BackgroundAdherence to evidence-based care processes and patient outcomes in intensive care units (ICUs) can be influenced by staffing and resource availability. We aimed to evaluate if there is a weekend effect on adherence to evidence-based care processes, and hospitalization outcomes and whether a checklist implementation could mitigate potential differences.MethodsPost hoc analysis of the Checklist for Early Recognition and Treatment of Acute Illness and Injury (CERTAIN) study dataset collected before and after checklist implementation in 34 ICUs across 15 countries (2013-2017). Admission days were classified as 'weekend/holidays' or 'weekdays' according to local work schedules and public holidays. The primary outcome was the omission of 10 evidence-based care processes addressed in the checklist. Mortality and length of stay differences between weekend/holiday and weekday admissions were evaluated as secondary outcomes.Results4256 patients contributed 1141 weekend versus 3501 weekday observation days pre-intervention, and 2014 versus 6507 post-intervention. Pre-intervention, peptic ulcer prophylaxis was omitted more frequently on weekends/holidays than weekdays (adjusted rate ratio [aRR], 0.58 [95%-confidence interval [CI] 0.38-0.88), whereas head-of-bed elevation was omitted more often on weekdays than on weekends/holidays (aRR, 3.17 [1.14-8.86]). Post-intervention, peptic ulcer prophylaxis omission rates became similar (aRR, 1.03 [0.68-1.56], but head-of-bed elevation became omitted more often on weekends than on weekdays (aRR, 0.63 [0.45-0.88]). Post-intervention, oral care was omitted more frequently on weekends/holidays than in weekdays (aRR, 0.63 [0.45-0.9]), and central catheter removal was more frequent on weekdays than in weekends/holidays (aRR, 1.11 [1.02-1.21]). No significant differences in mortality or length of stay were found.ConclusionA weekend effect influenced adherence to some care processes. While checklist implementation improved overall adherence, some disparities diminished, while new ones emerged. Organizational, cultural, and temporal factors should be further studied to optimize care delivery across all times and settings.Clinical Trial Registration NumberNCT01973829.

Dieulafoy's lesion (DL) is an uncommon cause of nonvariceal upper gastrointestinal bleeding (NVUGIB). The weekend effect refers to the phenomenon where patients admitted on weekends experience clinically poorer outcomes. This study aimed to explore the weekend effect on clinical outcomes after endoscopic hemostasis for DL in the upper gastrointestinal tract, and whether this relationship was mediated by the experience of the endoscopist. This retrospective analysis included patients with DL of the upper gastrointestinal tract who underwent standard endoscopic hemostasis treatment between April 2007 and June 2025. Univariate and multivariate analysis, propensity score matching (PSM), and mediation analysis were used to explore the relationships between the weekend effect, the experience of the endoscopist and the rebleeding rate of DL. A total of 283 patients were included in this study, consisting of 212 patients in the weekday admission group and 71 patients in the weekend admission group. Multivariate analysis showed weekend admission was an independent risk factor for rebleeding of DL. After matching, the baseline characteristics of 64 patients in the weekday admission group and 64 patients in the weekend admission group were balanced. The rebleeding rate of DL in the weekend admission group was significantly higher than that in the weekday admission group (31.3% vs. 10.9%, P = 0.005). Patients admitted on weekends were more likely to be treated by less-experienced endoscopists compared to those admitted on weekdays (48.4% vs. 25.0%, P = 0.006). Moreover, a significant indirect effect of the weekend effect on rebleeding of DL through less-experienced endoscopists was found, and the proportions mediated were 17.42%. The weekend effect was significantly associated with the higher rebleeding rate in patients with DL of the upper gastrointestinal tract, and less-experienced endoscopists on weekends might be playing a mediating role in this relationship.

