The low risk for early renal damage during lithium treatment has not changed over time

Background: Modern lithium management guidelines were introduced to improve the renal prognosis of lithium patients. Aims: To examine whether prospects for severe renal impairment (defined as chronic kidney disease at least stage 4 (CKD4)), in long-term lithium patients, have changed over time after the introduction of lithium monitoring guidelines. Methods: The time to and hazard for CKD4 were compared between three patient cohorts who started long-term lithium in three consecutive decades: 1980s, 1990s and 2000s. The follow-up time was 10 years after completion of 1-year treatment. The data were collected from Sahlgrenska University Hospital's laboratory database. Results: In all, 2169 patients were included: 623 in Cohort 1 (started lithium during 1980s), 874 in Cohort 2 (1990s) and 672 in Cohort 3 (2000s). Compliance with lithium monitoring guidelines improved, and mean serum lithium decreased, through the cohorts. In all, 22 patients developed CKD4 during follow-up. The time to CKD4 was the same in all three cohorts (overall: 10.96 years, 95% confidence interval: 10.94-11 years). Age and serum creatinine concentration at start were significant risk factors, while sex had no prognostic value. After adjusting for the significant covariates, there was no statistically significant difference in the hazard for CKD4 between the three cohorts. Conclusion: The risk for severe renal damage during the first decade of long-term lithium is low, but has not changed over time. Our data suggest that improved compliance with lithium guidelines is not reflected in less risk for severe renal damage.