Weekend Effect Research Articles

Analyzing the effect of weekend and July admission on patient outcomes following non-pyogenic intracranial venous thrombosis

ObjectiveTo investigate the effect of weekend admission and July admission on the short-term outcome of patients following a non-pyogenic cerebral venous thrombosis. MethodsData from the National Inpatient Sample were gathered from the years 2013–2016. Patients who had a non-pyogenic cerebral venous thrombosis were identified. Admissions on the weekend were compared to those on the weekdays, as well as July admissions compared to other months. Outcome measures included inpatient mortality, length of stay, APR-DRG severity and mortality risk scores, non-routine discharges, complications, and total charges. ResultsWe identified 1116 patients who were admitted with a non-pyogenic cerebral venous thrombosis between 2013 and 2016. Of those, 243 (21.8%) were admitted on a weekend day (Saturday/Sunday), and 873 (78.2%) were admitted on a weekday. Of the 963 patients admitted to a teaching hospital, 81 (8.4%) were admitted in July and 882 (91.6%) were admitted in other months. When analyzing the weekend effect, there were significant differences observed in patient mortality (7.4% vs 3.9%, P = 0.022, OR = 1.967), adjusted log length of stay (0.874 ± 0.567 vs 0.795 ± 0.494, P = 0.033), and the rate of sepsis (6.6% vs 3.4%, P = 0.029, OR = 1.978). The means of all other measures of outcome were elevated when comparing the weekend vs weekday. When analyzing the July effect, there were no significant differences observed for any outcome measures. ConclusionsPatients admitted on the weekend with a nonpyogenic intracranial venous thrombosis have significantly worse outcomes compared to those admitted on a weekday. There were no significant differences found between patients admitted in the month of July compared to other months.

The weekend effect for stroke patients admitted to intensive care: A retrospective cohort analysis.

ObjectivesTo examine the effect of weekend admission on short and long-term morbidity and mortality, for patients admitted to intensive care after suffering a cerebrovascular accident (stroke).Design, setting, and participantsA hospital-wide, retrospective cohort study of 3,729 adult stroke patients admitted to the Beth Israel Deaconess Medical Centre (BIDMC) intensive care unit (ICU) between 2001 and 2012, using the Medical Information Mart for Intensive Care III (MIMIC-III) database.Primary outcome measuresPrimary outcome measures were ICU length-of-stay and mortality, hospital length-of-stay and mortality, proportions of patients discharged home after admission, and 6-month mortality.ResultsOverall, 23% of BIDMC ICU stroke admissions occurred over the weekend. Those admitted over the weekend were likelier to have suffered haemorrhagic stroke than those admitted during the week (60.6% vs 47.9%). Those admitted on the weekend were younger, and likelier to be male and unmarried, with similar ethnic representation. The OASIS severity of illness (32.5 vs. 32) and lowest day-one GCS (12.6 vs. 12.9) were similar between groups. Unadjusted ICU-mortality was significantly higher for patients admitted over the weekend (OR 1.32, CI 1.08–1.61), but when adjusted for type of stroke, became non-significant (OR 1.17, CI 0.95–1.44). In-hospital mortality was significantly higher for patients admitted to ICU over the weekend in both unadjusted (OR 1.45, CI 1.22–1.73) and adjusted (OR 1.31, CI 1.09–1.58) analyses. There was no significant difference in ICU or hospital length of stay. While patients admitted on the weekend appeared less likely to be discharged back to home and more at risk of 6-month mortality compared to weekday admissions, results were non-significant.ConclusionsThe effect of weekend ICU-admission for stroke patients appears to be significant for in-hospital mortality. There were no significant differences in adjusted ICU-mortality, ICU or hospital length-of-stay, or longer-term morbidity and mortality measures.

Does the "Weekend Effect" Extend to Friday Admissions? An Analysis of Ischemic Stroke Hospitalizations in South Carolina.

