A study of renal function in the hypothyroid patients at the tertiary health centre

 

Swapna V S^1*, Vani B², Dinesh Javerappa³

 

¹Associate Professor, ²Tutor, ³Professor and HOD, Department of Biochemistry, Viswabharathi Medical College, Penchigalpadu, Kurnool, Andhra Pradesh, INDIA.

Email: drswapnavs07@gmail.com

 

Abstract               Background: Thyroid diseases are the most common endocrine disorders world-wide. India too is no exception. According to a projection from various studies on thyroid disease, it has been estimated that about 42 million people in India suffer from thyroid diseases. Aims and Objective: To study Renal function in the Hypothyroid patients at the tertiary health Centre. Methodology: After approval from institutional ethical committee this cross-sectional study was carried out in the patients of the hypothyroidism at Viswabharathi Medical College and Hospital during the year January 2016 to December 2016. The diagnosed patients of hypothyroidism who gave consent were enrolled into the study and similar eu-thyroid patients also included into the study. The renal function test with parameters like Creatinine Clearance, Creatinine Urea, Uric acid etc. was done in both the groups. The statistical analysis done by unpaired t-test calculated by SPSS 19 version software. Result: The majority of the patients were in the age group of 30-39 i.e. 48%, followed by 40-49 -16%, 50-59-12%, >60-10%. The majority of the patients were Female i.e. 66% followed by Male 24%. Creatinine Clearance was significantly lower i.e. 102.04±9.99, 80.72±10.58 (P<0.001), Creatinine -0.86±0.101, 0.728±0.0453 (P<0.001); Urea -28.14±3.14, 21.86±3.05(P<0.001); Uric acid- 5.086±0.7617, 3.122±0.159(P<0.001) significantly higher in the hypothyroid patients as compared to control. Conclusion: It can be concluded from our study that the majority of the hypothyroid patients were female and in the age group of 30-39, the hypothyroid patients shown significantly deranged renal function test in the form i.e. Creatinine Clearance was significantly lower, Creatinine, Urea, Uric acid, significantly higher in the hypothyroid patients as compared to euthyroid.

Key Words: Hypothyroid, Euthyroid, Renal function Test, Creatinine Clearance, Creatinine Urea, Uric acid.

 

 

INTRODUCTION

Thyroid diseases are the most common endocrine disorders world-wide. India too is no exception. According to a projection from various studies on thyroid disease, it has been estimated that about 42 million people in India suffer from thyroid diseases.¹ Thyroid hormones (TH) regulate the renal hemodynamics and basal metabolic rate of most cells. The thyroid gland synthesizes and releases triiodothyronine (T3) and thyroxine (T4), which represent the only iodine containing hormones in the vertebrates. T3 is the biologically active thyroid hormone.² These hormones are required for the normal growth, development and function of nearly all tissues, with major effects on oxygen consumption and metabolic rate^.3 TH synthesis and secretion is regulated by a negative feedback system that involves the hypothalamus, pituitary and the thyroid gland.⁴ THs regulate the basal metabolic rate of all cells including hepatocytes and hence, modulate hepatic function; the liver in turn metabolizes the thyroid hormones and regulates their systemic endocrine effects.⁵ Normal circulating levels of thyroid hormone are required for both normal hepatic circulation and normal bilirubin metabolism.⁶ Thyroid dysfunction may perturb liver function and vice-versa.⁵ In experimental animals, surgical or drug-induced hypothyroidism of a few weeks duration has been shown to result in a decrease in glomerular filtration rate.^7,8

 

MATERIAL AND METHODS

After approval from institutional ethical committee this cross-sectional study was carried out in the patients of the hypothyroidism at Viswabharathi Medical College and Hospital during the year January 2016 to December 2016. The diagnosed patients of hypothyroidism who gave consent were enrolled into the study and similar eu-thyroid patients also included into the study. The renal function test with parameters like Creatinine Clearance, Creatinine Urea, Uric acid etc. was done in both the groups. The statistical analysis done by unpaired t-test calculated by SPSS 19 version software.

 

RESULT

 

Table 1: Age wise distribution of the patients

The majority of the patients were in the age group of 30-39 i.e. 48%, followed by 40-49 16%, 50-59-12%, >60-10%.

