Hepatitis C virus (HCV)–associated kidney injury can affect both the glomeruli and the renal interstitium. The aim of this single-center, prospective real-world study involving HCV patients was to assess longitudinal changes in liver and kidney parameters during HCV treatment and to examine how renal function and urine findings evolved in those with kidney manifestations prior to therapy. In total, 217 patients treated for HCV-infection were enrolled for the study. Renal abnormalities were defined as either s-creatinine above the normal limit (male > 100 µmol/l, female > 90 µmol/l), or estimated glomerular filtration rate (eGFR) below < 60 ml/min/ 1.73 m2, or number of urine red blood cells above the normal (U–erythrocytes ≥ 20 × 10(E6)/l), or tubular proteinuria above the normal (U–α 1-microglobulin, UA1M, ≥ 12 mg/l), or glomerular proteinuria above the normal (U–albumin/creatinine ratio, UACR, in men ≥ 2.5 mg/mmol, in women ≥ 3.5 mg/mmol) levels in a spot urine test. Forty patients (20

Introduction: Membranoproliferative glomerulonephritis is currently divided into immunoglobulin-mediated glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G); however, the patients often overlap with histology, complement, clinical and prognostic factors. Our aim was to investigate if an unsupervised clustering method finds different patient groups in 44 IC-MPGN/C3G patients using only histological and clinical data available in everyday clinical work. Methods: Primary IC-MPGN/C3G adult patients were included whose diagnostic (baseline) native biopsy was obtained in 2006-2017. The biopsies were reassessed and the clinical data at baseline and during follow-up were obtained from the medical records. There were 39 baseline histological and clinical variables included in the unsupervised clustering. Follow-up information was combined with the clustering results. Results: The clustering resulted in two clusters (n = 24 and n = 20 patients for clusters 1-2, respectively), where cluster 1 had a significantly higher baseline plasma creatinine (mean 213 vs. 104, respectively, p value <0.001) and a lower baseline eGFR than cluster 2 (mean 37 vs. 70, respectively, p value <0.001). Regarding histology, chronic changes such as lobulated glomeruli, mesangial matrix expansion, and glomeruli double contours were more prevalent in cluster 1 (p value <0.001). Biopsy morphology was more often crescentic and membranoproliferative in cluster 1 (p value <0.001). Although the differences were insignificant, cluster 1 patients were in dialysis in the last follow-up or had a progressive disease more often than cluster 2 patients (21% vs. 5%, 38% vs. 10%). Conclusions: Our results indicate that these patients share greater similarity than the current classification IC-MPGN versus C3G indicates. (c) 2024 S. Karger AG, Basel

Key PointsWe observed a comparable cumulative incidence of major adverse cardiovascular event (MACE) in in-center hemodialysis (IC-HD) and continuous ambulatory peritoneal dialysis (PD) patients, which was higher than in automated PD and home hemodialysis patients.After adjustment for confounders, there was no difference in risk of MACE between patients on home dialysis modalities and IC-HD.Compared with IC-HD, PD was associated with lower risk of MACE among female patients and higher risk among male patients.BackgroundAmong dialysis patients, cardiovascular events are the leading cause of death. Little is known about how the frequency and type of cardiovascular events differ between various dialysis modalities. We compared risk of major adverse cardiovascular events (MACEs) in patients who started continuous ambulatory peritoneal dialysis (CAPD), automated peritoneal dialysis (APD), and home hemodialysis with in-center hemodialysis (IC-HD) patients.MethodsWe included 968 patients who entered dialysis in the Helsinki-Uusimaa health care district in Finland from 2004 to 2017, of whom 162 were on CAPD, 229 on APD, 145 on home hemodialysis, and 432 on IC-HD at day 90 from the start of dialysis. MACE was defined as acute myocardial infarction, stroke, or death due to cardiovascular disease. The cumulative incidence of the first MACE was calculated. Cox regression was used to compare risk of MACE between dialysis modalities with adjustment for potential confounding factors.ResultsOf all 968 patients, 195 (20%) experienced a MACE during the entire follow-up and 62 (6%) during the first year of follow-up. The cumulative incidence of first MACE was similar in IC-HD and CAPD patients and higher than that in APD and home hemodialysis patients. After adjustment for possible confounders, the hazard ratio (HR) of MACE was 1.22 (95% confidence intervals [CIs], 0.73 to 2.05) for CAPD, 0.86 (95% CI, 0.47 to 1.57) for APD and 0.67 (95% CI, 0.30 to 1.50) for home hemodialysis compared with IC-HD. Unexpectedly, compared with IC-HD, peritoneal dialysis associated with lower risk of MACE among female patients (HR, 0.37; 95% CI, 0.14 to 0.99) and higher risk among male patients (HR, 1.80; 95% CI, 1.11 to 2.92).ConclusionsIn this cohort, the risk of MACE was comparable across in-center and home dialysis modalities. However, the result differed between male patients and female patients, which requires further research.

