Association between l-thyroxine treatment, GH deficiency, and radiological vertebral fractures in patients with adult-onset hypopituitarism.
OBJECTIVE
In this study, we aimed at evaluating the association between radiological vertebral fractures and levo-thyroxine (l-T4) replacement doses in adult patients with hypopituitarism.


METHODS
Cross-sectional study.


METHODS
We studied 74 adult hypopituitary patients (males, 43; females, 31; mean age, 57 years; and range, 23-79) with central hypothyroidism treated with l-T4 (median daily dose: 1.1  μg/kg). All patients also had severe GH deficiency (GHD) and 38 of them were replaced with recombinant GH. Vertebral fractures were assessed by a quantitative morphometric analysis performed on thoracic and lumbar spine lateral X-ray.


RESULTS
Radiological vertebral fractures were found in 23 patients (31.1%) in association with untreated GHD (P=0.02), higher serum free T4 levels (P=0.03), a higher daily dose of l-T4 (P=0.005), and a longer duration of hypopituitarism (P=0.05). When GHD was treated, the prevalence of vertebral fractures was more frequent (P=0.03) in patients receiving high l-T4 doses (third tertile: >1.35  μg/kg per day) as compared with patients who were treated with lower drug doses (first tertile: <0.93  μg/kg per day). Such a difference was not observed in patients with untreated GHD who showed a higher prevalence of vertebral fractures regardless of l-T4 daily doses. Multivariate analysis showed that untreated GHD (odds ratio: 4.27, 95% CI 1.27-14.33; P=0.01) and the daily dose of l-T4 (odds ratio: 4.01, 95% CI 1.16-14.39; P=0.03) maintained a significant and independent association with vertebral fractures in patients with central hypothyroidism.


CONCLUSIONS
Our data suggest for the first time that a relative overtreatment with l-T4 may influence the fracture risk in some patients with hypopituitarism.
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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Mazziotti
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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Mormando
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
A
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Cristiano
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
A
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Bianchi
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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Porcelli
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
A
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Giampietro
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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Maffezzoni
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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Serra
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy.
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De Marinis
Chair of EndocrinologyUniversity of Brescia, A.O. Spedali Civili di Brescia, 25123 Brescia, ItalyPituitary UnitDepartment of Endocrinology, Catholic University of Rome, 00168 Rome, Italy a.giustina@libero.it.
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Giustina
D000328:Adult; D017668:Age of Onset; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D020249:Hormone Replacement Therapy / Q000706:statistics & numerical data; D019382:Human Growth Hormone / Q000172:deficiency*; D006801:Humans; D007018:Hypopituitarism / Q000150:complications / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011859:Radiography; D016103:Spinal Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D013974:Thyroxine / Q000627:therapeutic use*; D055815:Young Adult
D019382:Human Growth Hormone; D013974:Thyroxine