of the uterus in the uncomplicated postpartum period: a systematic review.

OBJECTIVE: The aim of this systematic review and meta-analysis was to define the means and the upper limits of normal for endometrial thickness and uterine measurements in uncomplicated pregnancies at different postpartum periods. DATA SOURCES: A search was conducted in the Medline, Embase, Cinahl, and Clinicaltrials.gov databases up to January 30, 2020. STUDY ELIGIBILITY CRITERIA: We included studies reporting sonographic parameters of the uterus in the normal postpartum period. METHODS: The continuous variables were expressed as means with standard deviations. The upper limits of normal were defined as the 95th percentile. Clinically significant differences in the uterine measurements between subgroups were defined as ≥2 cm; significant differences in the uterine volume were defined as >10%. The primary outcome was the endometrial thickness; others sonographic parameters that were analyzed were the uterine anteroposterior diameter, longitudinal diameter, width, and volume. RESULTS: A total of 5260 articles were identified. Of these, 80 were assessed for their eligibility for inclusion and 32 studies were included in this systematic review. These studies included 3106 women (55% multiparas and 82% with vaginal deliveries) who underwent transabdominal and/or transvaginal ultrasound from the first postpartum day to a maximum of 6 weeks postpartum. The upper limit of normal (95th percentile) for the endometrial thickness was 25 mm by 7 days postpartum and this continued to decrease (18 mm at 14 days, 12 mm at 4 weeks, and 9 mm at 6 weeks) in a similar manner for all the women regardless of parity or mode of delivery. All the other uterine measurements also gradually decreased during the puerperium for all the women regardless of parity or mode of delivery. CONCLUSION: These upper limits of normal for the postpartum endometrium and uterine measurements in uncomplicated pregnancies provide clinical guidance for the sonographic evaluation of women with complicated postpartum courses.

Prenatal imaging features and postnatal outcomes of isolated fetal duplex renal collecting system: A systematic review and meta-analysis.

OBJECTIVES: To perform a systematic review of studies reporting the outcome of fetuses with a prenatal diagnosis of isolated duplex collecting system (DCS). METHODS: Inclusion criteria were studies reporting the outcome of fetuses with a prenatal diagnosis of isolated DCS, defined as DCS not associated with other major structural anomalies at the time of diagnosis. The outcomes observed were: imaging features of DCS on prenatal ultrasound, associated anomalies detected exclusively at prenatal follow-up ultrasound and at birth, abnormal karyotype, symptoms at birth (including vesicoureteral reflux [VUR] and urinary tract infections [UTI]), need for and type of surgical approach, complications after surgery, and accuracy of prenatal ultrasound in correctly identifying this anomaly. RESULTS: Eleven studies (284 fetuses with a prenatal diagnosis of DCS) were included. On ultrasound, DCS was associated with ureterocele in 70.7% and with megaureter in 36.6% of cases. Worsening of pelvic/ureteric dilatation was reported to occur in 41.3% of fetuses. At birth, 4.3% of fetuses affected by DCS showed associated renal anomalies. After birth, VUR and UTI presented in 51.3% and 21.7% of children respectively, while 33.6% required surgery. Prenatal diagnosis of DCS was confirmed in 90.9% of included cases. CONCLUSION: DCS diagnosed prenatally is associated with a generally good outcome. Prenatal ultrasound has a good diagnostic accuracy, while detailed postnatal assessment is required in order to identify associated renal anomalies.