Prospective cohort analyzing risk factors for chronic kidney disease progression in children

To identify risk factors for chronic kidney disease progression in Brazilian children and to evaluate the interactions between factors. This was a multicenter prospective cohort in São Paulo, involving 209 children with CKD stages 3–4. The study outcome included: (a) death, (b) start of kidney replacement therapy, (c) eGFR decrease >50% during the followup. Thirteen risk factors were tested using univariate regression models, followed by multivariable Cox regression models. The terms of interaction between the variables showing significant association with the outcome were then introduced to the model. After a median follow‐up of 2.5 years (IQR=1.4–3.0), the outcome occurred in 44 cases (21%): 22 started dialysis, 12 had >50% eGFR decrease, seven underwent transplantation, and three died. Advanced CKD stage at onset (HR=2.16, CI=1.14–4.09), nephrotic proteinuria (HR=2.89, CI=1.49–5.62), age (HR=1.10, CI=1.01–1.17), systolic blood pressure Z score (HR=1.36, CI=1.08–1.70), and anemia (HR=2.60, CI=1.41–4.77) were associated with the outcome. An interaction between anemia and nephrotic proteinuria at V1 (HR=0.25, CI=0.06–1.00) was detected. As the first CKD cohort in the southern hemisphere, this study supports the main factors reported in developed countries with regards to CKD progression, affirming the potential role of treatments to slow CKD evolution. The detected interaction suggests that anemia may be more deleterious for CKD progression in patients without proteinuria and should be further studied. Identificar os fatores de risco para progressão da DRC em crianças do Brasil e avaliar as interações entre os fatores. Coorte prospectiva multicêntrica em São Paulo, envolvendo 209 crianças com DRC em estágios 3‐4. O desfecho do estudo incluiu: a) óbito, b) início da terapia de substituição renal, c) redução de > 50% na taxa estimada de filtração glomerular (eGFR) durante o acompanhamento. Foram testados 13 fatores de risco com o modelo de regressão univariada seguido do modelo de regressão multivariado de Cox. Os termos de interação entre as variáveis mostraram associação significativa e foram introduzidos ao modelo. Após média de acompanhamento de 2,5 anos (IIQ=1,4 a 3,0), 44 casos (21%) apresentaram desfecho: 22 iniciaram diálise, 12 apresentaram redução de > 50% na eGFR, sete foram submetidos a transplante e três morreram. Estágio avançado de DRC no acometimento (RR=2,16, IC=1,14‐4,09), proteinúria nefrótica (RR = 2,89, IC=1,49‐5,62), idade (RR = 1,10, I