How Genetics Can Improve Clinical Practice in Chronic Kidney Disease: From Bench to Bedside

Chronic kidney disease (CKD) is considered a major global health problem with high socio-economic costs: the risk of CKD in individuals with an affected first degree relative has been found to be three times higher than in the general population. Genetic factors are known to be involved in CKD pathogenesis, both due to the possible presence of monogenic pathologies as causes of CKD, and to the role of numerous gene variants in determining susceptibility to the development of CKD. The genetic study of CKD patients can represent a useful tool in the hands of the clinician; not only in the diagnostic and prognostic field, but potentially also in guiding therapeutic choices and in designing clinical trials. In this review we discuss the various aspects of the role of genetic analysis on clinical management of patients with CKD with a focus on clinical applications. Several topics are discussed in an effort to provide useful information for daily clinical practice: definition of susceptibility to the development of CKD, identification of unrecognized monogenic diseases, reclassification of the etiological diagnosis, role of pharmacogenetics

Renal function during long-term lithium treatment: a cross-sectional and longitudinal study

The effects of lithium treatment on renal function have been previously shown, albeit with discrepancies regarding their relevance. In this study, we examined glomerular filtration rate in patients treated with lithium for up to 33 years METHODS: All lithium patients registered from 1980 to 2012 at a Lithium Clinic were screened. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine concentration using the Modification of Diet in Renal Disease Study Group equation. A cross-sectional evaluation of the last available eGFR of 953 patients was carried out using multivariate regression analysis for gender, current age, and duration of lithium treatment. Survival analysis was subsequently applied to calculate the time on lithium needed to enter the eGFR ranges 45 to 59 mL/min/1.73 m2 (G3a) or 30 to 44 mL/min/1.73 m2 (G3b). Finally, 4-year follow-up of eGFR was examined in subgroups of patients who, after reduction to an eGFR lower than 45 mL/min/1.73 m2 either i) continued lithium at the same therapeutic range or ii) discontinued lithium or continued at concentrations below the therapeutic range (0.5 mmol/L) RESULTS: In the cross-sectional evaluation, eGFR was found to be lower in women (by 3.47 mL/min/1.73 m2), in older patients (0.73 mL/min/1.73 m2 per year of age), and in patients with longer lithium treatment (0.73 mL/min/1.73 m2 per year). Half of the patients treated for longer than 20 years had an eGFR lower than 60 mL/min/1.73 m2. The median time on lithium taken to enter G3a or G3b was 25 years (95% CI, 23.2-26.9) and 31 years (95% CI, 26.6-35.4), respectively. Progression of renal failure throughout the 4-year follow-up after a reduction to an eGFR lower than 45 mL/min/1.73 m2 did not differ between the subgroup who continued lithium as before and the subgroup who either discontinued lithium or continued at concentrations below the therapeutic range CONCLUSIONS: Duration of lithium treatment is to be added to advancing age as a risk factor for reduced glomerular filtration rate. However, renal dysfunction tends to appear after decades of treatment and to progress slowly and irrespective of lithium continuatio

Circulating antithyroid antibodies contribute to the decrease of glomerular filtration rate in lithium-treated patients: a longitudinal study

Background: Concerns about the adverse effects of long-term treatment with lithium include reduced renal function. In the present study, we examined comorbidities which may be associated with chronic kidney disease in a cohort of patients treated with lithium for up to 41 years.Methods: We studied 394 patients who were treated with lithium for >= 5 years. The potential role of comorbidities (diabetes, concurrent antihypertensive medication, treatment with l-thyroxine, and presence of antithyroid peroxidase/microsomes, anti-thyroglobulin, and/or anti-thyrotropin-receptor antibodies) was analysed. We focused on the categories of patients with an estimated glomerular filtration rate (eGFR) lower than 60 or 45 mL/min/1.73 m(2) as calculated from serum creatinine according to the Modification of Diet in Renal Disease Study Group. We applied multivariate regression analysis and Cox survival analysis to study the effects exerted by sex, age, duration of lithium treatment, and comorbidities using eGFR categories as the dependent variable. Kaplan-Meier curves were generated to measure the time to decline to an eGFR lower than 45 mL/min/1.73 m(2) in patients with positive or negative thyroid antibodies.Results: Age was associated with a decline to an eGFR lower than 60 mL/min/1.73 m(2) after controlling for sex, duration of lithium treatment, and comorbidities. Circulating thyroid antibodies were associated with a decline to an eGFR lower than 45 mL/min/1.73 m(2).Conclusions: The present study is the first to suggest a potential role of circulating thyroid antibodies in the severe decline of eGFR in lithium-treated patients

Prevalence of CKD and its relationship to eGFR-related genetic loci and clinical risk factors in the SardiNIA study cohort

The prevalence of CKD and of renal failure vary worldwide, yet parallel increases in leading risk factors explain only part of the differential prevalence. We measured CKD prevalence and eGFR, and their relationship with traditional and additional risk factors, in a Sardinian founder population cohort. The eGFR was calculated using equations from the CKD Epidemiology Collaboration and Modification of Diet in Renal Disease studies. With use of the Kidney Disease Improving Global Outcomes guidelines, a cross-sectional analysis of 4842 individuals showed that CKD prevalence was 15.1%, including 3.6% of patients in the high-risk and 0.46% in the very-high-risk categories. Longitudinal analyses performed on 4074 of these individuals who completed three visits with an average follow-up of 7 years revealed that, consistent with other populations, average eGFR slope was −0.79 ml/min per 1.73 m2 per year, but 11.4% of the participants had an eGFR decline >2.3 ml/min per 1.73 m2 per year (fast decline). A genetic score was generated from 13 reported eGFR- and CKD-related loci, and univariable and multivariable analyses were applied to assess the relationship between clinical, ultrasonographic, and genetic variables with three outcomes: CKD, change in eGFR, and fast eGFR decline. Genetic risk score, older age, and female sex independently correlated with each outcome. Diabetes was associated with CKD prevalence, whereas hypertension and hyperuricemia correlated more strongly with fast eGFR decline. Diabetes, hypertension, hyperuricemia, and high baseline eGFR were associated with a decline of eGFR. Along with differential health practices, population variations in this spectrum of risk factors probably contributes to the variable CKD prevalence worldwide