Bromocriptine Versus Levodopa and other treatments in Parkinson's Disease: an updated Meta-analysis Involving more than 4000 patients across 12 randomized clinical trials

Objectives: The purpose of this meta-analysis was to conduct a comparative study by systematically examining and analyzing trials that studied the impacts of levodopa and bromocriptine, either separately or together, in treating Parkinson's disease (PD).

Methods: An extensive literature search was conducted across PubMed (Medline), Scopus, and Web of Science databases, using targeted keywords for studies published up to October 2024. The methodological quality of included RCTs was assessed with the Cochrane Risk of Bias 2 (RoB 2) tool, and bias evaluation was performed using RevMan (version 5). Statistical analyses were conducted in STATA version 17, applying random-effects models. The overall quality of evidence was evaluated using the GRADE approach.

Results: The thorough evaluation identified 12 randomized controlled trials with a total of 4,060 participants, 1,956 in the intervention group and 2,104 in the comparison group, all diagnosed with PD. A combined effect size of 0.18 (SMD: 0.18; 95% CI: -0.03, 0.39) was found through quantitative analysis of motor scales for the Unified Parkinson's Disease Rating Scale (UPDRS). An effect size of 0.50 (OR: 0.50; 95% CI: 0.31, 0.80) was determined for dyskinesia. Dystonia occurrences showed a significant effect size of 0.44 (OR: 0.44; 95% CI: 0.24, 0.81; I2: 87.28%; P value: 0.0001). Hallucination and dizziness occurrences showed effect sizes of 0.91 (OR: 0.91; 95% CI: 0.36, 2.30) and 1.36 (OR: 1.36; 95% CI: 0.91, 2.04) overall, respectively. Quality assessment revealed high-certainty evidence for dyskinesia and dystonia reduction with bromocriptine, while other outcomes showed low to very low certainty. Meta-regression analyses showed no significant correlation between population characteristics and outcomes.

Conclusion: This thorough meta-analysis offers an understanding of how bromocriptine compares in effectiveness to levodopa and other treatments for managing PD.