The Change Of Thyroid Function In Patients With Maintenance Hemodialysis And Its Effection On Cognitive Impairment

Background and purpose: CKD affects both hypothalamus–pituitary–thyroid axis and TH peripheral metabolism, often characterized by low T3 and T4 syndrome, TSH level is not affected, but the symptom of thyroid function disorder are often covered by uremia, maintenance hemodialysis will also affect the thyroid hormone metabolism and circulation.The patients with low T3 and T4 status will impact on cognitive function.The thyroid function disorder in hemodialysis patients, whether will impact on cognitive function, there is no report.This study was to survey the changes of thyroid hormone level of maintenance hemodialysis patients,and to explore its effects on cognitive function.Objects and methods: A Cross-sectional study was conducted of 74 consecutive patients who were receiving maintenance hemodialysis in the Department of Nephrology of the third hospital of Hebei medical university during 2014.10-2014.12.In the 74 patients,consisting of 37 men(50%)and 37 women(50%); the average age is 55.1±15.1 years old, with the minimum age of 18 and the maximum age of 78; the average dialysis age is 34.2±31.4months, which distributed from 5 months to 154 months.Record 74 participants’ age, gender, age of dialysis, and the primary disease and other information, and record the blood pressure before and after dialysis.We measured cognitive function of patients by Montreal Cognitive Assessment(MOCA),if the total score<26,it can be dignoised with cognitive impairment; if schooling years are less than 12 years,we add 1 point. All of the invastigation was measured by a same investigator before hemodialysis.Results:All 74 patients completed the investigation, scored an average of 25.6 ±2.35, 28 cases were classified with cognitive impairment, the prevalence of cognitive impairment reached 37.83%.The levels of T3, on average, was 1.17± 0.32mmol/l, 44 cases were with low levels of T3,which reached 59.5%.Dialysis group and non dialysis patients at T3 level exists significant difference(P < 0.05), but there was no significant differences in cognitive level(P > 0.05).In dialysis group, between elderly group and non elderly group, there were significant differences in cognitive function and T3 level(P < 0.05);In the elderly group,between normal group and cognitive impairment group, schooling time and patients diagnosed with diabetes showed significant difference(P < 0.05), but has nothing to do with the T3 level(P > 0.05);In the non elderly group,between normal group and cognitive impairment group, schooling years and ultrafiltration volume showed significant difference(P < 0.05), but has nothing to do with the T3 level(P > 0.05).in the group on dialysis,between the group of nomal T3 levels and the group of reduced T3 levels,there were significant differences in albumin levels and age.in the group without dialysis,between elderly group and non elderly group, there were significant differences in cognitive function(P < 0.05).in theelderly group,cognitive level related to the level of education(P < 0.05),has nothing to do with the T3 level(P > 0.05).in the non elderly group,cognitive level related to the level of education(P < 0.05),has nothing to do with the T3 level(P > 0.05).in the group without dialysis,between the group of nomal T3 levels and the group of reduced T3 levels,there were significant differences in albumin levels and calcium levels(P < 0.05).Conclusion: patients with end-stage renal disease usually have T3 level decreases, the dialysis treatment can significantly elevated levels of T3, but had no significant effect on cognitive function.For dialysis and non dialysis patients, T3 level is mainly associated with albumin levels.Dialysis patients cognitive level mainly related to the level of education, the education the shorter the time the higher the risk of cognitive impairment.Rather than the cognitive level mainly related to the age group, the older the greater the possibility of a cognitive impairment.End-stage renal disease in patients with low T3 syndrome don’t effect metabolism and cognitive function,and there is need to take thyroid hormone replacement therapy.