N S Deshpande¹, Prafull Chege^2*, Prasad H B³, Ghate S V⁴

 

¹Professor and Head, ²Senior Resident, Department of Medicine, Government Medical College and Hospital, Latur, Maharashtra, INDIA.

³Professor and Head, ⁴Dean, Department of Medicine, Dr.V.M. Government Medical College, Solapur, Maharashtra, INDIA.

Email: drneelima08@gmail.com

 

Figure A: Patient of Overt Hypothyroidism with weight gain. Figure B: Patients of Hypothyroidism with Neck Swelling

Figure C: Patient of Hypothyroidism with Dry Coarse Skin and Alopecia Figure D: Patient of Hypothyroidism with excessive weight gain and sleepiness

OBSERVATIONS AND RESULTS  

Figure 1                                                      Figure 2                                           Figure 3

Figure 1: Sex distribution among 100 cases; Figure 2: Distribution of hypothyroid patients according to Age and Gender (n=100); Figure 3: Graph showing distribution of symptoms among the patients

This graph includes number of Subclinical and Overt Hypothyroid patients and their Age and Gender distribution. Maximum 37 cases belonged to the age group of 21-30 years (04 males and 33 females) and minimum number of patients was in the 61-70 years with 02 females only. In our study the mean age of cases was 36.25 years. In our study 32% of the cases had significant history of neck swelling. The next common symptoms in our study population were easy fatiguability (18%), weight gain (17%), increased sleep (11% of cases)

Table 1: Mean values and standards deviation of thyroid parameters in Subclinical Hypothyroidism (SCH) and Overt Hypothyroidism (OH)(n=100)

Mean values of T3 and T4 were lower in patients of overt hypothyroidism, (OH) while values of TSH higher as compared to that of subclinical hypothyroid (SCH) cases

Table 2: Incidence of Dyslipidemia in Hypothyroid patients

Hypothyroid Patients	No. of Patients with Hyper- cholesterolemia only	No. of Patients with Hypertriglyceridemia only	No. of Patients with Both	Total cases of Dyslipidemia
Subclinical	09	04	05	18
Overt	15	05	13	33
Total	24	09	18	51

The detailed breakup of 18 dyslipidemic Subclinical Hypothyroidism (SCH) cases included 09 cases had hypercholesterolemia, 04 were hypertriglyceridemia and 05 had both hypercholesterolemia and hypertriglyceridemia. The detailed breakup of 33 dyslipidemic OH cases included 15 had only hypercholesterolemia, 05 had only hypertriglyceridemia and 13 had both hypercholesterolemia and hypertriglyceridemia.

   

Figure 4                                                                       Figure 5                                                    Figure 6

Figure 4: Incidence of dyslipidemia in hypothyroid patients; Figure 5: Effect if Replacement with levothyroxine on Follow-up of dyslipidemia in subclincal hypothyroid patients (n-18); Figure 6: Effect of Replacement therapy with Levothyroxine on Follow up distribution in over Hypothyroid Patients

 

Table 3: Effect if replacement therapy with levothyroxine on follow- up of dyslipidemia in Subclinical Hypothyroid patients (n =18)

	Hyper- cholesterolemia	Hyper – riglyceridemia	Both Hyper- cholesterolemia and Hypertriglyceridemia	Total cases
Patients at 1st visit	09	04	05	18
Reversal at follow up	04	02	02	08
No reversal	04	01	02	07
Dropout	01	01	01	03

In short, out of 18 Subclinical Hypothyroid cases with dyslipidemia, 03 cases did not complete the study (drop-out), and of the remaining 15 cases, 08 cases showed reversal, 07 cases no reversal was noted.

 

Table 4: Lipid parameters before and after levothyroxine replacement the Subclinical Hypothyroid patients with dyslipidemia (n=15)

This table exhibits lipid parameters before and after levothyroxine replacement therapy in Subclinical Hypothyroid patients with dyslipidemia. It was observed that there was a statistically significant decrease in mean values of total cholesterol, triglycerides, and LDL-cholesterol levels and a statistically significant increase in mean HDL-cholesterol level following replacement therapy with levothyroxine.

 

 

 

 

 

 

Table 5: Effect Of Replacement Therapy With Levothyroxine On Follow Up Distribution In Overt Hypothyroid Patients (N=33)

Overall, of total 33 dyslipidemic Overt Hypothyroidism (OH) cases, 03 dropped out, and 30 Overt Hypothyroidism(OH)cases who completed the study, complete reversalofdyslipidemiawasnotedin17(56.7%) and noreversalin 13 cases.

 

Table 6: Lipid parameters before and after Levothyroxine replacement therapy in overt hypothyroid patents with Dyslipidemia (n=30)

Lipid Parameters (mg/dL)	Before Therapy Mean ± S.D.	After Therapy Mean ± SD	P – value
Total cholesterol	218. ±31.6	190.4 ± 26	<0.001	Significant
Triglycerides	147.4 ±30.1	136.3 ± 20.5	<0.001
HDL Cholesterol	41.2 ± 7.6	46.2 ±7.1	<0.001
LDL Cholesterol	135.6±26.5	121.8 ± 24.5	<0.001
VLDL Cholesterol	30.7 ± 5.3	30.8 ± 5.5	0.225	Non Significant

This table shows lipid parameters before and after levothyroxine replacement therapy in OH patients with dyslipidemia. A significant decrease in mean values of total cholesterol, triglycerides and LDL-cholesterol mean HDL-cholesterol levels was observed following replacement therapy with levothyroxine.

