Effect of thyroid dysfunction on hematological proles at Menelik II Referral Hospital, Addis Ababa, Ethiopia

Thyroid hormones have a crucial role in the metabolism, production, and proliferation of blood cells. So the current study aimed to assess the hematological prole of patients with thyroid dysfunction. A comparative prospective study was conducted from June to September 2021; on a total of 360 participants (120 health groups and 240 patients with thyroid dysfunction. 10 ml of venous blood samples were collected and separated into two test tubes (in the SST tube used for measurement of TSH, T3, and T4, and sample in the EDTA tubes was used for CBC analysis). The analysis was done by using SPPS software. Finally, the result was interpreted by using chi-square, Pearson's correlation, and multivariate logistic regression. The level of statistical signicance was set at a 95% condence and P-value is less than 0.05 was considered clinically signicant. The result of this study showed that there was a statistically signicant decrease in RBC count, Hgb, HCT, MCV, MCH, MCHC, MPV, and PLT counts in thyroid dysfunction patients when compared with apparently healthy controls (p-value <0.05). WBC, RDW, and Neutrophils were statistically signicantly higher in thyroid dysfunction patients when compared with apparently healthy controls (p-value <0.05). The valve of monocyte, basophils, and eosinophils were not shown a signicant difference between the groups (p-value >0.05) (Table 2, and 4).


Introduction Background
The thyroid gland is a small organ that's located in the front of the neck, wrapped around the windpipe (trachea). The thyroid gland is a vital hormone gland: It plays a major role in the metabolism, growth, and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream (1, 2). The thyroid gland releases the two basic triiodothyronine (T3) and thyroxine (T4) which play an important role in the regulation of your weight, energy levels, internal temperature, skin, hair, nail growth, and more. Hormonal output from the thyroid is controlled by thyroid-stimulating hormone (TSH) or thyrotropin secreted by the anterior pituitary which is mediated by thyrotropin-releasing hormone (TRH), secreted by the hypothalamus (3,4). Thyroid hormones have a crucial role in the metabolism and proliferation of blood cells. Thyroid dysfunction induces different effects on blood cells such as anemia, erythrocytosis leukopenia, thrombocytopenia, and in rare cases causes' pancytopenia. It also alters RBC indices include MCV, MCH, MCHC, and RDW (5,6).
Thyroid dysfunction happens when the thyroid gland makes either too much or too little of these important hormones and this condition is also known as thyroid disease. The cause of this problem can be primary or secondary and the types of thyroid disease can be hyperthyroidism, hypothyroidism, thyroiditis, and Hashimoto's thyroiditis (7,8). Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland doesn't produce enough of certain crucial hormones. Primary hypothyroidism is de ned by elevated TSH levels and reduced thyroid hormones (T3 andT4) and secondary hypothyroidism is de ned by reduced levels of TSH, T3, and T4 (9,10). Causes of primary hypothyroidism could be functional problems within the thyroid gland, in ltrate disease of the thyroid, and secondary hypothyroidism caused due to anterior pituitary gland failures (9)(10)(11). Hyperthyroidism (overactive thyroid) occurs when the thyroid gland produces too much of the hormone thyroxine and this problem can accelerate our body's metabolism, causing unintentional weight loss and a rapid or irregular heartbeat. The cause of hyperthyroidism can also be primary, secondary, or tertiary with the most known cause of autoimmune (12)(13)(14).
Some previous study ndings indicated thyroid dysfunction induces different effects on blood cells such as anemia, erythrocytosis leukopenia, thrombocytopenia, and in rare cases causes' pancytopenia (5).
Thyroid hormones involve in involvement in hemoglobin production, enhance erythropoiesis through a hyper proliferation of immature erythroid progenitors, increase secretion of erythropoietin (EPO) by inducing erythropoietin gene expression, motivate the growth of erythroid colonies (BFU-E, CFU-E), intensify erythrocyte 2, 3 DPG compactness, effect on megakaryocytes through modulation of bone marrow matrix proteins, such as bronectin, increase the expression of bronectin gene, an alter platelet function and affects hematopoiesis in many ways (15,16). So the current study aimed to assess the effect of thyroid dysfunction on the hematological pro le of patients.

