Thousands of patients prescribed high-risk drugs

Thousands of patients in Scotland who are particularly vulnerable to adverse drug events (ADEs) were prescribed high-risk medications by their GPs which could potentially cause them harm, according to research published in the British Medical Journal today.

Although at least some of this prescribing will be appropriate because prescribers and patients are balancing risks and benefits when there may be no clearly 'correct' course of action, the study also finds that there was significant variation in the prescribing practices between the GPs surgeries surveyed. This variation could not be explained by the patient case mix which suggests that there is considerable scope to improve prescribing practices, say the researchers.

The authors, led by Professor Bruce Guthrie from Dundee University, say that previous studies have shown that GP prescribing can cause considerable harm, and they highlight that "adverse drug events (ADEs) account for 6.5% of all hospital admissions, over half of which are judged to be preventable".

Patients could be vulnerable to high risk drugs because of their age, other existing illnesses or because of other prescription medications they may be on. GPs need to be alert to these risk factors and be cautious about the drugs they prescribe to these patients, say the authors.

A number of medications or scenarios are already flagged up as high risk, for example, non-steroidal anti-inflammatory drugs for certain patients, prescribing a new drug when a patient is on the blood-thinning medication warfarin, prescribing drugs when patients have heart failure and prescribing antipsychotic drugs for patients who have dementia.

Guthrie and colleagues expanded the list above and developed 15 indicators to examine how often patients vulnerable to ADEs were prescribed high-risk medication that could harm them.

The authors used the indicators to review data from 315 Scottish General Practices with 1.76 million patients, of which 139,404 (7.9%) were identified as being particularly vulnerable to ADEs.

The results show that 19,308 (13.9%) who were in the vulnerable group were prescribed one or more high-risk medications.

While the authors emphasise that not all high-risk prescribing is inappropriate they conclude that the study shows "that opportunities to improve primary care prescribing safety are considerable" across the UK.