Hyperhomocysteinemia and arteriovenous fistula thrombosis in hemodialysis patients.

BACKGROUND: To date, the relationship between vascular access (VA) failure and plasma total homocysteine level has been investigated only in mixed dialysis populations (ie, patients with a native arteriovenous [AV] fistula or arterial graft), whereas almost no data exist for hemodialysis patients with a native AV fistula. METHODS: In this prospective cohort study, we examined the relationship between plasma total homocysteine level and the methylenetetrahydrofolate reductase (MTHFR) gene and VA-related incident morbidity in a cohort of 205 hemodialysis patients, all with a native AV fistula. RESULTS: During follow-up, 78 patients experienced 1 or more VA thrombotic episodes. Patients with incident VA thrombosis had a significantly greater plasma total homocysteine level compared with patients without this event (P = 0.046). In Kaplan-Meier survival analysis, the hazard ratio for VA thrombosis increased in parallel with homocysteine level, such that patients in the third homocysteine level tertile had a relative risk for this outcome 1.72 times (95% CI, 1.21 to 2.24) greater than in those in the first tertile (log-rank test, 6.81; P = 0.009). In a multiple Cox regression model, plasma total homocysteine level was confirmed to be an independent predictor of AV fistula outcome. Plasma total homocysteine level was significantly greater (P < 0.001) in patients with the TT genotype of the MTHFR gene than in those with the CT or CC genotype. CONCLUSION: VA thrombosis in dialysis patients is associated with hyperhomocysteinemia. Intervention studies are needed to clarify whether decreasing plasma homocysteine concentrations may prevent VA failure in hemodialysis patients.

Salivary and lacrimal secretion is reduced in patients with ESRD.

BACKGROUND: A reduction in salivary and lacrimal secretion has been described in several diseases. However, such alterations have not been investigated fully in patients with chronic renal failure. The aim of the present study is to estimate the frequency of alterations in salivary and lacrimal secretion in long-term hemodialysis patients. METHODS: Sixty-three hemodialysis patients and 23 healthy control subjects were studied. In all of them, we tested salivary secretion (Saxon's test), lacrimal secretion (Shirmer's test), and the presence of xerostomia and xerophthalmia symptoms. In a subgroup of patients, we performed other tests to evaluate evidence of ocular lesions and tissue damage to salivary glands. We also tested the relationship between salivary and lacrimal secretion and autonomic nervous system function. RESULTS: On average, salivary and lacrimal secretion were markedly reduced in uremic patients compared with healthy controls, and alterations in salivary gland function were related strongly to salivary gland fibrosis and atrophy. Xerophthalmia often was asymptomatic, but frequently was associated with corneal lesions. Xerostomia and xerophthalmia were unrelated to autonomic dysfunction and hepatitis C virus infection. CONCLUSION: A reduction in lacrimal and salivary secretion is frequent in long-term dialysis patients. Such alterations often are asymptomatic and could be the expression of acceleration of an age-dependent decline in glandular function and attendant fibrosis and atrophy.