What do we mean when we say “population health”?

April 25, 2011

Lately I’ve noticed a resurgence of the term “population health” in the health policy literature. It seems to me that the term is being used differently today than in the past, and I wonder how that might affect our ability to actually affect and improve population health.

Like many who read this blog, I was trained in a school of public health where I was taught to think about population health as something bigger than simply the aggregation of the health of individuals. Rather, I learned that communities themselves have a health status, and that achieving good population health in a community means reducing disease burden in an entire community. Reducing disease burden, in turn, creates an environment in which individuals in that community can be healthy and productive.

Historically, our conceptions of population health have varied and expanded. At the turn of the last century, improving population health mainly meant learning to control infectious diseases. By mid-20th century, many thought of population health in the context of family planning and population control. And in the last decade or two, our conception of ways to improve population health expanded as we began to understand the impact of the social determinants on our ability to improve the health of entire communities. This broader notion of population health recognizes a wider range of contributing social, economic and environmental factors.

In the context of health care reform, I read and hear a lot today about the expectation that reorganizing our health system – for example, by establishing accountable care organizations (ACOs) or ensuring that patients have medical homes – will improve population health.

I like hearing these aspirations, but I wonder what authors really mean when they say “improve population health”? Do they simply mean that incentives will be aligned in ways that encourage ACOs to try to keep those in their direct care healthy, the way we think of managed care plans encouraging preventive services for plan members and coordinating care among health care providers? Or do these statements mean something broader than that? The proposed regulations on ACOs require substantial reporting of health information for individuals receiving care within these organizations. Will ACOs also generate or use health surveillance data for the communities in which their patients live and work, or make efforts to ensure that providers within their systems know about challenges to the health status of the community? Will ACOs conduct community outreach to engage them all in public health issues, not just those “attributed” to their organization?

Twenty-five years ago, in a book titled, “Just Health Care,” Norm Daniels emphasized the importance of designing a health care system that would achieve population health by fairly allocating resources. He suggested that health care is valuable because as it improves health status, it creates opportunity. I like to imagine what opportunities might be afforded to all individuals in our communities if we really focused on improving population-level health.

It is ok with me if the meaning of the term “population health” morphs in a way that improves our likelihood to achieve it, like it did when it became more inclusive of the broader social determinants of health. But I worry about the narrowing of the term when it refers just to those individuals “in the system.” I think if we spend a little more time clarifying what we mean by the term “population health” in the work that we do, we might have a better chance of actually improving it.