Background: Weekend admission has been found to be associated with higher hospital mortality and longer hospital stay among patients with acute cardiovascular conditions. Whether those admitted on Fridays face similar risk as those admitted on Sundays and Saturdays remain uncertain.Methods: This study used 2012–2013 data from hospital records for nonfatal patients with ischemic stroke in the state of South Carolina. The database contained the records of all hospitalizations in South Carolina except military and federal institutions. Multilevel logistic, negative binomial, and log-linear regression models were performed to explore the temporal pattern by hospital admission on specific day of a week for three outcomes: discharge to hospice care (vs. other alive discharges), length of stay, and total charge, respectively. Each model controlled for the patient age, gender, race/ethnicity, year of hospital admission, season of admission, payer, and Charlson Comorbidity Index.Results: A total of 19,346 nonfatal ischemic stroke hospitalizations were identified. Multilevel logistic regression shows that patients admitted on non-Friday weekdays had a significantly lower odds of being discharged to hospice care as compared with those admitted on Fridays [odds ratio = 0.80, 95% confidence interval (CI) = 0.65–0.99] where there was no significant difference between Friday admissions and weekend admissions. The length of hospital stay for admission on non-Friday weekdays was significantly shorter than that of Friday admissions [incident rate ratio (IRR) = 0.87, 95% CI = 0.84–0.90], whereas longer length of hospital stay was found on weekend admission (IRR = 1.06, 95% CI = 1.02–1.11). Friday admissions were not associated with higher charges as compared with non-Friday weekday admissions.Conclusions: Some hospitalization outcomes admitted on Fridays seemed to have the “weekend effects” too. Further studies are warranted to investigate underlying mechanism for such a difference in outcomes between Friday and other weekdays. Interventions to close the weekend–weekday gap of patient outcomes need to consider the elevated risk on Friday admission.

Weekend admissions with ascites are associated with delayed paracentesis: A nationwide analysis of the ‘weekend effect’

Introduction and objectivesWeekend admissions has previously been associated with worse outcomes in conditions requiring specialists. Our study aimed to determine in-hospital outcomes in patients with ascites admitted over the weekends versus weekdays. Time to paracentesis from admission was studied as current guidelines recommend paracentesis within 24h for all patients admitted with worsening ascites or signs and symptoms of sepsis/hepatic encephalopathy (HE). PatientsWe analyzed 70 million discharges from the 2005–2014 National Inpatient Sample to include all adult patients admitted non-electively for ascites, spontaneous bacterial peritonitis (SBP), and HE with ascites with cirrhosis as a secondary diagnosis. The outcomes were in-hospital mortality, complication rates, and resource utilization. Odds ratios (OR) and means were adjusted for confounders using multivariate regression analysis models. ResultsOut of the total 195,083 ascites/SBP/HE-related hospitalizations, 47,383 (24.2%) occurred on weekends. Weekend group had a higher number of patients on Medicare and had higher comorbidity burden. There was no difference in mortality rate, total complication rates, length of stay or total hospitalization charges between the patients admitted on the weekend or weekdays. However, patients admitted over the weekends were less likely to undergo paracentesis (OR 0.89) and paracentesis within 24h of admission (OR 0.71). The mean time to paracentesis was 2.96 days for weekend admissions vs. 2.73 days for weekday admissions. ConclusionsWe observed a statistically significant “weekend effect” in the duration to undergo paracentesis in patients with ascites/SBP/HE-related hospitalizations. However, it did not affect the patient's length of stay, hospitalization charges, and in-hospital mortality.

Treatment of Diabetic Ketoacidosis and the Weekend Effect at an Urban Tertiary-Care Center

Objective: Weekend admission has been associated with higher morbidity and mortality, but the relationship between diabetic ketoacidosis (DKA) outcomes and this weekend effect is unclear. To better characterize it, we examined the outcomes of patients admitted with DKA to an urban tertiary-care center. Methods: This retrospective study included pediatric and adult patients admitted to Montefiore Health System from January 1, 2008, through December 31, 2018, with a primary or secondary diagnosis of DKA as identified by International Classification of Diseases (ICD)-9 and -10 codes; all ICD diagnoses were present on admission. Only the first admission for each patient was analyzed, and patients were excluded if their initial anion gap was less than 13 mEq/L. A subcohort comprised of patients with documented biochemical evidence of DKA resolution was also analyzed. The Friday-Saturday weekend was defined as the period between midnight on Friday and midnight on Sunday; the Saturday-Sunday weekend was similarly defined. The following outcomes were compared between weekday and weekend groups: length of stay; time to initiation of subcutaneous insulin; and time to each of the following: venous pH >7.3, blood glucose <200 mg/dL, and anion gap ≤12 mEq/L. Odds of 30-day all-cause mortality and 30-day all-cause and DKA-specific readmission were also examined. Results: Over 11 years, 4,703 patients were included in the overall cohort, and 648 were included in the subcohort. For both weekend definitions, weekend admission did not produce differences in any outcome for either study cohort. Conclusion: No weekend effect on DKA outcomes was detected at an urban tertiary-care center. Abbreviations: AG = anion gap; CCI = Charlson Comorbidity Index; DKA = diabetic ketoacidosis; ICD = International Classification of Diseases; IVI = intravenous insulin; LOS = length of stay; SCI = subcutaneous insulin.

