, is the first to assess death rates among patients staying in hospital over the weekend, irrespective of the day of admission.
Previous studies have identified the 'weekend effect', where patients admitted to hospital at the weekend have an increased risk of dying. While this could be down to a shortage of staff, it could also be due to the fact that more severe patients will admit themselves to hospital during a weekend, while those with milder symptoms would wait to speak to their doctor the following week.
This new study analysed the 'weekend effect' in a different way by assessing whether patients who stayed in hospital over the weekend, even if they were admitted earlier in the week, were also experiencing an increased risk of death.
Researchers from the Lady Davis Institute at the Jewish General Hospital and McGill University, in Montreal, Quebec, Canada, used medical records to examine death rates in over 300,000 people over the age of 50 who were admitted to hospital with either COPD or pneumonia between 1990 and 2007.
The results demonstrated that, irrespective of when patients are admitted to hospital, if they stay over the weekend the risk of death is increased. During the weekday, the death rate was 80 per 10,000 per day. On a Friday, the risk of death increased by 5%, suggesting an additional 4 deaths per 10,000. On a Saturday and Sunday the risk increased by 7% suggesting an additional 5.6 deaths per 10,000 for each weekend day.
The findings therefore suggest that the increase in the risk of death is due to a reduced quality of care, or reduced access to high quality care at the weekend, an effect that appears to begin on Friday.
Lead author, Dr Samy Suissa, from the Jewish General Hospital and McGill University, said: "Our study is the first to report an increase in mortality for patients staying in hospital over the weekend. The findings of our study have huge implications for the way healthcare is delivered across the globe. It may be time to reconsider the weekend concept in the healthcare calendar to avert a significant number of likely preventable deaths."