Association between type 2 diabetes mellitus and hypothyroidism: a case-control study

Objectives: Type 2 diabetes mellitus (DM-H) is highly prevalent in Saudi Arabia and only few studies have assessed it as a risk factor for hypothyroidism. This study aimed to examine the association between DM-H and hypothyroidism. Subjects and methods: We conducted a hospital-based case control study. As cases, we included all adults admitted to King Abdulaziz University Hospital (KAUH) with laboratory - confirmed hypothyroidism. As controls, we drew a random sample of patients admitted to the orthopedic clinic at KAUH with laboratory-confirmed absence of hypothyroidism. We extracted data from the medical records regarding age, sex, presence of DM-H, HbAlc, comorbidities, treatment, and complications. We used multivariate logistic regression to identify factors associated with hypothyroidism. Results: We included 121 cases and 121 controls. In comparison to controls, cases were older (P=0.005), had higher prevalence of DM-II (P<0.001), had higher levels of HbAlc (P=0.03), used insulin (P<0.001) and oral hypoglycemic drugs (P<0.001) more often, and suffered more often from hypertension (P<0.001), coronary artery disease (CAD) (P<0.001), stroke (P=0.04), diabetic foot (P<0.001), and nephropathy (P<0.001). According to multivariate regression, the risk of hypothyroidism was significantly increased among patients with DM-H (OR=4.14; 95% 0=20.20-7.80; P<0.001) and CAI) (OR=14.15; 95% 0=1.80-111.43; P=0.01). Conclusion: Patients with DM-H were at increased risk of developing hypothyroidism. Adequate management and control of DM-H might reduce the risk of developing hypothyroidism. Further research using a prospective cohort study design is needed to confirm these findings. Key messages: Patients with DM-H had an increased risk of developing hypothyroidism.