The influence of lithium on calcium homeostasis in older patients in daily clinical practice

Authors

  • Els Jacoba Maria van Melick,

    Corresponding author
    1. Department of Geriatrics, Reinier de Graaf Gasthuis, Delft, The Netherlands
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  • Ingeborg Wilting,

    1. Department of Clinical Pharmacy, University Medical Centre Utrecht, Utrecht, The Netherlands
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  • Gijsbertus Ziere,

    1. Department of Geriatrics, Harbour Hospital, Rotterdam, The Netherlands
    2. Pharmacoepidemiology Unit, Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
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  • Robert Martin Kok,

    1. Department of Old Age Psychiatry, Parnassia Psychiatric Institute, The Hague, The Netherlands
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  • Toine Cornelis Gerardus Egberts

    1. Department of Clinical Pharmacy, University Medical Centre Utrecht, Utrecht, The Netherlands
    2. Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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Abstract

Background

Lithium can influence calcium homeostasis resulting in changes in parathormone set point and renal calcium handling. The clinical significance of these changes in older patients is unknown. The objective of this study was to investigate the possible association between duration of lithium treatment and corrected calcium, parathormone and 24-h urinary calcium excretion in older psychiatric patients corrected for renal function and vitamin 25OH D and also to estimate the point prevalence of hypercalcemia and raised parathormone.

Methods

A cross-sectional study of psychiatric outpatients visiting a specialized facility for older patients treated with lithium was performed. Patients underwent a comprehensive assessment and blood and urine testing. Potential confounders of calcium homeostasis were recorded. On the basis of the duration of lithium treatment, patients were divided into four groups.

Results

One hundred eleven patients were included, mean age 75.2 years. There was no significant association between the duration of lithium treatment and corrected calcium, parathormone and 24-h urinary calcium excretion. The point prevalence of hypercalcemia was 2.7% and 47.8% for raised parathormone. There was an unexpected but significant negative association between the duration of lithium treatment and vitamin 25OH D, with 76.9% vitamin 25OH D deficiency (<50 nmol/L) in the group using lithium for more than 10 years.

Conclusions

No association was found between duration of lithium treatment and calcium parameters in older psychiatric outpatients, but there was a high prevalence of raised parathormone and an unexpected negative association between duration of lithium treatment and 25OH D. Copyright © 2013 John Wiley & Sons, Ltd.

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