Treatment of apathy in Parkinson's disease: A bayesian network meta-analysis of randomised controlled trials

Background: Apathy is an important but unrecognised aspect of Parkinson's disease (PD). The optimal therapeutic options for apathy remain unclear. Early recognition and treatment of apathy can reduce the significant burden of disease for patients and their caregivers. Here we conducted a meta-analysis to evaluate the comparative efficacy of different treatment modalities of apathy in PD (CRD42021292099). Methods: We screened Medline, Embase, and PsycINFO databases for articles on therapies for apathy in PD. The outcome of interest is the reduction in apathy scores post-intervention and is measured by standardised mean differences (SMD) with 95% credible intervals (CrI). We included only randomised controlled trials examining interventions targeted at reducing apathy. Results: Nineteen studies involving 2372 patients were included in the quantitative analysis. The network meta-analysis found pharmacotherapy to be the most efficacious treatment, significantly better than brain stimulation (SMD -0.43, 95% CrI −0.78 to −0.07), exercise-based interventions (SMD -0.66, 95% CrI −1.25 to −0.08), supplements (SMD -0.33, 95% CrI −0.67 to 0), and placebo (SMD -0.38, 95% CrI −0.56 to −0.23). Subgroup analysis of pharmacotherapy versus placebo found similar efficacy of dopamine agonists (SMD -0.36, 95% CI -0.59 to −0.12, P = 0.003) and alternative medications (SMD -0.42, 95% CI -0.61 to −0.23, P