 

Table 2: Distribution of the patients as per the sex

The majority of the patients were Female i.e. 66% followed by Male 24%.

 

Table 3: Distribution of the Cases and Controls as per the Renal Function test

From above table it is clear that Creatinine Clearance was significantly lower i.e. 102.04±9.99 80.72±10.58 (P<0.001), Creatinine -0.86±0.101, 0.728±0.0453 (P<0.001); Urea -28.14±3.14, 21.86±3.05 (P<0.001); Uric acid- 5.086±0.7617, 3.122±0.159 (P<0.001) significantly higher in the hypothyroid patients as compared to control.

 

DISCUSSION

Recent epidemiological studies, identifying a high prevalence of thyroid dysfunction amongst patients with renal impairment, lend a new importance to the phenomenon of reversible hypothyroidism-induced renal impairment. Subclinical hypothyroidism (elevated TSH levels with normal FT4 levels) and clinically-apparent hypothyroidism occur in ∼18–20% of patients with chronic kidney disease not requiring renal replacement therapy, with the prevalence rising as the degree of renal impairment worsens^10,11. The benefits of thyroid hormone replacement therapy, including its effects on renal function, in patients with subclinical hypothyroidism remain unclear. Whilst the pathophysiology of impaired renal function in hypothyroidism is multifactorial, the reduction in GFR due to the lower cardiac output and renal blood flow is likely to be the predominant mechanism¹². It has also been suggested that thyroxine may mediate tubular secretion of creatinine¹³. Furthermore, hypothyroidism may increase creatinine release from muscle¹⁴. Although freely filtered, additional tubular secretion of creatinine renders it a poor marker of GFR. In patients with hypothyroidism, clarification of whether an elevated serum creatinine represents true renal impairment (i.e. reduced GFR) or simply increased generation, and tubular secretion, of creatinine therefore requires further analysis by the way of isotope GFR studies. Although hypothyroid myopathy is usually limited to myalgias, rhabdomyolysis leading to acute kidney injury is a rare complication of hypothyroidism¹⁵. Treatment with thyroid hormone replacement therapy reverses rhabdomyolysis and improves renal function¹⁶. Although creatine kinase was elevated in our first patient, the absence of urinary myoglobin and the normal biopsy findings excluded rhabdomyolysis. Although end-stage renal disease secondary to hypothyroidism has been reported¹⁷, changes in serum creatinine resulting from hypothyroidism are commonly subtle. Histological findings (including glomerular and tubular basement membrane thickening, mesangial enlargement and epithelial and interstitial cell inclusions) have all been described in patients with hypothyroidism¹⁸. These have proven both reversible and irreversible with treatment^18,19. Hypothyroidism has also been described as the consequence, rather than the cause, of renal dysfunction; thyroxine is heavily protein bound and is lost via the urine in nephrotic syndrome²⁰. In our study we have found that The majority of the patients were in the age group of 30-39 i.e. 48%, followed by 40-49 -16%, 50-59-12%, >60-10%. The majority of the patients were Female

 i.e. 66% followed by Male 24%. Creatinine Clearance was significantly lower i.e. 102.04±9.99, 80.72±10.58 (P<0.001), Creatinine -0.86±0.101, 0.728±0.0453 (P<0.001); Urea -28.14±3.14, 21.86±3.05 (P<0.001); Uric acid- 5.086±0.7617, 3.122±0.159 (P<0.001) significantly higher in the hypothyroid patients as compared to control. This was similar to HS Chaudhury et al ¹⁹ they found the mean (±SD) serum creatinine was significantly higher in hypothyroid Group than euthyroid Group (P<0.01) The estimated glomerular filtration rate (eGFR) was lower in hypothyroid Group compared to euthyroid Group (p=0.011)

 

CONCLUSION

It can be concluded from our study that the majority of the hypothyroid patients were female and in the age group of 30-39, the hypothyroid patients shown significantly deranged renal function test in the form i.e. Creatinine Clearance was significantly lower, Creatinine, Urea, Uric acid, significantly higher in the hypothyroid patients as compared to euthyroid.

 

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