Incidence of primary glomerulonephritis in a large North-Eastern Italian area: a 13-year renal biopsy study.

BackgroundThe reported incidence of biopsy-proven primary glomerulonephritis (PGN) varies according to geographical, temporal and environmental factors. Consequently, the development of national/regional registers may help clinicians and researchers to improve knowledge about this important clinical condition.MethodsTo better define the epidemiology of PGN in our North-Eastern Italian area ( 3c5 million inhabitants), we evaluated the kidney biopsy records of 2680 adult patients with PGN diagnosis reported from 1998 to 2010 in the 'Triveneto' Register of Renal Biopsies.ResultsStatistical analysis showed that the mean age of patients undergoing renal biopsy was gradually increased from 1998 to 2010 (R(2) = 0.82, P < 0.01) with a growing percentage of those aged over 65 years (R(2) = 0.72, P < 0.01). According to the clinical presentation of our PGN patients, we found a significant increase in biopsies performed for acute renal failure (P < 0.01) and a decrement of those for macroscopic haematuria (P < 0.01) and nephritic syndrome (P = 0.04). Moreover, although there has been an unchanged total annual rate of biopsy-proven PGN (P = 0.47), there has been a significant enhancement in the incidence of minimal change disease (MCD, P = 0.04) and extracapillary proliferative glomerulonephritis (ExGN, P = 0.03) over time primarily due to a progressive increase in the mean age of patients affected by both renal diseases. Immunoglobulin A (IgA) nephropathy was the most common glomerulonephritis.ConclusionsTherefore, even if the number of PGN did not diminish during the 13-year study period, we reported considerable changes in the demographical and clinical characteristics of our biopsied patients (older and with acute kidney injury). Additionally, we found a change in the bioptic pattern of our patients over time with a progressive rise of some histological features such as MCD and ExGN. This may reflect not only the progressive ageing of our nephrology patients, but also a change in the biopsy policy of local hospitals

Renal Biopsy in Chronic Kidney Disease: Lessons from a Large Italian Registry.

Background: Renal biopsy procedure in patients with chronic renal failure (CRF) may represent a valid tool to help clinicians in clinical practice. However, the use of this invasive method in CRF is variable and it reflects the hospital biopsy policy. Methods: To better define the CRF-related histological patterns and to assess the clinical utility of this procedure in this extensive group, we analyzed biopsy records of 1,185 CRF patients living in a large area of north-east Italy from 1998 to 2010. Results: Data analysis showed that, although the biopsy incidence rate and the histological features were unchanged, the mean age of our CRF patients increased during the study period (R2 = 0.42, p < 0.01). Primary and secondary glomerulonephritis (SGNs) were the main histological presentations (53.9 and 23%, respectively). SGNs were over-diagnosed in females. Leading histological types were immunoglobulin A nephropathy (22%), focal segmental glomerulosclerosis (12.4%), membranous glomerulonephritis (MGN, 7.5%) and nephroangiosclerosis (7.3%). These forms were also highly frequent in CRF patients with elevated proteinuria and moderate/severe renal damage. Elderly patients were primarily affected by MGN. After biopsy, 49.5% of CRF patients with and 34.1% without nephrotic syndrome received immunosuppression therapy. Conclusions: This study demonstrated that renal biopsy in CRF patients, regardless of age and glomerular filtration rates, is safe and essential to achieve a correct diagnosis and to commence the correct therapy. Additionally, it revealed that, even in patients with severe renal damage, it is possible to perform an accurate histological diagnosis and, interestingly, end-stage kidney disease seems not to be the primary form

INCIDENCE OF PRIMARY GLOMERULONEPHRITIS IN A LARGE NORTH-EASTERN ITALIAN AREA: A 13-YEAR RENAL BIOPSY STUDY

Introduction and Aims: The reported biopsy-proven glomerulonephritis (GN) incidence varies according to population characteristics. Published biopsy series have shown geographical and temporal variations in the pattern of GN. Therefore, the development of national or regional registries may help clinicians to learn more about epidemiology and distribution of this important clinical feature. Methods: To better understand the epidemiology of GN in a large north-eastern Italian area (including: Veneto, Friuli Venezia Giulia and Trentino Alto Adige regions; comprising approximately 4 millions inhabitants), we retrospectively analyzed data included in the \u201cTriveneto\u201d Register of Renal Biopsies (TVRRB). In particular, we evaluated kidney biopsy records, available from 1998 to 2010, of 4387 adult patients (male: 2734, female: 1653, mean patient age: 50.4 \ub1 17.7 years). No renal graft biopsies were included. During the study time, the criteria for renal biopsy were unchanged. The overall clinical indications to perform renal biopsy were: 38% nephrotic syndrome (NS), 23% chronic renal failure (CRF), 21% urinary abnormalities (UA), 15% acute renal failure (ARF) and 3% macroscopic hematuria (MH). Kidney diseases were divided in 5 groups: primary glomerulonephrities (PGN), secondary glomerulonephrities (SGN), tubulo-interstitial nephritis (TIN), vascular diseases and miscellaneous. For our study, we focused on PGN. Results: Demographic data showed that the mean age of biopsy has significantly and progressively increased from 1998 to 2010 (from 15% to 30% patients aged > 65 years, respectively). Older patients ( > 65 years) have been primarily biopsied for NS and ARF, while younger ( < 40 years) for UA. We found a significant increase in the number of biopsy for ARF (R2=0.44, p < 0.01) over time. According to the histological features: PGN was documented in the 61% of all biopsies and the leading types were: IgA nephropathy (31%), followed by membranous GN (25%), Focal Segmental Glomerulosclerosis (16%), mesangial proliferative GN without IgA deposition (9%), minimal change disease (7%), membrano-proliferative GN (6%), extracapillary proliferative GN (4%) and other (2%). Additionally, although we did not observe any difference in the overall number of biopsy-proven PGN during the study period, we found a significant increase in the incidence of minimal change disease (R2=0.28, p = 0.04) and extracapillary proliferative GN (R2=0.25, p = 0.03) over time. Conclusions: Our data clearly show that, in our large study area, the number of PGN has been substantially unchanged during the 13 years study period. However, we have assisted to an increment of the mean age of patients undergoing renal biopsy and to a significant enhancement of the incidence of some PGN types (minimal change disease and extracapillary proliferative GN). Therefore, our report represents a valuable contribution to better understand the GNP distribution in our country

