Impact of thyroid dysfunction on serum cystatin-c level

Abstract EN

Objective : The aim of the present study was to explore the variation in serum cystatin-C level in hypo- and hyperthyroidism before and after treatment and to determine its role in assessment of renal function in comparison to serum creatinine, β2 microglobulin and GFR.

Materials and methods : This study included fifteen primary hypothyroid patients (group-I = 7 males and 8 females, aged 22-48 years), fifteen primary hyperthyroid patients (group-II = 6 males and 9 females, aged 23-44 years) and fifteen healthy, age and sex-matched subjects as controls (group-Ill).

Serum samples were taken both before initiation of therapy and after recovery to euthyroid state.

All groups were subjected to full history and through clinical assessment and laboratory investigation, including BUN, serum creatinine, uric acid sodium, potassium, FT3, FT4 and TSH.

In addition, levels of β2 microglobulin and cystatin-C were determined and quantitative estimation of glomerular filtration rate (GFR).

Results: In treated-hypothyroid patients, serum cystatin-C and GFR were highly significantly elevated (p < 0.001) concomitant with non-significant change in (β2 microglobulin and highly significant decrease in serum creatinine (p < 0.

001) compared to untreated hypothyroid patients.

Meanwhile, in treated-hyperthyroid patients, cystatin-C, p \-microglobulin and GFR were highly significantly reduced (p < 0.

001), while serum creatinine was highly significantly increased (p < 0.001) compared to pre-treated hyperthyroid patients.

In addition, a significant correlation was observed between cystatin-C, free T4 and TSH in both hypo and hyperthyroidism before treatment and between cystatin-C and free T4 -ttl hypothyroidism after treatment.

Conclusion : Due to the major impact of thyroid hormones on cystatin-C, thyroid dysfunctions should be considered first when cystatin-C is determined as a renal function indicator.