Membranoproliferative glomerulonephritis (MPGN) is subdivided into immune-complex-mediated glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G). Classically, MPGN has a membranoproliferative-type pattern, but other morphologies have also been described depending on the time course and phase of the disease. Our aim was to explore whether the two diseases are truly different, or merely represent the same disease process. All 60 eligible adult MPGN patients diagnosed between 2006 and 2017 in the Helsinki University Hospital district, Finland, were reviewed retrospectively and asked for a follow-up outpatient visit for extensive laboratory analyses. Thirty-seven (62%) had IC-MPGN and 23 (38%) C3G (including one patient with dense deposit disease, DDD). EGFR was below normal (≤60 mL/min/1.73 m2) in 67% of the entire study population, 58% had nephrotic range proteinuria, and a significant proportion had paraproteins in their serum or urine. A classical MPGN-type pattern was seen in only 34% of the whole study population and histological features were similarly distributed. Treatments at baseline or during follow-up did not differ between the groups, nor were there significant differences observed in complement activity or component levels at the follow-up visit. The risk of end-stage kidney disease and survival probability were similar in the groups. IC-MPGN and C3G have surprisingly similar characteristics, kidney and overall survival, which suggests that the current subdivision of MPGN does not add substantial clinical value to the assessment of renal prognosis. The high proportion of paraproteins in patient sera or in urine suggests their involvement in disease development.

Abstract Background and Aims Among dialysis patients, cardiovascular events are the leading cause of death. Little is known about difference in the frequency of cardiovascular events between various dialysis modalities. Glucose load may contribute to a metabolic burden in peritoneal dialysis (PD). On the other hand, hemodialysis can cause intradialytic hypotension, cardiac stunning, and arrhythmias, which are associated with increased risk of death. We compared risk of major cardiovascular events in patients who started continuous ambulatory PD (CAPD), automated PD (APD) and home HD with in-center HD patients. Method We included 968 patients who entered dialysis in the Helsinki-Uusimaa healthcare district in Finland from 2004 to 2017, of whom 162 were on CAPD, 229 on APD, 145 on home HD and 432 on in-center HD at day 90 from the start of dialysis. Patients were followed up for 5 years or until the end of 2019. Major adverse cardiovascular event (MACE) was defined as acute myocardial infarction, stroke or death due to cardiovascular disease. The cumulative incidence of the first MACE was calculated by taking other causes of death into account as competing risk events and censoring at time of kidney transplantation. Cox regression was used to compare risk of MACE between dialysis modalities with adjustment for age, gender, primary renal disease, prior comorbidities (coronary heart disease, left ventricular hypertrophy, heart failure and stroke), and laboratory data (plasma albumin, phosphate and ionized calcium). Imputation was performed to replace missing values of comorbidities and laboratory data. Results Of all 968 patients, 195 (20%) experienced a MACE during the entire follow-up and 62 (6.4%) during the first year of follow-up. The cumulative incidence of first MACE was similar in in-center HD and CAPD patients and higher than that in APD and home HD patients (Figure 1). Without adjustments, the hazard ratio of MACE was 0.83 [95% CI 0.56–1.2] for CAPD, 0.49 [95% CI 0.31–0.77] for APD and 0.42 [95% CI 0.23–0.78] for home HD in comparison to in-center HD. After adjustment for possible confounders, the hazard ratio of MACE was 1.1 [95% CI 0.70–1.6] for CAPD, 0.88 [95% CI 0.53–1.5] for APD and 0.80 [95% CI 0.41–1.6] for home HD and not statistically significantly different in comparison to in-center HD. Conclusion We observed a lower risk of MACE among patients who entered APD or home hemodialysis compared to in-center hemodialysis, but after adjusting for potential confounding factors, the difference diminished and was no longer statistically significant.

