Search

Objective: Low thyroid function may be associated with a reduced glomerular filtration rate (GFR) calculated on the basis of creatinine metabolism. Thyroid hormone directly affects serum creatinine in muscle and low thyroid function might exert a similar direct effect in the kidney. The goal of the study was to evaluate this possibility by assessment of the inulin-based GFR and to examine the mechanism underlying the reduction of GFR. Patients and methods: Renal and glomerular hemodynamics were assessed by simultaneous measurements of plasma clearance of para-aminohippurate (CPAH) and inulin (Cin) in 26 patients with serum creatinine<1.00 mg/dl and without thyroid disease. All subjects were normotensive with or without antihypertensive treatment and were kept in a sodium-replete state. Renal and glomerular hemodynamics were calculated using Gomez's formulae. Results: Serum TSH, including within the normal range (0.69-4.30 µIU/ml), was positively correlated with vascular resistance at the afferent arteriole (Ra) (r=0.609, P=0.0010), but not at the efferent arteriole (Re). Serum TSH was significantly and negatively correlated with renal plasma flow (RPF), renal blood flow (RBF), and GFR (r = -0.456, P = 0.0192; r = -0.438, P = 0.0252; r = -0.505, P=0.0086 respectively). In multiple regression analysis, serum TSH was significantly positively associated with Ra after adjustment for age and mean blood pressure. Conclusions: These findings suggest that low thyroid function, even within the normal range, is associated with reduced RPF, RBF, and GFR, which might be caused by a preferential increase in Ra. [ABSTRACT FROM AUTHOR]

Background. Renal failure results in deficiency of active vitamin D3 that has diverse effects on metabolism and organ functions. Treatment with active forms of vitamin D3 ameliorates abnormalities in bone and mineral metabolism, cardiac function, immune response and others. We hypothesized that treatment with vitamin D3 may be beneficial for survival in patients with end-stage renal disease (ESRD). Methods. We compared the risk of death between regular users (n = 162) and non-users (n = 80) of oral 1α-hydroxyvitamin D3 (alfacalcidol) in a cohort of ESRD patients undergoing haemodialysis for a follow-up of 61 ± 23 months. The daily dose of alfacalcidol ranged from 0.25 to 1.5 μg, with a median of 0.5 μg. Results. The alfacalcidol users showed a lower risk of death from cardiovascular disease than the non-users in a univariate Cox model [hazards ratio (HR) 0.287, 95% confidence interval (CI) 0.127-0.649, P = 0.003], whereas the risk for death from non-cardiovascular disease was not different between the two groups. Stepwise multivariate Cox analysis showed that cardiovascular mortality was significantly associated with age, presence of diabetes mellitus and treatment with alfacalcidol (HR 0.377, 95% CI 0.246-0.578, P = 0.022). Conclusions. These results indicate that use of oral alfacalcidol was associated with reduced risk for cardiovascular death in this cohort of ESRD patients. The result of this observational study warrants further randomized controlled trials with 1α-hydroxy vitamin D3 to confirm the possibility that such medication improves survival of ESRD patients. [ABSTRACT FROM AUTHOR]