Anaemia is a condition characterised by a deficiency in the number or quality of red blood cells, which impairs the ability of the blood to carry sufficient oxygen to the body's tissues. In the context of primary hypothyroidism, anemia is a frequent comorbidity. Hypothyroidism is a common endocrine disorder resulting from insufficient production of thyroid hormones by the thyroid gland. These hormones are crucial for various bodily functions, including the regulation of metabolism and the stimulation of erythropoiesis (the production of red blood cells).

The prevalence of hypothyroidism varies across different populations. In community surveys, the prevalence of overt hypothyroidism ranges from 0.1% to 2%, while subclinical hypothyroidism is more common, affecting 4% to 10% of adults, with a higher frequency in older women[1]. Studies have shown that anaemia is a common finding in hypothyroidism, with varying prevalence rates depending on the study population and diagnostic criteria. For instance, in a study conducted by Erdogan et al., the prevalence of anaemia in subclinical hypothyroid patients was found to be 26.6% and 73.2% in overt hypothyroid patients[2].

The pathophysiology of anaemia in hypothyroidism is multifactorial. One of the primary mechanisms is the reduced stimulation of erythropoiesis due to low levels of thyroid hormones. Additionally, hypothyroidism can lead to malabsorption of essential nutrients like iron, vitamin B12, and folic acid, which are crucial for red blood cell production. For example, iron deficiency anemia can result from menorrhagia (heavy menstrual bleeding) and malabsorption, which are common in hypothyroid patients[3]. Vitamin B12 and folic acid deficiencies can lead to macrocytic anaemia, characterised by larger than-normal red blood cells with impaired functionality[4].

Moreover, hypothyroidism can cause normocytic normochromic anemia, which is characterized by normal-sized red blood cells but in insufficient numbers. This type of anemia is often due to the decreased production of erythropoietin and the direct inhibitory effects of hypothyroidism on bone marrow function[5]. Chronic disease anemia, another common type associated with hypothyroidism, is marked by inflammation and impaired iron metabolism, further complicating the anemia observed in these patients[6].

The study was conducted in the Department of General Medicine at G.R. Medical College, Gwalior (M.P.), from August 2022 to June 2024. This was a prospective observational study with a sample size of 100 patients. The study population comprised 100 patients who exhibited symptoms and signs and had biochemical evidence of primary hypothyroidism. These patients were admitted to the medicine ward of JAH and KRH.

Data collection involved conducting a detailed medical history and physical examination for all patients. The investigations performed included hemoglobin measurement, total count, differential count, ESR, platelet count, and peripheral smear. Additional investigations included serological study for HIV infection (if necessary), chest X-ray, ultrasound (USG) of the abdomen and pelvis, serum vitamin B12 assay, and serum folic acid level.

INCLUSION CRITERIA

• Age >15years
• Anaemia (Hb<13.5g/dl in males; 11.5 gm/dl in females)
• Patients of primary hypothyroidism.
• Patients who gave informed consent
• Age >15years

EXCLUSION CRITERIA

• Anaemia (Hb<13.5g/dl in males; 11.5 gm/dl in females)
• Patients of primary hypothyroidism.
• Patients who gave informed consent

Table No 1: Descriptive Statistics Distribution: -

The descriptive statistics for the 100 patients provide insights into key variables. The mean age of the patients is 43.73 years, indicating a mid-aged population. Hemoglobin levels (Hb) have a mean of 11.24 g/dL, suggesting mild anemia in this cohort. Thyroid function tests show a mean T3 level of 1.53 ng/mL, T4 level of 1.26 ng/mL, and TSH level of 11.79 µIU/mL, highlighting a hypothyroid state. Serum iron and ferritin levels also reflect varying degrees of iron deficiency among the patients.