ObjectivesInfections are the most common non-cardiovascular cause of death among dialysis patients. Earlier studies have shown similar or higher risk of infectious complications in peritoneal dialysis (PD) compared to hemodialysis (HD) patients, but comparisons to home HD patients have been rare. We investigated the risk of severe infections after start of continuous ambulatory PD (CAPD) and automated PD (APD) as compared to home HD. MethodsAll adult patients (n = 536), who were on home dialysis at day 90 from starting kidney replacement therapy (KRT) between 2004 and 2017 in Helsinki healthcare district, were included. We defined severe infection as an infection with C-reactive protein of 100 mg/l or higher. Cumulative incidence of first severe infection was assessed considering death as a competing risk. Hazard ratios were estimated using Cox regression with propensity score adjustment. ResultsThe risk of getting a severe infection during the first year of dialysis was 35% for CAPD, 25% for APD and 11% for home HD patients. During five years of follow-up, the hazard ratio of severe infection was 2.8 [95% CI 1.6-4.8] for CAPD and 2.2 [95% CI 1.4-3.5] for APD in comparison to home HD. Incidence rate of severe infections per 1000 patient-years was 537 for CAPD, 371 for APD, and 197 for home HD patients. When excluding peritonitis, the incidence rate was not higher among PD than home HD patients. ConclusionsCAPD and APD patients had higher risk of severe infections than home HD patients. This was explained by PD-associated peritonitis.

Membranoproliferative glomerulonephritis (MPGN) consists of immune-complex - mediated glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G). It is not clear if renal and overall prognosis differ between IC-MPGN and C3G. We investigated clinical characteristics, renal and overall survival of Finnish MPGN patients in a single center study.

IntroductionMonoclonal gammopathy of renal significance (MGRS) is a condition in which a monoclonal immunoglobulin (MIg) causes kidney injury. The MIg is secreted by a B-cell or plasma cell clone but is not abundant enough to meet the diagnostic criteria of an overt hematological malignancy.Injury can originate from the direct deposition of the MIg in the kidney tissue, or it can be caused by an indirect mechanism, in which the culprit MIg cannot be found from renal biopsy. Instead, it seems that the injury is likely mediated by complement activation either through the classical pathway or due to MIg acting as an autoantibody to factor H, factor I, CR1 receptor or C3 convertase, leading into an uncontrolled activation of the alternative pathway.MethodsResultsView Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)ConclusionsThere is a great need to investigate further how the paraprotein disturbs complement system and based on that, to develop ways to identify the patients who might benefit from anticlonal treatment. Currently, it is difficult to determine who has a kidney disease caused by the MIg by indirect mechanism and in whom the disease has another etiology.Conflict of interest Corporate sponsored research or other substantive relationships:Participation in research funded by Janssen-Cilag Oy IntroductionMonoclonal gammopathy of renal significance (MGRS) is a condition in which a monoclonal immunoglobulin (MIg) causes kidney injury. The MIg is secreted by a B-cell or plasma cell clone but is not abundant enough to meet the diagnostic criteria of an overt hematological malignancy.Injury can originate from the direct deposition of the MIg in the kidney tissue, or it can be caused by an indirect mechanism, in which the culprit MIg cannot be found from renal biopsy. Instead, it seems that the injury is likely mediated by complement activation either through the classical pathway or due to MIg acting as an autoantibody to factor H, factor I, CR1 receptor or C3 convertase, leading into an uncontrolled activation of the alternative pathway.

