One in seven patients admitted to a hospital experience adverse drug reactions to medical treatment, according to researchers at the University of Liverpool. Adverse drug reactions are a major cause of hospital admissions, but recent data on adverse drug reactions that develop following hospital treatment is lacking, the researchers say.

 

The research, published in the open access journal PLoS ONE, assessed drug reactions of more than 3,000 patients on 12 hospital wards over a six-month period. Previously the researchers found that approximately a quarter of a million people are admitted to hospital in the UK each year following adverse drug reactions to a variety of commonly prescribed drugs, but there was little data on adverse drug reactions experienced as a result of hospital treatment.

 

The study found that 15 percent of patients admitted to hospitals experienced one or more adverse reactions, which included constipation, confusion, renal problems, bleeding and infection with the potentially fatal bacteria Clostridium difficile, which is associated with hospital acquired infections.

 

Drugs most commonly associated with adverse reactions were anticoagulants, analgesics and diuretics. They also found that adverse drug reactions increased the length of a patient's hospital stay by an average of 0.25 days, and that those most susceptible were elderly patients on a number of different medications.

 

The researchers found a significant predictor of adverse drug reactions in hospitals is the number of medications a patient is taking. Each additional drug treatment increases the risk of experiencing an adverse drug reaction. This is one of the reasons why elderly people experience a higher incidence of adverse drug reactions than young people, as they have more health conditions and generally take more medications, the researchers say.

 

“Our results show that the overall burden of ADRs on hospitals is high and therefore new methods of intervention are needed to reduce this,” says Munir Pirmohamed, a professor at the University of Liverpool’s School of Biomedical Sciences. Pirmohamed says the results are consistent with data from other parts of the world and that this is an issue for hospitals throughout the Western world.

 

“We are currently looking at a number of ways of improving the safety of medicines, including increased monitoring of patients and the identification of genetic factors that could increase the risk of a patient developing adverse effects,” says Pirmohamed. “Our ultimate aim is to use a number of inter-related methods to allow us to maximize the benefits of medicines and minimize the harm.”