Clinical and pathological features of IgA nephropathy patients with thyroid dysfunction: A retrospective cohort study.

Objective: This study investigates the clinical characteristics, pathological features, and risk factors of thyroid dysfunction in patients with immunglobulin A (IgA) nephropathy to facilitate early intervention and improve prognosis.

Materials and methods: A total of 415 patients diagnosed with IgA nephropathy by renal biopsy between June 2019 and December 2021 were included. Thyroid function was evaluated for the first time during hospitalization, and clinical and pathological data were analyzed. Comparisons were made between patients with normal and abnormal thyroid function, and logistic regression analysis was used to identify independent risk factors for thyroid dysfunction.

Results: There were 136 patients with thyroid dysfunction. Patients with thyroid dysfunction had significantly higher diastolic blood pressure (DBP), mean arterial pressure (MAP), serum creatinine (SCR), blood urea nitrogen (BUN), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), complement component (C4), erythrocyte sedimentation rate (ESR), and 24-hour proteinuria (24hUP) but lower red blood cell (RBC), hemoglobin (Hb), albumin (Alb), IgG, IgA, and estimated glomerular filtration rate (eGFR) (all p < 0.05). These patients also exhibited a higher prevalence of T1+2 lesions and advanced chronic kidney disease (CKD) stages (3 - 5). Furthermore, thyroid dysfunction was associated with increased proteinuria severity and CKD progression. Thyroid-stimulating hormone (TSH) levels were positively correlated with age, mean arterial pressure, lipid levels, and 24hUP, whereas free triiodothyronine (FT3) and free thyroxine (FT4) levels were inversely correlated with these parameters. Logistic regression analysis identified elevated 24hUP (OR = 1.207, 95% CI: 1.117 - 1.305, p < 0.001) and eGFR < 60 mL/min/1.73m2 (OR = 2.330, 95% CI: 1.262 - 4.302, p = 0.007) as independent risk factors for thyroid dysfunction.

Conclusion: Thyroid dysfunction is common among IgAN patients and is associated with more severe clinical and pathological features, such as increased proteinuria and advanced CKD stages. These findings underscore the importance of monitoring thyroid function and implementing targeted interventions to improve outcomes in IgA nephropathy patients.