Clinical course of patients with idiopathic Parkinson's disease.

We determined the variables associated with the progression and duration of illness of patients with Parkinson's disease (PD) and investigated the cause of death. In 474 patients with parkinsonism, who visited the Academic Hospital between January 1, 1960 and August 31, 1993, we did a survival analysis with the following covariates: age at onset, initial symptom (tremor or rigidity/hypokinesia), age at reaching Hoehn and Yahr stage III, dementia-free period, and levodopa treatment. A total of 345 patients with parkinsonism fulfilled the criteria of idiopathic PD; 258 of them were still alive on the closing date of this study. There were significantly more men than women (1.43:1). Medical advice was sought in an earlier stage by men and by patients with tremor as presenting symptom. For patients with rigidity/hypokinesia as first symptom, the duration of illness until reaching Hoehn and Yahr stage III was shorter than for patients starting with tremor alone. If the initial symptom is tremor, patients develop dementia less frequently and later after onset than when tremor is not involved. Reaching Hoehn and Yahr stage III and developing dementia both, limit the patient's survival time. The mortality risk for a patient was found to be increased from the moment levodopa treatment was started as compared to those patients who had not yet started with the treatment. The effect of levodopa on survival could not be disentangled from effects of other factors related to the start of levodopa treatment.