Self-reported Health Status and Treatment Initiation in Parkinson’s Disease
Published: August 2007
Abstract
The drug treatment of Parkinson’s disease (PD), particularly in its early stages, remains controversial and some would advocate a ‘wait and watch’ policy with drug therapy initiated only when the disability becomes apparent and ‘functional impairment’ occurs. Others, however, argue for the initiation of early treatment. Modern treatment of PD should address motor as well as non-motor symptoms and needs to have a fundamentally positive effect on health-related quality of life (HRQoL), often measured by self-reported health status. However, controlled trials of drug therapy in early PD usually focus on dyskinesias and motor symptoms as end-points, while self-reported health status and non-motor symptoms, such as depression, hallucinations, falls, sleep problems, restless legs and dementia, are usually not considered. Thus, patients with critical disease-related issues may often be excluded from trials. Therefore, the ‘real-life’ role of such trials is questionable, owing to the exclusion of elderly patients and those with active co-morbidity. The argument for starting PD therapy at diagnosis would be strengthened if an adverse effect on self-reported health status of delaying treatment were documented. The newly reported and published audit of changes in quality of life in people with Parkinson’s disease (PD Life) trial, the largest real-life observational longitudinal clinical study of untreated PD, shows a significant deterioration in Parkinson’s Disease Questionnaire (PDQ)-39 scores in patients who are left untreated in comparison with those who are treated. As part of this study, serial self-reported health status data and demographic details were collected in PD patients who were not started on specific therapy at initial consultation, and who were subsequently followed for a mean of 18 months. It appears that in patients who are left untreated there is a clinically important and possibly irreversible deterioration in all eight domains of the PDQ-39 scale. Deterioration occurs in the motor andnon-motor domains, such as cognition, bodily discomfort, emotional wellbeing and communication. This contrasts with PD patients, in whom treatment is started whenthe PDQ-39 scores remain stable and show no deterioration.
There is still not a consistent treatment policy for Parkinson’s disease (PD). In the UK, for example, some doctors treat immediately on diagnosis, while others wait until the symptoms become intrusive. It is fair to say that health-related quality of life (HRQoL) is the most important measure that can be made of the response to any treatment in any disease, and PD is no exception. The Parkinson’s Disease Questionnaire (PDQ-39) is a valid and robust measure of HRQoL in PD. The non-motor symptoms (NMS) in PD are the major influence on HRQoL, but traditional drug trials in PD have almost entirely looked at motor end-points – dyskinesias and improvements in motor rating scales. This paper will look at the mounting evidence to suggest that the early use of dopaminergic drugs in patients with PD will lead to improvements in HRQoL, and will argue that if such treatments are not given early there may be some non-recoverable loss of HRQoL.
Determinants of Health-related Quality of Life
HRQoL is very difficult to measure and is determined by many factors. In PD the NMS, such as depression, anxiety, autonomic symptoms, imbalance, falls, bladder symptoms and dementia, for example, are important determinants of HRQoL in patients. The Global Parkinson’s Disease Survey looked at more than 1,200 patients with PD on all five continents and found that depression and emotional status was by far the biggest determinant of HRQoL.1 That was a surprise because, prior to starting the survey, a number of eminent neurologists had expressed the opinion that disability was the biggest factor.
Other studies have also shown that depression has a major influence on aspects of PD,2 and also that the cognitive symptoms as well as depression have a major influence on the wellbeing of those caring for people with PD.3 Furthermore, more than just mood, depression has also been shown to have an impact on mortality.4 In a prospective 11-year study of 90 PD patients and 50 controls, the hazard ratio for mortality in PD patients compared with controls was 1.64 (95% confidence interval (CI) 1.21–2.23). In a survey carried out by the UK PD Society in 2004, NMS were rated as most important, above motor symptoms, in terms of people’s perception of their illness. The six major NMS mentioned were depression, cognitive change/memory loss, pain, sleep disturbances, anxiety and balance disturbances.5 Therefore, the focus is shifting to a much-neglected area of PD that is now known to have critical importance.
Treatment Initiation in Parkinson’s Disease, Parkinson’s Disease, Levodopa Dosage, Dopamine Agonist treatment,
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- UK PD Society Survey, 2004.
- Grosset D, Taurah L, Burn DJ, et al., A multicentre longitudinal observational study of changes in self reported health status in people with Parkinson’s disease left untreated at diagnosis, J Neurol Neurosurg Psychiatry, 2007;78(5):465–9. Epub November 2006.
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- Movement Disorder Society of Australia Clinical Research & Trial Group and QUEST-AP Study Group. A randomized, doubleblind study to compare the effect on quality of life of levodopa/carbidopa/entacapone (Stalevo®) with levodopa/ carbidopa in patients with Parkinson’s disease with no or minimal, non-disabling motor fluctuations. Poster presented at Movement Disorder Society’s 10th International Congress of Parkinson’s Disease and Movement Disorders in Kyoto, Japan. P437.
