Archie Cochrane defined three concepts related to testing healthcare interventions. Efficacy is the extent to which an intervention does more good than harm under ideal circumstances ("Can it work?"). Effectiveness assesses whether an intervention does more good than harm when provided under usual circumstances of healthcare practice ("Does it work in practice?"). Efficiency measures the effect of an intervention in relation to the resources it consumes ("Is it worth it?"). Trials of efficacy and effectiveness have also been described as explanatory and pragmatic or management trials, respectively, and efficiency trials are more often called cost effectiveness or cost benefit studies.

Almost all clinical trials assess efficacy. Such trials typically select patients who are carefully diagnosed; are at highest risk of adverse outcomes from the disease in question; lack other serious illnesses; and are most likely to follow and respond to the treatment of interest.

This treatment is prescribed by doctors who follow a careful protocol; the comparison will be a placebo or existing best practice, and participants will receive special attention from staff who supplement or replace those employed in usual clinical settings. The results of such trials are very useful: if the intervention doesn’t work under such ideal conditions it surely won’t work under usual conditions. Most treatments don’t survive this stage of testing, and it makes good sense to sequence the testing of all interventions through this efficacy stage. However the next stages are not easy.

A recent BMJ paper by Llewellyn-Jones et al showed these problems. In attempting to help general practitioners to care for depressed elderly people in residential care, the authors found little evidence that general practitioners improved their prescribing habits. Many patients refused to participate or dropped out. The result was a barely detectable benefit, even among those patients who stuck with the programme.

However managers, planners, and politicians will want to know more than "Does it work?": they will want to know "Is it worth it?" – in comparison with use of the resources for other needs. Trials such as the one by Llewellyn-Jones et al show that we’re just now learning to run – with community trials that tackle difficult challenges in research design and implementation that can undermine the feasibility of a study or prejudice the interpretation of its findings.

Issues of economic analysis also are being resolved, so that questions of efficiency can be better addressed. This progress will seem slow to researchers caught up in it and to all of us waiting for the answers, but in the history of the world we’re heading for success at a blistering pace. Our progress is fuelled by efficacy studies and by researchers and governments intent on reaping the benefits they promise.

Drugs to treat dyspepsia and childhood asthma devices are included alongside therapies for cancer and multiple sclerosis in the first list of treatments to be assessed by NICE in the autumn. Dyspepsia drugs can be very clinically- and cost-effective when used in the right situation; however, there is good evidence that they are often used inappropriately, the DoH says.

There is much variation in the use of inhaler devices for children with asthma, and one of NICE’s tasks will be to assess the effectiveness of the different systems.

The roles of glatarimer and interferon beta in the treatment of multiple sclerosis will be considered ‘in the context of services for multiple sclerosis patients generally’. NICE will review the evidence for the use of paclitaxel as first-line treatment for ovarian cancer and will also issue advice on the role of docetaxel in breast cancer.

Hip prostheses, zanamivir and oseltamivir, hearing aids, routine extraction of wisdom teeth, liquid-based cytology for cervical screening, and coronary artery stents are also on the initial assessment list.

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Bandolier recently had an article on hand washing in hospital acquired infection.

Clearly it is considered an issue of importance, and a BMJ editorial¹ pointed out how infrequent and sporadic hand washing is in health care workers. One classic paper quoted showed that while doctors estimated that they washed their hands 73% of the time before patient contact, the observed frequency was just 9%.

Handwashing with chlorhexidine regularly gave 98-100% reductions in hand counts.

There is even a systematic review³ looking at compliance issues with hand washing and barrier precautions, which is a useful source of literature. It highlighted two other studies which showed that increased compliance with hand washing before and after patient contact resulted in large (50% or more) decreases in infection rates. Three more recent papers of interest are examined here.

The bottom line appears to be simple, hand washing with agents containing chlorhexidine really does lower the rate at which bacteria get onto the hands, and that hand washing protocols properly enforced reduce hospital acquired infections. It’s more than that, though. There would appear to be clear evidence of effectiveness, and of benefits of quality and cost-effectiveness.

It may even be a clinical governance issue.

References

1 Editorial. BMJ 1999 318:686.