Patient Rated Treatment Response in Parkinson's Disease

Patient Rated Treatment Response in Parkinson's Disease

Abstract and Introduction

Abstract

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.

Introduction

In both clinical practice and formal research criteria, one of the major supportive criteria used to make a diagnosis of idiopathic Parkinson's disease (PD), as opposed to another parkinsonian syndrome, is a marked improvement in the motor features with adequate dopaminergic replacement therapy. Response to treatment is also a key component in subsequent dose alteration. This raises the issue of how response to therapy is assessed.

In clinical practice, one of the major ways of accessing treatment response is by asking the patient to subjectively rate their improvement. However, it can also be measured objectively by performing motor tasks, such as timed tests, or completing an assessment of motor impairment such as the Unified Parkinson's Disease Rating Scale (UPDRS). To our knowledge, no studies have assessed how well the subjective reporting of improvement by patients correlates with objectively measured improvement.

The aim of this study was, therefore, to compare PD patients' subjective assessment of their response to treatment with objective improvement, in order to assess the usefulness of the subjective response when clinicians are deciding whether a patient has improved significantly with treatment.