Thyroid function among diabetic patients at Mengo Hospital Kampala

Abstract

Several thyroid malfunctions occur in diabetes mellitus, and thyroid dysfunction may complicate control of diabetes. An association between diabetes mellitus and autoimmune thyroid disease was suspected from previous studies; hence this study was designed to assess thyroid function and how it may be related to blood glucose levels in diabetic patients attending diabetic clinics at Mengo Hospital Kampala. This prospective study was carried out between December 2007 and September 2008 on 114 subjects aged between 14 and 93 years. Blood samples were collected and tested for blood sugar, thyroid stimulating hormone (TSH) and free thyroxine (T4) levels. The data were analyzed at a statistical significance level of 95% confidence interval and p-value of less than or equal to 0.05. Relationships were tested using Chi- Square Test. Blood sugar levels less than 6.0 mmol/l were interpreted as non-diabetic, 6.0 ñ 8.0 mmol/l borderline and greater than 8.0 diabetic respectively. Serum free thyroxine values less than 9 pmol/l were interpreted as low, and values greater than 23.8 pmol/l were considered raised. Serum thyroid stimulating hormone value less than 0.25 µIU/ml was interpreted as low and value greater than 5.0 µIU/ml was high. Findings showed a general prevalence of 13.2% of thyroid disease in the study sample and 34.2% for diabetes mellitus in the study population. The occurrence of thyroid disease in diabetic patients accounted for 7.7% and hypothyroidism accounted for 5.1% mostly in the males, while hyperthyroidism accounted for 2.6% mostly in the females. There was no statistical significant relationship between thyroid disease and diabetes mellitus concurrence (p = 0.997, 95% CI). There is low concurrence of thyroid dysfunction in diabetes mellitus in this study population. Thyroid function tests are very costly (cost between $26 and $28) for an average Ugandan and routinely performing thyroid function tests in every case of diagnosed diabetes mellitus may not be cost effective.