Lifetime risk of severe kidney disease in lithium-treated patients: a retrospective study.

BACKGROUND

Lithium is an essential psychopharmaceutical, yet side effects and concerns about severe renal function impairment limit its usage.

AIMS: Our objectives were to quantify the occurrence of chronic kidney disease stage 4 or higher (CKD4 +) within a lithium-treated population, using age- and time-specific cumulative incidence and age-specific lifetime risk as measures of disease occurrence. Additionally, we aimed to investigate the association between the duration of lithium treatment and the risk of CKD4 + .

METHODS

We identified patients from the Sahlgrenska University Hospital's laboratory database. We conducted a retrospective cohort study employing cumulative incidence functions that account for competing deaths to estimate cumulative and lifetime risk of CKD4 + . A subdistribution hazards model was employed to explore baseline covariates. For measuring the association between the duration of lithium treatment and CKD4 + occurrence, we used a matched 1:4 case-control study design and logistic regression.

RESULTS

Considering a 90-year lifetime horizon, the lifetime risk of CKD4 + for patients initiating lithium treatment between ages 55 and 74 ranged from 13.9% to 18.6%. In contrast, the oldest patient group, those starting lithium at 75 years or older, had a lower lifetime risk of 5.4%. The 10-year cumulative risk for patients starting lithium between ages 18 and 54 was minimal, ranging from 0% to 0.7%. Pre-treatment creatinine level was a predictive factor, with a hazard ratio of 4.6 (95% CI 2.75-7.68) for values within the upper third of the reference range compared to the lower third. Moreover, twenty or more years of lithium exposure showed a strong association with an increased risk of CKD4 + compared to 1-5 years of lithium use, with an odds ratio of 6.14 (95% CI 2.65-14.26).

CONCLUSIONS

The risk of CKD4 + among lithium-treated patients exhibited significant age-related differences. Patients under 55 years old had negligible 10-year risk, while the lifetime risk for those aged 75 and older was limited. Duration of lithium treatment, especially exceeding 20 years, emerged as a significant risk factor. For individual risk assessment and prediction, consideration of age, pre-treatment creatinine levels, and the chosen time horizon for prediction is essential.