Spectral Analysis of the Daily Evolution of Deaths Due to COVID-19 in France and in the World Shows a Weekend Effect: Myth or Reality?

Background: The weekend effect has been extensively observed for different diseases and countries and recognized as a fact but without obvious causes. Objectives: In this paper we first aimed at investigating the existence of a periodicity in the death count due to Covid-19, and second, at opening the discussion concerning the reality of this effect in this particular context. Methods: Daily statistics of deaths due to the Covid-19 pandemic were subjected to a discrete Fourier transform spectral analysis for France and the world, over the periods from March 29 to May 16, 2020 and from January 22 to May 18,2020 respectively. Results: In both cases, a frequency peak of one harmonic corresponding to a period of 7·11 days was observed for France and the world. In France, this weekly frequency corresponds to a decrease in deaths every Sunday, whereas for the world the systematic decrease is shifted on average by 1·5 days and corresponds to Saturday or Friday. Conclusion: At the world scale and for the epidemic period we confirm the existence of a consecutive weekend effect in the context of the Covid-19 pandemic. Funding Statement: None. Declaration of Interests: All authors declare no competing interests.

0443 Intra Week Sleep Patterns Analyzed Using Consumer Sleep Tracker Data

Abstract Introduction Big data collected using consumer sleep technology can provide objectively measured insights on sleep behavior in the real-life environment. It has the advantage over self-report data of being less prone to bias. Here we used a non-contact bio-motion sensor to remotely capture objective sleep data. We analyzed 168432 nights of sleep data to test if differences between weekday versus weekend sleep behavior, known from self-report, would still hold using objective data in a large population. Methods Sleep data was acquired using the SleepScore Max remote sleep sensor and included 168432 nights (2730 users, mean age: 46.6 +/- 11.8 years, 33% female, all resident in the USA). Analysis was restricted to those of working age; adults between 20-65. Any sleep which ended from Monday to Friday was considered weekday sleep, and any ending on Saturday or Sunday as weekend sleep. Data records were inspected and cleaned before analyzing. Descriptive statistics and independent t-tests were used to analyze the data. Results Total Sleep Time, Time In Bed and Sleep Onset Latencies were longer during weekend (TST: + 20.6 mins, TIB: +22.9 mins, SOL: +1.1 min, all p &amp;lt;0.001), resulting in a slightly poorer Sleep Efficiency (-.016%, p&amp;lt;0.01) for weekend nights. Time to bed and final awakening were both delayed in weekends as compared to weekdays (Time to bed +30.0 mins, and final awakening +53.4 mins, both p&amp;lt;0.001). Conclusion This big data analysis confirms the earlier observed difference in sleep and sleep behavior between weekdays and weekends. This should be considered for optimizing (automated) sleep interventions, that may not normally take the weekend effect into consideration. Support

Quality assessment of weekend discharge: a systematic review and meta-analysis

Hospital bed utility and length of stay affect the healthcare budget and quality of patient care. Prior studies already show admission and operation on weekends have higher mortality rates compared with weekdays, which has been identified as the 'weekend effect.' However, discharges on weekends are also linked with quality of care, and have been evaluated in the recent decade with different dimensions. This meta-analysis aims to discuss weekend discharges associated with 30-day readmission, 30-day mortality, 30-day emergency department visits and 14-day follow-up visits compared with weekday discharges. PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov were searched from January 2000 to November 2019. Preferred reporting items for systematic reviews and meta-analyses guidelines were followed. Only studies published in English were reviewed. The random-effects model was applied to assess the effects of heterogeneity among the selected studies. Year of publication, country, sample size, number of weekday/weekend discharges, 30-day readmission, 30-day mortality, 30-day ED visits and 14-day appointment follow-up rate. There are 20 studies from seven countries, including 13 articles from America, in the present meta-analysis. There was no significant difference in odds ratio (OR) in 30-day readmission, 30-day mortality, 30-day ED visit, and 14-day follow-up between weekday and weekend. However, the OR for 30-day readmission was significantly higher among patients in the USA, including studies with high heterogeneity. In the USA, the 30-day readmission rate was higher in patients who had been discharged on the weekend compared with the weekday. However, interpretation should be cautious because of data limitation and high heterogeneity. Further intervention should be conducted to eliminate any healthcare inequality within the healthcare system and to improve the quality of patient care.

