Impact of Disease Duration in Effectiveness of Treatment with Levodopa-Carbidopa Intestinal Gel and Factors Leading to Discontinuation.

Background: Levodopa-carbidopa intestinal gel (LCIG) is effective in the treatment of advanced Parkinson's disease (PD). However, the patients' profile that might benefit from treatment with LCIG has not been characterized.
Objective: This retrospective study explored the influence of disease duration (DD) on the effectiveness of LCIG and identified factors associated with treatment discontinuation in a cohort of advanced PD patients.
Methods: Patients initiating LCIG therapy between Jan-2006 and Dec-2011 in 18 Spanish centers were included. Effectiveness in treating motor symptoms (MSs), non-motor symptoms (NMSs), and adverse events (AEs) occurrence was compared in DD≥10 or <10 years and LCIG continuation/discontinuation groups. Factors associated with LCIG discontinuation were evaluated using univariate and multivariate analyses.
Results: Overall, 177 PD patients were included (52.5% male; mean age 70.6±8.4 years; mean LCIG duration 35.6±18.6 months). Patients with DD≥10 years (n = 125) experienced less reduction in "off" time (-29%) than those with DD <10 years (-38%; n = 51; p = 0.021), and reported more severe AEs (32.8% vs. 17.6%; p = 0.043). DD did not significantly influence changes in NMSs or discontinuation rates. Fifty-four patients discontinued LCIG therapy, factors associated with discontinuation were higher percentages of waking day in the "off" state (OR, 1.028; 95% CI, 1.002-1.055; p = 0.0360) and in the "on" state with troublesome dyskinesia (OR, 1.032; 95% CI, 1.002-1.064; p = 0.0376) at baseline.
Conclusions: Advanced PD patients with DD <10 years might benefit more from treatment with LCIG than patients with a longer DD. Although MSs severity at baseline was statistically associated with LCIG discontinuation, the probability was very low with little clinical significance.