Association of lithium treatment with cardiac structure and circulating leukocyte distribution in patients with bipolar disorder

Background Anti-inflammatory properties of lithium may have a protective effect on cardiac function in patients with bipolar disorder (BD). Complete blood count is a standard laboratory examination reflective of inflammation and prognostic risk for cardiovascular disease. This study investigated the association between lithium treatment, left ventricular (LV) geometric patterns, and complete blood count indices among patients with BD. Methods A total of 108 patients with euthymic BD-I older than 20 years were enrolled, and 58 were currently using lithium. All the patients underwent transthoracic echocardiography and complete blood count. Echocardiographic imaging was obtained and analyzed in accordance with the recommendations from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. LV concentricity was categorized as either LV concentric remodeling or LV concentric hypertrophy. Results Sixty percent of the patients exhibited LV concentricity, with a lower prevalence noted among lithium users (48.3 %) than among nonlithium users (72.0 %, p = 0.021). Patients receiving lithium exhibited a significantly lower LV relative wall thickness (RWT), lower lymphocyte count, and higher neutrophil–lymphocyte ratio than did those not receiving lithium therapy. Multiple linear regression revealed that the ratio of lithium exposure to bipolar illness chronicity, neutrophil–lymphocyte ratio, and monocyte–lymphocyte ratio were negatively associated with LV RWT. Conclusion Lithium may mitigate the risk of heart failure, as indicated by the reduced LV concentricity and LV RWT, in patients with BD through the regulation of leukocytes. Future research should strengthen these findings by incorporating markers that reflect leukocyte dynamics in the myocardium.