Study On The Prevalence And Correlates Of Hypothyroidism In Type2Diabetic Patients

Objective:To evaluate the prevalence and the distribution characteristics of thyroid dysfunction in inpatients with type2diabetes mellitus (T2DM), and to explore correlates of hypothyroidism in type2diabetic patients so as to provide scientific basis for the screening and prevention of hypothyroidism in patients with T2DM.Methods:Retrospectively consulted medical records of type2diabetic patients who firstly attended metabolic diseases hospital, Tianjin medical university, from August30,2011to May30,2012. Information was collected, including general demographic data, disease history, family history, behavior pattern, physical examination and laboratory test. A total of1254patients with T2DM who had known thyroid dysfunction or thyroid function test were included in the study, in order to assess the prevalence and the distribution characteristics of thyroid dysfunction. A case-control study was conducted, in which type2diabetic patients with hypothyroidism were as cases and euthyroid patients with T2DM were as controls, to analyze correlates of hypothyroidism in type2diabetic patients by non-conditional Logistic regression.Results:1. Among the1254type2diabetic patients for the study,126(10.1%) patients had thyroid dysfunction. Hypothyroidism was present in100(8.0%) type2diabetic patients, in which26(2.1%) with overt hypothyroidism and74(5.9%) with subclinical hypothyroidism. The prevalence of hypothyroidism was higher in females than in males, and increased with age and duration of diabetes. Hyperthyroidism was present in26(2.1%) type2diabetic patients, in which17(1.4%) with overt hyperthyroidism and9(0.7%) with subclinical hyperthyroidism. The prevalence of hyperthyroidism had no significant difference among different age, sex and duration of diabetes groups.2.100type2diabetic patients with hypothyroidism were used as case group and1031euthyroid type2diabetic patients as control group. Results of univariate logistic regression analysis showed that the higher risk of hypothyroidism in type2diabetic patients was associated with older age, female, retirement, higher systolic blood pressure(SBP) on admission, longer duration of diabetes, insulin therapy, complicated by coronary heart disease(CHD), osteoporosis, hyperuricemia, hyperfibrinogenemia, and positivity for thyroid peroxidase antibody(TPO-Ab); the lower risk of hypothyroidism in type2diabetic patients was associated with current smoking, current drinking, higher diastolic blood pressure(DBP) on admission and higher haemoglobin Alc(HbAlc) level. However, after adjusting for possible confounding factors, the association between the risk of hypothyroidism in type2diabetic patients with retirement, SBP and DBP on admission, HbAlc level, complicated by CHD, osteoporosis, hyperuricemia and current drinking was not existed. No associations were observed between the risk of hypothyroidism in type2diabetic patients with marital status, race, body mass index, fasting plasma glucose, drug therapy, metformin treatment, complicated by nephropathy, retinopathy, peripheral neuropathy, diabetic foot, hypertension, dyslipidemia, family history, serum triglycerides, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and urine microalbumin; however, after adjusting for age, sex and duration of diabetes, diabetic nephropathy was associated with the higher risk of hypothyroidism in type2diabetic patients.3. Results of multivariate non-conditional logistic regression analysis showed that positive TPO-Ab, age, current smoking and diabetic nephropathy were related to hypothyroidism in type2diabetic patients. The ORs and95%CIs were6.447(3.227～12.881),1.686(1.206～2.358),0.194(0.057-0.664) and2.254(1.146～4.431) respectively.Conclusion:Hypothyroidism was the main form of throid dysfunction in patients with T2DM, the prevalence of which was8.0%, higher in females than in males, and increased with age and duration of diabetes. Positive TPO-Ab, older age, diabetic nephropathy were associated with the higher risk of hypothyroidism in type2diabetic patients, while current smoking was associated with the lower risk of hypothyroidism in type2diabetic patients.