Study area
The study was conducted at Menelik II Referral Hospital which is found in Addis Ababa under Addis Ababa health bureau, Addis Ababa, Ethiopia.

Study design and period:
A hospital-based comparative cross-sectional study was conducted from June to August 2021, at Menelik II Referral Hospital in Addis Ababa, Ethiopia.

Study Population
Patients who have con rmed thyroid dysfunction at Menelik II referral hospital was considered as case group and healthy individuals were randomly selected from Menelik II referral hospital were recruited as control groups.
Inclusion and exclusion criteria: All age patients with thyroid dysfunction and visiting Menelik II referral hospital during the study period were taken as case groups and also all age group healthy individuals were taken as control groups for this study. On the other hand, patients taking any hormonal drugs which affect complete blood counts (CBC) such as non-steroidal anti-in ammatory drugs, Penicillin and its derivatives, Phenazopyridine, Quinidine, and patients with comorbid disease (such us: TB, HIV, Heart disease, and chronic kidney disease)were excluded from case groups. Also, control groups of individuals with signs of illness and those who are taking medications were excluded.

Sampling method and Data Collection Procedure
The sample was collected by using convenient sampling to enroll patients with thyroid dysfunction and healthy controls in Menelik II referral hospital (MRH). After consent and assent were obtained from each study participant, socio-demographic and clinical information was obtained using a pretested semistructured questionnaire. Then 1o ml of venous blood sample was aseptically collected from each study participant by an experienced laboratory technologist and transferred into two test tubes (5 ml in each tube). 5 ml blood to EDTA test tube for CBC analysis and 5 ml blood into SST test tube for thyroid function test analysis. Then the blood sample in EDTA test tubes was transported to the hematology department of Menelik II referral hospital and CBC is analyzed by using a fully automated Mindray BS-500 analyzer. The blood specimen in the SST tube was transported to the clinical chemistry department of the MRH laboratory department and centrifuged at 3000 RPM for 5 minutes to separate the serum.
Then the thyroid function test was determined from the serum sample by using Mindray CL-960i Chemiluminescence Immunoassay fully automated analyzer.

Laboratory analysis
Thyroid function tests were performed using Mindray CL-960i Chemiluminescence Immunoassay system which is a fully automated, random access, software-controlled system for immunoassay analysis. It works based on the electrochemiluminescence (ECL) assay principle. The competitive immunoassay principle was for the measurement of T3, T4, and the two-site sandwich immunoassay method was used for the measurement of TSH. For hematological pro le or complete blood count analysis mindray BS-500 ve differential fully automated hematological analyzer with test principle of impedance principle (electric resistance) was used.

Data Quality Assurance
To assure the quality of the data, training was given to the data collectors, and the data was collected by using a pretested questionnaire. Standard operating procedures (SOPs) were strictly followed during specimen collection and laboratory procedures. Before sample analysis commercially prepared low, normal, and high-quality control reagents were used to check the reliability (accuracy and precision) of the data generated by the hematology analyzer, and two-level control was used for the hormonal analyzer. The accuracy and completeness of the collected data were checked every day by the principal investigator. Data were cleaned, coded, and entered correctly.

Data analysis and interpretation
All the data collected from the laboratory investigation and questionnaire were analyzed using SPSS software (SPSS Inc., Chicago, IL, USA, version 21.0). Descriptive statistics were used to express the sociodemographic and clinical characteristics. Binary and multiple logistic regressions were computed to assess the association between variables. Differences in mean values were determined by an independent t-test for patients with thyroid dysfunction and healthy participants. P-values < 0.05 were taken as statistically signi cant.

