In this large retrospective cohort analysis including 695,740 patients extracted from a total of 9,529,049 patients with records of hospitalization, we explored the weekend effect on short-term and long-term mortality of four different cardiovascular emergencies, i.e. ruptured aortic aneurysm, acute myocardial infarction, ischemic stroke, and pulmonary embolism, using the nationwide insurance database between 2005 and 2015 in Taiwan. We found no difference in either in-hospital mortality or one-year mortality between patients admitted at the weekends and patients admitted on weekdays in all the four different cardiovascular emergencies.
As early as 1978, MacFarlane had reported that perinatal mortality was higher among babies born at weekends than among those born on weekdays in England and Wales.13 In 2001, Bell and Redelmeier explored six different medical emergencies including ruptured abdominal aortic aneurysm, acute epiglottitis, pulmonary embolism, acute myocardial infarction, intracerebral hemorrhage, and acute hip fracture in Canada. They found patients with diagnoses of ruptured abdominal aortic aneurysm, acute epiglottitis, and pulmonary embolism were more likely to die in the hospital if they were admitted on a weekend than if they were admitted on a weekday.3 However, the weekend effect did not exist in patients with diagnoses of acute myocardial infarction, intracerebral hemorrhage, and acute hip fracture.3 Many studies concerning the concept of a weekend effect on a patient’s survivability have been published thereafter with high levels of heterogeneity in study designs and conclusions. Furthermore, meta-analyses of a large number of studies have concluded that hospital inpatients admitted during weekends may have a higher mortality rate compared with inpatients admitted during the weekdays.4,5
Ruptured aortic aneurysm represents a major life-threatening condition that is associated with high mortality rates even in centers with advanced technology and high levels of expertise in cardiovascular surgery. In addition to the report conducted in Canada,3 studies conducted in Italy14 and the United States15 both concluded that weekend admission for ruptured aortic aneurysm was associated with an increased mortality when compared to those admitted on weekdays. Although Dasari and colleagues found more delay in reperfusion time and higher in-hospital mortality in patients presenting during off-hours than patients presenting during on-hours using the Acute Coronary Treatment and Intervention Outcomes Network-Get With The Guidelines (ACTION-GWTG) database in United States,16 most of the other studies from different countries found no difference in mortality rate in acute myocardial infarction patients admitted during off-hours as compared with ones admitted during regular hours.3,17−20 Some studies claimed that admissions on weekends were associated with higher mortality and poor outcome compared with weekday admission for patients with acute stroke.21–25 On the contrary, several studies found that off-hour admission was not associated with an unfavorable outcome in acute ischemic stroke patients.26–32 As for pulmonary embolism, hospitalization on weekends seemed to be associated with a significantly higher mortality rate than hospitalization on weekdays in two publications.3,33
Taiwan has commenced a universal NHI program, financed jointly by payroll taxes, subsidies, and individual premiums, since 1995.34 The Taiwan’s NHI provides a comprehensive national benefit package, which includes inpatient, outpatient, and dental care.35 As of 2013, over 99.9 percent of Taiwan’s 23.4 million residents were insured.35 Taiwan’s NHI offers all citizens timely and affordable access to needed health care on equal terms35 and the availability of the critical care service in Taiwan has increased over time under the NHI program.36 A significant reduction in deaths37 and an increase in life expectancy have been achieved after the introduction of Taiwan’s NHI system.34 Throughout this study, our findings have indicated that the weekend effect on major cardiovascular emergencies has been overcome in Taiwan’s NHI system similar to what had been achieved by different health care systems in other countries.29–31
Study limitations
Several limitations of our study have to be acknowledged. Firstly, as information about admission hours cannot be obtained from the Taiwan NHI claims database, we could only define the weekend admission as admission on Saturday, Sunday and national festival days without further clarification regarding working hours. Secondly, we explored four specific cardiovascular emergencies, i.e. ruptured aortic aneurysm, acute myocardial infarction, ischemic stroke, and pulmonary embolism in this study. We recommended caution in extrapolating these findings to other conditions especially non-cardiovascular emergencies in Taiwan.