A Retrospective Study of Children with Frequently Relapsing Nephrotic Syndrome Using Levothyroxine Added to Steroids During Relapses

Abstract Introduction: Levothyroxine treatment for thyroid hormone disorders, alongside standard Nephrotic Syndrome therapy during nephrotic syndrom relapses, might reduce relapse duration and corticosteroid consumption, despite debates over its necessity. This study explores levothyroxine's potential benefits in patients with frequent relapses and thyroid hormone disorders. Materials and Methods: This retrospective study investigated children with frequently relapsing nephrotic syndrome (FRNS) at ages 1–12 with elevated TSH levels, which have been treated according to IPNA guidelines for FRNS. Patients treated with levothyroxine were considered the levothyroxine group. This study compared outcomes between patients treated with levothyroxine and a control group, examining TSH levels, remission periods, and prognosis. Results: The mean dose of prednisolone and time to remission were significantly lower in the levothyroxine group compared to the controls (0.51 ± 0.40 versus 0.55 ± 0.50 mg/kg/day; p=0.03 and 6.0 ± 2.17 versus 9.7 ± 2.87 days; p<0.001, respectively). The relapse rate was 1.17 versus 1.53 with an incidence rate ratio of 0.76 (95% CL: 0.46–1.22; p = 0.24). There was a significant difference in the levels of TSH, free thyroxine (FT4), albumin, and creatinine. This significant difference disappeared during remission for albumin but remained significant for TSH and creatinine. Conclusion: This study suggests that administering levothyroxine during relapses can reduce the time to remission and, consequently, the cumulative dose of prednisolone. However, it does not significantly affect the prevention of future relapses, treatment failure, or steroid toxicity.