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Changes in the histological spectrum of glomerular diseases in the past 16 years in the North-Eastern region of Romania
© Volovăt et al.; licensee BioMed Central Ltd. 2013
Received: 28 February 2013
Accepted: 9 July 2013
Published: 15 July 2013
The aim of this study was to describe the findings of renal biopsies from a large nephrology center in Iasi, Romania, performed between 2005 and 2010. We compared these findings with our previous ones, from 1995 to 2004, as well as with similar reports.
We studied retrospectively 239 renal biopsies. The indications for renal biopsy were categorized into: nephrotic syndrome, acute nephritic syndrome, asymptomatic urinary abnormalities, acute kidney injury, and chronic kidney disease of unknown etiology.
During the past 16 years, a gradual increase in the annual number of renal biopsies/per million population (p.m.p.)/year was observed, although this incidence remained lower than in other European countries. Nephrotic syndrome was the indication for renal biopsy in over 50% of cases. Glomerulonephritis (GN) was the main histological diagnosis in 91% of cases, of which 56% were primary GN and 35% were secondary GN. The frequency of various types of primary GN was: membranoproliferative GN (MPGN) - 29.3%, membranous nephropathy (MN) -27.5%, focal segmental glomerulosclerosis (FSGS) - 17.2%, mesangial GN (including IgAN) -13.7%, crescentic GN - 9.4%, and minimal change disease (MCD) - 2.5%. Compared to the previously reported period (1994–2004), we observed a significant decrease in the frequency of MPGN and significant increases in the frequency of FSGS and, particularly MN - which more than doubled.
We report significant changes in the histological spectrum of GN in North-Eastern Romania in 2005–2010, compared to the previously reported 10-yrs. These changes seem to be following a trend that has also been observed in Western countries a few decades ago, and which may have a socioeconomic explanation.
KeywordsGlomerular disease Glomerulonephritis Kidney disease Tubulointerstitial disease
Histopathological diagnosis is a sine qua non prerequisite for the adequate management of most primary glomerular diseases in adults. National renal biopsy registries are available in Western European countries like France, Italy, Scotland, and Spain [1–6]. In contrast, in several Eastern European countries such registries are often lacking, incomplete or outdated . However, the few existing reports suggest significant differences in the epidemiology of glomerulonephritis (GN) between Eastern and Western Europe, including, for example, a higher prevalence of IgA nephropathy (IgAN) and a lower prevalence of membranoproliferative glomerulonephritis (MPGN) in the latter region .
The aim of this study was to describe the findings of renal biopsies that were performed in a single large nephrology center in Iasi, covering the North-Eastern region of Romania (six counties, over 4.75 million inhabitants), between 2005 and 2010. Furthermore, we compared these findings with our previous ones in the same center, from 1995 to 2004 , as well as with similar reports from other countries.
We studied retrospectively 239 renal biopsies, performed between 2005 and 2010 in the Nephrology Department of the “Dr. C. I. Parhon” Hospital in Iasi. Our unit is the referral nephrology center for Moldavia, the Eastern region of Romania, which includes eight counties and a population of over 4.75 million inhabitants. The study protocol was approved by the Ethics Committee of University Hospital “Dr. C.I. Parhon” (Iasi, Romania).
The percutaneous technique with ultrasound guidance, Tru-Cut 14-gauge needles and Bard Magnum® reusable core biopsy instrument (Bard Biopsy Systems®) was used for all biopsies [9, 10]. Fresh biopsy cores were evaluated on the dissecting microscope. A small renal cortical tissue (2–4 mm in length) was separated for immunofluorescence study. The remaining biopsy specimen was fixed in formaline and B5 (mercury- based fixative) to be evaluated under light microscopy. Paraffin sections were prepared and stained with hematoxylin and eosin, periodic acid Schiff, Masson trichrome, Congo red, and Jones silver methenamine stains . All the renal biopsies were examined by the same pathologist and evaluated with light microscopy and immunofluorescence (using Ig A and Ig G staining in all biopsies, and C3 staining in only 67 biopsies). Kidney transplant biopsies were excluded and there were no pediatric cases included in our study.
