A cross-sectional study of glomerular function in 740 unselected lithium patients

Area of Science:

• Nephrology
• Psychiatry
• Clinical Pharmacology

Background:

• Lithium is a widely used mood stabilizer for bipolar disorder.
• Renal function is a key factor in lithium pharmacokinetics and toxicity.
• Monitoring serum creatinine is standard practice in lithium-treated patients.

Purpose of the Study:

• To investigate the relationship between lithium treatment parameters and renal function (creatinine clearance).
• To identify factors influencing creatinine clearance in lithium-treated patients.
• To provide recommendations for optimizing lithium monitoring.

Main Methods:

• Creatinine clearance was estimated using a formulaic method based on serum creatinine, age, and sex.
• Data were collected from 740 unselected lithium-treated patients in southeastern Scotland.
• Psychiatric history, lithium prescribing, and monitoring data were obtained from case registers.

Main Results:

• A weak relationship was observed between lithium treatment duration and glomerular filtration rate (controlling for age), but only in males.
• Patients with higher serum lithium concentrations exhibited lower creatinine clearance compared to those within the therapeutic range.
• A higher proportion of patients with the lowest quartile of renal function were supervised in general practice versus hospital clinics.

Conclusions:

• Elevated serum lithium concentrations are associated with reduced renal function.
• Clinical practice should emphasize diligent monitoring of both serum lithium concentrations and serum creatinine levels.
• Further research may be warranted to explore sex-specific differences in lithium's impact on renal function.