Do not get sick and go to the hospital on the weekend!

Consider the following article.


Hospital death rates higher on weekends

 

Those admitted during weekend find better staffing 
BY JIM RITTER, HEALTH REPORTER

    You have a greater chance of dying in the hospital if you are admitted on the weekend, when fewer doctors and nurses are working researchers have found.   In 23 of the 100 leading causes of death, mortality rates for patients admitted on weekends were higher than rates patients admitted during the week, University of Toronto researchers report.  There were no conditions in which death rates were lower on the weekends.  Researchers defined weekends as the period from midnight Friday to midnight Sunday.  Fewer staffers work then and hose who do tend to have less seniority and experience.  Moreover there are fewer supervisors on weekends and they often in charge of staffers they don't know well.  Dr. Bell and Dr. Redelmeier of The University of Toronto report in today's New England Journal of Medicine.
   So many people go away on Saturday and Sunday, when they know that human disease does not take a day off Redelmeier  said.  The study like will be widely discussed in the medical community, said Dr. Gewertz, chairman of the department of surgery at the University of Chicago Hospitals.  "It's important, timely and provacative," Gewertz said.  
   Researchers analyzed 3.8 million admissions from emergency rooms in Ontario, Canada.  They found, for example, that 42 percent of patients admitted on weekends for ruptured abdominal aortic aneurysms died compared with 35 percent of patients admitted during the week.  Similarly, 1.7 percent of people admitted on weekends for a life-threatening throat infection called acutee epiglottitis died, compared to 0.3 percent of people admitted during the week. 
   But for some conditions, there were no difference in death rates.  For example, weekend heart attack patients were no more likely to die, probably because emergency rooms are fully staffed on weekends.  Data rates for brain hemorrhages were  also the same throughout the week, probably because there's no effective treatment no matter how may people are working.  And patients with hip fractures weren't more likely to die if admitted on the weekend probably because operating room are more available then.
  Police and fire departments are fully staffed on weekends, and hospitals should try to follow the pattern of these essential services.  Hospitals could entice doctors and nurses by paying more for weekend duty.  Hospitals could save money because it would be more efficient to fully use expensive equipment seven days a week, Redelmeier said.

 

From the "New England Journal of Medicine", the data this article is based on is:

Ruptured abdominal aortic aneurysms
An aneurysm is when a blood vessel becomes abnormally large or balloons outward. The abdominal aorta is a large blood vessel that supplies blood to your abdomen, the pelvis, and legs When an abdominal aortic aneurysm ruptures, it is a true medical emergency.  
Data Set 1:
Weekend = 1,559 cases,  655 deaths,  Weekday = 3,895 cases, 1,403 deaths. 

Acute epiglottitis
The epiglottis is a small flap of tissue in the larynx that guards the airway entrance to the lungs.  Epiglottitis causes inflammation and swelling of the epiglottis, vallecula, arytenoids, and aryepiglottic folds. As the tissues swell, they protrude downward and over the glottic opening, making breathing difficult.
Data Set 2:

Weekend = 346 cases, 6 deaths,   Weekday = 793 cases, 3 deaths.
 

Show all four steps for each hypothesis test needed to test the claim: "The proportion of deaths (mortality rates) is greater on the weekend than weekday for each of these diseases.  At a 0.05 level of significance, test the claim using the two data (weekend vs weekday) sets.  

Note:  The headline is an example of a lurking variable.  Weekends themselves are not the cause of the higher mortality rates.  Other factors that occur on the weekend give the appearance that weekends are the culprit.  Lurking variables will be studied later in the course.

Click on the hand to view the solution.