Background: Disparities in hospital staffing and resource availability during weekends may delay treatment and worsen clinical outcomes for patients with acute ischemic stroke (AIS) undergoing endovascular therapy (EVT), leading to a possible ‘weekend effect’. Research Question/Hypothesis: Are weekend admissions associated with differences in in-hospital outcomes among patients with AIS undergoing EVT compared with weekday admissions? Methods: We analyzed the National Inpatient Sample database to identify adults (≥18 years) hospitalized with a primary diagnosis for AIS (ICD-10-CM codes I63.0 – I63.9) between 2018 and 2020. Procedure codes were then used to identify hospitalizations that underwent EVT (ICD-10-PCS codes 03C[A-Z]3ZZ). The primary outcome was in-hospital mortality; secondary outcomes included length of stay (LOS), inflation-adjusted total hospital charges, mechanical ventilation use, intracranial hemorrhage (ICH), and favorable discharge. Using multivariable logistic and linear regression models adjusted for demographics, comorbidities, insurance, and hospital characteristics, we evaluated associations between weekend (versus weekday) admission and in-hospital outcomes. Results: Out of a total of 61,955 patients with AIS who underwent EVT (mean age: 69 years; males: 50%), 27.2% (n=16,850) were admitted on weekends and 72.8% (n=45,105) on weekdays. In-hospital mortality occurred in 12% (n=7,175) of patients, with no significant difference between weekend and weekday admissions (adjusted odds ratio [aORs], 0.99 (95% confidence interval [CI] 0.87–1.12; p=0.9). Similarly, weekend admission had no significant effect on LOS (β=-0.16 [95% CI, -0.52 – 0.19]; p=0.4) or total hospital charges (β=286 [95% CI, -6747 – 7320]; p>0.9) compared with weekday admission. In addition, no significant differences were observed for mechanical ventilation use (p=0.9), incidence of secondary ICH (p=0.4), and favorable discharge disposition (p=0.3) between patients admitted on weekends versus weekdays. Conclusions: No weekend effect on in-hospital outcomes and resource utilization was observed in patients with AIS undergoing EVT, suggesting consistent care quality and operational efficiency regardless of admission day.

Background: Acute myocardial infarction (AMI) is a leading cause of global morbidity and mortality, with prompt percutaneous coronary intervention (PCI) essential to improve outcomes. Resource constraints and reduced staffing on weekends may lead to delayed care and worse outcomes, termed the “weekend effect.” Limited data exist on this effect specifically in AMI patients undergoing PCI. Research Question: Does weekend admission impact in-hospital outcomes among AMI patients undergoing PCI compared to weekday admission? Methods: Using the 2018–2020 National Inpatient Sample, we identified adult AMI hospitalizations treated with PCI. Admissions were categorized as weekend (Saturday–Sunday) or weekday (Monday–Friday). Multivariable logistic and linear regression analyses assessed associations with outcomes, adjusting for demographics, comorbidities, socioeconomic factors, and hospital-level characteristics. Results: Among 931,555 AMI hospitalizations receiving PCI, 26.7% (n = 249,045) were admitted on weekends. The mean age was 65 years (SD ±13), and 68% were male. The crude in-hospital mortality rates were similar between weekend and weekday admissions (3.4% vs. 3.3%; p = 0.5). However, weekend admissions were associated with significantly longer median stays (3.00 vs. 2.00 days; p < 0.001), higher median charges ($92,098 vs. $89,989; p < 0.001), and a higher proportion of mechanical ventilation use (6.1% vs. 5.7%; p = 0.009). Favorable discharge rates were comparable (88% vs. 88%; p = 0.7). Multivariate analysis showed weekend admission was not significantly associated with increased mortality (OR 1.05; 95% CI 0.99–1.12; p = 0.082) but was linked to higher odds of mechanical ventilation (OR 1.08; 95% CI 1.03–1.13; p < 0.001) and lower odds of favorable discharge (aOR 0.96; 95% CI 0.92–0.99; p = 0.013). Linear regression further showed that weekend admissions were linked to longer stays (β = 0.21 days; 95% CI 0.16–0.25; p < 0.001) and higher charges (β = $2,159; 95% CI $1,002–$3,317; p < 0.001). Conclusion: Weekend admission was not linked to higher mortality but was associated with worse outcomes—more mechanical ventilation, lower favorable discharge, longer stays, and higher costs. These findings highlight the “weekend effect” and the need for consistent, high-quality care throughout the week.

