KIDNEY DAMAGE IN LONG-TERM LITHIUM PATIENTS - A CROSS-SECTIONAL STUDYOF PATIENTS WITH 15 YEARS OR MORE ON LITHIUM

The renal risks associated with long-term lithium treatment are a grow ing concern. We have therefore studied renal function by means of glom erular filtration rate (GFR) and maximum urinary concentrating capacit y (Umax) in 142 of 215 patients with more than 15 years of lithium tre atment in nine psychiatric clinics. Data on psychiatric and somatic di seases, hospital admissions, cumulative lithium doses, and other psych otropic treatments were extracted from the medical records. The patien ts were investigated according to a standardized protocol. GFR was mea sured as Cr-51 EDTA clearance and Umax using the DDAVP test. Thirteen patients had had signs of lithium intoxication. GFR was reduced in 21% of the patients and Umax in 44%. Nephrogenic diabetes insipidus was p resent in 12%. Umax but not GFR was inversely correlated to the cumula tive lithium dose. Kidney function was more reduced in patients on lit hium combined with psychotropic treatment and/or concomitant treatment for somatic disorders. Thirst was a complaint of 53% of the patients, predominantly those with additional psychotropics. We conclude that k idney damage is common in patients on long-term lithium treatment and that both glomerular and tubular function are affected.