According to the World Health Organization, iron-deficiency anemia (IDA) is by far the most prevalent chronic health condition around the globe. In order of the number of people afflicted, anemia is followed by hearing loss, migraine, low vision, asthma, diabetes mellitus, osteoarthritis and depressive disorders.
In contrast, the conditions with the largest number of mobile apps in Google Play, iTunes and other online stores were diabetes, with 1,812; and depression, with 1,537. Migraine and asthma had just 112 apps each; low vision, 64; hearing loss, 52; osteoarthritis, 24; and anemia, 14. In other words, the most prevalent health condition worldwide has the fewest apps written for it.
The study's authors noted, "The majority of IDA [anemia] cases are located in underdeveloped or developing countries where smartphones or tablets are not as widely spread as in the developed countries, and therefore, it is not worthwhile developing apps for IDA." In contrast, they noted, diabetes and depression are common conditions in the more advanced countries.
[ Not all mobile health apps are created equal. See When To Ignore That Mobile Health App. ]
More than 80% of the world's population now has mobile phones, but only about 20% of those devices are smartphones that can surf the web and accommodate complex programs. The penetration of these expensive products is highest in affluent countries like the U.S., Canada, Singapore and Sweden.
The researchers also reviewed the medical literature to count the studies of mobile apps for these eight conditions. There weren't many studies overall, but the 140 studies of diabetes programs outnumbered those of apps for all the other conditions combined. The other conditions with significant numbers of studies were asthma (36) and depression (32).
The authors thought it curious that asthma had more studies than depression but far fewer commercial applications. "The opposite occurs with migraines, which move from the last position in number of literature results to the third position in the commercial review," they pointed out.
While they didn't explain this anomaly, the researchers noted that asthma is the most common chronic disease in childhood, and that most asthma-related deaths occur in poor and developing countries. Migraines are the most prevalent chronic neurological disorder in adults around the world.
Overall, they concluded, "The four most prevalent conditions have fewer apps and research than the remaining four, excluding OA [osteoarthritis]."
The majority of the reviewed apps, the researchers noted, are designed to monitor, assist, or inform about the condition. Apps for diabetes, migraine, and asthma tend to be designed for monitoring the condition while also providing some information on it. Apps for low vision are meant to assist vision, and apps for depression are intended to lift the mood of users. As one might expect, apps for osteoarthritis are intended to help manage pain, and those for hearing loss include hearing checks.
For most of these apps, the Internet is not required or is required only for functions such as sending e-mails. The majority of apps have non-clinical purposes and can be used by consumers without the involvement of clinicians, the researchers said.
Altogether, chronic disease apps form only a small subset of the mobile health apps available today. Most mHealth apps are designed for wellness or fitness, partly because those areas do not require FDA approval. In addition, physicians and other healthcare professionals have only recently begun to show interest in looking at the data generated by mobile apps for patients with chronic diseases.