Impact of Pharmacotherapy on Quality of Life in Patients with Parkinson’s Disease

Abstract

Quality of life (QoL) is a patient-reported outcome frequently included in Parkinson's disease (PD) clinical trials as a secondary or tertiary endpoint. However, QoL is an important variable that reflects the impact of disease and treatment from the patients' perspective. In a chronic, neurodegenerative disease such as PD, with a wide range of complex symptoms, QoL provides valuable and comprehensive information on the patients' health status. This narrative review aims to evaluate the effect of specific PD treatments currently in use on patients' QoL measured with the Parkinson's Disease Questionnaire, 39-item (PDQ-39) or 8-item (PDQ-8) version. A quantification of this effect is provided by calculation of the relative change and effect size. These two parameters allow an intuitive standardized approach to the importance of change based on its magnitude. Some high-quality studies (Level I) were found for levodopa (immediate- or extended-release formulations), levodopa with added-on catechol-O-methyltransferase (COMT) inhibitors, levodopa/carbidopa gel for intestinal infusion, some dopamine agonists (ropinirole, cabergoline, pergolide), and the monoamine oxidase B (MAO-B) inhibitor safinamide. As a whole, these studies found a beneficial effect of variable magnitude, weak to moderate, on patients' QoL. Studies with a lower level of evidence or not providing enough data to estimate relative change and effect size, including those for the apomorphine subcutaneous pump, also reported improvement of QoL, but the evidence was insufficient to confirm the effect. More high-quality studies focused on QoL are needed to determine the real impact of PD drug treatments for this important outcome.

The Evolution of Quality of Life After Subthalamic Stimulation for Parkinson's Disease: A Meta‐Analysis

“…This improvement in QoL clearly exceeds the minimal clinically important improvement of the PDQ‐39 with a threshold of −4.72 points . It also exceeds the improvement in PDQ‐39 achieved by the administration of levodopa (improvements range between −1.9 to −6 points), catechol‐O‐methyltransferase inhibitors (improvements range between −0.7 to −7.1 points) and dopamine agonists (improvements range between −0.8 to −6.9 points) . In advanced PD continuous intrajejunal infusion of levodopa–carbidopa intestinal gel improves PDQ‐39 up to −10 points .…”

Changes in Quality of Life in Parkinson's Disease: How Large Must They Be to Be Relevant?

“…However, currently available data suggests an approximately 3-6-fold difference between the MCID estimates of PDQ-39-SI and PDQ-8. In all likelihood, the lack of severity-based assumptions and these high discrepancies between MCID thresholds lead to many studies using alternative evaluation techniques instead of the established threshold values to judge clinical relevance [30]. To investigate these important issues, we designed a study capable of effectively resolving the above-mentioned weaknesses.…”

An Evaluation of the Central Nervous System Medication Use and Frailty among Residents of Aged Care Homes in Malaysia

“…Pearson's correlation test was used to assess the correlation between the variables (e.g., between GFI score and MAI score). The potential covariates were selected based on a priori knowledge or their association with main variables (e.g., frailty) [44,45,46,47,48]. …”