Lithium-induced renal insufficiency: a longitudinal study of creatinine increases in intellectually disabled adults.

Background: Lithium has been shown to increase serum creatinine levels in a subgroup of patients. However, lithium-induced increases in serum creatinine have not been well studied with regard to timing, trajectory, or predictability.

Methods: The medical records of 16 intellectually disabled individuals treated with lithium between 1980 and 2010 in whom serum creatinine levels peaked at 1.5 mg/100 mL or higher (ie, who developed renal insufficiency) were reviewed. These individuals were compared with a group of 36 similar lithium-treated individuals in whom serum creatinine did not reach 1.5 mg/100 mL.

Results: The 16 lithium-treated individuals who developed renal insufficiency had a mean peak serum creatinine level of 1.8 ± 0.3 mg/100 mL while on lithium. The mean time from institution of lithium until the 1.5 mg/100 mL serum creatinine level was first reached was 7.9 years. After lithium was discontinued, overall mean serum creatinine levels did not significantly change. Reaching a serum creatinine level of 1.3 or 1.4 mg/100 mL predicted reaching a 1.5 mg/100 mL level or higher. No significant differences in the age lithium was started, baseline serum creatinine levels, years receiving lithium, sex, or race differentiated those who developed renal insufficiency.

Conclusions: Prescribing lithium led to elevated serum creatinine levels in some individuals. A serum creatinine level of 1.3 and/or 1.4 mg/100 mL predicted renal insufficiency. Clinical implications of this study are that if 1 serum creatinine result reaches 1.3 mg/100 mL or more, intensive monitoring for further increases is indicated.