Background: The "weekend effect," marked by higher mortality and complications for weekend hospital admissions, is established for myocardial infarction and stroke but understudied in acute decompensated heart failure (ADHF). Reduced staffing and delayed interventions may contribute. We examined this phenomenon in ADHF using a national cohort. Research Question: Are weekend admissions for ADHF associated with higher mortality and complication rates? Methods: We conducted a retrospective cohort study using the 2016–2020 Nationwide Inpatient Sample. Adult ADHF admissions were identified via ICD-10 codes and stratified by weekend versus weekday admission. Over 30 variables, including age, sex, and comorbidities (e.g., diabetes, hypertension), were analyzed. We applied 1:1 propensity score matching, yielding 489,204 patients per group, and used univariate and multivariate logistic regression to assess outcomes, adjusting for key covariates. Results: Of 2,131,915 ADHF hospitalizations, 501,076 (23.5%) occurred on weekends. The cohort was 48% female, with a mean age of 72 years (SD ± 12.3). Following 1:1 matching, weekend admissions showed higher odds of cardiac arrest (aOR: 1.10; 95% CI: 1.06–1.13, p < 0.001) and inpatient mortality (aOR: 1.07; 95% CI: 1.05–1.09, p < 0.001), alongside elevated risks of acute kidney injury (aOR; 1.07; 95% CI: 1.06–1.08) and acute respiratory failure (aOR: 1.28; 95% CI: 1.27–1.30). No differences emerged in mechanical circulatory support use (11,933 cases total) or length of stay (mean 6.89 days, SD ± 7.6). Weekday admissions incurred higher total hospital charges, likely due to more procedural interventions. Conclusion: Weekend ADHF admissions were associated with a 7–10% higher risk of mortality and complications, potentially due to fewer specialists or delayed diagnostics. These findings underscore the need for standardized ADHF protocols to ensure equitable care across all days. Further research should validate and address these disparities.

Introduction: Chronic hypertension (CHTN) in pregnancy is defined as blood pressure ≥140/90 mmHg diagnosed before pregnancy or before 20 weeks’ gestation. Clinically distinct from gestational hypertension or preeclampsia. CHTN affects 0.9 to1.5% of pregnancies, with incidence rising due to increasing rates of advanced maternal age, obesity, and comorbid conditions. Pregnant patients with CHTN face elevated risks for maternal and fetal complications. The weekend effect refers to observed increases in adverse outcomes for patients admitted to the hospital on weekends compared to weekdays. Research Question: Our study investigates whether the timing of hospital admission day is associated with higher rates of several maternal morbidity (SMM) among pregnant patients with CHTN. Methods: This retrospective cohort study used the 2022 data from the National Inpatient Sample, including females (≥15 years &<54 years) hospitalized with a secondary diagnosis of maternal hypertension complicating pregnancy, identified via ICD10 codes. The primary outcome was SMM, a validated metric encompassing 21 distinct and unexpected complications during the peripartum period. The secondary outcomes included intubation, cesarean section, length of stay, and total hospitalization charges. Multivariate logistic regression adjusted for age, race, payer, community and hospital characteristics. Results: There were 96,605 hospitalizations with patients with hypertension complicating pregnancy in 2022. Weekend admissions comprised 15.24% (n=14,725) of the cohort. Weekend patients were older (32.3 vs. 31.9 years). A total of 6,540 patients experienced SMM. The SMM rate for patients admitted on the weekend was 9% vs 6% on weekdays (P = 0.0000, CI 1.346-1.802). There were no differences in intubation rates, but there were differences in cesarean rates with a 46.46% lower odds of receiving a cesarean if admitted on the weekend (P=0.000, CI 0.492-0.58.3). Weekend admits had no differences in mean charges (P=0.297, CI -$2341 to $714). Patients admitted on weekends had similar mean length of stays as weekday (p=0.56, CI -0.22 days to 0.12 days) Conclusion: Patients admitted on weekends had worse SMM outcomes compared to weekday. This may be due to reduced staffing levels and limited specialist availability. Weekend admissions had lower odds to undergo a cesarean, which may be due to fewer scheduled procedures. Understanding this relationship is clinically relevant and warrants further study.

