How many people in the US have Parkinson’s disease?

How many people have Parkinson’s disease?

You may have heard the statistic that there are approximately one million people with Parkinson’s disease (PD) living in the US. That number has increased in past decades and will continue to increase.

physician pointing at screen of digital tablet

Recent epidemiological studies have led to that current estimate of one million. The Prevalence of Parkinson’s Disease Across North America study used health care records from medical facilities, Medicare data, and data from large ongoing healthcare research studies in five different sections of North America, to estimate how many people in the US have PD. If instead of extrapolating the number from data, wouldn’t it be an improvement if there was an actual account of every person with PD?

To do that, the PD community needs registries and databases that contain an entry for every person with PD.

Using Parkinson’s registries to understand how many people have PD

What can Parkinson’s disease registries accomplish?

There are many benefits to having a more accurate understanding of the PD population. Many of the crucial uses for the data a registry include:

  • To inform the government as to how many people have PD. By knowing the true large number of people affected by PD, lawmakers will understand the importance of increased research funding and will favor legislation that benefits people with PD.
  • To allow health care organizations and the public health infrastructure to plan for the requirements of people with PD.
  • To be used as a source of information about people with PD for research purposes and thereby increasing our knowledge of PD
  • To act as a database of people with PD who can be potential participants in clinical studies. For example: In California, the PD registry has recently been used as a tool to contact people with PD about a clinical trial called TOPAZ, studying the use of a medication called zoledronate to reduce fractures in people with PD. A registry can expedite critical PD research by helping clinical trials fill up faster.

There is no national PD registry due to significant logistical and legislative issues, and the creation of one is not likely for the foreseeable future. Yet, several states have created state-specific registries – with more to come.

State registries for Parkinson’s disease

For a Parkinson’s disease registry to be established in a particular state, the state legislature needs to pass a law to create the registry. Passing a law, however, does not mean that the state legislature also agrees to fund the registry. Funding may need to come from sources outside of the government.

It is interesting to note that the legislative process in the states is surprisingly quick. In a typical state legislature, discussion of all new bills happens over a three-month period, typically over the winter. About 5,000 bills are discussed, so the pace is very rapid. If the bill gets passed, and a registry is approved, then it typically goes into effect in the summer or fall. If it does not get passed, then the bill needs to be reintroduced the following year for a fresh discussion.

To have the best chance of being a useful and successful registry:

  • The law establishing the registry should require health care providers who see a patient with PD, to report that case to the registry, as opposed to making submission to the registry voluntary. California law, for example, requires healthcare providers diagnosing or providing treatment to PD patients to report each case of PD to the California Department of Public Health.
  • The registry entries should be populated automatically from the patient’s electronic medical record, as opposed to relying on health care providers to submit a separate entry to the registry. This reduces the burden on health care providers and makes them more amenable to support the registry.

Which states have PD registries?

The following states have registries in different stages of development:

  • Nebraska – a registry was founded in 1996, but experienced various stops and starts over the years. After a lack of funding put the registry on hold in 2004, it was reinstated in 2006 thanks to co-funding from APDA. Despite it having been established so many years ago, many health care providers are not aware of it and do not report their cases. It does not pull from electronic medical records automatically, but requires additional steps from health care providers, which limits its comprehensiveness.
  • Utah – a registry was founded in 2015 and collects cases of Parkinson’s disease in the state of Utah.
  • California – a registry was founded in 2017. It will soon be expanded to include other neurodegenerative diseases such as Alzheimer’s disease. In many ways, California is the paradigm which other states are using as a model as they put their registries in place. The registry is populated automatically from electronic health care records with no additional steps required from the practitioner. There are currently 93,000 entries in the database which is approximately the number of PD cases expected in the state based on other studies, indicating that the registry is doing a reasonable job comprehensively capturing PD cases.
  • South Carolina, West Virginia, and Maryland – These states passed legislation to create registries and are now in the beginning stages of getting them established. The South Carolina and West Virginia registries will work in collaboration with universities (Medical University of South Carolina and West Virginia University) to create, operate, store, and fund the registries.
  • Colorado, Hawaii, Massachusetts, New York, Ohio, and Oregon – all of these states expect to have legislation presented to their legislatures at some point in 2023.
  • Washington State – a voluntary registry has been in place since 2007, funded by the APDA Northwest Chapter. The registry is mainly used as a database for clinical trial recruitment and has been very successful in this regard. Since its inception, it has been used for recruitment by a total of 68 research studies conducted by 31 investigators at eight different institutions in the Pacific Northwest.

The complexities of registries

As more states set up PD registries, the community of clinicians, data scientists, and researchers interested in PD are in active discussion to optimize the registries and the information being collected.

The following issues are at the forefront of the discussion

There are no clear answers to these questions yet, but as state registries develop, each will need to consider these points:

What are the best ways to ensure privacy and protection of data?

Privacy is of supreme concern to all those who are involved in registries. As registries evolve and grow, the focus remains on ensuring that data is protected and secure.

What data should be collected in a registry?

The data could theoretically be more limited, including just basic demographics, or it could be expanded to include more wide-reaching information such as date of diagnosis, symptoms, and treatments. This additional information could be very useful to researchers to better understand how PD is diagnosed and treated across the population. Ideally, the data elements collected would be standardized across registries so that data could be aggregated amongst the different registries.

Who should be in the registry?

Should it include only people with a clear diagnosis of PD, or should it include cases of atypical parkinsonism which are related neurodegenerative disorders?

What is the best way to enroll cases in the registry?

As discussed above, automatically pulling cases from the electronic medical records is how it is done in California. Other options include having patients report themselves into the database or pulling pharmacy records for prescriptions of Parkinson’s medications.

I am interested in knowing more about registry efforts in my state. What should I do?

If you are interested in becoming involved in registry efforts in your state, email us at and we can connect you to our PD advocacy partners.  To learn more about this topic, please watch our recent episode of Dr. Gilbert Hosts where we talk with advocacy expert Ted Thompson.

Tips and takeaways

  • A PD registry is a database that contains an entry for every person with PD in a particular geographic area.
  • Currently, there are state PD registries in different stages of development, with established registries in Nebraska, Utah, California, and Washington State; and multiple other states working towards approval of PD registries including South Carolina, Maryland, West Virginia, and more.
  • A PD registry can be used to: give an accurate count of people with PD, allow the health care system to plan properly, act as a research database about PD, and support recruitment into clinical trials.

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