ABSTRACT Background Several studies have shown superior survival of patients on home haemodialysis (HD) compared with peritoneal dialysis (PD), but patients on automated PD (APD) and continuous ambulatory PD (CAPD) have not been considered separately. As APD allows larger fluid volumes and may be more efficient than CAPD, we primarily compared patient survival between APD and home HD. Methods All adult patients who started kidney replacement therapy (KRT) between 2004 and 2017 in the district of Helsinki-Uusimaa in Finland and who were on one of the home dialysis modalities at 90 days from starting KRT were included. We used intention-to-treat analysis. Survival of home HD, APD and CAPD patients was studied using Kaplan–Meier curves and Cox regression with adjustment for propensity scores that were based on extensive data on possible confounding factors. Results The probability of surviving 5 years was 90% for home HD, 88% for APD and 56% for CAPD patients. After adjustment for propensity scores, the hazard ratio of death was 1.1 [95% confidence interval (CI) 0.52–2.4] for APD and 1.6 (95% CI 0.74–3.6) for CAPD compared with home HD. Censoring at the time of kidney transplantation (KTx) or at transfer to in-centre HD did not change the results. Characteristics of home HD and APD patients at the start of dialysis were similar, whereas patients on CAPD had higher median age and more comorbidities and received KTx less frequently. Conclusions Home HD and APD patients had comparable characteristics and their survival appeared similar.

Abstract BACKGROUND Dialysis patients have a more than ten-fold risk of dying from infections compared with general population. In earlier studies, the risk of infections was similar in peritoneal dialysis (PD) and haemodialysis (HD), but comparison to home HD has not been performed. Our aim was to study the incidence of severe infections after start of home HD as compared with continuous ambulatory PD (CAPD) and automated PD (APD). METHODS We included all 536 adult patients, who were on home dialysis at day 90 from start of kidney replacement therapy (KRT) between 2004 and 2017 in Helsinki healthcare district. Severe infections were identified from patients’ laboratory data as a plasma C-reactive protein over 100 mg/L and confirmed from the patient data system. The cumulative incidence of the first severe infection was estimated considering death as a competing risk event. Hazard ratios of first severe infection were assessed using Cox regression with propensity score adjustment. Incidence rate (IR) and ratios (IRR) of all severe infection episodes were calculated. RESULTS The probability of getting a severe infection during the first year of dialysis was 35% for CAPD, 25% for APD and 11% for home HD patients. During a 5-year follow-up, the hazard ratio of severe infection was 2.8 [95% confidence interval (95% CI) 1.6–4.8] for CAPD and 2.2 (95% CI 1.4–3.5) for APD in comparison to home HD with adjustment for propensity scores. IR of infections/100 patient-years was 54 for CAPD, 37 for APD and 20 for home HD patients. The IR of peritonitis was 37 for CAPD and 25 for APD patients. When infection episodes caused by peritonitis were excluded, the IR of severe infections was not higher among PD than home HD patients. CONCLUSION The risk of severe infection was considerably lower among home HD than PD patients. This difference was mainly explained by the peritonitis episodes among the PD patients.

