Renal function during long-term lithium treatment: a cross-sectional and longitudinal study.

Area of Science:

• Nephrology
• Psychiatry
• Pharmacology

Background:

• Lithium is a common treatment for bipolar disorder.
• Its long-term effects on renal function are debated.
• This study investigates glomerular filtration rate (GFR) in patients undergoing long-term lithium therapy.

Purpose of the Study:

• To examine the relationship between lithium treatment duration and estimated glomerular filtration rate (eGFR).
• To identify risk factors for reduced GFR in patients on lithium.
• To assess renal function changes after significant GFR decline.

Main Methods:

• Cross-sectional analysis of eGFR in 953 lithium-treated patients using multivariate regression.
• Survival analysis to determine time to reach specific eGFR thresholds (G3a and G3b).
• 4-year follow-up of eGFR in subgroups based on lithium continuation after eGFR decline.

Main Results:

• Lower eGFR was associated with female gender, older age, and longer lithium treatment duration.
• Half of patients with over 20 years of lithium treatment had eGFR < 60 mL/min/1.73 m².
• Renal function decline progressed similarly whether lithium was continued or discontinued after eGFR < 45 mL/min/1.73 m².

Conclusions:

• Lithium treatment duration is a risk factor for reduced GFR, alongside age.
• Lithium-induced renal dysfunction typically manifests after decades of use.
• Renal dysfunction progression is slow and independent of lithium continuation after a certain threshold.