In healthcare, the weekend effect is the finding of a difference in mortality rate for patients admitted to hospital for treatment at the weekend compared to those admitted on a weekday. The effects of the weekend on patient outcomes has been a concern since the late 1970s, and a ‘weekend effect’ is now well documented. Although this is a controversial area, the balance of opinion is that the weekend (and bank holidays) have a deleterious effect on patient care (and specifically increase mortality)—based on the larger studies that have been carried out. Variations in the outcomes for patients treated for many acute and chronic conditions have been studied.'Hospitals undertaking the admission of acutely ill medical patients should have a consultant physician on‐site for at least 12 hours per day, seven days per week, at times related to peak admission periods. The consultant should have no other duties scheduled during this period.While much of the work of the consultant physician will be on the acute medical unit, provision should be made for a daily consultant visit to all medical wards. In many hospitals this will require input from more than one physician.''To assume that are avoidable would be rash and misleading.' In healthcare, the weekend effect is the finding of a difference in mortality rate for patients admitted to hospital for treatment at the weekend compared to those admitted on a weekday. The effects of the weekend on patient outcomes has been a concern since the late 1970s, and a ‘weekend effect’ is now well documented. Although this is a controversial area, the balance of opinion is that the weekend (and bank holidays) have a deleterious effect on patient care (and specifically increase mortality)—based on the larger studies that have been carried out. Variations in the outcomes for patients treated for many acute and chronic conditions have been studied. Schmulewitz et al., in the UK in 2005, studied 3,244 patients with chronic obstructive pulmonary disease, cerebrovascular accidents, pulmonary embolism, pneumonia, collapse and upper gastrointestinal bleed. They found 'Weekend admission was not associated with significantly higher in-hospital mortality, readmission rates or increased length of stay compared to the weekday equivalent for any of the six conditions'. However, in 2010, Clarke et al., in a much larger Australian study of 54,625 mixed medical/surgical non-elective admissions showed a significant weekend effect (i.e. worse mortality) for acute myocardial infarction. Marco et al. (2011), in a US study of 429,880 internal medical admissions showed that death within 2 days after admission was significantly higher for a weekend admission, when compared to a weekday one (OR = 1.28; 95% CI = 1.22-1.33). In the same year, in an Irish study of 25,883 medical admissions (Mikulich et al.), patients admitted at the weekend had an approximate 11% increased 30-day in-hospital mortality, compared with a weekday admission; although this was not statistically significant either before or after risk adjustment. Thus the authors pointed out that 'admission at the weekend was not independently predictive in a risk model that included Illness Severity (age and biochemical markers) and co-morbidity'. There is some evidence for intervention from physicians, in an attempt to address this issue. Bell et al., in 2013, surveyed 91 acute hospital sites in England to evaluate systems of consultant cover for acute medical admissions. An 'all inclusive' pattern of consultant working, incorporating all guideline recommendations (and which included the minimum consultant presence of 4 hours per day) was associated with reduced excess weekend mortality (p<0.05). In 2014, it was shown in a huge US study, that the presence of resident trainee doctors (and nurses) may also be of benefit (Ricciardi, 2014). In this study of 48,253,968 medical patients, the relative risk of mortality was 15% higher following weekend admission as compared to weekday admission. This is currently the largest known study in this area. After adjusting for diagnosis, age, sex, race, income level, payer, comorbidity, and weekend admission, the overall odds of mortality was higher for patients in hospitals with fewer nurses and staff physicians. Mortality following a weekend admission for patients admitted to a hospital with resident trainees was significantly higher (17%) than hospitals with no resident trainees (p<0.001). In the following year, Vest-Hansen et al.—in a whole nation study, in Denmark—studied 174,192 acute medical patients. The age-standardised and sex-standardised 30-day mortality rate was 5.1% (95% CI 5.0-5.3) after admission during weekday office hours, 5.7% (95% CI 5.5-6.0) after admission during weekday (out of hours), 6.4% (95% CI 6.1-6.7) after admission during weekend daytime hours, and 6.3% (95% CI 5.9-6.8) after admission during weekend night-time hours. In 2016, Huang et al., in Taiwan, studied 82,340 patients, admitted to the internal medicine departments of 17 medical centres. Patients admitted at the weekend had higher in-hospital mortality (OR = 1.19; 95% CI 1.09-1.30; p < 0.001). In a 2016 study of 12 Italian Acute Medical Units, Ambrosi et al. found that elderly patients were six times (95% CI 3.6-10.8) more likely at risk of dying at weekends. They also found that 'those with one or more ED admissions in the last 3 months were also at increased risk of dying (RR = 1.360, 95% CI 1.02-1.81) as well as those receiving more care from family carers (RR = 1.017, 95% CI 1.001–1.03). At the nursing care level, those patient receiving less care by Registered Nurses (RNs) at weekends were at increased risk of dying (RR = 2.236, 95% CI 1.27-3.94) while those receiving a higher skill-mix, thus indicating that more nursing care was offered by RNs instead of Nursing Auxiliaries were at less risk of dying (RR = 0.940, 95% CI = 0.91-0.97).' Conway et al., in 2017, studied of 44,628 Irish medical patients. Weekend admissions had an increased mortality of 5.0%, compared with weekday admissions of 4.5%. Survival curves showed no mortality difference at 28 days (P = 0.21) but a difference at 90 days (P = 0.05). The effects of the introduction of a 7-day consultant service have been investigated in medical patients. In 2015, Leong et al. studied elderly medical patients in the UK; noting admission numbers increasing from 6,304 (November 2011-July 2012) to 7,382 (November 2012-July 2013), with no change in acuity score. They stated that the 'introduction of seven-day consultant working was associated with a reduction in in-hospital mortality from 11.4% to 8.8% (p<0.001)'. Weekend discharges increased from general medical wards (from 13.6% to 18.8%, p<0.001) but did not increase from elderly medicine wards.