Prescribing Advice for GPs

Composite end points

April 13, 2007 on 2:26 pm | In Critical Appraisal Tips |  Print | No Comments

The British Medical Journal has published a systematic review that examined the use of composite end points in cardiovascular trials. The aim was to assess the importance to patients of each component in the composite end points and to examine the frequency of these events in the studies.

The study examined cardiovascular randomised controlled trials published in the 18 months from 1st January 2002 in six medical journals (Lancet, Annals of Internal Medicine, Circulation, European Heart Journal, JAMA and New England Journal of Medicine). The advantage of using composite endpoints is that trials can be smaller in terms of numbers of patients and duration. 114 trials were identified that used composite endpoints.

Only 68% of the studies reported full data for each of the composite end point components. Over half of the studies (56%) showed a high degree of variability of importance to patients in the composites. This is due to inclusion of outcomes that are very important to patients, for example cardiac death, in combination with outcomes that are insignificant to patients, for example doubling of serum creatinine concentration.

This analysis also found that the measures that were of least importance to patients contributed the most to the event rates and treatment effects. Removing these less important outcomes from the composite would mean fewer trials reached statistical significance.

It is clear from this review that when interpreting randomised controlled trials using composite endpoints, each of the components of a composite endpoint should be viewed separately. This will ensure that claims relating to outcomes of greatest importance to patients are not exaggerated.

For example, if a study was highly statistically significant on a composite endpoint of cardiovascular death, non-fatal MI and re-admission to hospital but had similar event rates for cardiovascular death and non-fatal MI with the significance being driven by a large difference in the rate of re-admission to hospital it would be important to ensure that the intervention was not interpreted as reducing deaths or non-fatal heart attacks.

JBS2 contain serious deficiencies

April 12, 2007 on 2:23 pm | In Prescribing Extra - Other |  Print | No Comments

The International Journal of Clinical Practice has published a paper assessing the quality of the second Joint British Societies’ guidelines on the prevention of cardiovascular disease (JBS2).

These are the guidelines that have been used to promote lower cholesterol targets of 4mmol/L for total cholesterol (TC) and 2mmol/L for low-density lipoprotein cholesterol (LDL-C). As previously discussed, National Policy has been clarified and recommends targets of 5mmol/L for TC and 3mmol/L for LDL-C.

Recognised criteria for reviewing the quality of guidelines (Appraisal of Guidelines Research and Evaluation) were used to evaluate JBS2. In summary it was found that these guidelines “contain serious deficiencies, are of low quality and should not be recommended for clinical practice“.

Action: National Policy is clear, current cholesterol targets remain at 5mmol/L for TC and 3mmol/L for LDL-C. Given the criticism of JBS2, it would seem prudent to view recommendations based upon this guideline with some scepticism.

Prescription charges

April 4, 2007 on 8:49 pm | In Prescribing Extra - Other |  Print | No Comments

The Department of Health has announced the price increases affecting NHS Prescription Charges in England.

Effective from 1st April 2007 the price for a single NHS Prescription item rose from £6.65 to £6.85.

Prices for pre-payment certificates (PPC) were also affected:

• 12 month PPC now £98.70 (from £95.30)
• 4 month PPC now £35.85 (from £34.65)
• 3 month PPC new at £26.85

The same prices as above apply in Scotland although the Scottish Executive is finalising a consultation on prescription charges. Meanwhile, in Wales all prescription charges have been abolished.

Action: Clinicians should be aware of the cost of the NHS prescription charge because some items may be less expensive to purchase for some individuals.

DH influenza season debrief

April 2, 2007 on 2:54 pm | In Prescribing Extra - Other |  Print | No Comments

The Department of Health has issued a letter from the Chief Medical, Nursing and Pharmaceutical Officers thanking healthcare professionals for their efforts in the 2006/07 seasonal influenza vaccination programme and to provide information to aid planning for the 2007/08 programme.

Despite some problems in the supply of vaccines at the start of the 2006/07 programme approximately 900,000 more vaccine doses were distributed compared to the previous year and, in England, 74% of people aged over 65 were vaccinated and 42% of those identified as being in an at risk group.

The letter also provides details of the vaccines and suppliers for next years programme. It also clarifies the clinical risk groups to allow forecasting of demand for vaccines in 2007/08.

Action: Clinicians will find this document useful as an aid to planning activity for the 2007/08 seasonal influenza vaccination programme.