Annotated Abstracts of Journal Articles
2015, 1st Quarter
Annotations by Paula Zimbrean, MD, FAPM and Marta Novak, MD, PhD
Also of interest:
ANNOTATION (Zimbrean & Novak)
The Finding: Thirty-two per cent of the patients had an eGFR below 60 mL/min per 1.73m2 after 10 years or more on lithium. Almost 5% of the patients developed stage 4 or 5 CKD, as judged by the eGFR values. There was a continuous yearly increase in median serum creatinine levels already from the first year of treatment. The relative yearly rise increased with time of exposure to lithium.
Strengths and Weaknesses: This is a retrospective longitudinal study, including patients with at least one positive lithium measurement between 1 January 1981 and 31 December 2010, using the database at the Department of Clinical Chemistry at Sahlgrenska University Hospital in Sweden. The database was established in the 1970s and includes laboratory data from all laboratories serving population of approximately 650,000 inhabitants. Limitations include: lack of access to individual patient records or additional laboratory investigations so comorbid medical conditions could not be ruled out; no information on evolution of patients with pre-existing kidney disease started on lithium (242 out of 2931 patients (8.3%) were excluded from the study due to suspected pre-existent renal involvement). The final analysis included 630 adult patients with at least 10 years of cumulative lithium treatment and normal or low serum creatinine at the start of lithium treatment.
Relevance: This study brings additional relevant information regarding the prevalence and time-frame for development of kidney disease in patients receiving chronic lithium therapy.
Long-term lithium treatment is associated with end-stage renal disease, but there is little evidence of a clinically significant reduction in renal function in most patients. We previously found that 1.5% of people who took lithium from the 1960s and 1970s developed end-stage renal disease; however, none of the patients who started after 1980 had end-stage renal disease. Here we aimed to study the prevalence and extent of kidney damage during the course of long-term lithium treatment since 1980. We retrieved serum lithium and creatinine levels from 4879 patients examined between 1 January 1981 and 31 December 2010. Only patients who started their lithium treatment during the study period and had at least 10 years of cumulative treatment were included. The study group comprised 630 adult patients (402 women and 228 men) with normal creatinine levels at the start of lithium treatment. There was a yearly increase in median serum creatinine levels already from the first year of treatment. About one-third of the patients who had taken lithium for 10-29 years had evidence of chronic renal failure but only 5% were in the severe or very severe category. The results indicate that a substantial proportion of adult patients who are treated with lithium for more than a decade develop signs of renal functional impairment, also when treated according to modern therapeutic principles. Our results emphasise that lithium treatment requires continuous monitoring of kidney function.