Abstract

The aim of this study was to investigate whether lower lithium levels (LoLi) or olanzapine doses (LoOL) are risk factors for future mood episodes in patients with bipolar I disorder.A post-hoc analysis of the olanzapine-lithium-maintenance study [31] was performed using proportional hazards Cox regression models and marginal structural models (MSMs), adjusting for non-random assignments of dose during treatment.The LoLi group (<0.6 mmol/L) had a significantly increased risk of manic/mixed (hazard ratio [HR]=1.96, p=0.042), but not depressive (HR=2.11, p=0.272) episodes, compared to the combined medium (0.6-0.79 mmol/L) and high lithium level (=0.8 mmol/L) groups. There was no significant difference in risk between the two higher lithium level groups (0.6-0.79 mmol/L; =0.8 mmol/L) for new manic/mixed (HR=0.96, p=0.893) or depressive (HR=0.95, p=0.922) episodes. The LoOL group (<10mg/day) showed a significantly increased risk of depressive (HR=2.24, p=0.025) episodes compared to the higher olanzapine (HiOL) dose group (HiOL: 10-20 mg/day), while there was no statistically significant difference in risk for manic/mixed episodes between the two groups (HR=0.94, p=0.895).Lithium levels=0.6 mmol/L and olanzapine doses=10mg/day may be necessary for optimal protection against manic/mixed or depressive episodes, respectively in patients with bipolar I disorder.

View details for DOI 10.1016/j.eurpsy.2009.10.009

View details for Web of Science ID 000286037800002

View details for PubMedID 20430594