The Effect of Long-Term Lithium Use on Renal Functions in Patients with Bipolar Disorder

It is known that especially glomerular side effects of lithium lead to serious consequences such as end-stage renal disease. Therefore, it is critical to evaluate patients on long-term lithium therapy for glomerular pathologies. The present study investigated the changes in renal functions, prevalence of renal failure and progress in patients have been followed up for at least six years with bipolar disorders (BD) and on regular lithium treatment. 51 patients with BD and 38 age and sex matched healthy controls were enrolled for the study. The serum blood urea nitrogen (BUN), creatinine, uric acid, electrolytes, calcium (Ca), phosphorus (P), vitamin D (25-OH D3), parathyroid hormone (PTH) and eGFR levels were measured to compare the kidney functions of patients and control group. The relation between the renal functions and mean serum lithium levels and duration of lithium treatment were also investigated. Mean eGFR level, 25-OH D3 and urine density of patients with were significantly lower whereas creatinine, uric acid, Ca and PTH were significantly higher than that of controls.. The duration of lithium treatment and mean lithium levels were negatively correlated with eGFR level. Eight of 51 patients have critical eGFR level as lover than 60ml/minute thus further nephrological investigation was needed. The study revealed that the renal functions of the patient group was significantly lower than controls. The findings suggested that both duration of lithium treatment and high serum lithium levels may have a negative impact on renal functions. These findings suggest that it is important to clarify the response type to lithium in patients who are on long term treatment with lithium and maintain the treatment with the lowest possible therapeutic serum levels and carefully monitoring the renal functions in patients with good response to lithium.