Overlapping Obesity-Related Glomerulopathy And Immunoglobulin A Nephropathy:Clinical And Pathologic Characteristics And Prognosis

Background and objectiveObesity is a worldwide health issue and it is predicted that 51%of the global population will be obese by 2030.The incidence of obesity-related glomerulopathy(ORG)has increased with the obesity epidemic.In 1974,Weisinger et al.first reported nephropathic proteinuria in severely obese patients,and since then,there have been reports of obesity-related glomerular hypertrophy or obesity-related focal segmental glomerulosclerosis,which was named as ORG.ORG presents as either subnephrotic,or less commonly nephrotic range proteinuria,but without hypoalbuminemia or nephrotic syndrome,and some patients with impaired renal function even progress to end-stage renal disease(ESRD).Immunoglobulin A nephropathy(IgAN)is characterized by the predominant deposition of IgA in the glomerular mesangium.IgAN represents one of the most frequent causes of primary glomerulonephritis in China,constituting approximately 45%of all primary glomerulonephritis cases,and remains the primary cause of the end-stage renal disease(ESRD).Within 20 years from the onset of disease,nearly 36%of adult patients with IgAN might progress to ESRD in China.It has been found that ORG does not always exist alone,but can be combined with other nephropathy,especially IgAN.Both ORG and IgAN are common primary glomerular diseases.However,there are few studies on obesity-related glomerulopathy combined with IgA nephropathy(ORG+IgAN)and only a few case reports have been published.In this study,we retrospectively analyzed the clinical,pathologic and prognostic characteristics of patients with ORG+IgAN compared with those of patients with ORG alone to raise awareness of the disease.MethodsThis was a retrospective cohort study of a total of 80 patients with ORG+IgAN who underwent a renal biopsy between January 1,2012 and June 30,2019 at the Department of Nephrology of The First Affiliated Hospital of Zhengzhou University.(All patients were≥18 years old,the number of glomeruli in the kidney biopsy tissues was≥10,and the follow-up time was≥1 year;Patients were excluded if they had secondary IgAN(Henoch-Schonlein purpura nephritis and hepatitis B or C)or presented with nephropathy other than IgAN.147 ORG patients and 150 IgAN patients were selected by random sampling as two control groups.General information,clinical data,renal pathology data of all the enrolled patients were collected,and medication,urinary protein and renal function were recorded during the follow-up period.The clinicopathological data of ORG+IgAN patients were compared,and the prognosis of the patients and the prognosis factors were analyzed.ResultsIn clinical,compared to patients with ORG alone,ORG+IgAN patients had a lower serum albumin level,higher incidence of hyperuricemia and higher incidence of microscopic hematuria.Compared to patients with ORG alone,ORG+IgAN patients had lower eGFR and lower incidence of microscopic hematuria,but with higher age,BMI,serum albumin,and higher incidence of hypertension,hyperuricemia,hyperglycemia,and hypertriglyceridemia(P<0.05).Patholog ically,compared to patients with ORG alone,the proportion of mesangial hyperplasia,crescent formation and O-FSGS was higher in ORG+IgAN patients(P<0.05).Compared to patients with IgAN alone,the proportion of endothelial cell proliferation and crescent formation was lower in ORG+IgAN patients,but the proportion of spherical sclerosis was higher in ORG+IgAN patients(P<0.05).In terms of treatment and prognosis,compared to patients with ORG alone,the proportion of corticosteroid or immunosuppressive therapy and remission rate of renal disease were higher in ORG+IgAN patients(P<0.05),but there was no significant difference in cumulative renal survival rate(P>0.05).Compared to patients with IgAN alone,there were no significant differences in renal remission rate and cumulative renal survival rate between the two groups(P>0.05).Multivariate Cox regression analysis showed that corticosteroid or immunosuppressive therapy was a favorable factor for remission of nephropathy in ORG+IgAN patients,and BMI was a risk factor for long-term prognosis in ORG+IgAN patients(P<0.05).Conclusions1.ORG+IgAN is not uncommon.OR-G+IgAN-should be considered in obese patients who present with metabolic abnormalities and microscopic hematuria.2.Although corticosteroid or immunosuppressive therapy was a favorable factor for remission of nephropathy,there was an increased risk of infection.3.BMI was significantly associated with poor prognosis.Therefore,obese patients should pay attention to weight control in order to improve the prognosis.