Long-term follow-up of early dopa treatment in Parkinson's disease.

A group of 19 patients with Parkinson's disease, who began dopa therapy 1 to 3 years after onset of symptoms, were followed for 12 years. They were evaluated every 3 to 4 months on the UCLA disability scale and the Hoehn and Yahr functional classification scale. This present group was compared to two other historical groups reported on earlier [8], one that began treatment with dopa 4 to 6 years after onset of symptoms and the other that began dopa treatment 7 to 9 years after onset of symptoms. Results on both scales showed that the mean disability scores of the three groups did not differ significantly when duration of disease was matched, even though duration of dopa therapy among the groups varied from 1 to 12 years. The highly significant differences between the groups prior to dopa treatment continued throughout the study. These longitudinal data support the conclusion that the worsening over time is the result of progression of Parkinson's disease and not a result of the duration of dopa treatment. Early treatment improves the beginning years of the disease and has no adverse effect on later years. Twelve years after beginning dopa therapy, 32% of the present group had died at a mean age of 76.0, in contrast to 50% (mean age, 74.7) and 57% (mean age, 71.5) in the groups who began dopa increasingly later in the course of their disease. Incidence of dementia increased with disease duration regardless of treatment duration.(ABSTRACT TRUNCATED AT 250 WORDS)