Weekend admission and in‑hospital outcomes in cancer-related pulmonary embolism (CAP): A 2016–2022 national inpatient sample study

Abstract The hourly tropospheric NO 2 vertical column density values measured by Tropospheric Emissions: Monitoring of Pollution (TEMPO) were used to study the NO 2 diurnal variability in 32 urban areas. A recently developed algorithm isolated three components in tropospheric NO 2 data: background NO 2 , NO 2 from urban emissions, and from industrial point sources, and then each of these components was analyzed separately. The background component demonstrated a clear diurnal cycle with a maximum in the early morning and a minimum in the late afternoon. The urban component, measured as total NO 2 mass in urban plumes, ranged from 50% to 150% of the noon values throughout the day and showed considerable variation across the TEMPO domain. TEMPO data also demonstrated a significant weekend effect: On Sundays, urban plume NO 2 levels typically decreased by 30%–60% compared to workday values throughout the day. On Saturdays, the reduction was less pronounced.

IntroductionWe investigated the relationship between admission day, serum sodium concentration, and outcomes in medical inpatients. Hyponatremia, the most common electrolyte abnormality in hospitalized adults, is associated with prolonged hospital length of stay (LOS) and higher mortality. Weekend admissions are also linked to worse outcomes, but the magnitude of this “weekend effect” may vary with diagnoses and particular day of admission.DesignRetrospective multicenter cohort study.SettingFour Ministry of National Guard – Health Affairs hospitals in Saudi Arabia (January 1, 2016 – May 9, 2022).Participants43,361 adult medical admissions. Patients with hypernatremia (n = 1,892) or LOS > 30 days (n = 2,988) were excluded.InterventionsAdmissions were categorized by admission day (Sunday – Saturday) and serum sodium concentration (normonatremia and hyponatremia with severity sub-classification).Main outcome measuresLOS, intensive therapy unit (ITU) admission, and mortality.Statistical analysesMultivariable gamma generalized linear models (GLM) were used to evaluate LOS, and logistic regression for ITU admission and mortality, adjusting for age, sex, and hospital site. Sensitivity analyses examined associations with the COVID-19 pandemic.ResultsHyponatremia on admission (42.4%) was associated with longer LOS than normonatremia, on all admission days (except Fridays). Association strength between admission day and LOS decreased as the severity of hyponatremia increased. In Saudi Arabia the statutory weekend is Friday-Saturday. Friday admissions had the longest LOS, while Mondays had the shortest (reference = Sunday). Tuesday admissions showed an unexpectedly prolonged LOS, potentially reflecting internal medicine resident half day teaching activities. Mortality was not significantly associated with admission day or serum sodium concentration in adjusted analyses, but the study was underpowered to detect modest mortality differences (58% power for 10% relative risk reduction). Sensitivity analyses demonstrated that admission day associations with LOS and ITU admission remained consistent across the pre-COVID-19 and COVID-19 periods. Admission during the COVID-19 pandemic was associated with increased mortality (OR 1.41) in the primary analysis. Sensitivity analyses demonstrated that this excess mortality probably reflected an additive main effect of the COVID-19 period rather than a differential effect by day of admission, confirming that the primary findings on admission day associations are robust.ConclusionThis study reveals associations between admission day, serum sodium, and hospital outcomes. LOS varied with both admission day and hyponatremia severity. Friday admissions had the longest LOS, but admission day associations with LOS weakened with increasing hyponatremia severity. Institutional scheduling and staffing patterns may create day-specific variations that extend beyond the traditional weekend-weekday dichotomy. These temporal variations highlight opportunities for targeted workflow adjustments and resource allocation that could improve care delivery, and potentially reduce morbidity and mortality.

This paper finds that online reviews submitted during the weekend tend to have lower rating scores than reviews submitted during the week. Analyzing 400 million reviews across 33 e-commerce, hospitality, entertainment, and employer platforms, the authors find that weekend reviews have a 3% lower relative share of 5-star ratings and a 6% higher relative share of 1-, 2-, or 3-star ratings compared to weekday reviews. The pattern emerges even when controlling for quality of reviewed items. This weekend effect is surprising given that studies usually report higher happiness levels and a better mood on weekends. The authors discuss several explanations related to where the review is submitted (platform characteristics), what the review is about (listing characteristics), and who submits the review (reviewer characteristics). They present evidence that temporal self-selection of reviewers is a dominant driver of the weekend effect. During the weekend, a different set of users—those more prone to write negative reviews—is more likely to select to leave a review. These findings complement extant research on review self-selection by adding a temporal layer to the self-selection processes inherent in online reviews. This paper also highlights managerial implications by demonstrating that solicitations sent during the weekend (versus weekday solicitation) lead to collecting more negative reviews.

