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Evidence suggests evidence is flawed

NHS trusts are failing to take account of changing evidence in their apparent obsession with drug switching schemes

NHS trusts are failing to take account of changing evidence in their apparent obsession with drug switching schemes

In the modern NHS, evidence is sacred.

A whole series of NHS bodies are dewy-eyed in their devotion to it. NICE, the National Prescribing Centre, Health Technology Assessments and the NHS Institute for Innovation and Improvement all fall over themselves to demonstrate their command and analysis of the data.

Everything GPs do is supposed to be evidence-based - and woe betide any maverick doctor who dissents from the consensus clinical view.

Evidence-based medicine is of course sensible. Working out which drugs work, and in which patients, is vital if a publicly funded health system is to spend its money wisely.

Instinct and hunch remain part of the armoury of a modern doctor, but GPs have accepted that these can no longer be regarded as sufficient.

Yet there is a drawback to evidence.

It is not a constant. It shifts, at times dramatically, so that what one day seemed clear-cut can the next look murky and uncertain.

It is essential NHS managers take into account the potential for evidence to change when they devise policy, yet time and again they do not.

So it is with moves to force up rates of generic prescribing. Pulse's investigation reveals the number of trusts with switching schemes for bisphosphonates, ARBs and antiplatelets has jumped by 150% in a year.

PCTs thought they were safe on bisphosphonates, after NICE guidance came down firmly in favour of alendronate. Similarly, studies suggested clopidogrel was often little better than aspirin, for substantial extra cost, and that ARBs were a more expensive equivalent of ACE inhibitors.

But over the past few months, as trusts busied themselves with cost-saving, evidence has continued to emerge - and not all of it supports what they are doing. NICE is having to revisit its appraisal of clopidogrel after a trial suggested it might be better than other drugs for preventing stroke recurrence.0

Researchers claimed ARBs might have advantages over ACE inhibitors, most recently in diabetes patients at risk of retinopathy. And clinicians lined up to criticise NICE guidance on bisphosphonates.

All these challenges to the current evidence-based consensus may yet dissolve, as further data emerges.

But each could, if stood up, force a rethink on significant chunks of PCT policy.

Trusts should surely have been more cautious, and more selective, before rushing ahead with disruptive generic-prescribing schemes.


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