Objective: To evaluate the Movement Disorder Society prodromal Parkinson’s disease criteria to two independent longitudinal studies

Background: The MDS research criteria for prodromal Parkinson’s disease (PD) propose a statistical approach for the calculation of the individual probability of prodromal PD. These criteria require testing to assess their reliability in the general population

Methods: Prodromal PD probabilities at baseline and follow-ups of the symptoms-enriched TREND cohort (n=650; baseline/2-/4-/6-year follow-up) and the population-based PRIPS cohort (Tübingen subsample; n=715, baseline/3-/5-year follow-up) were calculated. Posttest probabilities at baseline of incident PD cases and non-converting individuals were compared. Time to PD diagnosis, marker constellations and longitudinal changes of prodromal PD probabilities were investigated

Results: Incident PD cases (TREND: n=10; PRIPS: n=7) showed significantly higher likelihood ratios of risk and prodromal markers at baseline compared to non-convertors. However, only 2/17 incident PD cases met criteria for probable prodromal PD (i.e. posttest probability >80%) and 5 had possible prodromal PD (i.e. >50%). The diagnostic accuracy of probable prodromal PD was characterized by high specificities and high negative predictive values (>98%), but low sensitivities (TREND: 30%; PRIPS: 14%) and low positive predictive values (TREND: 19%, PRIPS: 50%). Individual PD likelihood ratios showed an inverse correlation with conversion time (Spearman rho =-.80, p=0.006) and unlike PD-free individuals, increased during follow-up in incident PD

Conclusions:  The MDS prodromal criteria identify subjects at high risk for PD. Although specificity of the criteria is high, most patients will not meet criteria before diagnosis, unless thorough diagnostic testing is performed.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/mds-prodromal-pd-research-criteria-validation-in-two-independent-prospective-cohorts/