Alarm over hospital medication errors

Behind the Headlines

Wednesday December 14 2011

Patients with swallowing problems were more prone to medication errors

The headline “Four in 10 drugs wrongly administered in hospitals” may have caused undue concern to readers of The Daily Telegraph today. Similar claims in The Independent gave a misleading impression of some valuable new research into the way medicines are given in hospital.

The stories are based on a UK study looking at how nurses administered oral medicines to 679 patients with and without dysphagia (difficulty swallowing) on four stroke and care-of-elderly wards in the east of England. They found that of the 2,129 medicine doses administered, 817 doses (38%) contained some type of error. However, about three out of every four of these errors were “time errors” (the drug was given more than one hour earlier or later than planned) and it is not clear what, if any, adverse effects these might have had on patients. The percentage of other errors was closer to 10%. Once time errors were excluded from the analysis, researchers found that drug errors were more likely to affect those who had ongoing swallowing problems.

This finding may be useful in highlighting the need for healthcare professionals to take due care when prescribing and giving drugs to people who may have swallowing problems.

The media headlines were alarmist, as most implied that the findings applied to all healthcare settings and to all medical patients. However, it is not clear whether this research, carried out in just four stroke and care-of-elderly wards in the east of England, applies to all healthcare settings in England.


Where did the story come from?

The study was carried out by researchers from the University of East Anglia and was funded by a PhD grant from Rosemont Pharmaceuticals. The study authors declared that the company was not involved in the study design, did not have access to the data and had no involvement in the publication of results.

The study was published in the peer-reviewed Journal of Advanced Nursing.


What kind of research was this?

This research was a cross-sectional observational study looking at how nurses administered oral medicines to patients with and without dysphagia (difficulty swallowing). The researchers wanted to see whether the medications given to patients were appropriate and if any errors were made.

The authors said that previous research has shown the administration of oral medicines to patients with dysphagia is potentially more error-prone because the medicine needs to be given in a form that the patient can take, despite their swallowing problems. For example, dysphagia patients are sometimes given tablets that have been crushed to make them easier to swallow. However, this is inappropriate in some cases because often drugs are required to be taken in their whole capsule or tablet form to ensure the correct dosage or to avoid side-effects.


What did the research involve?

Researchers collected information on how oral medicines were prepared and administered for 625 patients with and without dysphagia, including some patients using feeding tubes.

The way the medicine was administered was observed directly by a nurse researcher experienced in observing medicine rounds. Between March and June 2008, the researchers attended 65 nurse-led medicine administration rounds on stroke and care-of-elderly wards at four acute general hospitals in the east of England. The researchers observed the administration of medicines “undisguised” (there was no attempt to hide the fact that the administration was being observed).

The nurse observers used detailed forms to ensure consistent data collection on:

  • dosage
  • formulation (how the drug is formed from different active and non-active chemicals)
  • preparation (how the drug is prepared before it is given; for example, mixed with water)
  • administration (how the drug is given to the patient; for example, by mouth)

They also recorded acts of tablet crushing, capsule opening, addition of food and consistency or liquid medicines.

Errors were assessed and classified using established guidelines. The researchers also defined extra categories of error, including time errors (defined as giving a drug more than one hour before or after the ideal time). The error rate was calculated as the number of errors divided by the total opportunities for error. This does not match the chance of an error occurring for each patient during their stay in hospital, because most patients had many medications given to them and multiple chances for error to occur.

Each medicine was only recorded as having one error and medicines were only recorded as time errors if there was no other error. For example, when an incorrect dose was given late, the error category “wrong dose” would be used.

Researchers then compared the amount of errors in patients with and without dysphagia.


What were the basic results?

A total of 2,129 oral medicine administrations were observed being given to 679 patients. Errors were observed in 817 (38.4%) administrations, with 313 involving patients with dysphagia.

The most common error was either administering the drug over an hour early or (more commonly) over an hour late. These time errors occurred in approximately three in every four medicines administered (72.1%). These errors were not more or less common in people with dysphagia, so all subsequent analysis ignored this type of error.

The researchers found that medicine administration errors (excluding time errors) occurred in 21.1% of patients with dysphagia (around 1 in 5) compared with 5.9% of those without dysphagia (around 1 in 20). They found the differences were largely due to differences in drug formulation and preparation. These included instances when nurses chose to crush tablets instead of administering more appropriate, licensed alternatives that were available.

Excluding time errors, the researchers found that there was a higher risk of errors affecting patients with dysphagia who had a feeding tube.


How did the researchers interpret the results?

To combat the higher rate of errors observed in patients with dysphagia, the researchers concluded that healthcare professionals needed to take extra care when prescribing, dispensing and administering medicines to patients with this swallowing problem.



This study provides new information on the error rate during the preparation and administration of oral medicines to patients with and without dysphagia on stroke and care-of-elderly wards at four acute general hospitals in the east of England. This study suggests that drug administration errors may affect more people with swallowing difficulties than those without.

While this study provides a useful assessment of oral medicine practices in these specific hospital wards, the following limitations should be taken into account when considering the implications of the results:

  • The most common error was a “time error”, which accounted for the majority of the “40% of hospital drugs administered incorrectly” as quoted in the news headlines. It is not clear how much, if any, harm a patient would have been subjected to by having their medication over an hour early or an hour late. This is likely to depend on the individual patient’s condition and the type of medication being given.
  • The study was restricted to four stroke wards and four care-of-elderly wards in the east of England. It is not clear whether similar findings would be observed in different hospital wards, other hospitals outside of the east of England or in community settings where medicines can also be delivered.
  • The error rate was calculated as the number of errors divided by the total opportunities for error. Therefore, the error rate does not match the chance of an error occurring for each patient, as most patients had more than one medication administered.
  • Each medicine was only recorded as having one error and medicines were only recorded as time errors if there was no other error. This could lead to misclassification of the type of error.
  • Differences in how the nurse observers recorded drug errors was minimised through using standard recording forms; however, there is always a possibility that some differences remained in the way errors were recorded between nurse observers.

The researchers pointed out that: “Elderly people compose 20% of the population but take 50% of prescribed medications.” Therefore, this study may be useful in highlighting the issue of drug administration errors to health professionals, potentially leading to more vigilance and improvements.

Newspapers reporting that “40% of hospital drugs are administered incorrectly” have overstated the results of this study, as this includes the figures for time errors. The percentage of other errors was closer to 10%. It is unclear whether the findings of this study would be replicated in healthcare settings outside of the four care-of-elderly wards and stroke units studied.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Medicine administration errors in patients with dysphagia in secondary care: a multi-centre observational study. Journal of Advanced Nursing. 2011:67;2615–2627

Links to the science

40% of hospital drugs 'administered incorrectly'. The Independent, December 14 2011

Patients with swallowing difficulties 'most at risk of being given wrong drug'. The Daily Telegraph, December 14 2011


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