Frequency and Types of Anemia in Primary Hypothyroidism Patients: A Prospective Observational Study

Background Primary hypothyroidism is a common endocrine disorder resulting from inadequate production of thyroid hormones. Anemia is a common condition that can occur in hypothyroidism. Anemia may occur due to nutrient deficiency, such as iron or vitamin B12 deficiency due to chronic disease in hypothyroidism. Therefore, it is important to evaluate the cause of anemia in hypothyroidism.  Objective The aim of this study was to determine the frequency of anemia and its types in patients with primary hypothyroidism. Methods This was a prospective cross-sectional observational study conducted at the Department of Medicine, Jinnah Postgraduate Medical Center, Karachi, Pakistan, using non-probability consecutive sampling. A total of 176 adults aged 18-65 years of either gender, newly diagnosed with primary hypothyroidism, or with any of its symptoms were included in the study. Patients already on anti-thyroid medication and with post-thyroidectomy hypothyroidism were excluded from the study. The duration of the study was 1.5 years, from January 2020 to July 2021. After ethical approval, written informed consent was obtained from each patient. Demographical data along with results of complete blood picture, including Hb and MCV for diagnosing anemia and its types were recorded on a pre-designed proforma. The chi-square test was applied keeping p < 0.05 as statistically significant. Results The mean age of the patients was 42.19 ± 8.43 years, with 59.66% (n = 105) females and 40.34% (n = 71) males. A total of 67% (n =118) patients were found to be anemic. Of these, 38.64% (n = 68) patients had normocytic anemia, 19.32% (n = 34) microcytic anemia, and 9.25% (n = 16) patients had macrocytic anemia; 56.34% (n = 40) males and 74.29% (n = 78) females were reported to be anemic (p = 0.01). Conclusion In our study, the frequency of anemia in patients with hypothyroidism was high, with normocytic anemia being the most common type. It is important to know the type of anemia in hypothyroidism, as normocytic anemia is due to the chronic disease process (anemia of chronic disease) and may not respond to nutrient supplementation. Conversely, microcytic anemia is commonly due to iron deficiency and macrocytic anemia is due to vitamin B12 deficiency and therefore, they require replacement therapy. In any case, it is important to identify and treat the underlying cause of anemia.