Ethical considerations
The study was conducted after ethical approval is obtained from the Research and Ethics Institutional Review Board. An o cial permission letter was submitted to the Addis Ababa Health Bureau and Menelik II referral hospital. Informed written consent and assent were also obtained from each participant in Menelik II referral hospital before the actual data collection.

Result
A total of 360 participants of the 240 (110 males, 130 females) patients with thyroid dysfunction and the rest 120 (55 males, 65 females) healthy controls were recruited for this study. Out of 240 patients with thyroid dysfunction, 120 (50%) were with hypothyroidism and the rest 120 (50%) were with hyperthyroidism. Most of the study participants who participated in the current study were in the age range of 25-44 years (41.7) with an average age of 28.7 years(a minimum of 1 year and a maximum of 82 years). The majority of study participants in the current study were females 195 (54.2%). The age of the case group and the control group in the current study was relatively matched (Table 1).  and those whose PLT value less than 150x10 9 cells /L were 2.7 times more likely to develop thyroid dysfunction (AOR 2.7, 95% CI:1.26-11.36, p value=0.004) compared with control groups (Table 3).

Discussion
The thyroid gland is a small organ that's located in the front of the neck and is vital for the secretion of two hormones (T3 & T4) gland which plays a major role in the metabolism, growth, and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream (1,2). The most common thyroid dysfunctions, hypothyroidism, and hyperthyroidism affect blood cells and cause anemia with different ranges of severity [25].

Findings of total RBC and RBC Indices between case and control groups
Thyroid hormones stimulate the proliferation of erythrocyte precursors, directly and indirectly, in uencing erythropoietin (EPO) production enhancement. EPO regulates the survival, proliferation, and differentiation of elytroid progenitor cells and the number of red blood cells in the peripheral blood. So the problem in this gland directly or indirectly affects the production of blood cells. In our study, the mean RBC, Hgb, HCT, MCV, MCH, and MCHC valve of participants with thyroid dysfunction were have shown statistically signi cant decrement and the RDW valve were showed increased valve compared with control groups(p-value <0.001) ( Table 2). Our result is in agreement with different study ndings conducted in Saudi Arabia (17), Iraq (18), Iran (19), Saudi Arabia (20)and was in opposite with the study nding conducted in Kenya (21). This difference may be due to geographical, physiological, and dietary variations.
On the opposite, the current study nding showed a signi cant increment in the value of red cell distribution width in participants with thyroid dysfunction compared with the control groups (p-value <0.001) ( Table 2). And this nding was supported different previous study ndings (22)(23)(24).
Findings of total WBC and WBC differential between case and control groups As the multivariate analysis indicated total WBC count and neutrophil percentage were signi cantly increased in participants with thyroid dysfunction compared with apparently healthy controls (p-value = 0.021) ( Table 2). A similar result was also reported by different previous studies (20,23). On the other hand, the ndings of lymphocyte, monocyte, eosinophil, and basophils were not showing a signi cant difference between the two groups (p-value >0.05).

Platelet count nding and thyroid dysfunction
The current study nding also showed a signi cantly decreased valve of PLT among individuals with thyroid problems compared with the healthy control groups (p-value = 0.021) ( Table 2). This nding was in line with the previous studies conducted in Italy (25), Austria (26), and in opposite with previous studies conducted in Turkey (27) Conclusion And Recommendation

Conclusion
Depending on the current study nding thyroid hormones (T3 and T4) have a signi cant in uence on blood cell count and blood cell indices. The current study nding showed that thyroid dysfunction has a signi cant effect on RBCs, Hgb, HCT, MCV MCHC, MCH, WBC, neutrophils, PLT count, and MPV ndings (p<0.05). But no show signi cant effect on monocyte, eosinophil and basophils (p-value > 0.05).

Recommendation
Routine hematological tests particularly RBCs, Hb, RDW, MCHC, PLT, WBCs, and differential count should be done for patients with thyroid dysfunction. So that complications could be detected and managed.