Amplified ozone pollution in cities during the COVID-19 lockdown

The effect of lockdown due to coronavirus disease (COVID-19) pandemic on air pollution in four Southern European cities (Nice, Rome, Valencia and Turin) and Wuhan (China) was quantified, with a focus on ozone (O3). Compared to the same period in 2017–2019, the daily O3 mean concentrations increased at urban stations by 24% in Nice, 14% in Rome, 27% in Turin, 2.4% in Valencia and 36% in Wuhan during the lockdown in 2020. This increase in O3 concentrations is mainly explained by an unprecedented reduction in NOx emissions leading to a lower O3 titration by NO. Strong reductions in NO2 mean concentrations were observed in all European cities, ~53% at urban stations, comparable to Wuhan (57%), and ~65% at traffic stations. NO declined even further, ~63% at urban stations and ~78% at traffic stations in Europe. Reductions in PM2.5 and PM10 at urban stations were overall much smaller both in magnitude and relative change in Europe (~8%) than in Wuhan (~42%). The PM reductions due to limiting transportation and fuel combustion in institutional and commercial buildings were partly offset by increases of PM emissions from the activities at home in some of the cities. The NOx concentrations during the lockdown were on average 49% lower than those at weekends of the previous years in all cities. The lockdown effect on O3 production was ~10% higher than the weekend effect in Southern Europe and 38% higher in Wuhan, while for PM the lockdown had the same effect as weekends in Southern Europe (~6% of difference). This study highlights the challenge of reducing the formation of secondary pollutants such as O3 even with strict measures to control primary pollutant emissions. These results are relevant for designing abatement policies of urban pollution.

Weekend readmissions associated with mortality following pancreatic resection for cancer

BackgroundThe weekend effect is associated with an increased risk of adverse events, with complex patient populations especially susceptible to its impact. The objective of this study was to determine if outcomes for patients readmitted following pancreas resection differed on the weekend compared to weekdays. MethodsThe Healthcare Cost and Utilization State Inpatient Database for Florida was used to identify patients undergoing pancreas resection for cancer who were readmitted within 30 days of discharge following surgery. Measured outcomes (for readmission encounters) included inpatient morbidity and mortality. ResultsPatients with weekend readmissions had an increased odds of inpatient mortality (aOR 2.7, 95% C.I.: 1.1–6.6) compared to those with weekday readmissions despite having similar index lengths of stay (15.9 vs. 15.5 days, P = .73), incidence of postoperative inpatient complications (22.4% vs. 22.3%, P = .98), reasons for readmission, and baseline comorbidity. DiscussionWeekend readmissions following pancreatic resection are associated with increased risk of mortality. This is not explained by measured patient factors or clinical characteristics of the index hospital stay. Developing strategies to overcome the weekend effect can result in improved care for patients readmitted on the weekend.

Patient Delay in Hospital Visiting and the Weekend Effect of Surveillance Report on Hand-Foot-and-Mouth Disease and Epidemic Parotitis in Hanzhong City, China.

Background We aimed at investigating the prevalence and associated factors of patient delay in hospital visiting and weekend effect of disease surveillance on hand-foot-and-mouth disease and epidemic parotitis/mumps. Methods Daily report data on hand-foot-and-mouth disease and epidemic parotitis cases between January 1, 2014, and December 31, 2017, in Hanzhong, Shaanxi, China, were collected. The patient delay in hospital visiting was defined by the date difference between disease onset and patient's visit to hospital. Differences of delayed durations and percentages were compared by using nonparametric or χ2 tests across gender, age, occupation, disease classification, epidemic and nonepidemic seasons, and years of disease onset. Additionally, to determine whether there existed a weekend effect of disease surveillance, the mean cases reported on weekdays and weekends were also compared. Results A total of 14,814 patients with hand-foot-and-mouth disease and 4013 with epidemic parotitis were recorded, respectively. We found that 43.1% of the hand-foot-and-mouth disease and 36.5% of the epidemic parotitis patients had delayed visiting to hospital. All patients were reported through the online surveillance system on the day of visiting hospital. The percentage of delayed visiting to hospital differed significantly by years and epidemic and nonepidemic seasons and between children in and not in childcare center (all p values <0.05). In addition, the reported numbers of both diseases fluctuated on weekdays but obviously decreased on weekends regardless of the epidemic or nonepidemic seasons. Conclusions The reported cases of HFMD and epidemic parotitis had an obvious weekend effect, with an increasing tendency of cases delaying in hospital visiting over the recent years in Hanzhong, China. Parents and caregivers rather than health systems should be primarily targeted for the prevention and control of infectious diseases and their local outbreaks such as community-based education on the second-dose vaccination of mumps and/or hand hygiene.

