Red cell distribution width - a new marker for exacerbation of heart failure in patients with hypothyroidism following radioiodine therapy.

INTRODUCTION: Cardiovascular diseases constitute a major cause of health problems and death in developed countries across the world. The increased value of the index of distribution of red blood cells volume (RDW) may be a prognostic marker in patients diagnosed with chronic heart failure (CHF). Hypothyroid patients present higher RDW values if compared to healthy controls. Taking into consideration that RDW might be both affected by thyroid status and CHF, we decided to determine the effect of concomitant hypothyroidism following radioiodine therapy (RIT) and CHF on hematological parameters.

MATERIALS AND METHODS: Patients with toxic nodular goiter and heart failure with concomitant anemia were included. Patients underwent treatment with radioiodine before the planned heart transplant or pacemaker implantation (combined ICD/CRT-D). After RIT patients were divided into the three subgroups: with overt hypothyroidism (TSH ≥ 10µIU/mL, Group I), subclinically hypothyroid patients (TSH 4.3-9.0 µIU/mL, Group II) and with high-normal level of TSH (2.6-4.2 µIU/mL, Group III).

RESULTS: Significant correlation between TSH and RDW was observed (r=0.46; P < 0.0001) after RIT, whereas no correlation between serum TSH levels and TIBC and Fe was observed. In Group I significant correlation between TSH and RDW (r= 0.48; P = 0.002) after RIT was observed, whereas in two other subgroups there were no significant correlation.

CONCLUSIONS: Subclinical hypothyroidism or high-normal levels of TSH did not affect RDW in a significant manner in the studied population. Our results demonstrates that overt hypothyroidism may contribute to deterioration of CHF reflected in changes of RDW value. < p > < /p >.