August 11, 2026

@michaelokun

How do we accurately count Parkinson's disease across the United States? Disease surveillance refers to the systematic collection and analysis of health information to understand how many folks have a disease, where they live, and how those numbers change over time. Esper and colleagues describe in a new paper in JAMA Network Open how the National Neurological Conditions Surveillance System (NNCSS) identified the best methods for tracking Parkinson's disease across the United States. Key points: - The investigators systematically reviewed 156 studies and found wide variation in how Parkinson's disease has been identified using administrative data, claims, electronic health records, and surveys. - No single case definition perfectly distinguished Parkinson's disease from atypical or secondary parkinsonian disorders because of diagnostic uncertainty early in the disease course and because of limitations of ICD coding. - Rather than reporting one potentially misleading prevalence estimate, the authors recommend using two complementary surveillance definitions: one emphasizing diagnostic certainty (Parkinson's disease probable) and another emphasizing sensitivity (Parkinson's disease possible), with claims data emerging as the strongest national surveillance data source. My take: This paper may not grab headlines like a new treatment trial, but it is foundational for the future of Parkinson's disease research and public health. If we cannot accurately count Parkinson's disease, we cannot accurately plan for research funding, workforce needs, health care resources, caregiver support, or prevention strategies. Measuring the burden of Parkinson's disease correctly is one of the first steps toward changing its future. Here are 3 points that resonated w/ me: 1- You cannot solve a problem you cannot measure. National surveillance is essential for understanding how Parkinson's disease is changing over time. 2- Diagnosing Parkinson's disease remains challenging, especially early in the disease course, and this uncertainty must be reflected in surveillance methods, rather than ignored. 3- Using both a probable and possible Parkinson's disease definition is important.