Importance of specific reference values for evaluation of the deteriorating thyroid function in patients with end-stage renal disease on hemodialysis

Thyroid dysfunction and insulin resistance in end-stage renal disease patients before and 1 year after starting maintenance hemodialysis: A prospective multicenter study

BACKGROUND

Thyroid dysfunction and insulin resistance (IR) are common findings in patients with ESRD. We aimed to evaluate thyroid dysfunction and IR in ESRD before and after 1 year of starting hemodialysis (HD).

METHODS

This was a prospective study that recruited newly starting HD patients who fulfilled the inclusion criteria. Patients were evaluated for TSH, free T4, free T3, fasting insulin, fasting glucose, HOMA-IR, serum ferritin, and hs-CRP levels before starting their first dialysis session and after 1 year of regular HD.

RESULTS

Eighty-one patients have completed the 1-year follow-up period. After 1 year of regular HD, there were statistically significant increments of hs-CRP, serum ferritin, and TSH levels. On the other hand, fasting insulin level and HOMA-IR showed statistically significant increments after 1 year of starting HD. After 1 year of regular HD, TSH level showed a positive correlation with hs-CRP and serum ferritin level, while free T3 was negatively correlated with HOMA-IR. On the other hand, there was a significant positive correlation between HOMA-IR, hs-CRP, and serum ferritin levels, while HOMA-IR was negatively correlated with Kt/V.

CONCLUSIONS

This study suggests overlapping complex pathogenesis of thyroid dysfunction, chronic inflammation, and IR in chronic HD patients.

Hemodilution Impacts Assessment of Thyroid Status before and after Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

To elucidate the role of hemodilution in the alteration of thyroid hormone levels in end-stage renal disease (ESRD), we compared thyroid function before and after hemodialysis (HD).

METHODS

Twenty-three male ESRD patients (age <65 years) with either chronic glomerulonephritis (CGN) or diabetic nephropathy (DN), who were enrolled between June 2019 and August 2019, were included in the study. The free thyroxine (fT4), free tri-iodothyronine (fT3), and thyroid-stimulating hormone (TSH), thyroxine-binding globulin (TBG), and thyroglobulin (Tg), measured before and after HD in 12 patients with CGN (48.7 ± 11.8 years [mean ± standard deviation]) and 11 patients with DN (57.6 ± 6.5 years), were compared with 45 healthy controls (52.5 ± 11.9 years).

RESULTS

The fT4, fT3, and TBG were significantly low before HD and increased in parallel with an increase in hematocrit and albumin after HD in both ESRD subgroups. The TSH was high before HD and decreased significantly after HD, while Tg remained almost unchanged. In DN, the fT4 levels were nearly identical, while fT3 was lower with slightly higher TSH, compared with CGN. The TSH/fT4 ratios before HD were significantly higher in both subgroups, and the fT3/fT4 ratios after HD were significantly lower in DN than the control.

CONCLUSIONS

Our findings suggest that the low fT4 and fT3 levels found in ESRD are due to hemodilution before HD, resulting in a slightly higher TSH level but almost unchanged Tg level, and that DN is associated with decreased T4-to-T3 conversion.

Hypothyroidism in hospitalized elderly patients: a sign of worse prognosis

PURPOSE

Overt hypothyroidism has adverse clinical consequences and might worsen prognosis in critically ill elderly patients. However, the difficult interpretation of thyroid function tests (TFT) due to non-thyroidal illness (NTI) has led to discouragement of screening for thyroid dysfunction. Our aim was to determine the prevalence of TFT compatible with hypothyroidism and to study its influence on mortality among hospitalized elderly patients.

METHODS

In this prospective study we consecutively included all patients ≥60 years admitted by the Internal Medicine Department to the hospital ward (n = 451) of the Cesar Milstein Hospital in Buenos Aires, Argentina. TFT were done on day 1 and 8. Thyroid function categories were defined as overt and subclinical hypothyroidism, overt and subclinical hyperthyroidism, euthyroidism and NTI. Stage of chronic kidney disease (CKD), Adult Comorbidity Evaluation (ACE)-27, and intra-hospital mortality were recorded. The association between mortality and TFT categories was studied by Cox regression.

