Clinical Trials are constructed to statistically test a hypothesis. Once the study has been completed the results are analysed based upon the original hypothesis (primary outcome) and conclusions are drawn based upon the analysis.
It is generally accepted that the play of chance could have produced the observed results up to 1 time in 20. This is often expressed as a P value of 0.05 or less.
Where studies demonstrate that there is little likelihood that the results occurred by chance the quoted P value will be below 0.05 and the results are said to be statistically significant.
However, statistical significance may not be the same thing as clinical significance. This is because statistical differences are also reliant on the size of the population studied therefore a small difference can be statistically valid if the population size is large enough. A large difference is required if the population size is small.
For example, a 2 point difference on a 60 point depression rating scale was found to be statistically significant in comparing escitalopram (cipralex) to citalopram (cipramil). In a clinical setting detection of this 2 point difference would be virtually impossible.
The Department of Health has written to health professionals today after rising levels of influenza activated the NICE guidance for the supply of oseltamivir (Tamiflu)®.
The letter contains a summary of the NICE guidance for the prevention and treatment of influenza.
Prevention: Oseltamivir can be prescribed for the prevention of flu to people aged 13 years or older who:
- belong to an 'at-risk' group, and
- have not had a flu jab this season, or who had one but too recently for it to have given good protection, or have had a flu jab but the vaccine does not match the virus circulating in the community, and
- have been in close contact with someone with flu-like symptoms, and
- can start taking oseltamivir within 48 hours of being in contact with the person with flu-like symptoms.
Treatment: Within licensed indications, influenza treatment can be prescribed as follows, provided that the treatment can start within 48 hours of the onset of symptoms:
- oseltamivir or zanamivir can be prescribed to adults
- oseltamivir can be prescribed to children over 1 year old
Figures published on the Health Protection Agency website indicate that there is a regional variation in the report of influenza like illness, with low reporting in the North of England and rising reporting in Central and South England. It may be appropriate to seek the advice of local Health Protection Units before prescribing.
Action: Clinicians should be prepared to prescribe for the treatment and prevention of influenza if advised to do so by local health protection units.
The Sunday Times recently reported the outcome of a complaint to the Association of the British Pharmaceutical Industry (ABPI). The article describes how a representative of the pharmaceutical company was given access to NHS medical records in order to identify patients who might benefit from a new drug.
This type of activity breaks the ABPI Code of Practice for the pharmaceutical industry and violates patients' right to privacy.
The article also discusses the role of the independent agencies that provide nurse and pharmacist advisers. These agencies are usually funded by the pharmaceutical industry. While these agencies are independent of the promotional activities of the pharmaceutical industry there is still the issue of patient confidentiality and consent.
Access to patient notes is rightly restricted to persons directly involved in patient care. Consent must be obtained before information is disclosed outside the NHS.
Despite that fact that the nurses and pharmacists provided by these agencies are bound to confidentiality by their own professional ethical standards it may be appropriate to seek consent from patients before undertaking any audit work offered by agencies external to the NHS.
Action: Clinicians should carefully consider consent and patients' expectation of privacy before agreeing to undertake any externally operated audit work. The Department of Health has produced guidance on confidentiality and consent in the NHS that may be helpful.
The manufacturer of Actrapid®, Mixtard® and Insulatard® has announced that the Pork versions of these products will no longer be available from 31st December 2007.
Currently these products are only available in 10ml vials and it is expected that very few patients are using these products. Human insulin versions of all three of these products are available and may be suitable alternatives.
The affected products are as follows:
- Pork Actrapid 10ml vial
- Pork Mixtard 10ml vial
- Pork Insulatard 10ml vial
The manufacturers recommend that when patients are changed from one product to another the dose is reduced by 10-20% and a period of more careful monitoring should be undertaken. The dose should be titrated based upon monitoring results until the patient is stable again.
Action: Clinicians should be aware of this announcement. Patients can be change at any point over the next two years should the opportunity present but there is no immediate urgency to change existing therapy.
New national arrangements for the supply of oxygen on the NHS came into force on 1st February 2006.
The provision of oxygen should by now be transferred to new regional suppliers. Oxygen will need to be ordered using a Home Oxygen Order Form (HOOF) rather than a prescription (FP10). Additionally, the patient will need to give consent for their details to be passed to the new suppliers on a Home Oxygen Consent Form (HOCF).
Further information is available for clinicians and patients here including helpline numbers and frequently asked questions.
Action: Clinicians need to be aware of this change and ensure they are using the correct paperwork to order oxygen therapy.