Clinicopathological Characteristics and Outcomes of Immunoglobulin A Nephropathy with Different Types of Dyslipidemia: A Retrospective Single-Center Study

Introduction: Immunoglobulin A nephropathy (IgAN) is one of the most common glomerulonephritic diseases in the world. Several lines of evidence have suggested that dyslipidemia is related to the disease progression and prognosis of IgAN. However, the study is scarce on the clinicopathological characteristics and outcomes of IgAN with dyslipidemia. Methods: This study retrospectively analyzed 234 patients with biopsy-proven idiopathic IgAN at the Department of Nephrology, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, between January 2015 and June 2021. The participants were divided into dyslipidemia (n = 119) and non-dyslipidemia (n = 115), and the dyslipidemia group was also divided into the following 4 groups: hypertriglyceridemia group, hypercholesterolemia group, mixed hyperlipidemia group, and low high-density lipoprotein cholesterol group. The estimated glomerular filtration rate (eGFR) was estimated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Results: The prevalence of dyslipidemia in IgAN patients in our center was 50.9% (119/234). The patients with dyslipidemia presented with higher systolic blood pressure (BP), diastolic BP, serum creatinine, uric acid, hemoglobin, proteinuria, and eGFR (p < 0.05). Proportions of males, hypertension, and chronic kidney disease stage 2 similar to 5 were also higher in the dyslipidemia group (p < 0.05). Similarly, the pathological characteristics performed were worse in the dyslipidemia group. Most dyslipidemia patients had a higher percentage of mesangial hypercellularity (M1) and tubular atrophy/interstitial fibrosis (T1 similar to 2) in the Oxford Classification's scoring system (p < 0.05). Multivariate logistic regression analysis revealed that male gender (odds ratio [OR] = 2.397, 95% confidence interval [CI]: 1.051-5.469, p = 0.038) and proteinuria (OR = 1.000, 95% CI: 1.000-1.001, p = 0.035) were possible risk factors for dyslipidemia. A total of 13 patients (13.8%) in the dyslipidemia group had an endpoint event, of which 6 patients (6.4%) had a >= 50% decrease in eGFR from baseline and 7 patients (7.4%) reached the end-stage renal disease stage. Kaplan-Meier survival curve analysis showed that patients in the dyslipidemia group had a worse outcome than those in the non-dyslipidemia group (log-rank test, p = 0.048). Conclusions: IgAN patients with dyslipidemia presented more severe clinicopathological characteristics. Male gender and proteinuria are significantly associated with the occurrence of dyslipidemia in IgAN patients. Patients in the dyslipidemia group had a worse prognosis than those in the non-dyslipidemia group, which may be essential for the disease management of IgAN and help identify the high-risk patients.