The risk of developing motor complications with Levodopa immediate versus dual release upon treatment initiation in Parkinson's disease.

Introduction: Motor complications (MCs) compromise therapy in many patients suffering from Parkinson's Disease. By achieving more physiologic stimulation of dopamine-receptors, the continuous dopamine stimulation hypothesis suggests that longer-acting levodopa formulations may improve outcome. The aim of this study was to compare the duration until onset of MCs and motor disease progression in patients during their treatment initiation with either an immediate (IR) or a combined rapid- and sustained-release (i.e. dual-release; DR) levodopa formulation.

Methods: Using a sample of 69 patients, we applied time-varying survival regression analyses and linear mixed effect models to analyze the data. The latter involved preprocessing of the data to temporally align the response and predictors, including analyzing the extent of visit irregularity and potential predictors of visit intensity.

Results: This retrospective study suggests that levodopa-benserazide DR is not superior to levodopa-benserazide IR in affecting duration until MCs and disease progression. Conversely, using DR levodopa-benserazide, similar disease progression was achieved with lower and more constant doses.

Conclusions: The effects of DR levodopa-benserazide might not be strong enough to delay onset of MCs. The development of more powerful levodopa formulations remains a pressing clinical need.