• Jeremy Wyatt
• Guardian Professional, Friday 6 January 2012 10.40 GMT

The Whole System Demonstrators showed that, “if used correctly”, telehealth reduced death rates by 45%, NHS resource usage by 15-20% and tariff costs by 8%. With these striking results and the launch of the industry/NHS funded 3 Million Lives campaign, telehealth is steaming out of its backwater into the clinical mainstream.

Clearly it will help many patients navigate their long-term conditions (LTCs), and I personally would recommend it to my parents. However, doctors must be careful to embark only those passengers most likely to benefit. There are three main reasons for concern.

First, a handful of telehealth trials, and one systematic review in people with chronic obstructive pulmonary disease, show that telehealth can harm some people, with higher death rates in patients randomised to telehealth compared to usual care. Possible explanations are that some people may use their telehealth system to take on too much responsibility for their own health – perhaps refusing hospital admission when medically advised – while some clinical staff may mistakenly consider telehealth a safe substitute for face-to-face care in the seriously ill.

Also it is possible that some people with long-term conditions could experience lower quality of life with telehealth than without it. This follows if the technology reminds them daily of an illness they would rather forget, restricts their movements, reduces valued contact with health and social care professionals, or they experience frequent anxiety around their disease monitoring results, and what to do about them.

This highlights the fundamental telehealth fallacy – that technology alone is the solution – when actually the technology is there to deliver a safe, effective self-care package tailored to support people with LTCs. The problem is, very few self-care packages are sufficiently well-defined to be replicated and tested, let alone shown to be effective.

A second concern is that some “worried well” may use data from their telehealth system to argue for more clinical attention than they really need. Any increased resource use – even by only say one of the 17 million UK population with LTCs – threatens NHS productivity. It might prolong those people’s lives, but more clinical attention is unlikely to improve its quality and will reduce resources available to others with more severe problems.

An even more unsettling scenario for politicians is that widespread adoption of telehealth could expose to media view large volumes of unmet demand that the NHS cannot satisfy.

Third, JP Ionnides rightly criticised clinical optimists and innovators for our breathless excitement about the positive results of drug trials that are later contradicted — but this also applies to telehealth. For example, a 2010 Cochrane review concluded that telehealth in heart failure reduced death rate by 34% but now – when we include several large negative trials – this figure is halved. Many of the positive trials, though tightly regulated, have been industry funded.

The good news is that most telehealth trials and systematic reviews show that telehealth helps broad groups of patients. However, only 7% of 700 people with LTCs in a recent Ipsos Mori survey for the Department of Health would value “devices in their homes to monitor a long term health condition”.

This sounds uncomfortably like a rejection of telehealth – especially when three times as many people valued simple information about their condition.

So, we don’t yet know which passengers should be encouraged to join this voyage of discovery, nor how many will take up the offer and use it correctly. This will not surprise mature observers of the health scene: it has taken us decades to understand who really benefits from most common drugs and operations and how to encourage uptake, so why should telehealth differ?

Jeremy Wyatt is professor at the Institute of Digital Healthcare, Warwick University