A Cochrane review «»1 «Caslake R, Macleod A, Ives N, Stowe R, Counsell C....»1 included 2 studies with a total of 593 patients with idiopathic Parkinson’s disease. Both trials compared selegiline with a dopamine agonist (bromocriptine or lisuride), whilst one also compared selegiline with levodopa. The median follow-up was 20 months in the other and 36 months in another trial. MAO-B inhibitors were not associated with a significant increase or decrease in deaths compared with levodopa (odds ratio (OR) 0.96; 95% CI 0.52 to 1.76) or dopamine agonists (OR 1.30; 95% CI 0.69 to 2.45). Those receiving MAO-B inhibitors were more likely to require add-on therapy during follow-up than those receiving levodopa (OR 12.02; 95% CI 6.78 to 21.31) or dopamine agonist (OR 2.00; 95% CI 1.05 to 3.81). There was a reduction in motor fluctuations with MAO-B inhibitors compared with levodopa (OR 0.55; 95% CI 0.32 to 0.94) but not dopamine agonists (OR 1.15; 95% CI 0.65 to 2.05). Withdrawals due to adverse events were less common with MAO-B inhibitors than with dopamine agonists (OR 0.11; 95% CI 0.01 to 0.99).
Comment: The quality of evidence is downgraded by study quality (lack of blinding, more than 20% loss of follow-up in larger trial) and indirectness (comparison made with older dopamine agonists than currently used).