Analysis of National Sample Cohort From Korea for Epidemiological and Prognostic Aspects of Parkinson's Disease According to Time of Onset.

Background: Parkinson's disease (PD) affects adults of all ages, with prognostic aspects varying based on the age of onset. This study compared the prognostic aspects of early-onset PD (EOPD) and late-onset PD (LOPD) in South Korea.

Methods: We analyzed PD patients aged ≥ 20 years registered at the National Sample Cohort between 2002 and 2019. PD patients were categorized into EOPD and LOPD. Five randomly selected individuals without PD were included as controls. Epidemiological data were analyzed for the two groups. Medical and socioeconomic variables, including body mass index (BMI), Charlson Comorbidity Index (CCI), smoking, and household income, were compared to controls to identify prognostic factors.

Results: PD incidence and prevalence per 100,000 significantly increased from 11.36 and 29.15 in 2003 to 26.10 and 174.52 in 2018, respectively. The proportion of EOPD among the PD patients decreased from 8.81% to 4.42%. LOPD patients had higher CCI scores than EOPD patients, and there were no significant changes in either group after 3 years from the index date. BMI significantly decreased in both LOPD and its control group 3 years after the index date. After the index date, smoking rate significantly decreased in LOPD and controls groups, but not in EOPD. EOPD patients exhibited significant differences in household income after 3 years from the index date.

Conclusion: PD incidence and prevalence gradually increased from 2003 to 2018, while the proportion of EOPD patients gradually decreased from a high value of 8.81%. For 3 years after PD diagnosis, EOPD and LOPD patients exhibited different comorbidities, smoking rate, and BMI patterns. EOPD patients were more vulnerable to negative economic outcomes.