Tirzepatide Initiation in Lithium-Treated Bipolar Disorder: Renal Biomarker Trajectories and Lithium Safety Signals Over 12 Months in a Real-World Cohort
- Design
- Retrospective cohort · 23 participants · Intermediate outcome
- Match to healthy normal-weight adults aged 55–75
- Partial matchPARTIAL: the population was selected for lithium-treated bipolar disorder rather than for obesity or diabetes; age, BMI, obesity and diabetes status are not reported in the abstract.
- Could weight loss explain it?
- PossiblyWeight decreased by 17.7 ± 6.0% among 12-month completers, and the authors warn that creatinine-based eGFR changes during major weight loss neither show kidney benefit nor rule out injury; the analysis does not separate weight loss from other effects.
- Study tier
- Study tier 4VERY_LOW: single-centre retrospective study of 23 adults with no comparison group.
- Assessment
- Version 3 · Two reviewers differed; settled by a recorded ruling · Oct 19, 2026
Study facts come from the paper. Population match, weight-loss explanation and study tier are our judgments, made against the reference group of healthy normal-weight adults aged 55–75.
This retrospective study followed 23 adults at one centre who were taking lithium for bipolar disorder when they started tirzepatide. At 12 weeks creatinine and eGFR did not change significantly, but lithium levels rose (p = 0.030); two patients had lithium above 1.2 mmol/L and one stopped tirzepatide after symptomatic toxicity. Among 20 completers at 12 months weight decreased by 17.7 ± 6.0% and eGFR rose, which the authors say does not show kidney benefit. With no comparison group and a small sample, these are observations, not proof of cause.
01Findings
What the study reported
- Drugs
- Tirzepatide
- Comparator
- not reported in abstract
- Primary outcome
- 12-week change in serum creatinine and CKD-EPI 2021 creatinine-based eGFR (renal safety)
- Effect
- At 12 weeks creatinine changed by -3 ± 12 μmol/L (p = 0.196) and indexed eGFR by +2.6 ± 15.1 mL/min/1.73 m2 (p = 0.259), neither significant; lithium rose by +0.08 ± 0.17 mmol/L (p = 0.030). Among 20 completers at 12 months weight decreased by 17.7 ± 6.0% and indexed eGFR increased by 13.0 ± 12.1 mL/min/1.73 m2.
- 95% confidence interval
- Not extracted
- P value
- creatinine p = 0.196; indexed eGFR p = 0.259; lithium p = 0.030
- Follow-up
- 12 months
- Adverse events
- Lithium rose at 12 weeks (p = 0.030); two patients had lithium > 1.2 mmol/L, one with clinician-attributed symptomatic toxicity who discontinued tirzepatide; no acute kidney injury meeting KDIGO creatinine criteria could be confirmed from available records.
- Limitations
- Small (23 adults), single-centre, retrospective study with no comparison group; the authors note that creatinine-based eGFR changes during major weight loss neither establish renal benefit nor exclude kidney injury.
Who was studied
- Obesity status
- not reported in abstract
- Diabetes status
- not reported in abstract
- Cvd status
- not reported in abstract
- Ckd status
- not reported in abstract
- Baseline condition
- bipolar disorder treated with lithium
- Sample size
- 23
- Inclusion exclusion
- lithium-treated adults with bipolar disorder starting tirzepatide, single centre
Study quality details
- Study design
- Retrospective cohort
- Sample size
- 23
- Randomization
- no
- Blinding
- n/a
- Comparator
- not reported in abstract
- Follow up duration
- 12 months
- Outcome type
- intermediate
- Replication
- not assessed
- Consistency with other evidence
- not assessed
- Population applicability
- PARTIAL
- Statistical precision
- no CI reported; mean ± SD with p values; 23 adults, 20 completers at 12 months
- Risk of bias
- not assessed
- Funding conflicts
- unclear
- Peer review status
- yes
02Funding
Funding and conflicts
- Funding
- not reported in abstract
- Industry funded
- Unclear
- Manufacturer
- not stated in source
- Sponsor role
- not reported in abstract
- Author conflicts
- not reported in abstract
- Independent replication
- unknown
Funding is shown on every study and never used to score it.
04Source
The source, as retrieved
Abstract
[OBJECTIVE] To assess early renal and lithium-related safety and 12-month renal biomarker trajectories after tirzepatide initiation in lithium-treated adults with bipolar disorder. [METHODS] We retrospectively studied 23 adults at one centre. The principal 12-week renal safety measures were serum creatinine and derived CKD-EPI 2021 creatinine-based eGFR. Secondary outcomes included lithium, electrolytes, gastrointestinal symptoms, acute kidney injury meeting KDIGO creatinine criteria and discontinuation. Twelve-month trajectories and body-surface-area-unindexed eGFR were exploratory. [RESULTS] At 12 weeks, creatinine changed by -3 ± 12 μmol/L (p = 0.196), indexed eGFR by +2.6 ± 15.1 mL/min/1.73 m2 (p = 0.259) and lithium by +0.08 ± 0.17 mmol/L (p = 0.030). Among 20 on-treatment completers at 12 months, weight decreased by 17.7 ± 6.0%, creatinine by 12 ± 9 μmol/L, indexed eGFR increased by 13.0 ± 12.1 mL/min/1.73 m2 and unindexed eGFR by 4.5 ± 14.3 mL/min. Two patients had lithium > 1.2 mmol/L; one developed clinician-attributed symptomatic toxicity and discontinued tirzepatide. No acute kidney injury meeting KDIGO creatinine criteria could be confirmed from available records. [CONCLUSIONS] Co-prescription warrants structured monitoring and sick-day education. Creatinine-based eGFR changes during major weight loss do not establish renal benefit or exclude kidney injury.