RESULTS

Out of 451 patients (77.0 ± 7.9 years, 54% females) 76% were categorized as NTI, 4% as overt hypothyroid, 10% as subclinical hypothyroid, 1% as subclinical hyperthyroid and 9% as euthyroid. Overt hypothyroid patients showed significantly higher mortality than the rest of the groups (25%, p < 0.05) while ACE-27 was similar among all of them (p = 0.658). In addition, patients within the overt hypothyroid category showed a higher mortality rate than NTI in a model adjusted by Stage 5-CKD, ACE-27, sex and age [HR 3.1 (1.14-8.41), p < 0.026].

CONCLUSION

Overt hypothyroidism during hospitalization was associated with elevated mortality. Further studies would reveal if TFT alterations compatible with hypothyroidism should be diagnosed/treated in hospitalized elderly patients.

Subclinical hypothyroidism and diabetic nephropathy in Iranian patients with type 2 diabetes

PURPOSE

Association of subclinical hypothyroidism with type 2 diabetes and its complications has been previously documented. These reports were, however, inconclusive and mainly gathered from Chinese and East Asian populations. In this study, we aimed to determine the prevalence of subclinical hypothyroidism and its relationship with diabetic nephropathy in Iranian individuals with type 2 diabetes, drawn from a white Middle Eastern population with an increasing prevalence of diabetes.

METHODS

In this cross-sectional study, 255 Iranian participants with type 2 diabetes and without history of thyroid disorders were included. Patients with TSH > 4.2 mIU/L and normal T4 were classified as having subclinical hypothyroidism. Diabetic nephropathy was diagnosed based on abnormal 24-h urinary albumin or protein measurements (24-h urinary albumin ≥30 mg/day or 24-h urinary protein ≥150 mg/day). Multivariate logistic regression was employed to obtain the OR for the relationship between subclinical hypothyroidism and diabetic nephropathy.

RESULTS

We found that subclinical hypothyroidism and diabetic nephropathy were as prevalent as 18.1 and 41.2 %, respectively, among the participants. We also found that subclinical hypothyroidism was independently associated with higher rates of diabetic nephropathy, after multivariable adjustment (OR [95 % CI] 3.23 [1.42-7.37], p = 0.005).

CONCLUSIONS

We found that the prevalence of subclinical hypothyroidism in Iranian diabetic population was among the highest rates reported to date. Our data supported the independent association of subclinical hypothyroidism with diabetic nephropathy, calling for further investigations to evaluate their longitudinal associations.

Evaluation of oxidative stress and thyroid hormone status in hemodialysis patients in Gorgan

AIMS

The aim of this study focused on serum malondialdehyde (MDA) levels and erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities in hemodialysis patients and compared with control groups.

MATERIALS AND METHODS

Forty-five hemodialyzed patients and 45 control groups recruited in this study. Serum creatinine and urea, thyroid hormones (THs) levels and erythrocyte antioxidant enzyme activities were determined.

RESULTS

Hemodialysis (HD) patients showed higher levels of MDA than control groups (P < 0.01), but the levels of thyroxin (T3), free triiodothyronine (fT3), and free thyroxin (fT4), SOD and CAT were low in HD patients (P < 0.01). Serum T3, fT3, and fT4 levels were significantly negative correlated with MDA (P < 0.01).

CONCLUSION

It is concluded that serum lipid peroxidation is markedly increased in HD patients. This means that elevated reactive oxygen species may interact with the lipid molecules in HD patients. HD may cause significant changes in TH levels. Thyroid-stimulating hormone level in HD patients is slightly similar to that of control groups. This suggests that thyroid is able to resynthesize for hormonal urinary losses.