Prevalence of Thai patients with advanced Parkinson's disease and external validation of the 5-2-1 Criteria and the CDEPA Questionnaire: A single-centered, cross-sectional study.

Background: Advanced stage of Parkinson's disease (APD) diagnosis is challenging for general neurologists. The 5-2-1 Criteria and the Cuestionario De Enfermedad de Parkinson Avanzada (CDEPA) have been validated for screening for APD.

Objective: This article reports the period-prevalence of APD defined by a movement disorder expert, the 5-2-1 Criteria, and CDEPA and to improve the screening performance of the 5-2-1 Criteria METHODS: A cross-sectional retrospective study at the Parkinson's disease (PD) clinic of a tertiary hospital in Bangkok, Thailand amongst all PD patients aged ≥ 18 years was performed from January 2016 to January 2020. We compared the characteristics of APD and non-APD patients. We externally validated the 5-2-1 Criteria and CDEPA. We explored improving the 5-2-1 Criteria.

Results: Of 480 PD patients with complete data, the period-prevalence of APD by the movement disorder expert, the 5-2-1 Criteria and CDEPA were 37.1 %, 48.5 %, and 27.5 %, respectively. Adding requiring help with an activity of daily living and freezing of gait to the original 5-2-1 Criteria enhanced the sensitivity from 86.5 % (95 %CI 80.6, 91.2) to 94.9 % (95 %CI 90.6, 97.7) and negative predictive value (NPV) from 90.3 % (95 %CI 85.9, 93.7) to 96 % (95 %CI 92.6, 98.2). However, the CDEPA had a sensitivity of 62.9 % (95 %CI 55.4, 70) and NPV of 81.0 (95 %CI 76.5, 85).

Conclusion: The 5-2-1 Criteria had a good screening tool performance for general neurologists to refer APD patients for optimal treatments. The modified 5-2-1 Criteria had better performance than the original one. External validation is needed.