Using daily BTC-USD data from September 19, 2014 to January 21, 2024, this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins: average returns, close-to-close volatility, and trading activity. We implement Welch mean comparisons and HAC-robust OLS with month fixed effects (bandwidths 5, 7, and 14). In the full sample and across subsamples (2016–2019; 2020–2023; early 2024), we find no detectable weekend–weekday gap in average returns, while volatility and trading activity are lower on weekends. The patterns are robust to using squared returns as a volatility proxy. The joint evidence is consistent with liquidity and attention mechanisms—quieter weekends rather than compensating return premia. Replication files reproduce all tables and figures.

A crypto-stock weekend effect: Predicting Monday stock returns using weekend cryptocurrency returns

Abstract. This study presents a comprehensive spatiotemporal analysis of air quality across various urban functional zones in China from 2017 to 2022, uncovering distinct impacts on air quality due to the unique characteristics of each zone. A general decrease in various pollutant concentrations is observed, a result of stringent pollution control policies. Specifically, the concentration of PM2.5 decreased from 46.1–30.6 µg m−3. Residential, commercial, and industrial zones show significant declines, whereas the transportation zone experiences the least decrease. However, ozone levels rebound significantly in densely populated residential and commercial zones and exhibit distinct weekend effects. The research highlights U-shaped seasonal patterns for five key pollutants and inverse seasonal patterns for ozone, which gradually decrease. Furthermore, the daily and seasonal variations of pollutant concentrations in the industrial zone are the largest, while those in the public management and service zone are the smallest. For example, the seasonal fluctuation of PM2.5 and PM10 in the industrial zone was 50.5 and 66.1 µg m−3, respectively. Urban scale has the most significant impact on public management and service zone. Notably, spatial heterogeneity is evident, with regional pollutant distributions linked to local emissions, control measures, urban morphology, and climate variability. This study emphasizes the critical link between urbanization and air quality, advocating for continuous monitoring and the development of zone-specific air quality strategies to ensure sustainable urban environments.

Background: Weekend presentation to the emergency department (ED) has been associated with increased morbidity and mortality in various clinical settings. However, the literature is scant whether such an effect exists for patients presenting with COVID-19 infection. Additionally, comparative analyses of mortality predictors in COVID-19 patients evaluated at the emergency department need further exploration. Methods: This retrospective cohort study examined factors associated with mortality among adult patients (aged ≥ 18 years) who presented with COVID-19 to the emergency departments of five hospitals within the Johns Hopkins Health System (combined capacity: 2513 beds) between March 1 and 4 May 2020. Data were extracted from electronic health records. Multivariable logistic regression was utilized to assess the relationship between mortality and a range of variables, including sociodemographic characteristics, clinical presentation, laboratory parameters, pre-existing comorbidities, and weekend versus weekday presentation. Results: Of the 2767 patients, 685 (25%) presented to the emergency department on weekends. Compared to weekday presenters, weekend patients were more likely to be hospitalized (64%), and these patients had a mean symptom duration of 5 days (SD ± 6). Weekend presenters also exhibited higher rates of clinical frailty, dehydration, hypoxia, and respiratory distress upon arrival. In multivariable logistic regression analysis adjusting for sociodemographic characteristics, clinical risk factors, and laboratory findings, independent predictors of increased mortality included absence of a primary care provider (OR 3.47; 95% CI: 2.37–5.07), peripheral oxygen saturation (SpO2) < 95% at presentation (OR 1.46; 95% CI: 1.001–2.12), and hyperglycemia (OR 2.13; 95% CI: 1.25–3.65). Notably, the presence of crackles on physical examination demonstrated a trend toward reduced mortality (OR 0.47; 95% CI: 0.24–0.92). Conclusions: While weekend presentation was associated with higher hospitalization rates among patients with COVID-19, it did not independently predict increased mortality. Absence of a primary care provider, hypoxia, and hyperglycemia at presentation emerged as strong, independent predictors of mortality in the ED setting. Race, gender, and obesity were not significantly associated with mortality in this cohort, warranting further investigation. These findings may support more effective triage and risk stratification strategies in current and future public health emergencies.

