Alterations in Thyroid Function Tests in Aged Hospitalized Patients
Alterations in Thyroid Function Tests in Aged Hospitalized Patients
Background Thyroid dysfunction is common in aged people and has recently been associated to mortality.
Aims Our aims have been (1) to assess the prevalence of alterations in thyroid function tests in hospitalized patients over age 60 years and (2) to study the relationship between thyroid functional status and mortality during hospitalization.
Methods We studied a group of 447 patients (62% women), aged 61–101 year, hospitalized during 2005. Thyroid dysfunction was assessed by measuring serum concentrations of thyrotrophin (TSH), free thyroxine (FT4), and free thriiodothyronine (FT3). Thyroid autoimmune status was evaluated through thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies quantification.
Results Twenty-one patients (4·7%, 19 women) showed previously known thyroid dysfunction. 332 patients (74·3%) showed alterations in thyroid function tests. Euthyroid sick syndrome (ESS) was the derangement more frequently found (n = 278, 62·2%). After excluding ESS patients, 60 patients (13·4%) showed thyroid dysfunction: overt hypothyroidism, 14 (3·1%); subclinical hypothyroidism, 25 (5·6%); overt hyperthyroidism, 11 (2·5%), and subclinical hyperthyroidism, 10 patients (2·2%). Thyroid autoimmunity was positive in only 4·0% and 2·3% of patients, for TPOAb and TgAb, respectively. The presence of alterations in thyroid function tests was positively associated with the age of the patients and mortality during hospital stay (P < 0·001). Serum levels of FT3 were negatively related to death during hospitalization (OR 0·56; CI 95%, 0·38–0·81; P < 0·01).
Conclusions About three quarters of patients admitted in our geriatric unit exhibited alterations in thyroid function tests. This finding was associated with elevated age and poor prognosis. The reduction of FT3 values was a powerful predictor for mortality during hospitalization in elderly patients.
Thyroid dysfunction affects a significant portion of the general population. Epidemiological studies performed in the last years have shown that the prevalence of hypothyroidism ranges between 1 and 7%. Most studies have also found a higher prevalence of hypothyroidism in women, increasing with age. Prevalence of hyperthyroidism has been found to range 0·5–3·0%. This prevalence is higher than 5% when considering the subclinical hyperthyroidism. Also in this case the prevalence is more elevated in women and increases in elderly population.
Thyroid disorders in the elderly are associated with significant morbidity if they are not treated. Several studies have related thyroid status with morbidity and mortality in old age. An abnormally low levels of thyrotrophin (TSH) or elevated levels of free thyroxine (FT4) were associated with increased mortality rate; and, on the contrary, a higher TSH level was associated with a lower mortality.
We performed a cross-sectional study in a large cohort of elderly patients admitted to our hospital for an acute disease. Our aim has been to assess the prevalence (previously known and unknown) and the aetiology of thyroid dysfunction, and the prevalence of the euthyroid sick syndrome (ESS) in this population, as well as to study the relationship between these alterations and mortality during hospitalization in these patients.
Abstract and Introduction
Abstract
Background Thyroid dysfunction is common in aged people and has recently been associated to mortality.
Aims Our aims have been (1) to assess the prevalence of alterations in thyroid function tests in hospitalized patients over age 60 years and (2) to study the relationship between thyroid functional status and mortality during hospitalization.
Methods We studied a group of 447 patients (62% women), aged 61–101 year, hospitalized during 2005. Thyroid dysfunction was assessed by measuring serum concentrations of thyrotrophin (TSH), free thyroxine (FT4), and free thriiodothyronine (FT3). Thyroid autoimmune status was evaluated through thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies quantification.
Results Twenty-one patients (4·7%, 19 women) showed previously known thyroid dysfunction. 332 patients (74·3%) showed alterations in thyroid function tests. Euthyroid sick syndrome (ESS) was the derangement more frequently found (n = 278, 62·2%). After excluding ESS patients, 60 patients (13·4%) showed thyroid dysfunction: overt hypothyroidism, 14 (3·1%); subclinical hypothyroidism, 25 (5·6%); overt hyperthyroidism, 11 (2·5%), and subclinical hyperthyroidism, 10 patients (2·2%). Thyroid autoimmunity was positive in only 4·0% and 2·3% of patients, for TPOAb and TgAb, respectively. The presence of alterations in thyroid function tests was positively associated with the age of the patients and mortality during hospital stay (P < 0·001). Serum levels of FT3 were negatively related to death during hospitalization (OR 0·56; CI 95%, 0·38–0·81; P < 0·01).
Conclusions About three quarters of patients admitted in our geriatric unit exhibited alterations in thyroid function tests. This finding was associated with elevated age and poor prognosis. The reduction of FT3 values was a powerful predictor for mortality during hospitalization in elderly patients.
Introduction
Thyroid dysfunction affects a significant portion of the general population. Epidemiological studies performed in the last years have shown that the prevalence of hypothyroidism ranges between 1 and 7%. Most studies have also found a higher prevalence of hypothyroidism in women, increasing with age. Prevalence of hyperthyroidism has been found to range 0·5–3·0%. This prevalence is higher than 5% when considering the subclinical hyperthyroidism. Also in this case the prevalence is more elevated in women and increases in elderly population.
Thyroid disorders in the elderly are associated with significant morbidity if they are not treated. Several studies have related thyroid status with morbidity and mortality in old age. An abnormally low levels of thyrotrophin (TSH) or elevated levels of free thyroxine (FT4) were associated with increased mortality rate; and, on the contrary, a higher TSH level was associated with a lower mortality.
We performed a cross-sectional study in a large cohort of elderly patients admitted to our hospital for an acute disease. Our aim has been to assess the prevalence (previously known and unknown) and the aetiology of thyroid dysfunction, and the prevalence of the euthyroid sick syndrome (ESS) in this population, as well as to study the relationship between these alterations and mortality during hospitalization in these patients.