Dominik Georg Haider

Background Physicians refer proteinuric patients to kidney biopsy in order to clarify the issue of underlying renal disease. We compared kidney biopsy results with classical outcome parameters in a large cohort of patients with biopsy proven glomerulonephritis (GN). Methods In a retrospective analysis, 2687 patients with different forms of GN from 123 Austrian centres were investigated. Patient characteristics, the diagnosis of GN and its respective subtype and clinical symptoms such as arterial hypertension, haematuria, amount of proteinuria and estimated glomerular filtration rate (eGFR) were tested for their association with all‐cause mortality and progression to end‐stage renal disease (ESRD). Results During a median follow‐up of 129·9 months (IQR 89·6; 177·7), 688 patients (25·6%) died and 718 patients required dialysis (29·4%). In multivariate Cox's regression analysis age (HR 1·06), female sex (HR 0·71), eGFR (HR 0·74), the diagnosis of GN and its subtypes predicted patient survival (all P < 0·01), whereas the amount of proteinuria was not associated with patient survival. The incidence of progression to ESRD was associated with female sex (HR 0·71), eGFR (HR 0·65), amount of proteinuria (HR 1·15) and the diagnosis of GN and its subtypes (all P < 0·01). Nephrotic or nephritic syndromes were not associated with patient survival or progression to ESRD and did not add further predictive value to outcome of GN. Conclusions Our study demonstrates histological diagnosis of GN and its specific subtype predicts patient survival and dialysis incidence. Therefore, kidney biopsy should be an integral part of routine diagnostic assessment in patients with any forms of suspected GN.

Background: Treatment with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin 2 receptor blockers (ARBs) is associated with an increased risk for acute kidney injury after cardiovascular interventions. However, for patients undergoing kidney biopsy, no data is available. Methods: Four hundred and sixty-six patients undergoing kidney biopsy were retrospectively analyzed of whether or not concomitant intake of ACEIs or ARBs impairs kidney function. Results: Three hundred and twenty-three patients received ACEIs or ARBs or both before kidney biopsy. ACEI/ARB intake had no effect on kidney function compared to patients without this medication (all p > 0.05). Conclusion: Treatment with ACEIs or ARBs is not associated with risk of acute kidney injury in subjects undergoing kidney biopsy.

Interventional diagnostic procedures are established for several diseases in medicine. Despite the KDOQI guideline recommendation for histological diagnosis of kidney disease to enable risk stratification, its optimal time point has not been evaluated. We have therefore analyzed whether histological diagnosis of glomerulonephritis (GN) at an early stage of chronic kidney disease (CKD) is associated with different outcome compared to diagnosis at a more advanced stage. A cohort of 424 consecutive patients with histological diagnosis of GN were included in a retrospective data analysis. Kidney function was assessed by glomerular filtration rate (GFR) estimation at the time point of kidney biopsy and after consecutive immunosuppressive therapy. Censored events were death, initiation of dialysis or kidney transplantation, or progression of disease, defined as deterioration of CKD stage ≥1 from kidney biopsy to last available kidney function measurement. Occurrence of death, dialysis/transplantation or progression of disease were associated with GFR and CKD stage at the time of kidney biopsy (p < 0.001 for all). Patients with CKD stage 1 and 2 at kidney biopsy had fewer endpoints compared to patients with a GFR of p < 0.001). Kidney function at the time point of histological GN diagnosis is associated with clinical outcome, likely due to early initiation of specific drug treatment. This suggests that selection of therapy yields greatest benefit before renal function is impaired in GN.

Background: Neurohumoral effects have been suggested to affect kidney function. Stroke is a condition where regulation of the renin–angiotensin system and sympathetic nerve activity are altered. Methods: Renal function as estimated by serum creatinine was analyzed over 1 week in 220 patients after acute ischemic stroke. Results: In patients with chronic kidney disease defined as those with serum creatinine >1.2 mg/dL at admission (n = 62), renal function transiently improved, measured by a mean decrease of creatinine of 0.34 mg/dL during the first days after stroke. A significant and transient decrease of creatinine was also observed in patients with diabetes (n = 69) or patients with heart failure (n = 89). In both subgroups creatinine decreased by a mean of 0.49 and 0.24 mg/dL, respectively (p < 0.05 for both). In patients with normal renal function at admission, no change in serum creatinine occurred during the first week after stroke. There was no association between stroke severity and creatinine change. Conclusion: An acute ischemic cerebrovascular event intermittently improves impaired kidney function. The underlying mechanism may involve central regulation of renal function.