Parkinson's disease: progression and mortality.

Patients with Parkinson's disease were compared during two 15-year periods before and after the introduction of levodopa. With levodopa treatment: The duration of illness at each stage of severity was 3 to 5 years longer; at every duration of illness, death and disability were reduced 1.5- to 3-fold, except in patients whose treatment had been delayed; abnormal involuntary movements that interfered with function occurred in 24% of patients; severe fluctuations that required rescheduling of activities occurred in 29% of patients; severe AIMs and fluctuations were rare during the first 3 years of treatment, but remained constant thereafter, without progressive increase; prevalence of severe fluctuations was related only to age of onset of disease: If under 50, severe fluctuations developed in 66%, if age 50 to 59 at onset, they developed in 30%, if over age 60, in only 6%; average age at death was 6 years older; and observed/expected mortality was 1.2, not significantly different from the unaffected population.