Natural history and effectiveness of early detection of Parkinson's disease: results from two community-based programmes in Taiwan (KCIS no. 11).
OBJECTIVE
The natural course of Parkinson's disease (PD), as measured on the Hoehn-Yahr (H-Y) scale, and the impact that early detection would have on prognosis for those with the disease, has barely been addressed since the introduction of L-dopa. This study aimed to elucidate the natural history of PD and effectiveness of early detection in reducing advanced disability and mortality.


METHODS
A total of 21 362 participants aged 40 years or older were invited to two community-based programmes for the early detection of PD. The step-by-step annual progression rates from H-Y stage I to stage IV or V, and cumulative survival rates, by the H-Y scale, were estimated and applied to simulated data to assess the impact of different screening intervals upon stage at diagnosis and subsequent survival.


RESULTS
The average duration in stages I, II and III was estimated as 2.83, 6.62 and 1.41 years, respectively. The average delay time before deteriorating into H-Y stage III was 9.45 year. Application of these parameters to simulated model predicted a 36% (95% CI: 28-39%), 26% (95% CI: 20-32%) and 19% (95% CI: 13-24%) reduction in death for annual, 5-yearly and 10-yearly screening programmes, respectively.


CONCLUSIONS
The present study recommended a 5-yearly screening programme, with 74% of PD cases prevented from progressing to H-Y stage III or worse within 10 years of diagnosis, and leading to a corresponding 26% reduction in mortality.
Liou
Horng-Huei
HH
Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
Wu
Chia-Yun
CY
Chiu
Yueh-Hsia
YH
Yen
Amy Ming-Fang
AM
Chen
Rong-Chi
RC
Chen
Ta-Fu
TF
Chen
Chih-Chuan
CC
Hwang
Yuarn-Chung
YC
Wen
Ying-Rong
YR
Chen
Tony Hsiu-Hsi
TH
D000328:Adult; D003153:Community Health Services; D003198:Computer Simulation; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification / Q000175:diagnosis / Q000503:physiopathology; D015397:Program Evaluation; D013223:Statistics as Topic; D013624:Taiwan