title: Favorable clinical heart and bone effects of anti-thyroid drug therapy in endogenous subclinical hyperthyroidism.
abstract: Although subclinical hyperthyroidism (SCH) has been associated with increased risk of osteoporosis and cardiac arrhythmias, its treatment is still controversial. This study was designed as a prospective, randomized, intervention, control-study with a 1-year follow-up in order to investigate whether normalization of serum TSH in SCH using methimazole has favorable bone and heart clinical effects. Fourteen patients with endogenous SCH (not Graves' disease) were enrolled, 7 (5 women/2 men; group T) were treated with methimazole (2.5-7.5 mg/day), and 7 (5 women/2 men; group C) were followed without treatment; 10 healthy subjects were also included in the study as controls. Serum free-T3 (FT3), free-T4 (FT4) and TSH, thyroid echography, bone stiffness index (SI), as measured by heel ultrasonometry, and 24-h electrocardiography monitoring were obtained. SCH patients exhibited higher systolic and diastolic blood pressure than control subjects. They also had a significantly higher number of both ventricular premature beats (VPB) (mean+/-SEM: 681+/-238 vs 6+/-2 beats/24 h; p<0.02) and atrial premature beats (APB) (mean+/-SEM: 495+/-331 vs 7+/-2 beats/24 h; p<0.0001), and a lower SI (66+/-5 vs 96+/-3; p<0.001). Twelve months after normalization of TSH with the use of methimazole, the number of VPB decreased significantly (947+/-443 vs 214+/-109 beats/24 h; p<0.05) while it remained unchanged in untreated SCH patients (414+/-163 vs 487+/-152 beats/24 h; p=ns). An insignificant therapy effect was observed as far as APB were concerned (826+/-660 vs 144+/-75 beats/24 h; p=ns), however their number increased significantly in the untreated group (463+/-49 vs 215+/-46 beats/24 h; p<0.05). The SI increased significantly as a result of therapy in group T (64.1+/-4.8 vs 70.0+/-5.3; p<0.02) and was further reduced in group C at the end of the study (69.1+/-7.3 vs 62.9+/-7.1; p<0.001). No adverse effect was observed in group T. In conclusion, anti-thyroid therapy seems to have favor-able bone and heart clinical effects in subjects with endogenous SCH.
authors.affiliation: Department of Internal Medicine, Cardiovascular and Kidney Diseases, Faculty of Medicine, University of Palermo, Palermo, Italy. silbus@tin.it
authors.forename: S
authors.initials: S
authors.lastname: Buscemi
authors.forename: S
authors.initials: S
authors.lastname: Verga
authors.forename: S
authors.initials: S
authors.lastname: Cottone
authors.forename: G
authors.initials: G
authors.lastname: Andronico
authors.forename: L
authors.initials: L
authors.lastname: D'Orio
authors.forename: V
authors.initials: V
authors.lastname: Mannino
authors.forename: D
authors.initials: D
authors.lastname: Panzavecchia
authors.forename: F
authors.initials: F
authors.lastname: Vitale
authors.forename: G
authors.initials: G
authors.lastname: Cerasola
mesh_terms: D013956:Antithyroid Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D013956:Antithyroid Agents; D013963:Thyroid Hormones