Lithium use in octogenarians

Age as a determinant of instability of serum lithium concentrations

BACKGROUND

Lithium is used both in bipolar disorder and as augmentation in treatment-resistant unipolar depression. Long-term treatment is often indicated. Pharmacokinetic and pharmacodynamic changes in older age, as well as increasing comorbidities and polypharmacy, could result in instability of serum lithium concentrations. In this study, several parameters, considered proxy for instability, were compared between age groups. These parameters were derived from studies involving oral anticoagulants.

METHODS

A retrospective study (1995-2004) was conducted using serum lithium concentrations from the laboratories of 3 hospitals in the Netherlands; 759 patients treated with lithium, 40 years or older, with at least 2 years' follow-up were identified. They were divided into 4 age groups: 40-49, 50-59, 60-69, and 70+ years; the youngest group was used as a reference group. The variance growth rate and percentage of time below, in, and above treatment range are all proxies for instability. They were analyzed between the age categories.

RESULTS

There was no significant difference for these variables between the reference group and the older age groups. In a subgroup of 454 patients, the parameters considered as proxy for instability during titration, number of days and number of serum lithium concentration measurements during titration, were evaluated; no significant difference was found between the age groups. In a small group of 117 patients, titration and maintenance treatment for at least 2 years could be analyzed separately. Also in this group, there was no difference between the age groups.

CONCLUSIONS

Age is not a determinant of serum lithium concentration instability. Therefore, age is not a reason to not initiate or discontinue lithium therapy.

The effects of lithium on renal function in older adults--a systematic review

Chronic renal failure (CRF) and nephrogenic diabetes insipidus (NDI) are potential consequences of chronic lithium use, while acute renal failure (ARF) has been described in lithium intoxication. We performed a systematic review of all studies pertaining to the effects of lithium on the kidney in older adults. The ARF incidence was 1.5% per person-year and concurrent loop diuretic and angiotensin-converting enzyme inhibitor use with lithium increased the risk. The CRF prevalence estimates varied from 1.2% to 34%, with risk factors including age, previous lithium intoxication, polyuria, previously impaired renal function, and decreased maximal urine osmolality. The prevalence of NDI varied widely from 1.8%  to 85%. Risk factors included lithium duration, dose, level, slow-release formulation, and clinical nonresponse. Except for amiloride use in NDI, there is little evidence for treatment of other lithium-induced adverse renal effects. Currently, there is no compelling evidence to suggest that lithium should be avoided in elderly patients for fear of renal side effects.

Lithium and prevention of cognitive impairment

OBJECTIVE

To examine the rate of cognitive decline and occurrence of dementia among patients attending a lithium clinic for those aged 65 years and over.

METHOD

Retrospective chart review of the cognitive function of 29 patients receiving maintenance lithium treatment attending the Dublin South East Old Age Psychiatry service, over a nine-year time period.

RESULTS

Twenty-nine patients were included in the study (20 female, nine males), with a mean age of 79 years. Two patients had concurrent dementia. Six patients fulfilled ICD10 criteria for mild cognitive disorder and all of these patients also fulfilled revised consensus criteria for mild cognitive impairment amnestic subtype. Sixteen patients were commenced on lithium as an augmentation treatment for recurrent depressive disorder, 12 patients were on treatment for bipolar affective disorder and one patient on treatment for schizoaffective disorder. Patients had been receiving lithium treatment for an average of 109 months with follow-up by the service for a mean duration of 38 months. The initial mean MMSE score of patients at first presentation to the service was 26.9 (SD = 5.6) compared to a mean MMSE score 25.8 (SD = 5.8) (CI of change in MMSE score at 95% level = -2.1 and 0) at follow-up. The mean MMSE of patients with mild cognitive impairment prior at first contact with the service was 26.8 (SD = 3.2) and at follow-up was 26 (SD = 3.2) which was not statistically significantly different (p=0.40) (CI for change in MMSE at 95% level = -3.2 to 1.5). No patient had developed incident dementia during the follow-up period of the study.

CONCLUSION

The results tentatively suggest that lithium may have a protective effect against cognitive decline and a neuroprotective role in patients with concurrent affective disorder and cognitive impairment. Multi-centre prospective studies of cognitive function in patients attending lithium clinics are needed to examine the neuroprotective properties of lithium.

Drug-induced lithium toxicity in the elderly: a population-based study

OBJECTIVES

To study the association between hospital admission for lithium toxicity and the use of diuretics, angiotensin-converting enzyme (ACE) inhibitors, and nonsteroidal antiinflammatory drugs (NSAIDs) in the elderly.

DESIGN

Population-based nested case-control study.

SETTING

Ontario, Canada.

PARTICIPANTS

Ontario residents aged 66 and older treated with lithium.

MEASUREMENTS

Estimated relative risk of hospital admission for lithium toxicity.

RESULTS

From January 1992 to December 2001, 10,615 elderly patients continuously receiving lithium were identified, of whom 413 (3.9%) were admitted to the hospital at least once for lithium toxicity. After adjustment for potential confounders, a dramatically increased risk of lithium toxicity was seen within a month of initiating treatment with a loop diuretic (relative risk (RR)=5.5, 95% confidence interval (CI)=1.9-16.1) or an ACE inhibitor (RR=7.6, 95% CI=2.6-22.0). Conversely, neither thiazide diuretics nor NSAIDs were independently associated with a significantly increased risk of hospitalization for lithium toxicity.

CONCLUSION

The use of loop diuretics or ACE inhibitors significantly increases the risk of hospitalization for lithium toxicity, particularly in naïve recipients.