Comparison of patient rated treatment response with measured improvement in Parkinson's disease

Background: A marked response to dopamine replacement therapy is important in supporting a diagnosis of idiopathic Parkinson's disease (PD). The aim of the study was to compare PD patients' subjective rating of improvement with measured improvement on a number of scales.
Methods: People with clinically defined PD were identified from a prospective long term follow-up study of incident parkinsonian patients. Changes in the Unified Parkinson's Disease Rating Scale (UPDRS) (activities of daily living and motor subsections), timed tests and Parkinson's Disease Questionnaire, full version, between assessments immediately before starting adequate dopamine replacement and the two subsequent follow-up assessments (mean 6 and 12 months after baseline) were calculated. These were compared with the patients' own subjective ratings of improvement (nil, slight, moderate, good, excellent).
Results: 133 patients were included (mean age 71 years, 56% men). Thirty-eight patients were treated with a dopamine agonist and 95 with l-dopa (median l-dopa equivalent dose 300 mg). Most patients showed improvements in their measured scores but there was no statistically significant association between these scores and the patient subjective response, except for the motor UPDRS at the first follow-up. A third of those who showed no improvement in their motor UPDRS at the first follow-up rated their improvement as moderate or better, while 29% of those whose motor UPDRS improved by over 50% said they had no or slight improvement.
Conclusion: PD patients' subjective ratings of their degree of improvement often do not accurately reflect the degree of objective change in parkinsonian impairment or disability. Clinicians should record a simple measure of motor impairment before and after treatment to assess treatment response more accurately.