A breakdown of the apps for specific therapy areas.

There are more than 43,000 healthcare apps available from the US iTunes store, but only about 16,275 of those are patient-facing apps with "genuine" health content, according to a new study from the IMS Institute for Healthcare Informatics. Furthermore, in an analysis of the Google Play Store, IMS found that 50 percent of health apps are downloaded fewer than 500 times and just five apps account for 15 percent of all health app downloads.

Starting with all the apps in the "Healthcare and Fitness" and "Medical" sections on iTunes, IMS eliminated 20,000 apps they considered mis-categorized or "only loosely healthcare related," which included veterinary apps and apps that made vague claims, but also included fertility trackers. They then eliminated another 7,500 apps for being healthcare provider-focused rather than aimed at the consumer.

IMS evaluated the remaining apps, assigning them a functionality score and pulling out specific categories, including apps linked to external sensors.

"Analysis of the widely available consumer healthcare apps on the iTunes app store shows that at present there are 159 apps which link to sensors," IMS writes in the report. "However these are dominated by fitness and weight apps which monitor pulse rates when exercising and measure weight and body mass index (BMI). Fewer than 50 of these 159 apps relate to actual condition management or provide tools and calculators for users to measure their vitals. There is therefore considerable room for growth in this sector."

IMS found that 10,840 of the 16,275 apps reviewed can provide and display information, but only half of those also provide instructions. Only 20 percent of the 10,840 can also capture user-entered data.

The study also identified just under 2,000 apps that dealt with specific therapy areas. Among these, mental health was the most common area with 558 apps, 196 of which were geared at autism with another 96 aimed at anxiety. Vision and hearing was the second most common category, followed by endocrine and metabolic conditions.

The report also identifies a number of barriers that need to be addressed to increase app adoption and improve the quality of apps, including a curation platform of some kind, app integration with other parts of care, better safety and security, and more robust efficacy measures to prove the value of apps to all stakeholders in the ecosystem.

IMS's 16,275 figure is just a little higher than the more than the 13,000 consumer-oriented health apps MobiHealthNews found in 2012 when we released our report on consumer health apps for the iPhone, suggesting a modest but significant growth over the past year.