 

DISCUSSION

Thyroid disorders are among the most common endocrine disorders and these usually alter lipid metabolism. It is estimated that about 2-18% of people in the world are suffering from Hypothyroidism and its prevalence is influenced by geographic location, sex, diet and race. The number of Subclinical Hypothyroidism cases (51) were more than Overt Hypothyroidism cases(49) in the present study. Our findings are in concurrence with other studies like Jung et al, Ravisekhar et al etc^3,7. In the present study, a predominance of females was noted in cases of hypothyroidism with M: F ratio 1:6.1 which correlated to many other previous studies^3,7,8. Maximum number of hypothyroid females belonged to the age group of 21-30 years 37%, followed by 31-40 years age group 34%.Among males maximum incidence was found in the age group of 41-50 years. This suggested that involvement of younger age group in females than males. Thyroid hormones influence nearly all major metabolic pathways and lipid metabolism is more influenced by thyroid hormones.9 In this study, yslipidemiawaspresentin51 (51%) cases. Of 49 Overt Hypothyroidcases, 33(67.34%) were dyslipidemic. Amongst 51 Subclinical hypothyroid cases, 18(35.30%) had associated dyslipidemia. Jung et al³, Duntas4 and Ravisekhar et al⁷ Prakash and Lal5 also documented same in agreement with those of our findings. In the present study lipid profile of the hypothyroid patients showed that maximum number of 47.05% cases had only raised cholesterol, 17.64% cases had only raised triglycerides, and both hypercholesterolemia and hypertriglyceridemia was seen in 35.29% cases. Our findings are similar with Kotsis et al¹⁰. In short, in hypothyroid cases lipid profile particularly total cholesterol and LDL-cholesterol were adversely affected. Replacement therapy with levothyroxine in dyslipidemic Subclinical Hypothyroidism (SCH) cases showed that 50% cases having only hypercholesterolemia and 66.7% cases having only hypertriglyceridemia reverted to normal values. In 5 cases where both total cholesterol and triglycerides were raised 50% case showed complete reversal. Overall, complete reversal of dyslipidemia was seen in 08 out of 15(53.33%) Subclinical Hypothyroidism (SCH) cases. Replacement therapy with Levothyroxine in Overt Hypothyroidism (OH) showed that 50% cases having only hypercholesterolemia and 75% cases having only hypertriglyceridemia reverted to normal. In 13 cases who had both a raised total cholesterol as well as triglycerides, levels 58.4% cases showed complete while 41.6%cases had no reversal. Thus, overall complete reversal of dyslipidemia was noted in 17 out of 30 cases of hypothyroidism who completed levothyroxine replacement therapy. Various other workers like Monzani et al12 and other studies^1,4,8,14 also reported significant reduction in the levels of total cholesterol and LDL-cholesterol following levothyroxine replacement therapy thus supportingourobservations^12,13. In short, replacement therapy with levothyroxine in Hypothyroid patients with dyslipidemia cases produced definite beneficial effects in cases of hypercholesterolemia and hypertriglyceridemia, besides an increase in HDL levels. This is beneficial for decreasing the incidence of CAD, stroke and peripheral vascular diseases¹¹. A correlation between levothyroxine and lipid profile can be explained as: Fat cells produce leptin which physiologically regulates energy homeostasis. Leptin is also an important neuro-endocrine regulator of hypothalamic-pituitary- thyroid axis by regulating TRH gene expression in the paraventricular nucleus, and TSH in turn will stimulate leptin secretion by human adipose tissue^15,16. Leptin also effects thyroid deiodinase activities with activation of T4 to T3conversion¹⁷. Leptin increases susceptibility to autoimmune thyroid dysfunction which is the main cause of hypothyroidism in adults, by regulating immune processes in obese men and premenopausal obese women¹⁹. Association between TSH and serum lipid in women with normal thyroid function is regulated via insulin sensitivity and that insulin sensitivity can be affected by thyroid function20. A reduction in LDL receptors resulted in reduced LDL catabolism in women with overt hypothyroidism leading to increased level of cholesterol and LDL-C and reductions inHDL-C^3,21.

 

SUMMARY AND CONCLUSIONS

Our study demonstrated that dyslipidemia is a definite entity in hypothyroidism [both Subclinical Hypothyroidism (SCH) and Overt Hypothyroidism (OH)]. Replacement therapy with Levothyroxine in both Subclinical Hypothyroidism (SCH) and Overt Hypothyroidism (OH) patients causes beneficial effects on lipid parameters like hypercholesterolemia and hypertriglyceridemia. Early diagnosis and treatment of hypothyroidism may prevent the onset of overt hypothyroidism and its associated effects. Levothyroxine replacement in such patients reverses thyroid hormone deficiency as well as dyslipidemia. This study is helpful for early detection of Hypothyroidism and dyslipidemia thus prevents complications like Coronary Artery Diseases, Cerebrovascular Diseases and Peripheral Vascular Diseases in future.

 

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