INCIDENCE OF PRIMARY GLOMERULONEPHRITIS IN A LARGE NORTH-EASTERN ITALIAN AREA: A 13-YEAR RENAL BIOPSY STUDY

Introduction and Aims: The reported biopsy-proven glomerulonephritis (GN) incidence varies according to population characteristics. Published biopsy series have shown geographical and temporal variations in the pattern of GN. Therefore, the development of national or regional registries may help clinicians to learn more about epidemiology and distribution of this important clinical feature. Methods: To better understand the epidemiology of GN in a large north-eastern Italian area (including: Veneto, Friuli Venezia Giulia and Trentino Alto Adige regions; comprising approximately 4 millions inhabitants), we retrospectively analyzed data included in the “Triveneto” Register of Renal Biopsies (TVRRB). In particular, we evaluated kidney biopsy records, available from 1998 to 2010, of 4387 adult patients (male: 2734, female: 1653, mean patient age: 50.4 ± 17.7 years). No renal graft biopsies were included. During the study time, the criteria for renal biopsy were unchanged. The overall clinical indications to perform renal biopsy were: 38% nephrotic syndrome (NS), 23% chronic renal failure (CRF), 21% urinary abnormalities (UA), 15% acute renal failure (ARF) and 3% macroscopic hematuria (MH). Kidney diseases were divided in 5 groups: primary glomerulonephrities (PGN), secondary glomerulonephrities (SGN), tubulo-interstitial nephritis (TIN), vascular diseases and miscellaneous. For our study, we focused on PGN. Results: Demographic data showed that the mean age of biopsy has significantly and progressively increased from 1998 to 2010 (from 15% to 30% patients aged > 65 years, respectively). Older patients ( > 65 years) have been primarily biopsied for NS and ARF, while younger ( < 40 years) for UA. We found a significant increase in the number of biopsy for ARF (R2=0.44, p < 0.01) over time. According to the histological features: PGN was documented in the 61% of all biopsies and the leading types were: IgA nephropathy (31%), followed by membranous GN (25%), Focal Segmental Glomerulosclerosis (16%), mesangial proliferative GN without IgA deposition (9%), minimal change disease (7%), membrano-proliferative GN (6%), extracapillary proliferative GN (4%) and other (2%). Additionally, although we did not observe any difference in the overall number of biopsy-proven PGN during the study period, we found a significant increase in the incidence of minimal change disease (R2=0.28, p = 0.04) and extracapillary proliferative GN (R2=0.25, p = 0.03) over time. Conclusions: Our data clearly show that, in our large study area, the number of PGN has been substantially unchanged during the 13 years study period. However, we have assisted to an increment of the mean age of patients undergoing renal biopsy and to a significant enhancement of the incidence of some PGN types (minimal change disease and extracapillary proliferative GN). Therefore, our report represents a valuable contribution to better understand the GNP distribution in our country

Kidney diseases with chronic renal failure in the Italian renal biopsy registries

The prevalence of chronic renal failure (CRF) at the time of kidney biopsy ranges between 5% and 37% in different renal biopsy registries. This wide variability is mainly dependent on the different definitions of CRF. In the period 1998-2006, the Triveneto Renal Biopsy Registry recorded 816 cases with CRF (defined as serum creatinine persistently > or =1.5 mg/dL), accounting for a prevalence of 27%. At the time of biopsy, the average age and glomerular filtration rate were 54 years and 41 mL/min, respectively; 70% of CRF patients are men and the prevalence of CRF increases with age. IgA nephropathy (IgAN) is the main histological form of glomerulonephritis, accounting for 23% of all cases of CRF. However, in subjects older than 65 years, membranous glomerulonephritis (MG) exceeds IgAN, thus becoming the main diagnosis in elderly patients with renal impairment. With a cutoff value for proteinuria of 3 g/day, the main diagnoses in cases with proteinuria below and above the cutoff are IgAN and MG, respectively. IgAN remains the main histological form of nephropathy throughout all levels of renal failure. These data confirm the findings of the Italian Registry of Renal Biopsies, but correspond only in part with data from other registries. The differences can to a certain extent be explained by the different criteria for the definition of renal impairment, patient selection, and differences in diagnosis among registries