Kidney function in an unselected lithium population. A cross-sectional study.

We studied kidney function in 124 short-term and long-term lithium outpatients from a population of 127 patients. Glomerular and distal tubular function were measured and correlated with a number of demographic and treatment variables. There was a significant negative correlation between age and glomerular filtration rate. There were no other significant correlations. Tubular function was below normal in 51% of the patients. Glomerular function was below normal in 3% of the patients. We conclude that lithium treatment in non-toxic dose affects kidney function and that tubular function is more affected than glomerular function. Tubular function probably is better than our figures indicate, glomerular function not as good. Types of lithium preparation do not affect kidney function differently nor does combined treatment with neuroleptics.