Abstract:
Background: Thyroid dysfunction is more prevalent among patients with diabetes (10-
24%) compared to the general population (2-7%). Coexistence of thyroid disorders
among patients with diabetes results in impaired lipid metabolism, endothelial
dysfunction and impaired glycemic control. These risk factors have been implicated in
worsening of cardiovascular disease which is the leading cause of death in diabetes. Early
recognition and treatment of thyroid dysfunction in diabetes is important for mitigation of
associated cardiac complications. Whereas diabetes is common in our region, little is
known about the prevalence of thyroid dysfunction among patients with diabetes.
Objectives: To determine the prevalence and clinical correlates for thyroid dysfunction
among patients with Type 2 Diabetes Mellitus (DM) in Moi Teaching & Referral
Hospital (MTRH).
Methods: This was a cross-sectional study conducted at the diabetes outpatient clinic in
MTRH between February and April 2018. The study population included 2500
ambulatory patients with Type 2 DM, aged 35 years and above at the time of diagnosis,
out of which 368 participants were enrolled by systematic random sampling. Structured
interviewer administered questionnaires were utilized to collect socio-demographic,
clinical and laboratory data. Third generation immunoassays were used for measurement
of Thyroid Stimulating Hormone (TSH), glycated hemoglobin (HbA1c) and low-density
lipoprotein-cholesterol (LDL-C). Descriptive statistics such as the median and
interquartile ranges were used to summarize continuous variables. Frequencies and
percentages were used to summarize categorical variables. Association between thyroid
dysfunction and categorical independent variables was assessed using Pearson’s Chi
Square test. Fisher’s exact test was reported whenever the Chi Square assumptions were
violated. Multiple logistic regression was used to determine the effect of independent
variables on thyroid function.
Results: The median age of the participants was 59.2years, with 230(62.5%) of these
being females. Prevalence of thyroid dysfunction among patients with Type 2 DM was
9.2% (95%CI: 6.4, 12.7) representing 34 participants. Subclinical hypothyroidism was
the most frequent dysfunction at 7% (22). Sociodemographic (age, gender) and clinical
characteristics (duration of Type 2 DM, insulin use, hypertension, body mass index and
LDL-C) studied indicated no association with thyroid dysfunction. There was no
significant correlation between thyroid dysfunction (TSH, freeT4) and glycemic control
(HbA1c).
Conclusion: The prevalence of thyroid dysfunction among patients with Type 2 DM is
high compared to what has been reported in the general population. There was no
significant correlation found between thyroid dysfunction and the studied clinical
correlates.
Recommendations: Routine assessment of thyroid hormone levels should be part of
evaluation for patients with Type 2 DM. A prospective study should be considered to
further evaluate other clinical correlates that may be associated with thyroid dysfunction.