The weekend effect in hip fracture: The critical role of resource management.

Abstract. Ground-level ozone (O3) formation in urban areas is nonlinearly dependent on the relative availability of its precursors: oxides of nitrogen (NOx) and volatile organic compounds (VOCs). To mitigate O3 pollution, a crucial question is to identify the O3 formation regime (NOx-limited or VOC-limited). Here, we leverage ground-based O3 observations alongside space-based observations of O3 precursors, namely, nitrogen dioxide (NO2) and formaldehyde (HCHO), to study the long-term shifts in O3 chemical regimes across global source regions. We first derive the regime threshold values for the satellite-derived HCHO/NO2 ratio by examining its relationship with the O3 weekend effect. We find that a regime transition from VOC-limited to NOx-limited occurs around 3.1 [2.7–3.4] for HCHO/NO2 with slight regional variations. By integrating data from four satellite instruments, including Global Ozone Monitoring Experiment (GOME), SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY), Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI), we built a 27-year (1996–2022) satellite HCHO/NO2 record from which we assess the long-term trends in O3 production regimes. A discernible global trend towards NOx-limited regimes is evident, particularly in developed regions such as North America, Europe, and Japan, with emerging trends in developing countries like China and India over the past 2 decades. This shift is supported by both increasing HCHO/NO2 ratios and a diminishing O3 weekend effect. Yet, urban areas still hover in the VOC-limited and transitional regime on the basis of annual averages. Our findings stress the importance of adaptive emission control strategies to mitigate O3 pollution.

Abstract This study quantifies how traffic congestion influences the surface urban heat island intensity (SUHII) in Chicago using GOES LST data and Chicago Transit Authority (CTA) bus speed data. While SUHII is characterized by a well pronounced diurnal cycle that peaks around noon, we observed changes in strength of SUHII that were correlated with changes in traffic speed. This leads to distinct weekend and rush hour effects on SUHII. Citywide, we observed a statistically significant correlation in which each 10 mph decrease in bus speed is associated with an increase of 0.36°C in SUHII. That effect is stronger in highly vegetated, low‐building areas, where traffic‐emitted waste heat is more dominant than other anthropogenic sources. These findings highlight the importance of incorporating congestion metrics into urban heat research, offering new insights for planners and policymakers seeking to mitigate local thermal extremes.

ObjectiveDeficiencies have been highlighted in acute hospital care for alcohol-related liver disease (ARLD). Such problems may be worse at weekends (WEs). Increased 30-day mortality for WE admissions has been reported for several acute conditions, but data for ARLD are limited. We aimed to compare patient and pathway characteristics between WE and weekday (WD) admissions and investigate the ‘weekend effect’ on mortality.MethodsRetrospective cohort study (2008–2018) using linked electronic databases (Hospital Episode Statistics-Clinical Practice Research Datalink and death registration) including 17 575 first emergency admissions identified using the Liverpool ARLD algorithm. Exposure: WE admission (Saturday or Sunday). Main outcome: all-cause death within 30 days. Covariates included socio-demographic characteristics, pathway characteristics (pre-admission contacts and admission method) and markers of severity (recorded stage of liver disease, ascites and varices, comorbidity). Alternative risk-adjustment methods were used, including standard regression and propensity-weighted analysis (Inverse Probability of Treatment Weighting).Results3249 admissions (18.5%) were at WE. Unadjusted 30-day mortality was significantly higher for WE versus WD (17.1% vs 15.5%, p=0.018). All models demonstrated increased odds of death for WE admissions with adjusted ORs ranging from 1.15 to 1.23 (relative risk of 1.12–1.19). Causes of death did not vary by admission day and effect was consistent across subgroups. Findings were robust to sensitivity analyses restricting the cohort to patients admitted directly from Accident and Emergency department (A&E), or cirrhosis or ascites but not varices.ConclusionFirst ARLD admissions at the WE experienced a 12–19% increase in 30-day mortality risk compared with WD. Although residual confounding cannot be excluded, this suggests the possibility of avoidable mortality among those hospitalised at WEs. Services should be alert to risks of WE effects when planning care.

