TOPLINE:

In patients with Alport syndrome, a higher baseline urine albumin-to-creatinine ratio (UACR) was independently associated with a greater yearly decline in kidney function. This study suggested that combining measurements of albuminuria and urinary immunoglobulin G (IgG) —which showed high sensitivity for a rapid decline — might improve the identification of patients at the highest risk.

METHODOLOGY:

• Researchers conducted a retrospective observational study to determine whether urinary biomarkers can predict the rate of kidney function decline in patients with Alport syndrome.
• They analysed data of 127 patients (mean age, 36 years; 54% women) from two outpatient clinics in Germany; most had genetically confirmed Alport syndrome.
• Urinary markers assessed included UACR, urine protein-to-creatinine ratio, IgG, and alpha-1-microglobulin; their prognostic value in predicting kidney function decline was compared.
• The estimated glomerular filtration rate (eGFR) was evaluated using the Chronic Kidney Disease Epidemiology Collaboration equation based on serum creatinine; the annualised change in the eGFR was assessed over a mean follow-up duration of 42 months.
• A fast eGFR decline was defined as a loss of greater than 3 mL/min/1.73 m² per year, and a rapid decline was defined as a loss of more than 6 mL/min/1.73 m² per year.

TAKEAWAY:

• Over the follow-up period, 40% of patients had a fast decline in the eGFR, of whom 24% experienced a rapid decline.
• The baseline UACR showed the strongest negative correlation with the change in the eGFR (Spearman correlation coefficient, -0.435; P < .001) and remained independently associated with the annual decline in the eGFR after adjustment for confounders.
• Receiver operating characteristic curve analysis demonstrated that the UACR was significantly associated with a rapid eGFR decline (area under the curve, 0.779; P < .001); a cutoff of 1059.5 mg/g creatinine at the Youden index provided a sensitivity of 80.8% and a specificity of 73.5%.
• Urinary IgG showed the highest sensitivity among the tested biomarkers for identifying a rapid decline in kidney function.

IN PRACTICE:

"[The study] results suggest that the incorporation of both albuminuria and urinary IgG into regular clinical monitoring may facilitate the identification of patients at the highest risk for rapid kidney function decline," the authors wrote.

SOURCE:

This study was led by Jan Boeckhaus, University Medical Center Göttingen, Göttingen, Germany. It was published online on June 10, 2026, in Clinical Kidney Journal.

LIMITATIONS:

The study had a relatively small sample size. The retrospective and observational design of the study prevented establishing causality. Additionally, data on blood pressure, BMI, nephrotoxic medication, diet, and physical activity were not obtained for all patients.

DISCLOSURES:

This study did not receive any funding. Few authors reported receiving research funding from the European Renal Association and Deutsche Forschungsgemeinschaft and being members of the European Reference Network for Rare Kidney Diseases.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.