Table No. 2: Distribution of clinical signs and symptoms

The most frequent clinical signs and symptoms observed in patients were weight gain and fatigability, both at 56%. Pallor was noted in 44% of the patients. Symptoms like palpitations, shortness of breath, and cold intolerance were present in 31%, 32%, and 26% of patients. Edema was found in 25% of the cases, while menstrual disturbances and koilonychia were less common at 13% and 3%, respectively.

Table No. 3: Peripheral Smear Distribution

Most patients (85%) showed normocytic normochromic peripheral smears, indicating average red blood cell size and haemoglobin content. The presence of macrocytic normochromic (3%) and macrocytic hyperchromic (5%) smears suggests some patients have larger than normal red blood cells, potentially indicative of certain types of anaemia. Microcytic hypochromic smears (7%) suggest iron deficiency anaemia or other conditions causing smaller, paler red blood cells.

Table No. 4: TLC Distribution

TLC Distribution: The majority of patients (37%) fall within the (8000-12000] range, indicating a common TLC range for the studied group.

The study’s descriptive statistics indicated that the average age of the patients was 43.73 years, suggesting a predominantly middle-aged cohort. Haemoglobin levels averaged 11.24 g/dL, pointing to mild anaemia. Thyroid function tests showed mean levels of T3 at 1.53 ng/mL, T4 at 1.26 ng/mL, and TSH at 11.79 µIU/mL, confirming a hypothyroid state[7].

Serum iron and ferritin levels were 45.43 µg/dL and 13.67 ng/mL, respectively, indicating varying degrees of iron deficiency among the patients. These findings are consistent with the study by Patel and Jain (2017), which also observed mild anaemia and hypothyroidism in a similar patient population[8].

The study identified weight gain and generalized weakness as the most common clinical symptoms, each affecting 56% of patients. Additionally, pallor was observed in 44% of patients, and palpitations in 31%[9]. These symptoms highlight a significant overlap between hypothyroidism and anemia.

Similar findings were reported by Patel and Jain (2017), where weight gain and generalized weakness were prevalent among patients with both conditions, emphasizing the need for comprehensive management approaches. Blood Investigations (T3, T4, TSH, Hb, MCV, MCHC, and MCH) Frequency Distributio[10].

The blood investigations showed that the most frequent T4 levels were in the 38-39 ng/dL range (23% of patients), while T3 levels were predominantly at 2 ng/mL (53%). Hemoglobin levels mainly fell within the 12-13 g/dL range (27%), and MCV levels within the 86-94 fL range (34%). These results correspond with the study by Qadir Fatima et al. (2020), which observed similar distributions in blood parameters among hypothyroid patients, underscoring the commonality of these findings across different studies .

The peripheral smear analysis revealed that 85% of patients had normocytic normochromic red blood cells, indicating average cell size and haemoglobin content[11]. Macrocytic hyperchromic cells were seen in 5%, and microcytic hypochromic cells in 7% of patients. These findings are consistent with Patel and Jain (2017), who also identified normocytic normochromic anaemia as the most prevalent type among hypothyroid patients, highlighting the common haematological manifestations of the condition .

Frequency Distribution Peripheral Smear (VIT B12, Serum Iron, Serum Ferritin, Total Iron Binding Capacity) [12]. The study showed that Total Iron Binding Capacity was the most frequently measured parameter (12%), followed by serum iron and ferritin (each 11%), and Vitamin B12 (8%). These measurements reflect a selective diagnostic approach based on clinical assessments. This pattern is corroborated by Qadir Fatima et al. (2020), who emphasised the importance of evaluating iron-binding capacity in patients with hypothyroidism, highlighting its relevance in managing anaemia associated with the condition .

The study concludes that anaemia is a common condition in patients with primary hypothyroidism, especially among middle-aged adults and predominantly females. Frequently observed clinical symptoms included weight gain, Fatigability, and pallor. Blood tests indicated that most patients had normocytic normochromic anaemia along with significant iron deficiency. These findings highlight the critical need for specific diagnostic and treatment strategies to manage anaemia in patients with hypothyroidism effectively.

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