Imagine trying to drive across country with a map from the 1970s. How can you plan for the journey ahead with outdated information? That is the problem we face in Parkinson’s disease (PD) when it comes to figuring out how many people are living with it.
Forty years ago, scientists gave us initial estimates of how many people live with Parkinson’s. They range anywhere from 600,000 to one million. But those numbers are imperfect and out-of-date. And it is important to the future of research and care that we update them. It’s possible, for example, that there are dramatically more people living with Parkinson’s disease than we realize. That knowledge may, in turn, increase investments from government and industry.
To make this happen, PDF is investing $250,000 in a project we call P4 — the PDF Parkinson’s Prevalence Project. We are funding six groups of epidemiology experts who are using different sets of data (i.e., medical records, clinical trial data) to help us understand who has Parkinson’s in the US and Canada. Here’s a quick update:
- Connie Marras, M.D., Ph.D., is mining a database of 11 million health records from Ontario, Canada (that’s one-third of the entire Canadian population!) to understand how many people in Ontario live with PD. The results could be helpful for the US too, as the demographics of Ontario are very similar to those in states like Kansas, Indiana and Missouri.
- G. Webster Ross, M.D., and Caroline Tanner, M.D., Ph.D., are analyzing data from the Honolulu-Asia Aging Study, which followed Japanese-American men living in Oahu, HI (born between 1900-1919) for 47 years. Because the men were followed for such a long time, the results will help us understand how prevalence of PD changes with age.
- James Bower, M.D., and Rodolfo Savica, M.D., M.Sc.,are examining all electronic medical records of residents of Olmsted County, MN, which were collected as part of the Mayo Clinic’s Rochester Epidemiology Project. By analyzing such high quality records for evidence of PD, they may capture a complete picture of the disease in a community.
- Stephen Van Den Eeden, Ph.D., is probing the electronic medical record database for Kaiser Permanente Northern California to determine the prevalence of parkinsonism in California’s Greater San Francisco Bay and Sacramento metropolitan areas. Because Kaiser’s 3.8 million members represent 25 to 30 percent of the population in these regions, this may give a fairly accurate picture of PD in that area.
- Dr. Tanner (mentioned earlier) is examining the prevalence of PD in four California counties (Santa Clara, Kern, Tulare, and Fresno) as part of the California Parkinson’s Registry Pilot Project. She is examining health records from nearly 300 medical practices collected from 2008 to 2010. Because the records are from both urban and rural populations, she can analyze any differences in PD prevalence between the two types of communities.
- Allison W. Willis, M.D., M.S., and colleagues are extending their previous research into data from the Centers for Medicaid and Medicare Services (CMS). The CMS provides health coverage for about 30 million people in the US — nearly 95 percent of people over the age of 65. Dr. Willis previously studied neurology-related insurance claims from the CMS database related to PD, to estimate how many people among those 30 million might have the disease. But, because PD is so difficult to diagnose, she is taking a harder look at those claims — and diagnosis records — to see if they are accurate.
Conclusion: What's in a Number?
PDF’s hope is that with P4, we will not only have better estimates of Parkinson’s disease prevalence, but also greater assurance that these numbers are more meaningful. Our scientists are studying rural and urban communities, men and women, and people of different racial and ethnic backgrounds. Their findings will help us to understand prevalence in general, and how it might vary in different communities. And when we have better information — how many people have Parkinson’s disease and who they are — we’ll have a much better roadmap to the cure.