Among patients with acute mania associated with bipolar I disorder, olanzapine was shown to be effective across a wide range of initial symptom severity and was particularly beneficial in patients with the most severe form of the disease, according to the results of a recent study published in The Lancet Psychiatry.
In this meta-analysis, researchers from the department of psychiatry and psychotherapy at Technische Universität München, in Munich, Germany, studied the association of baseline severity with olanzapine efficacy using data from 5 randomized controlled trials (n=552 for olanzapine; n=387 for placebo). Olanzapine efficacy was evaluated based on changes in the Young Mania Rating Scale (YMRS; range 0-60) after up to 3 weeks of treatment.
The researchers reported that baseline severity was positively associated with treatment efficacy (β=0.22; 95% CI 0.05-0.39; P =.013). Compared with placebo, olanzapine reduced YMRS scores by 2.56 more points in patients with baseline YMRS scores of 20 to 25 (P =.003), by 4.74 more points for patients with baseline scores of 25 to 35 (P =.001), and by 8.01 points for patients with baseline scores of 35 to 60 (P =.002).
The number needed to treat for at least a 10% improvement in YMRS score is 8 for patients with a baseline YMRS score of 20. For those with a score of 30 to 45, the number needed to treat is 6.
The investigators concluded that “these results showed that olanzapine is efficacious for the treatment of acute manic or mixed episodes across the initial symptom severity spectrum. Nevertheless, the difference in symptom improvement between olanzapine and placebo increased as the baseline severity increased. Clinicians should weigh up the benefits and risks of treatment with olanzapine.”
Samara MT, Goldberg Y, Levine SZ, et al. Initial symptom severity of bipolar I disorder and the efficacy of olanzapine: a meta-analysis of individual participant data from five placebo-controlled studies [published online September 19, 2017]. Lancet Psychiatry. doi: 10.1016/S2215-0366(17)30331-0