Response to levodopa in Parkinson's disease over time. A 4-year follow-up study

Background and objective: A good response to levodopa is a key factor to indicate device-aided therapies in people with Parkinson's disease (PwPD). The aim of the present study was to analyze the response to levodopa in PwPD with motor fluctuations followed for 4 years.Patients and methods: PwPD with motor fluctuations recruited from January 2016 to November 2017 from the COPPADIS cohort and assessed annually (from baseline to 4-year follow-up) during the OFF and ON states were included in this analysis. At each visit, the Unified Parkinson's Disease Rating Scale - part III (UPDRS-III) was applied during the OFF state (without medication during the last 12 h) and during the ON state. General linear model repeated measures were used to test for changes in the mean UPDRS-III-OFF, UPDRS-III-ON, and AUPDRS-III (UPDRS-III-OFF - UPDRS-III-ON) between visits. Levodopa equivalent daily dose (LEDD) was included as covariate.Results: Sixty-three patients (63.94 +/- 8.42 years old; 68.3% males) were included. Mean disease duration was 7.81 +/- 3.64 years. From baseline to 4-year follow-up visit, a significant increase in both the UPDRS-III-OFF (from 27.98 +/- 9.58 to 31.75 +/- 12.39; p = 0.003) and the UPDRS-III-ON (from 15.92 +/- 7.93 to 18.84 +/- 8.17; p = 0.006) was observed despite the significant increase in the LEDD (from 896.35 +/- 355.65 to 1085.51 +/- 488.29; p = 0.003). However, no significant differences were detected between visits in the AUPDRS-III. Conclusion: In this cohort of PwPD with motor fluctuations, the response to levodopa did not weaken after a 4 -year follow-up.