BALJINDER SINGH et al. TABLE 1 PATIENT'S DEMOGERAPHIC DETAILS, TREATMENT SCHEDULE AND ABSOLUTE GLOMERULAR FILTRATION RATE (GFR) IN TEST AND CONTROL GROUPS Number of subjects (M : F) TABLE 2 CORRELATION ANALYSIS AMONGST DIFFERENT VARIABLES IN THE TEST GROUP Group Age Lithium Treatment Absolute GFR (years) treatment duration (mL/min) (Li-dose in (months) mg/day) Lithium treated 30(20: 10) Mean=40.2±10.8 Mean=895±150 Mean=86.6±66.6 Mean=94.6±27.8 Median=38 Median=900 mg Median=60 Median=90 (range=20-62) (range=50-156) Control 30(16; 14) Mean=40.2±10.5 Nil Nil Mean=98.8±19.3 Median=39 Median=99 (range=22-61) (range=77-146) The difference in GFR amongst the test and the control groups is statistically non-significant been calculated to be 98.8±19.3 ml/min/1.73 m2 patients not receiving lithium. They indicated that and 94.6±27.8 ml/min/1.73 m2 respectively and lithium clearance can be used as a measure of the difference in GFR between the test and the GFR and the results were not comparable with control groups is statistically non-significant that of the AD awaiting initiation of lithium (Table 1). therapy. Further, they observed a significant correlation with age, sex and GFR. We have not observed any correlation between age and GFR in lithium treated patients, however treatment duration and GFR in the present study seems to Age Dose Duration GFR Creatinine be negatively correlated (r = -0.23), but was Age 1.00 significant. Furthermore, we have not seen any Dose -0.069 1.0 correlation between GFR and Li-dosing and the Duration 0.53 -0.03 1.0 similar observations had been made by Hetmar GFR -0 19 0.11 -023 1.0 and Rafaelson (1987). Acute reduction in GFR Creatinin 0.02 -0.29 0.07 0.10 1.0 associated with acute toxicity can result in acute Critical values (1-tail, 0.05) = + or-0 3064 renal failure secondary to acute tubular necrosis. Some patients may require temporary dialysis DISCUSSION support and this impairment of GFR is entirely reversible. Unlike, the relationship between The first indication about progressive impaired urinary concentrating ability and impairment of glomerular filtration rate in patients duration of lithium therapy, a progressive taking lithium on chronic basis came from deterioration in GFR with duration of lithium Hestbech et al. (1977). This observation therapy and/or total lithium dose has not stimulated a number of cross sectional studies generally been observed in patients on stable inpatients taking lithium and most failed to show maintenance therapy without episodes of acute evidence of impaired renal function (Miller et lithium intoxication. A review of 1172 patients al.,1979; Perez etal,1975). In the present study, treated with lithium from 14 reported series we had also observed similar findings of non- (Boton et al.,1987) suggests that approximately impaired GFR in lithium treated AD patients. In 15% of those on maintenance therapy have GFR a recent report (Kallner et af. ,1995) in a cohort less than age-correlated 95% confidence limits. of 207 patients receiving lithium, all the renal Occasional cross sectional studies, indicate that functions were observed to be within the patients with impaired GFR tend to be in a group reference range. Hetmar and Rafaelsen (1987) that has been taking lithium for many years. compared renal functions in 44 patients receiving Studies in patients with shorter duration of lithium lithium for an average of 8 years with that of AD 412