Spatiotemporal distribution of ground-level ozone in China at a city level

In recent years, ozone (O3) pollution in China has shown a worsening trend. Due to the vast territory of China, O3 pollution is a widespread and complex problem. It is vital to understand the current spatiotemporal distribution of O3 pollution in China. In this study, we collected hourly data on O3 concentrations in 338 cities from January 1, 2016, to February 28, 2019, to analyze O3 pollution in China from a spatiotemporal perspective. The spatial analysis showed that the O3 concentrations exceeded the limit in seven geographical regions of China to some extent, with more serious pollution in North, East, and Central China. The O3 concentrations in the eastern areas were usually higher than those in the western areas. The temporal analysis showed seasonal variations in O3 concentration, with the highest O3 concentration in the summer and the lowest in the winter. The weekend effect, which occurs in other countries (such as the USA), was found only in some cities in China. We also found that the highest O3 concentration usually occurred in the afternoon and the lowest was in the early morning. The comprehensive analysis in this paper could improve our understanding of the severity of O3 pollution in China.

Inferring Changes in Summertime Surface Ozone-NOx-VOC Chemistry over U.S. Urban Areas from Two Decades of Satellite and Ground-Based Observations.

Urban ozone (O3) formation can be limited by NOx, VOCs, or both, complicating the design of effective O3 abatement plans. A satellite-retrieved ratio of formaldehyde to NO2 (HCHO/NO2), developed from theory and modeling, has previously been used to indicate O3 formation chemistry. Here, we connect this space-based indicator to spatiotemporal variations in O3 recorded by on-the-ground monitors over major U.S. cities. High-O3 events vary nonlinearly with OMI HCHO and NO2, and the transition from VOC-limited to NOx-limited O3 formation regimes occurs at higher HCHO/NO2 value (3 to 4) than previously determined from models, with slight intercity variations. To extend satellite records back to 1996, we develop an approach to harmonize observations from GOME and SCIAMACHY that accounts for differences in spatial resolution and overpass time. Two-decade (1996-2016) multisatellite HCHO/NO2 captures the timing and location of the transition from VOC-limited to NOx-limited O3 production regimes in major U.S. cities, which aligns with the observed long-term changes in urban-rural gradient of O3 and the reversal of O3 weekend effect. Our findings suggest promise for applying space-based HCHO/NO2 to interpret local O3 chemistry, particularly with the new-generation satellite instruments that offer finer spatial and temporal resolution.

Managing natural gas demand for free consumers under uncertainty and limited storage capacity

Demand for energy sources depends on several factors such as population growth, urbanization, industrialization, and climate. Among fundamental energy sources, natural gas is characterized by storage limitations and take-or-pay contracts, which makes it especially critical to forecast the demand accurately for cost management policies. Suppliers of natural gas require take-or-pay contracts to ensure that consumers pay for any unused amount up front; and if the demand exceeds the agreed amount, they pay for over-use as well. Consumers with a demand above the eligible consumer limit are categorized as free consumers; and they have to specify their daily, monthly, and annual demand in these take-or-pay contracts. In residential areas, natural gas is used predominantly for heating, hence its consumption has a strong seasonality. In winter, the variability in the atmospheric temperature leads to fluctuations in the demand, while in summer, weekend effects dominate. In order to take these features into account, a demand forecasting model based on a modulated expansion in Fourier series, supplemented by deviations from comfortable temperatures, is used in this study to determine the threshold value for the onset of natural gas usage for heating purposes. The upper and lower bounds for consumption are obtained as a function of temperature only, after analyzing the details of the temperature-consumption relationship using historical data. Moreover, a temperature-based simulation methodology is proposed and simulation results that provide guidelines to manage the costs of storage under uncertainty are presented by suggesting the minimum storage capacity required and showing the distribution of the costs.

