Renal effects of long-term lithium therapy in the elderly: a cross-sectional study.
OBJECTIVE
To determine the effect of long-term lithium therapy on glomerular filtration rate (GFR) and maximum renal concentrating capacity (Umax) in the elderly, to identify possible risk factors, to determine the clinical impact of a reduced Umax in this population and in case of polyuria to establish a diagnosis.


METHODS
This is a cross-sectional study with 48 outpatients of 65 years or over (mean 74.8 years), who were treated with lithium for more than 6 months (mean 9.2 years). The GFR was determined with the Cockcroft-Gault formula (GFR-CG) and the Umax was measured in a urine sample collected between 3 and 5 h after the patients received 40 microg desmopressin (DDAVP) intranasally.


RESULTS
No relation was found between duration of lithium treatment and GFR-CG, but there was a significant negative relation between duration of lithium treatment and Umax (B -0.73; CI: -1.249/-0.212); 73% of the patients had a moderate to severe concentrating defect. No other risk factors than duration of lithium therapy were identified. A reduced Umax caused polyuria (>2500 mL/24 h) in 33% but did not cause significant more thirst, incontinence or disturbed sleep.


CONCLUSIONS
In this geriatric population a negative relation was found between duration of lithium treatment and Umax. But a reduced Umax did not result in significant more clinical symptoms. In case of polyuria other mechanisms beside nephrogenic diabetes insipidus were found to play a role in this age group.
van Melick
Els J M
EJ
Department of Geriatrics, Parnassia Psycho-Medical Centre, The Hague, The Netherlands. e.van.melick@parnassia.nl
Meinders
Arend E
AE
Hoffman
Tonko O
TO
Egberts
Toine C G
TC
D000368:Aged; D000369:Aged, 80 and over; D018692:Antimanic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D018500:Diabetes Insipidus, Nephrogenic / Q000150:complications; D004334:Drug Administration Schedule; D004812:Epidemiologic Methods; D005260:Female; D005919:Glomerular Filtration Rate / Q000187:drug effects; D006801:Humans; D007668:Kidney / Q000187:drug effects* / Q000503:physiopathology; D007671:Kidney Concentrating Ability / Q000187:drug effects; D018020:Lithium Compounds / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D011141:Polyuria / Q000139:chemically induced / Q000209:etiology
D018692:Antimanic Agents; D014150:Antipsychotic Agents; D018020:Lithium Compounds