Thrombotic microangiopathy (TMA) can sometimes manifest only histologically. Our aim was to retrospectively compare biopsy-proven adult TMA patients showing only histological (h-TMA) or both histological and clinical (c-TMA) TMA in 2006–2017. All native kidney biopsies with TMA were included. Biopsies were re-evaluated by light and electron microscopy, and immunofluorescence. Clinical characteristics, laboratory variables, and treatments were recorded from the electronic medical database. Patients were categorized into h-TMA and c-TMA and these groups were compared. In total, 30 biopsy-proven cases among 7943 kidney biopsies were identified and, of these, 15 had h-TMA and 15 c-TMA. Mean follow-up was 6.3 y, and 73.3% had secondary hemolytic uremic syndrome (HUS) and the rest were atypical HUS. Patient characteristics, treatments, and kidney, and patient survival in the groups were similar. Statistically significant differences were found in histological variables. Vascular myxoid swelling and vascular onion-skinning were almost exclusively detected in c-TMA and, thus, vascular occlusive changes indicate clinically apparent rather than merely histological TMA. In addition, regardless of clinical presentation, kidney and patient survival times were similar in the patient groups highlighting the importance of a kidney biopsy in the case of any kidney-related symptoms.

BACKGROUND:Disordered mineral metabolism reverses incompletely after kidney transplantation in numerous patients. Post-transplantation bone disease is a combination of pre-existing chronic kidney disease and mineral disorder and often evolving osteoporosis. These two frequently overlapping conditions increase the risk of post-transplantation fractures.MATERIAL AND METHODS:We studied the prevalence of low bone volume in bone biopsies obtained from kidney transplant recipients who were biopsied primarily due to the clinical suspicion of persistent hyperparathyroidism between 2000 and 2015 at the Hospital District of Helsinki and Uusimaa. Parameters of mineral metabolism, results of dual-energy x-ray absorptiometry scans, and the history of fractures were obtained concurrently. One hundred nine bone biopsies taken at a median of 31 (interquartile range, IQR, 18-70) months after transplantation were included in statistical analysis. Bone turnover was classified as high in 78 (72%) and normal/low in 31 (28%) patients. The prevalence of low bone volume (n = 47, 43%) was higher among patients with low/normal turnover compared to patients with high turnover [18 (58%) vs. 29 (37%), P = 0.05]. Thirty-seven fragility fractures in 23 (21%) transplant recipients corresponding to fracture incidence 15 per 1000 person-years occurred during a median follow-up 9.1 (IQR, 6.3-12.1) years. Trabecular bone volume did not correlate with incident fractures. Accordingly, low bone mineral density at the lumbar spine correlated with low trabecular bone volume, but not with incident fractures. The cumulative corticosteroid dose was an important determinant of low bone volume, but not of incident fractures.CONCLUSIONS:Despite the high prevalence of trabecular bone loss among kidney transplant recipients, the number of fractures was limited. The lack of association between trabecular bone volume and fractures suggests that the bone cortical compartment and quality are important determinants of bone strength and post-transplantation fracture.

Chronic kidney disease (CKD) is one of the most well-known extrahepatic manifestations caused by hepatitis C infection (HCV). CKD is typically discovered at a late stage. HCV-nephropathy may show different histopathologic patterns, as both glomerular and tubulointerstitial damage have been described. Identification of patients with early renal manifestations would be beneficial to provide treatment and avoid progression to CKD. The observational prospective single-center HCVKID study assessed the prevalence of early renal manifestations in patients with chronic HCV and compared these patients with HCV-negative healthy controls cross-sectionally. HCV-positive patients with and without renal manifestations were also compared to define biomarkers suitable for identifying early manifestations in standard clinical practice. Tubular proteinuria as judged by urine α 1-microglobulin was the most common early renal manifestation found in 11% in HCV-positive patients, followed by hematuria in 8%. Kidney filtration was statistically significantly lower among HCV-positive patients with renal manifestation according to any calculation method. There were no significant differences in duration of infection or stage of liver fibrosis between patients with or without renal manifestations. Tubular cell damage may be the earliest sign of renal dysfunction caused by HCV. Complement activation also correlates with the dysfunction, indicating of contribution to HCV-induced renal manifestations even in their early phase.

