Diagnostic Delays in Parkinson's Disease in Thailand: Clinical Pitfalls and Health System Barriers

Parkinson's disease (PD) is a progressive neurodegenerative disorder in which early diagnosis improves quality of life and reduces disability. However, diagnostic delays remain common, particularly in low- and middle-income countries. This study investigated clinical and system-level factors contributing to diagnostic delay in Thailand.

A retrospective chart review was conducted on patients newly diagnosed with PD at Thammasat University Hospital between June 2020 and June 2024. Demographic, clinical, and healthcare access data were analyzed. Diagnostic intervals were defined as onset-to-visit (OTV), visit-to-diagnosis (VTD), and onset-to-diagnosis (OTD). Age-at-onset groups included early-onset Parkinson's disease (EOPD, <50 years), regular-onset PD, and very-late-onset PD (≥80 years).

Of 1093 patients screened, 109 newly diagnosed PD cases met the inclusion criteria. The median OTV was 360 days, and the median VTD was 10 days. Tremor was the most frequent initial symptom (75%). Patients with higher education and extended family support sought care earlier, whereas those under the Universal Coverage Scheme (UCS) experienced longer OTD durations (median, 541 vs. 181 days in privately insured patients). More than half of patients were initially misdiagnosed, especially when first evaluated by non-neurologists.

Diagnostic delay in Thai PD patients stems mainly from late help-seeking and inequities in healthcare access. Addressing these gaps requires public awareness, physician training, streamlined UCS referral pathways, and adoption of biomarker-supported digital tools to ensure earlier and more equitable diagnosis.