Montserrat Prats Julià1. 1. Departamento de Medicina Interna, Hospital de Terrassa, Ctra. Torrebonica s/n, 08227 Terrassa, Barcelona, España. 29665mpj@comb.cat
Abstract
OBJECTIVE: Controversy surrounds the issue of whether levothyroxine treatment improves lipid profile in patients with subclinical hypothyroidism (SHT). The objective was to detect substantial differences -> or = 20% in total cholesterol (TC) and > or = 15 mg/dl in low-density lipoprotein cholesterol (LDL-c)- in the lipid profiles of patients with subclinical hypothyroidism (SHT) after initiating levothyroxine replacement therapy (T4). PATIENTS AND METHOD: Observational retrospective cohort study with paired data. LOCATION: Primary care center in Manresa (Barcelona). PARTICIPANTS: 100 patients with SHT treated with levothyroxine. MAIN MEASURES: Demographic and clinical variables from the clinical history, as well as temporal data -SHT diagnosis, beginning of T4 treatment and thyroid-stimulating hormone (TSH) normalization, and the quantity of T4 administered to treat SHT-were gathered. Data for TSH, lipid profile and body mass index were recorded at specific moments (beginning of treatment, after 6-18 months on T4, at the euthyroidism stage, and the last value registered in the previous 12 months). RESULTS: The mean age was 61+/-15 [95% confidence interval (CI), 46-76] years and 95% of the patients were women. Obesity was found in 40%, high blood pressure in 39%, dyslipidemia in 37%, diabetes mellitus in 10%, smoking in 7%, and cardiovascular disease in 6% of the patients. No significant differences were detected in TC or in LDL-c after treatment with levothyroxine. Nonsignificant reductions were found in TC (-4 mg/dl; p=0.77) and LDL-c (-10 mg/dl; p=0.31) when euthyroidism was achieved, as well as in TC (-10mg/dl; p=0.58) after 5+/-3 years of treatment. CONCLUSIONS: Levothyroxine treatment in patients with SHT does not lead to substantial reductions in TC or LDL-c, independently of TSH concentrations prior to treatment.
OBJECTIVE: Controversy surrounds the issue of whether levothyroxine treatment improves lipid profile in patients with subclinical hypothyroidism (SHT). The objective was to detect substantial differences -> or = 20% in total cholesterol (TC) and > or = 15 mg/dl in low-density lipoprotein cholesterol (LDL-c)- in the lipid profiles of patients with subclinical hypothyroidism (SHT) after initiating levothyroxine replacement therapy (T4). PATIENTS AND METHOD: Observational retrospective cohort study with paired data. LOCATION: Primary care center in Manresa (Barcelona). PARTICIPANTS: 100 patients with SHT treated with levothyroxine. MAIN MEASURES: Demographic and clinical variables from the clinical history, as well as temporal data -SHT diagnosis, beginning of T4 treatment and thyroid-stimulating hormone (TSH) normalization, and the quantity of T4 administered to treat SHT-were gathered. Data for TSH, lipid profile and body mass index were recorded at specific moments (beginning of treatment, after 6-18 months on T4, at the euthyroidism stage, and the last value registered in the previous 12 months). RESULTS: The mean age was 61+/-15 [95% confidence interval (CI), 46-76] years and 95% of the patients were women. Obesity was found in 40%, high blood pressure in 39%, dyslipidemia in 37%, diabetes mellitus in 10%, smoking in 7%, and cardiovascular disease in 6% of the patients. No significant differences were detected in TC or in LDL-c after treatment with levothyroxine. Nonsignificant reductions were found in TC (-4 mg/dl; p=0.77) and LDL-c (-10 mg/dl; p=0.31) when euthyroidism was achieved, as well as in TC (-10mg/dl; p=0.58) after 5+/-3 years of treatment. CONCLUSIONS:Levothyroxine treatment in patients with SHT does not lead to substantial reductions in TC or LDL-c, independently of TSH concentrations prior to treatment.