Bone histomorphometric analysis is the most accurate method for the evaluation of bone turnover, but non-invasive tools are also required. We studied whether bone biomarkers can predict high bone turnover determined by bone histomorphometry after kidney transplantation. We retrospectively evaluated the results of bone biopsy specimens obtained from kidney transplant recipients due to the clinical suspicion of high bone turnover between 2000 and 2015. Bone biomarkers were acquired concurrently. Of 813 kidney transplant recipients, 154 (19%) biopsies were taken at a median of 28 (interquartile range, 18-70) months after engraftment. Of 114 patients included in the statistical analysis, 80 (70%) presented with high bone turnover. Normal or low bone turnover was detected in 34 patients (30%). For discriminating high bone turnover from non-high, alkaline phosphatase, parathyroid hormone, and ionized calcium had the areas under the receiver operating characteristic curve (AUCs) of 0.704, 0.661, and 0.619, respectively. The combination of these markers performed better with an AUC of 0.775. The positive predictive value for high turnover at a predicted probability cutoff of 90% was 95% while the negative predictive value was 35%. This study concurs with previous observations that hyperparathyroidism with or without hypercalcemia does not necessarily imply high bone turnover in kidney transplant recipients. The prediction of high bone turnover can be improved by considering alkaline phosphatase levels, as presented in the logistic regression model. If bone biopsy is not readily available, this model may serve as clinically available tool in recognizing high turnover after engraftment.

Abstract Background and Aims Monoclonal gammopathy is an entity where a B-cell or plasma cell clone produces monoclonal immunoglobulin. When paraproteinemia and a kidney disease is discovered without criteria for treatment of haematological malignangy, the entity is called monoclonal gammopathy of unknown significance (MGUS) or of renal significance (MGRS). It can cause variable histology, among which membranoproliferative glomerulonephritis (MPGN) has been described. Direct entrapment of paraprotein in glomeruli/tubules can be observed by immunofluorescence (IF), but IF can also be negative as paraprotein can cause complement-associated disease by acting as an activator of the classical pathway or as a dysregulator of the alternative pathway. Electron microscopy (EM) is needed to differentiate possible organized deposits. Method We investigated the prevalence, clinical parameters, histology, and the type of monoclonal gammopathy in biopsy-proven MPGN between 2006-2017. A total of 15 adult patients with a detected urine and/or serum paraprotein with concurrent biopsy-proven diagnosis were discovered among 60 patients (Figure 1). Two diagnostic biopsies were from transplants. Results MGUS was diagnosed in 15/60 (25%) of patients. Clinical variables are summarized in Table 1. The mean age at presentation was 59 years (37-79), 47-% were males. Smoldering myeloma was diagnosed in 2 (13%) patients and overt malignancy in 3 (20%) patients. Histological features are summarized in Table 2. There were 7 (47%) with dominant staining for C3 (6 with C3 glomerulonephritis, 1 Dense Deposition Disease) and 8 (53%) with dominant staining for Ig, of which 4 (31%) had mesangioproliferative, 4 (31%) membranoproliferative, 3 (23%) minimal change, 2 (15%) crescentic and 1 (8%) exudative pattern in light microscopy (LM). Seven (47%) biopsies, which did not stain for kappa or lambda light chains. The most common EM deposit location was subendothelial (69%). Conclusion MPGN was associated with a significant risk of underlying monoclonal gammopathy, as many (25%) patients were diagnosed with concurrent MGUS. When MPGN is observed, it should prompt investigations of the possible underlying monoclonal gammopathy and possibly, hematological neoplasm.

