Medical devices

Inhaling information

How to collect data on asthma while, at the same time, treating it

IN 1985 and 1986 an epidemic of asthma hit Barcelona. The city's researchers first turned to the usual suspects, such as air pollution, pollen and mould. But a series of telephone interviews with the sufferers pointed to a much more precise cause. All the attacks had occurred by the harbour, and at times when ships were unloading soya beans. The cause was clear: soya-bean dust. So was the solution: the installation of filters on the harbour's silos.

Asthma is one of the world's most common chronic diseases. It affects about 300m people (almost 5% of the population). Yet what triggers any given asthma attack is often unclear and, as a consequence, most asthmatics are not properly treated. Stories of success, like that of Barcelona, are rare.

Part of the reason for that lack of clarity is inadequate data on where and when attacks happen. But David Van Sickle, an epidemiologist and medical anthropologist who once worked for America's Centres for Disease Control and Prevention (CDC), has come up with a solution. This is to use the asthma inhalers carried around routinely by patients to record the time and location of symptoms as they happen.

To develop his idea, Dr Van Sickle left CDC and founded a company, Asthmapolis, which is based in Madison, Wisconsin. The result is Spiroscout, an inhaler with a built-in Global Positioning System locator and (in advanced models) a wireless link to the internet. Whenever someone uses the inhaler, it broadcasts the location and time to a central computer. Asthmapolis plots and analyses the data, and sends weekly reports to participating patients and their doctors summarising the observations and making recommendations.

That is useful for the individuals involved, since it may illuminate patterns of which they were unaware (the proximity of a particular kind of crop, for example). It could also help doctors identify those patients whose asthma is not under proper control. Use of the inhaler more than a couple of times a month suggests there is something wrong, and that the patient's medication may need to be changed. Patients do not, however, always report such problems, and so do not get the right drugs. The big public gain, though, will come from pooling all the data from the inhalers, once they have been suitably anonymised. That will open the way for a much more detailed analysis of what is going on, and may allow the triggers to be identified and ranked in order of importance.

Over the past three years Dr Van Sickle has run two pilot studies to test the new tool. Both of these showed useful improvements in patients' management and understanding of their disease. They have also resulted in him questioning some longstanding theories about asthma, including the ideas that symptoms occur primarily at home and that the affliction is more prevalent in urban areas than rural ones. If those insights are confirmed, they will change the way asthma is managed.

The next step, commercialisation, is planned for the autumn. With nearly 500,000 asthma-related hospital admissions every year in America alone (often involving cases where the disease could have been properly controlled by drugs, but was not), the market could be large. Alternatively, Dr Van Sickle's old friends at the CDC or some other medical-research agency might think the data sufficiently valuable to buy and distribute the things themselves. Either way, the upshot would be better lives for patients in the short term and, if all went well, a true understanding of the triggers of this debilitating and occasionally life-threatening condition.