Over 350 'adverse' drug events

Prescribed medication led to the deaths of five people in New Zealand hospitals, a study has found.

Research by the Counties Manukau, Capital and Coast and Canterbury district health boards has found 353 people were harmed by medication-related problems between March 2010 and February 2011.

The researchers used a ''trigger tool'' on more than 1200 patient charts in the three districts to identify medication issues.

The study, published in today's New Zealand Medical Journal, found painkillers, such as morphine and tramadol, and anti-clotting drug warfarin were the most common causes of drug-related harm among hospital patients.

An adverse drug event, classed as something that causes injury, contributed to the deaths of five people.

A further nine patients needed medical intervention to keep them alive and four people suffered permanent harm, the research found.

Among those who died was an 80-year-old woman who had been admitted to hospital after a fall the previous day.

She was on blood-thinning agent warfarin when she died of a large subdural haematoma, when blood collects between the brain and the skull.

Canterbury DHB chief medical officer of health Nigel Millar was among the researchers who analysed patient notes to "look for clues" of medication-related harm.

Of 353 adverse drug events, most were in the "lower severity scales" and caused only temporary or minor harm.

"When you look at the numbers, they are quite concerning and we are, of course, concerned about people being harmed in hospitals," Millar told The Press.

The research found the most common harms were nausea, vomiting and constipation associated with opioids (painkillers).

Rashes, kidney damage, bleeding and infection were among the drug-related health problems.

"Before this we had to rely on people telling us when there was a problem, but this is about looking for clues in someone's chart, and one of those clues is when they have been given something to reverse the effect of another medication," Millar said.

Sudden cessation of a medication was another clue, he said.

Millar said this was the first time medication problems had been "efficiently recorded" in New Zealand.

"We're being honest about the problems we have and this study has identified those,'' he said. ''Now we know what we're looking for, so we can start setting up barriers and improving systems."

The study found patients who suffered from an adverse drug event were more likely to be female, older with more complex medical illnesses and have a longer stay in hospital.

The Press