Abstract Background and Aims Many studies have compared survival of patients on peritoneal dialysis and hemodialysis, but knowledge on survival differences between various types of home dialysis is limited. Therefore, our study aimed to assess the associated survival in CAPD, APD and home HD. Method During 2004 to 2017, 1640 patients aged 18 years or older started RRT in Helsinki University Hospital. Patients who were on one of the home dialysis modalities at 90 days (n=536), have been studied. The follow up endpoint was either death or the end of 2019. A research database was established and extensive data were systematically collected from the patient files, comprising 35 different comorbidities, laboratory results, primary renal disease, and renal replacement therapy-related factors. Study design was intention-to-treat, and patients were analyzed in the home dialysis modality group they were at 90 days after onset of RRT. Patient survival was compared between patients on CAPD, APD, and home HD using Kaplan-Meier curves and Cox regression. Results Characteristics of home HD and APD patients at the start of dialysis and proportion of patients who received a kidney transplant during follow-up were similar (Table), whereas patients on CAPD had higher median age, more comorbidities, and received a kidney transplant less frequently. The probability of surviving 5 years was 56% for CAPD, 88% for APD, and 90% for home HD patients (Figure). Relative risk of death associated with APD was 0.96 (95% CI 0.60–1.5), and that of CAPD was 3.7 (2.4–5.7) as compared to home HD. After adjustment for age and number of comorbidities, the relative risks were 0.82 (0.39–1.7) and 2.5 (1.2–5.0), respectively. Additional adjustments for other possible confounding factors listed in the Table did not change the results. Censoring for kidney transplantation did not alter the conclusion. Conclusion APD and home HD patients had similar characteristics and comparable survival. CAPD patients were older, had more often comorbid conditions, and their prognosis was worse even after adjustment for confounders.

Background: A kidney biopsy is an important tool in managing kidney diseases. Bleeding is the most significant complication. The biopsy can be performed as an inpatient or an outpatient procedure with a shorter post-biopsy bed rest and monitoring period. It is cost-effective, but raises some questions about patient safety. At Helsinki University Hospital, the majority of elective kidney biopsies have been performed as outpatient procedures since 2010. The aim of this study was to retrospectively evaluate the safety and risk factors of this protocol. Methods: We collected data from all patients undergoing an elective outpatient biopsy of a native or transplanted kidney following the outpatient protocol between January 2011 and February 2016. We recorded the data on the biopsy procedure and complications: bleeding (hematoma or macrohematuria), severe pain, death, or "other" (infection, accidental puncture of another organ). A complication was classified as major, if it required interventions such as transfusion or radiological or surgical intervention. Results: Over a 5-year period, 824 (448 native and 326 transplant kidney) patients were biopsied. In total, 94 (11.4%) had a complication, but only 4 patients (0.5%) had a major complication; no deaths were recorded. All major and 70 minor complications emerged during post-biopsy monitoring (4-6 h). Patients with complications were younger (p = 0.001), female (p < 0.001), and had lower hemoglobin (p = 0.001) than those without. Transplant biopsies were associated with fewer complications than native kidney biopsies (p= 0.002). Conclusions: In selected patients, an outpatient kidney biopsy is a relatively safe procedure.

Post-infectious glomerulonephritis (PIGN) is a self-limiting glomerulonephritis (GN). It manifests as a diffuse endocapillary GN and in immunofluorescence staining (IF) co-deposition of IgG and C3 is commonly seen, as well as C3-dominant glomerular depositions. Classically, there are subepithelial humps on electron microscopy (EM). However, there are reports where the initial histological presentation was PIGN, but the patients turned out to have a chronic C3 glomerulopathy (C3G). The aim of this study was to investigate etiological, histological and clinical factors of these patients.

Hepatitis C infection is known to cause kidney derangements. HCV-related nephropathy may show different histopathologic patterns and both glomerular and tubulointerstitial damage have been described. Kidney injury may result from immune-mediated tissue damage or from direct effects of HCV and other, yet unknown mechanisms may be involved. HCV-related nephropathy may appear at any time during the natural history of HCV infection. Objective of the prospective, observational HCVKID-study is to assess the prevalence of renal manifestations among patients suffering from chronic HCV in Finland cross-sectionally, complemented by long-term analysis to identify changes from baseline.