The implications of focal segmental glomerulosclerosis in children with IgA nephropathy

Points of view in nephrology: personalized management of IgA nephropathy, beyond KDIGO

IgA nephropathy is the most common primary glomerulonephritis worldwide, and an important cause of kidney failure, as 20-40% of patients progress to renal replacement therapy 20-30 years after diagnosis. Its clinical presentation ranges from isolated microscopic hematuria to nephrotic syndrome, and even to a rapidly progressive course. Ethnicity and epigenetics play a key role in its clinical aggressiveness. Selection of patients at risk needing immunosuppressive treatment is a challenge for the nephrologist. Some active and chronic kidney lesions detected on kidney biopsy have been demonstrated to have prognostic value according to the Oxford Classification of IgA nephropathy, later validated by numerous studies. However, KDIGO 2021 guidelines still consider persistent proteinuria > 1 g/24 h to be the most relevant risk factor for the progression of IgA nephropathy and the only one requiring immunosuppressive treatment. KDIGO guidelines have proposed a therapeutic algorithm, but many patients present peculiar characteristics that are not addressed by the current guidelines, pointing to the need for alternative approaches. In these cases, a tailored approach to each patient should be followed in which clinical, histological, laboratory, social and ethical aspects must be considered. In this manuscript we present three cases of IgA nephropathy from different countries, highlighting many of the aspects encountered in clinical practice that illustrate an individualized approach to the treatment of these patients.

Dyslipidemia may be a risk factor for progression in children with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) is often chronically progressive and commonly accompanied by dyslipidemia. However, the intrinsic relationship between dyslipidemia and IgAN remains to be elucidated. This study aimed to investigate the impact of different types of dyslipidemia on clinical and pathological characteristics in children with IgAN.

METHODS

In our retrospective cohort study from January 2006 to January 2021, 276 children with IgAN were ultimately included in the baseline analysis, and 169 were included in the follow-up analysis. The clinical and pathological features of different types of dyslipidemia and their effect on kidney prognosis were analyzed.

RESULTS

Children in the dyslipidemia group had more severe clinical characteristics (higher blood urea nitrogen, serum uric acid, and 24-h proteinuria; higher proportion of hypertension; and lower serum albumin and estimated glomerular filtration rate) and pathological changes (higher proportion of Lee grades IV-V and E1, S1, and C2 in MEST-C). Furthermore, the clinical and pathological characteristics were worse in the mixed hyperlipidemia group. Multivariate logistic analysis showed that hypertension, steroid treatment, lower serum albumin, severe proteinuria, and segmental glomerulosclerosis were independent risk factors for dyslipidemia in children with IgAN. The Kaplan-Meier analysis revealed that the probability of kidney survival in children with dyslipidemia was lower than that in those without dyslipidemia, with a median follow-up of 5.9 years.

CONCLUSIONS

Children with IgAN and dyslipidemia, especially mixed hyperlipidemia, are prone to more severe clinical and pathological changes. Our study provides further insight into dyslipidemia as a potential risk factor in children with IgAN. A higher resolution version of the Graphical abstract is available as Supplementary information.

IgA nephropathy in children and in adults: two separate entities or the same disease?

IgA nephropathy (IgAN) is observed in subjects of any age, however perspective and management of this disease are different between adult and pediatrician Nephrologists. Most children with IgAN present with gross hematuria rapidly vanishing or persistent mild microscopic hematuria, which rarely progresses to end stage renal disease (ESRD) over the pediatric observation. The perspective of IgAN in adults is of a slowly progressive glomerular disease with 30-40% probabilities to reach ESRD. However, mild cases of IgAN in children might be missed with manifestation of irreversible damage only decades after the true onset, as 50% of subjects with IgAN enter renal replacement treatment before the age of 50 years. In both adults and children the assessment of risk profile is crucial to avoid overtreatment in benign cases or institute a prompt and valid therapy in potentially progressive cases. In case of common risk factors, new therapeutic opportunities tested in adults might be applied to children with the expectation of similar results. If IgAN is the same disease in spite of different clinical profiles in children and adults, an early intervention may be the correct way to prevent progression decades later. On the contrary, if we are dealing with different clinical entities, the treatment in pediatric and in adult settings must be kept apart. This review addresses to report similarities and differences of IgAN across the life periods in order to reason on the application of newly offered treatments over the entire spectrum of this disease or in focused age indications.