Using hypernatraemic events to predict reduced renal function in elderly lithium patients: a brief report

Lithium treatment, nephrogenic diabetes insipidus and the risk of hypernatraemia: a retrospective cohort study

BACKGROUND

Hypernatraemia is a serious condition that can potentially become life threatening. It is known that lithium is associated with polyuria and nephrogenic diabetes insipidus, risk factors for hypernatraemia. In this study, we tested the hypothesis that lithium treatment was a risk factor for hypernatraemia.

METHODS

We performed a retrospective cohort study in the Swedish region of Norrbotten into the effects and potential adverse effects of lithium treatment and other mood stabilizers (LiSIE). For this particular study, we included all patients who had experienced at least one episode with a sodium concentration ⩾150 mmol/L between 1997 and 2013. Medical records were reviewed regarding past or current lithium exposure, diabetes insipidus and other potential risk factors for hypernatraemia.

RESULTS

Of 2463 patients included, 185 (7.5%) had experienced 204 episodes of hypernatraemia within the 17-year review period. In patients 65 years or older, infections dominated as the cause with 51%. In patients younger than 65 years, intoxications, particularly with alcohol, dominated as the cause with 35%. In the whole sample, dehydration accounted for 12% of episodes, 25% of which in the context of suspected or confirmed nephrogenic diabetes insipidus. Of all episodes, 25% resulted in death, with infection being the most common cause of death in 62% of cases.

CONCLUSIONS

In our sample, infections and harmful use of substances including alcohol were the most common causes of hypernatraemia. Both current and past use of lithium also led to episodes of hypernatraemia, when associated with nephrogenic diabetes insipidus. Clinicians should remain vigilant, have a low threshold for checking sodium concentrations and consider even risk factors for hypernatraemia beyond lithium.

Lithium and nephrotoxicity: a literature review of approaches to clinical management and risk stratification

Background

Despite lithium being the most efficacious treatment for bipolar disorder, its use has been decreasing at least in part due to concerns about its potential to cause significant nephrotoxicity. Whilst the ability of lithium to cause nephrogenic diabetes insipidus is well established, its ability to cause chronic kidney disease is a much more vexing issue, with various studies suggesting both positive and negative causality. Despite these differences, the weight of evidence suggests that lithium has the potential to cause end stage kidney disease, albeit over a prolonged period.

Methods

A search strategy for this review was developed to identify appropriate studies, sourced from the electronic databases EMBASE, PubMed (NLM) and MEDLINE. Search terms included lithium with the AND operator to combine with nephrotoxicity or nephropathy or chronic kidney disease or nephrogenic diabetes insipidus or renal and pathophysiology.

Results

The risks for the development of lithium induced nephropathy are less well defined but appear to include the length of duration of therapy as well as increasing age, as well as episodes of over dosage/elevated lithium levels. Whilst guidelines exist for the routine monitoring of lithium levels and renal function, it remains unclear when nephrological evaluation should occur, as well as when cessation of lithium therapy is appropriate balancing the significant attendant mental health risks as well as the potential for progression to occur despite cessation of therapy against the risks and morbidity of bipolar disorder itself.

Conclusion

This paper will elucidate on the current evidence pertaining to the topic of the clinical management of lithium induced nephrotoxicity and provide a guide for clinicians who are faced with the long-term management of these patients.

Prevalence and correlates of renal disease in older lithium users: a population-based study

OBJECTIVE

Lithium is an important treatment for mood disorders, but concern about its association with renal disease has contributed to its limited use, particularly in older adults. Because high-quality evidence examining renal disease in this population is lacking, this study aims to quantify the prevalence and identify clinical correlates of renal disease in geriatric lithium users.

METHODS

In a population-based cross-sectional study on 2,480 lithium users aged 70 or more years, the authors searched the provincial administrative health data from Ontario, Canada between April 1, 2005 and March 31, 2011. Prevalence of chronic kidney disease (CKD), acute kidney injury (AKI), and nephrogenic diabetes insipidus (NDI) was measured using International Classification of Diseases, Tenth Revision codes. Logistic regression analyses were used to identify independent correlates of renal disease.

RESULTS

The 6-year prevalence rates of CKD, AKI, and NDI were 13.9%, 1.3%, and 3.0%, respectively. Hypertension (odds ratio [OR]: 2.05; 95% confidence interval [CI]: 1.50-2.79), diabetes mellitus (OR: 1.86; 95% CI: 1.45-2.38), ischemic heart disease (OR: 1.65; 95% CI: 1.24-2.20), NDI (OR: 2.54; 95% CI: 1.47-4.40), AKI (OR: 11.7; 95% CI: 5.26-26.1), lithium use for more than 2 years (OR: 1.71; 95% CI: 1.05-2.81), loop diuretic use (OR: 1.74; 95% CI: 1.26-2.41), hydrochlorothiazide use (OR: 1.48; 95% CI: 1.07-2.05), and atypical antipsychotic use (OR: 1.49; 95% CI: 1.17-1.89) were all independently associated with CKD.

CONCLUSION

Older lithium users have high rates of CKD. Lithium use duration was independently associated with CKD. Longitudinal studies including individuals without lithium exposure will be necessary to confirm whether lithium is indeed a risk factor for CKD in older adults.

The McGill Geriatric Lithium-Induced Diabetes Insipidus Clinical Study (McGLIDICS)

OBJECTIVE

Despite being a common and potentially serious condition, nephrogenic diabetes insipidus (NDI) remains poorly understood in older lithium users. Our main objective was to compare the prevalence of NDI symptoms and decreased urine osmolality ([UOsm] < 300 milli-Osmoles [mOsm/kg]) among geriatric and adult lithium users. We also assessed NDI symptoms, serum sodium (Na+), and urine specific gravity (USG) as possible surrogate measures of decreased UOsm, and ascertained whether potential etiologic factors independently correlated with decreased UOsm.

METHOD

This was a cross-sectional study of 100 consecutive outpatients treated with lithium from 6 tertiary care clinics, of which 45 were geriatric (aged 65 years and older) and 55 adult (aged 18 to 64 years). Patients completed a symptom questionnaire and underwent laboratory tests, including UOsm, serum Na+, and USG.

RESULTS

Geriatric and adult lithium users had similar rates of decreased UOsm (12.5%, compared with 17.9%, P = 0.74), but geriatric patients reported less symptoms (P < 0.05). Although UOsm did not correlate with symptoms or current serum Na+, USG of less than 1.010 was suggestive of UOsm of less than 300 mOsm/kg. Age, lithium duration, and serum lithium level were independently associated with UOsm.

CONCLUSIONS

The prevalence of decreased UOsm is similar in geriatric and adult lithium users, but older patients are less likely to report urinary and thirst symptoms. Although subjective symptoms do not correlate with UOsm, USG may be a cost-efficient clinical surrogate measure for UOsm. We suggest clinicians increase their vigilance for decreased UOsm, especially in lithium users with advanced age, longer duration of lithium exposure, and higher lithium levels. This may potentially prevent lithium intoxication, falls, hypernatremic events, and renal dysfunction.