ABSTRACTAimsTo evaluate the prognostic significance of the weekend effect in patients undergoing emergency laparotomy.MethodsA STROCSS‐compliant retrospective cohort study (in three centres between January 2014 and January 2022) with complementary PRISMA‐compliant meta‐analysis (last search on 10 February 2025) was conducted. All adult patients undergoing non‐traumatic emergency laparotomy were considered eligible. Emergency laparotomy during weekends (Saturday, Sunday and public holidays) was the prognostic factor of interest, and emergency laparotomy during weekdays (Monday, Tuesday, Wednesday, Thursday and Friday) was the comparison. Thirty‐day mortality was the outcome.ResultsThe cohort study included 1952 patients and a search of electronic databases identified five retrospective cohort studies including 5374 patients. Consequently, 7326 patients (weekend group: 2035; weekdays group: 5291) were included for analyses. Both groups were comparable in terms of median age (67 years vs. 65, p = 0.194), being an octogenarian (17.9% vs. 17.9%, p = 0.970), male sex (41.9% vs. 45.7%, p = 0.153), ASA I status (4.5% vs. 6.7%, p = 0.080), ASA II (33.6% vs. 35.2%, p = 0.524), ASA III (46.6% vs. 41.6%, p = 0.060), ASA IV (14.7% vs. 15.2%, p = 0.764), ASA V (0.6% vs. 1.3%, p = 0.249), need for bowel resection (54.0% vs. 57.6%, p = 0.172) and peritoneal contamination (26.4% vs. 29.2%, p = 0.236). There was no difference in the risk of 30‐day mortality between the two groups (OR: 1.04, 95% CI 0.87–1.25, p = 0.650; I2 = 0%). The GRADE certainty was high.ConclusionsRobust evidence with high certainty suggests that the weekend effect does not influence the risk of mortality after emergency laparotomy. This could be explained by the standardisation of perioperative care in patients undergoing emergency laparotomy.

BackgroundThe weekend effect is a controversial epidemiological phenomenon that has rarely been reported in the assisted reproductive technology (ART) setting, particularly among first-cycle fresh embryo transfer (ET) populations undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).MethodsThis was a retrospective cohort study including first fresh ET cycles in the Reproductive Medicine Center, Xiangya Hospital of Central South University from January 1, 2014 to March 1, 2022. Patients were divided into three groups based on the day of oocyte retrieval: Weekend Group, Near-Weekend Group and Midweek Group. Univariable and multivariate logistic regression analyses were performed to identify confounding factors and to evaluate associations between procedural timing and clinical pregnancy rate (CPR).ResultsA total of 8,200 first fresh ET cycles qualified for analysis after exclusions (16,121 screened), and were categorized based on the day of oocyte retrieval: Weekend Group (Saturday/Sunday, 27.06%, n = 2,219), Near-Weekend Group (Friday/Monday, 29.70%, n = 2,435), and Midweek Group (Tuesday/Wednesday/Thursday, 43.24%, n = 3,546). Oocyte retrievals near the weekend significantly reduced the odds of achieving CPR compared to midweek group (adjusted OR: 0.836, 95%CI: 0.728–0.960, p = 0.011). Weekend retrievals also showed lower odds of CPR, though not statistically significant (adjusted OR: 0.900, 95%CI: 0.781–1.037, p = 0.144). Compared to midweek oocyte retrievals, both the Weekend and Near-Weekend Groups demonstrated significantly lower live birth rates (46.73% vs. 43.88% vs. 43.49%, respectively; p = 0.023).ConclusionsThe timing of oocyte retrieval near weekends was associated with reduced CPR and live birth rate in fresh cycles. This study highlights the importance for maintaining consistent clinical vigilance—regardless of the day of the week—to optimize both pregnancy success rates and patient satisfaction.