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Abstract Background: Lupus nephritis (LN) is a major source of morbidity and mortality in patients with systemic lupus erythematosus (SLE), with 10-25% of patients progressing to end-stage renal disease (ESRD). Objective: This study aims to elucidate the predictive capabilities of 24-h proteinuria (24PTU) and serum creatinine (sCr) after 12 months of treatment with respect to long-term renal outcomes in LN in a single-center cohort of LN patients. Methods: A retrospective analysis was performed on 214 patients diagnosed with LN followed in our center. Values of 24PTU and sCr were assessed at baseline and after 3, 6 and 12 months, and after 5 years and/or the last evaluation. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 for 3 months or longer. End-stage renal disease (ESRD) was defined as the need for permanent dialysis. Receiver operating characteristics curves (ROC) were used to test the best cut-off value of 24PTU and sCr at 12 months who predict bad long-term renal outcomes. Results: The mean follow-up period was 11.2 ± 7.2 years. The best cut-off values for 24PTU and sCr as predictor of CKD were, respectively, 0.9 g/24 h and 0.9 mg/dL. ROC curve for 24PTU had a slightly lower performance than ROC curve for sCr as predictor for CKD (PTU AUC = 0.68; sCr AUC = 0.70), but sensitivity and specificity were better for 24PTU (24PTU: sensitivity = 63.5%, specificity = 71.2%; sCr: sensitivity = 54.8%, specificity = 75.3%). When the outcome was ESRD the best cut-off points were 0.9 g/24hs and 1.3 mg/dL for 24PTU and sCr, respectively, and the curve performance was better for 24PTU (PTU AUC = 0.72; sCr AUC = 0.61). Conclusions: In this ethnically diverse population with LN followed for a long time (> 10 years), levels of 24PTU > 0.9/day at 12 months was a good predictor of bad long-term renal outcome. The serum creatinine > 0.9 mg/dL and > 1.3 mg/dL at 12 months were also good predictors of CKD and ESRD, respectively. Patients with 24PTU < 0.9 g/day and sCr < 1.3 mg/dL at 12 months are not likely to develop ESRD because of the high negative predictive values (NPV) (93.2% and 82%). 24PTU and sCr are relevant as components for a treat-to-target strategy for LN treatment, since their high NPV corroborates their importance as good predictors of long-term renal outcome.
ABSTRACT
ABSTRACT Introduction: Knowledge of validated primary causes of end-stage renal disease (ESRD) is extremely relevant in the realm of public health. The literature lacks validated studies on the primary causes of ESRD. Objective: The aim of this study was to estimate the prevalence of the causes of ESRD in a State Capital in Northeastern Brazil. Methods: This cross-sectional study was based on the analysis of medical records of patients on hemodialysis at five specialized centers in Fortaleza, CE, Brazil. Deaths and patients referred to other centers outside Fortaleza were excluded from the study. The data of 830 patients were initially collected, but 818 remained enrolled after the exclusion criteria were applied, the equivalent to 48% of the patents on dialysis in the city. Results: 61.1% of the patients were males. Twenty-two percent of all enrolled individuals were aged 60-69 years. Patient mean age was 55.7 ± 16 years. The most common validated cause of ESRD was unknown (35.3%), followed by diabetes mellitus (26.4%), adult polycystic kidney disease (6.2%), graft failure (6.2%), obstructive uropathy (5.7%), and primary glomerulonephritis (5.3%). Before validation, primary hypertension was the most frequent cause of chronic kidney disease (22.9%), decreased to 3.8% after validation. Conclusion: The data contradicted national studies reporting primary hypertension as the main cause of chronic kidney disease (CKD). A high rate of unknown causes and categorization bias were observed mainly in relation to primary hypertension as a cause of CKD, which affects the overall prevalence of causes of ESRD in patients on dialysis.
RESUMO Introdução: O conhecimento das causas primárias, validadas, de doença renal crônica terminal (DRCT) é primordial no contexto epidemiológico da doença. Existe uma lacuna na literatura em termos de estudos validados sobre tais causas. Objetivo: Estimar a prevalência das causas de DRCT em uma capital do Nordeste brasileiro. Métodos: Estudo transversal baseado na análise dos prontuários de pacientes em hemodiálise de cinco centros especializados em Fortaleza, CE. Foram excluídos casos de óbito no período da coleta e de transferências para outras unidades fora do município em questão. Coletou-se dados de 830 pacientes, restando 818 após aplicação dos critérios de exclusão, o correspondente a 48% dos pacientes que dialisam na cidade. Resultados: Observou-se que 61,1% dos pacientes eram do sexo masculino. A faixa etária mais prevalente foi 60 a 69 anos, 22%. A idade média foi 55,7 ± 16 anos. A causa mais comum de DRCT pós-validação foi indeterminada, 35,3%; seguida por diabetes mellitus, 26,4%; doença renal policística do adulto, 6,2%; falência do enxerto, 6,2%; uropatia obstrutiva, 5,7%; e glomerulonefrite primária, 5,3%. Antes da validação, a hipertensão primária foi a causa mais frequente de DRCT, com 22,9%, e, após validação, caiu para 3,8%. Conclusão: Os dados contrariam estudos nacionais que afirmam que a primeira causa de DRCT seria hipertensão primária. Evidenciou-se alta taxa de causas desconhecidas e viés de classificação, principalmente com relação à HAS primária como causa de DRCT, o que afeta a prevalência geral das causas de DRCT dos pacientes em diálise.