PLoS Medicine has published the results of study that aimed to assess the effect of presenting statistics to patients in different ways when making decisions about taking statin medication to reduce cardiovascular risk.
The study recruited 2,978 eligible participants who were given access to online information that presented benefit data relating to statin medication in one of six different ways. The data were presented as relative risk reduction (RRR), absolute risk reduction (ARR), number needed to treat (NNT), event rate (ER), tablets needed to take (TNT) or natural frequency (NF).
The RRR data resulted in a greater number of participants indicating that they would accept treatment when compared to the five methods of absolute rate reporting. Of the five different statistical methods of presenting data in an absolute form, natural frequency appears to be preferable based on the participant preference, understanding, satisfaction and confidence in the data.
The authors note that this study "supports the contention that RRR is a more persuasive summary statistic. It is also noted that the study aimed to recruit 4,500 participants (750 to 800 participants for each intervention arm). The sample size requirement was therefore not met but the authors assert that the randomisation protocol worked well. In addition it is unclear how these results might apply in other situations.
Action: Clinicians should already be aware of the different methods of presenting data to patients to aid an informed decision. This study may help to identify which methods are likely to be best understood and be most trusted.
Cancer Research has published the results of a population-based case-control that aimed to assess the association between hormonal treatment of oestrogen receptor positive tumours with tamoxifen and the development of primary oestrogen receptor negative tumours. The results of this study have been reported in the general media (BBC).
The study analysed data from 367 women who developed a receptor positive tumour in one breast followed by a receptor negative tumour in the other breast some time later. These data were compared with 728 control case patients who did not develop a second tumour. Telephone interviews and assessment of medical records collected data on adjuvant hormonal therapy, other treatments and breast cancer risk factors.
Users of adjuvant hormonal therapy for 5 years or more were found to have a 60% reduction in the risk of developing a receptor positive tumour in the other breast but a 440% increased risk of developing a receptor negative tumour. Tamoxifen use for less than 5 years was not associated with an increased risk.
The authors conclude that "oestrogen-blocking drugs like tamoxifen have important clinical benefits" but that these drugs have risks and an increased risk of receptor negative cancer may be one of these risks. It is also stated that the benefits of this therapy are well established and doctors should continue to recommend hormonal therapy for breast cancer patients.
Cancer Research UK have also offered reassurance in light of these results stating that "the benefits of taking hormone-blocking drugs, such as tamoxifen, after their first diagnosis of breast cancer far outweigh any potential risks".
Action: Clinicians should be aware of this study and its coverage in the media coverage. Patients taking adjuvant hormonal therapies should be reassured and encouraged to continue with treatment.
Clinical Knowledge Summaries (CKS) has been updated in August 2009 for the following clinical areas:
Action: Clinicians who see patients with any of these conditions may find the new and updated information useful when reviewing current clinical practice.
The British Medical Journal has published the results of a study that aimed to assess the effect of the withdrawal of co-proxamol on analgesic prescribing and poisoning mortality.
In January 2005, it was announced that the product licence for co-proxamol would be withdrawn at the end of 2007. This study found a 59% reduction in prescribing of co-proxamol between 2005 and 2007.
Mortality data for suicides, accidental poisonings or open verdicts revealed an overall decrease of 349 deaths over the same period. There was no statistically significant change for other analgesics.
The authors conclude that the withdrawal of the licence for co-proxamol "has been an effective measure" in reducing deaths from poisoning. These data, and that from a similar study in Scotland, appear to support the decision to withdraw the product licence.
Action: Clinicians should continue to review and reduce prescribing of co-proxamol.
The British Medical Journal has published the results of a retrospective cohort study that aimed to assess the risk of acute myocardial infarction, heart failure and death in patients with type 2 diabetes treated with rosiglitazone and pioglitazone.
The study collected data for 39,736 individuals aged 66 years and older who were prescribed pioglitazone (16,951) or rosiglitazone (22,785) between April 2002 and March 2008. The composite primary outcome was reached by 5.3% of the patients taking pioglitazone compared to 6.9% of those taking rosiglitazone. The adjusted hazard ratio was 0.83 with a 95% confidence interval between 0.76 and 0.91.
Each of the endpoints in the primary outcome was analysed individually and statistically significant reduction in death and heart failure in those taking pioglitazone. This study found no significant difference in the risk of myocardial infarction.
By using rosiglitazone rather than pioglitazone in 93 patients for a period of one year would result on one additional patient being harmed through experiencing the composite outcome. The authors of the study conclude that, "continued use of rosiglitazone may not be justified" especially since rosiglitazone offers no distinct clinical advantage over pioglitazone.
Action: Rosiglitazone continues to be linked to an increased risk of harm. Clinicians should consider whether continued use of this drug is appropriate in any circumstance.