Louisville, Kentucky-based health insurer Humana is joining Propeller Health's Air Louisville public-private partnership. The project, launched in March 2015 in collaboration with the City of Louisville and funded by a Robert Wood Johnson Foundation grant, aims to connect sensors to 2,000 asthma inhalers and share that data, in aggregate, with city officials so it can be used to improve public health.

So far 440 people have joined. Humana will actively promote the program to its employees, which Propeller hopes will lead to a big boost in enrollment.

“Our ambitious goal is only achievable if we work together with organizations like Air Louisville,” Dr. Ray Godsey, the corporate medical director for Humana said in a statement, referring to a goal of improving the health of the community by 20 percent. “Our research indicated that asthma, allergies, smoking and other respiratory illnesses are significant barriers to Kentucky’s health. Air Louisville is helping us develop and implement collaborative strategies to remove these barriers and assist us all in breathing easier.”

Thirteen percent of Louisvillians have asthma, compared to 8 percent in the wider US population. Air Louisville is designed to find out why, and how the problem might be mitigated both by individuals with asthma and on the city level.

"We believe in this model," Propeller COO Chris Hogg told MobiHealthNews last year. "We saw just in a small pilot that there’s a lot of value to be brought here for cities and employers in these communities. Louisville for us will be the first, but we have plans to roll this type of community-specific program out to other cities as well. Because once you have enough data in a geography and it’s concentrated, you can start doing interesting things. You can start to really understand the pattern with asthma and how it relates to temperature, wind, and air quality. You can start to notify all the residents of Louisville about asthma risk or the things that they might not be aware of, even if they don't have sensors."

Those data are already starting to come in, and Propeller shared a sample with MobiHealthNews. On the individual demographic level, the company is seeing that their sample is comprised of fairly severe asthma sufferers: 85 percent of participants reported their asthma wakes them up at night at least once a week and 84 percent said their asthma negatively impacts their lives, keeping them from being as productive at work, school or at home. 

The program has also had a positive effect on users. Participants saw an average 71 percent reduction in rescue inhaler use and a 30 percent increase in "asthma-free" days. Overall, 63 percent fewer people have asthma that is defined as uncontrolled.

They've also gleaned a few insights about asthma in the community. For one, public air quality does seem to be at least partly to blame -- only 31 percent of rescue inhaler uses happened in homes. Asthma symptoms were worst when air quality was poor and temperatures were high, but they found that medium wind speeds could negate that effect. High winds, however, made symptoms worse.