Occurence of left main occlusion on Tuesday: Chronobiology of acute myocardial infarction due to left main disease.

ObjectivesThe existence of a “weekend effect” for onset of acute myocardial infarction (AMI) has been suggested in the past, but the relation with the culprit vessel has not been investigated. MI due to left main coronary artery lesion represents a particularly serious life-threatening condition. Our study was aimed to assess the chronobiology of admission to the emergency department for AMI considered to be induced by a left main culprit lesion.MethodsWe retrospectively reviewed patients who experienced an AMI due to a left main culprit lesion between January 1, 2008 and January 1, 2018 stratifying them according to the day of admission, on the basis of the symptom onset time; the 30-day cardiovascular mortality was also analyzed on the basis of the time of symptom onset.ResultsOut of 1789 patients with AMI, 130 (7.2%, 104 males and 26 females, mean age 74.5 ± 8.1 years) had left main disease as the culprit lesion. Tuesday was significantly over-represented as the admission day (p < 0.001 for Tuesday vs. other days; p = 0.009 for Tuesday vs. Sunday, respectively). The 30-day cardiovascular survival was not different between patients admitted on Tuesday and those admitted on remaining days (Log-rank, Mantel Cox, p = 0.43; Chi-square = 0.611). A significant difference was noted in patients with AMI on Sunday versus remaining days (Log-rank, Mantel-Cox, p = 0.005; Chi-square = 7.96). The diameter of the left main artery was larger in patients admitted on Tuesdays than on Sundays (p < 0.01).ConclusionThe relation between AMI onset and the day of the week is confirmed by our study, which also suggests that in case of a left main lesion, some delay of the weekend effect might be expected.

Too Stressed for Sex? Low Sex Marriages in Singapore

This paper investigates the associations between stress and fatigue arising from hectic lifestyles and marital coital activity in Singapore, where the fertility rate is among the lowest in the world. Using data on 657 married women’s self-reported daily coital activity collected through online diaries over 14 weeks (n = 54,600), I estimate that marital sexual frequency is 3.69 and 2.55 per 30 days on average among women aged 25-29 and 30-34 respectively, well below ideal frequencies of 6.40 and 5.23. Results from two-way logistic models show that there is a strong positive weekend effect and a positive but weaker public holiday effect, with very low probabilities of sex during the workweek among older married women. Stress has a significant inhibition effect through the week among older women, and has a stronger effect on couples who are likely to want more children. On the other hand, fatigue reduces probability of sex mainly during the workweek, and has a stronger effect on couples who have already achieved their ideal family size. The results suggest that the incompatibility between demanding work-life environments and healthy marital sex lives contributes to the decline in coital frequency with age and helps to explain the very low fertility rate in Singapore.

Weekend effect on mortality by medical specialty in six secondary hospitals in the Helsinki metropolitan area over a 14-year period

BackgroundThe weekend effect is the phenomenon of a patient’s day of admission affecting their risk for mortality. Our study reviews the situation at six secondary hospitals in the greater Helsinki area over a 14-year period by specialty, in order to examine the effect of centralization of services on the weekend effect.MethodsOf the 28,591,840 patient visits from the years 2000–2013 in our hospital district, we extracted in-patients treated only in secondary hospitals who died during their hospital stay or within 30 days of discharge. We categorized patients based on the type of each admission, namely elective versus emergency, and according to the specialty of their clinical service provider and main diagnosis.ResultsA total of 456,676 in-patients (292,399 emergency in-patients) were included in the study, with 17,231 deaths in-hospital or within 30 days of discharge. A statistically significant weekend effect was observed for in-hospital and 30-day post-discharge mortality among emergency patients for 1 of 7 specialties. For elective patients, a statistically significant weekend effect was visible in in-hospital mortality for 4 of 8 specialties and in 30-day post-discharge mortality for 3 of 8 specialties. Surgery, internal medicine, and gynecology and obstetrics were most susceptible to this phenomenon.ConclusionsA weekend effect was present for the majority of specialties for elective patients, indicating a need for guidelines for these admissions. More disease-specific research is necessary to find the diagnoses, which suffer most from the weekend effect and adjust staffing accordingly.

