Chronic renal failure in lithium-using geriatric patients: effects of lithium continuation versus discontinuation--a 60-month retrospective study.

Objective: Lithium remains an important treatment in bipolar disorder. Although lithium is often discontinued because of signs of renal failure, it is unclear if this alters the course of renal function in the majority of patients. We hypothesize that in geriatric patients with chronic renal failure (CRF), who have a high burden of medical illness, lithium continuation does not significantly impact renal function (glomerular filtration rate (eGFR)).

Methods: We conducted a retrospective study of tertiary-care geriatric psychiatry outpatients with a history of lithium use and evidence of CRF (eGFR ≤ 60 ml/min/1.73 m2 on ≥ 2 occasions in ≥ 3 months). The 27 patients who met these criteria were divided into lithium 'continuers' (continued use ≥ 2 years following CRF) and 'discontinuers'. Mean eGFR and creatinine were followed at 21 and 60 months after developing CRF.

Results: Mean serum eGFR and creatinine were not significantly different between groups at any time during follow-up. When comparing renal function at 60 months to baseline, a trend towards increased creatinine was seen in continuers (p = 0.06) but not in discontinuers. Changes in eGFR in continuers and discontinuers after 60 months did not achieve statistical significance (p = 0.35 and 0.98). However, clinically important decreases in eGFR occurred in the majority of continuers but in none of the discontinuers.

Conclusions: There was a trend towards declining renal function in lithium continuers at 60-month follow-up. Future prospective longitudinal studies will be needed to confirm our findings. We suggest vigilance and close monitoring of renal function when continuing CRF patients on lithium for extended periods.