Prevalence of hypothyroidism in patients with type 2 diabetes mellitus and hypertension in India: a cross-sectional observational study

Purpose: To determine the prevalence of hypothyroidism in patients with type 2 diabetes mellitus (T2DM), hypertension, and both T2DM and hypertension (T2DM + hypertension) in India. Patients and methods: In this cross-sectional observational study, adult patients with an established or newly diagnosed T2DM, hypertension, and T2DM + hypertension who were visiting their physicians for a routine clinical checkup were enrolled across 29 sites in India. All the patient-related data were extracted from their medical records. The prevalence of hypothyroidism was evaluated by thyroid function test (levels of serum free thyroxine, free triiodothyronine, and thyroid-stimulating hormone [TSH]). The proportion of obese and overweight hypothyroid patients and dose of thyroxine in overt and subclinical hypothyroidism (SCH) cases (as per TSH values) were assessed during the study. The results were summarized by descriptive statistics. Results: A total of 1,508 patients (T2DM: 504; hypertension: 501; T2DM + hypertension: 503) were enrolled in the study. The prevalence of hypothyroidism in patients with T2DM, hypertension, and T2DM + hypertension was 24.8%, 33.5%, and 28.9%, respectively. The overall prevalence of hypothyroidism in T2DM (n=1,002) and hypertension (n=1,001) was 26.9% and 31.2%, respectively. The proportion of obese against overweight hypothyroid patients was higher in all indications (T2DM: 16.5% vs 3.4%; hypertension: 23.8% vs 5.4%; T2DM + hypertension: 21.5% vs 3.8%). A considerable proportion of patients with SCH was prescribed thyroxine in T2DM (61.5%), hypertension (61%), and T2DM + hypertension (62.5%) cases. The most commonly prescribed dose (mean) of thyroxine was 50 and 25 mu g for overt hypothyroidism and SCH cases, respectively, in all cohorts. Conclusion: There is a high (>20%) prevalence of hypothyroidism in patients with T2DM, hypertension, and T2DM + hypertension. Screening for hypothyroidism should be routinely considered for early diagnosis and effective management.