The “weekend effect” – Does it impact acute stroke care? (4937)

The “weekend effect” – Does it impact acute stroke care? (4937)

Two decades of ozone standard exceedances in Santiago de Chile

A drastic decline of 2.4 ppbv decade−1 in the ozone mixing ratio has been measured in Santiago de Chile during the 2000s. Subsequently, in the 2010s, ozone trends stabilized in downtown and showed upward trends in eastern Santiago. The number of days with an 8-h average ozone mixing ratio above 61 ppbv, deemed harmful to health according to Chilean legislation, has declined significantly both in western and central Santiago. However, in eastern Santiago, one finds a 2010–2018 decade average of 43 days per year above recommended levels. Also, at a Receptor Site located ~ 70 km downwind from Santiago, this number rose to up to 3 months per year. A common denominator for the last two decades has been a steady increase in both gasoline and diesel-powered private cars. In the 2010s, the ozone weekend effect was frequently noted, providing evidence that the ozone formation regime in Santiago is VOC-limited. Nitrogen oxides and carbon monoxide (a proxy of anthropogenic VOCs) have increased steadily since 2014 in a relatively constant CO-to-NOx ratio. Therefore, we propose that primary emissions of NOX and VOCs from motor vehicle exhaust have remained as the main driver of the photochemical air pollution in Santiago as well as explaining the weekly variation. Santiago, like other megacities in the world, faces several challenges associated with increasing urbanization as well as the effects of climate change. An increasing population, growth in private car use, and urban sprawl have contributed to maintain high levels of ozone. New threats such as increasing temperatures observed in the central valleys of Chile, along with more frequent occurrences of heat waves, whose number has doubled in the last decade, will require a different approach to manage ozone pollution during the next decade. Santiago will not meet its own goals in the upcoming years without implementing robust, scientifically sound, and cost-effective strategies designed specifically to tackle photochemical pollution.

ASSESSING THE WEEKEND EFFECT IN THE SURGICAL MANAGEMENT OF OVARIAN TORSION

The weekend effect refers to a phenomenon of disparate care among patients admitted on weekends compared to patients admitted on weekdays1. This effect has been documented in the literature in a variety of medical and surgical subspecialties including gynecology2. Ovarian torsion is a gynecologic emergency occurring when the adnexa rotates around its suspensory ligaments estimated to account for 3% of emergency room presentations for acute abdominal pain in women3. The management of ovarian torsion involves urgent surgical correction of torsion with removal of ovarian pathology or ovary as indicated. Prompt diagnosis and treatment are required to preserve future fertility and decrease morbidity. The purpose of this study was to evaluate whether weekend presentation of ovarian torsion impacts timing to surgical management. We utilized data from the 2002-2014 abstracts of the Nationwide Inpatient Sample, identifying surgical cases of ovarian torsion using diagnosis and procedure ICD-9CM codes. Time to surgery was evaluated as the time from admission to surgery, quantified in days with the primary predictor of interest being day of admission (weekend versus weekday). Multivariable log-linear regression models were fit to assess the outcomes of same day surgery and risk of oophorectomy as the treatment for torsion. Models were adjusted by patient demographics and hospital risk factors. The risk of oophorectomy model was further adjusted by time to surgery categorized as same-day, one day, or two or more days. Measures of association were expressed in adjusted risk ratios (aRR) and 95% confidence intervals (CI). From 2002 to 2014, a nationwide cohort of 122,816 inpatient hospital admissions for surgical management of ovarian torsion were analyzed. Of the surgical ovarian torsion cases, 20.2% were admitted on the weekend with a 60% same day surgery rate compared to 69% of those admitted on weekdays. In adjusted analysis, patients admitted on the weekend were 14% less likely to undergo same day surgical management of ovarian torsion (RR=0.86, 95% CI: 0.84, 0.88) compared to those admitted on weekdays (Table 1). Non-Hispanic Black, Hispanic, Medicare, Medicaid, and lower income quartile patients were similarly less likely to undergo same day surgical management (Table 1). Weekend admission was not associated with increased risks of oophorectomy as management strategy of torsion, however ovarian torsion cases who waited more than one day were at 5% higher risk of oophorectomy compared to those with same-day management (Table 2). While the weekend effect is associated with lower likelihood of same-day management of ovarian torsion, weekend admission is not associated with increased risk of oophorectomy in the surgical management of ovarian torsion. Our data suggests that timely management of these cases is more strongly associated with fertility preservation. Socioeconomic disparities exist in both timely management as well as fertility preserving surgical treatment.