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Student: Thomas Chima
Supervisors: Dr Ben Hudson, Ms Pip Mason
Sponsor: Pegasus Health (Charitable) Ltd

Lay Report


My project builds upon a summer studentship from last year. The student created and did a small trial on a decision aid (DA) for patients to help them decide whether to take medication that prevents hip fractures. A DA is used when it is difficult for patients to make a decision on the treatment options available.

The difficulty is in helping patients to understand the pros and cons of the treatment, a range of drugs called bisphosphonates. Hip fractures lower a patient's quality of life and the risk of fracture may be reduced by using bisphosphonates. However the risk reduced by these drugs is typically small and they cause side effects. So the problem is that patients must weigh up the benefits of lowering the already low risk, with the cons of the potential side effects.

Before this decision aid can be used in practice, we need to find out how the DA will affect general practitioners (GPs) in the way they prescribe bisphosphonates.


To trial the use of the DA with GPs to determine how the presentation of fracture risk in either written or visual form affects the likelihood of GPs' recommending bisphosphonates.


GPs were sent questionnaires in which three clinical cases were presented. The cases included a patient at low, medium and high risk of hip fracture. For each case GPs were asked to show the strength of their recommendation for the patient to take a bisphosphonate. GPs were randomised to receive either a control or intervention questionnaire. In the control questionnaire fracture risk and its reduction with treatment was shown in a written format. The intervention questionnaire showed fracture risk and its reduction with treatment visually using a grid of 1000 squares each representing a person. Some demographic and professional details were also recorded.


720 GPs from the Christchurch and Auckland areas were randomised and sent the questionnaires and 179 were returned (response rate 24.9%). In all three cases GPs who received the intervention questionnaire were less likely to prescribe bisphosphonates than those who received the control questionnaire, but only in Case 2 was this difference statistically significant. Case 1 (low fracture risk) had an 18% prescription rate for controls and a 10% for interventions. Case 2 (medium risk) had a 52% prescription rate for controls and 35% for interventions. Case 3 (high risk) had a prescription rate of 81% for controls and 69% for interventions.


GPs presented with fracture risk, and its reduction with treatment in a visual format, were less likely to prescribe in a medium fracture risk case. In cases of low and high fracture risk, likelihood of prescribing was lower when risk information was presented visually, but this difference may have been due to chance. DAs that include the visual representation of fracture risk may reduce GPs' likelihood of prescribing bisphosphonates. This effect on physician behaviour suggests the need for further investigation and should be taken into account when creating DAs.

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