Spectrum of thyroid function test among type 2 diabetic patients attending a rural health facility, southwest Nigeria: A hospital-based study

OBJECTIVES: The thyroid gland produces hormones that have significant influence on carbohydrate metabolism; its disorders may affect carbohydrate metabolism in type 2 diabetic patients (T2DM) more than the non-diabetic (NDM) patients as reported in various studies. We determined the spectrum of thyroid function tests (TFTs) profile among T2DM in our rural health facility. METHODS: T2DM patients and NDM patients were recruited for the study. The age, educational level, occupation, marital status, and duration of diabetes were extracted from interviewer’s administered questionnaire. The weight, height, body mass indices (BMIs), and the waist and hip circumferences were measured. Waist-hip ratios (WHR) were calculated for all participants. Venous blood was collected and assayed for free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) using a Chemiluminescence Immunoassay (CLIA) 2nd Generation Autoanalyzer. The mean, standard deviation, frequencies, and percentages were calculated for the variables. The student’s t-test and chi-square test were also determined as appropriate. RESULTS: Seventy-eight patients made up of 56 T2DM and 22 NDM were evaluated in this study. Fifty-one were males while 27 were females; 67.9% and 59.1% of the female participants were T2DM and NDM, respectively. The WHR was significantly higher in T2DM than NDM (0.92 ± 0.05 versus 0.88 ± 0.06). The TSH was higher in T2DM than the NDM. Forty-four (78.6%) of the T2DM had euthyroid (normal) biochemical pattern; 12 (21.4%) showed abnormal biochemical pattern of euthyroid sick syndrome, subclinical hyperthyroid, and subclinical hypothyroid. Thirty (53.6%) of the T2DM were diagnosed less than five years ago. The value of TSH was increasing with the duration of diabetes but not in a statistically significant way. None of the T2DM showed overt hypothyroid or hyperthyroid test result. CONCLUSION: Thyroid function test may identify diabetics with altered thyroid hormone status that may impact on their metabolic control. Knowledge of the functional state of the thyroid gland can help in achieving a better metabolic control and attenuate the development of complications in T2DM.