Primary GN: IgA nephropathy (IgAN), crescentic GN (CGN) (defined as CGN not fulfilling the criteria for systemic disease), minimal change disease (MCD), mesangial GN other than IgAN (MesGN), membranous nephropathy (MN), focal segmental glomerulosclerosis (FSGS), and membranoproliferative GN (MPGN);
Secondary GN: lupus nephritis (LN), systemic vasculitis (VAS) (defined and classified according to the 1994 International Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitides ), Goodpasture’s syndrome, amyloidosis, cryoglobulinaemic GN, acute poststreptococcal GN (PSGN), other post-infectious GN, diabetic nephropathy (DN), Alport’s syndrome and other hereditary GN, GN associated with liver disease, GN associated with malignancy;
Tubulointerstitial nephropathies (TIN), including acute TIN and chronic TIN;
Vascular nephropathies (VN): benign and malignant nephroangiosclerosis (NAS) and haemolytic uraemic syndrome (HUS);
Miscellaneous findings, including normal renal tissue, unclassified nephropathies, and global glomerulosclerosis.
Significant clinical data were gathered from the patients’ medical files, including the following: clinical diagnosis, serum creatinine (sCr), 24-hour proteinuria, presence of haematuria, and presence of arterial hypertension. Hypertension was defined as a blood pressure above 140 mm Hg for the systolic and/or 90 mm Hg for the diastolic and/or ongoing antihypertensive therapy. Complications of renal biopsy were also noted. Severe complications were defined as: severe renal bleeding requiring blood transfusions, acute kidney injury from obstruction with blood clots, urosepsis, and death [14, 15].
Clinical syndromes were categorized into: nephrotic syndrome (NS), acute nephritic syndrome (ANS), asymptomatic urinary abnormalities (AUA), acute kidney injury (AKI), and chronic kidney disease (CKD). The NS was defined as the association of proteinuria >3.5 g/day/1.73 m2 with oedema, hypoproteinaemia, hypoalbuminaemia, and hyperlipidemia. Acute nephritic syndrome was defined as variable associations of at least three of the following manifestations: proteinuria, haematuria, hypertension, oedema, oliguria, and reduced glomerular filtration rate (GFR). The AUA encompassed isolated moderate proteinuria and/or microscopic haematuria. Acute kidney injury was defined as a sudden decrease in glomerular filtration rate (GFR), while CKD was diagnosed when low GFR (< 60 ml/min/1.73 m2) persisting for at least 3 months .
The SPSS 16.0 statistics package was used (SPSS SystatInc, Chicago IL, USA). The annual incidence was defined as the number of new cases per year and per million populations (p.m.p.). Chi-square and Fisher’s exact tests were used to compare qualitative variables. P values <0.05 were considered statistically significant.
Between 1994 and 2010 a number of 559 renal biopsies were performed in our center, of which 320 from 1994 to 2004 (period 1) and 239 from 2005 to 2010 (period 2). Adequate samples of renal tissue were obtained in 514 (91.23%) biopsies, which underwent histological examination and were included in this report. The mean±standard deviation (SD) number of glomeruli per sample was 9.1±4.9.The incidence of renal biopsies increased from 10.7 per million population (p.m.p.)/year in 1994 to 11.5 p.m.p/year in 2004 and to 12.8 p.m.p/year in 2010. These figures are much lower than those reported by other European registries (e.g. 44.1–69.3 p.m.p./year in the Czech Republic , 48 p.m.p./year in Spain , and 16.3–20.1 p.m.p./year in France ), except for the Serbian registry where the renal biopsy rate is similar to ours (10.8 p.m.p./year ).
Differences in clinical presentation depending on period and age of patients
Whole population N= 559 (%)
Period 1 (1995–2004)N= 320 (%)
Period 2 (2005–2010) N= 239 (%)
<60 years N=435 (77.8%)
≥60years N=124 (22.18)
Period 1 N= 252 (%)
Period 2 N= 183 (%)
Period 1 N= 68 (%)
Period 2 N= 56 (%)
Acute nephritic syndrome
Distribution of histological diagnoses
Italian Registry] (N=14 607) % (p.m.p/year)
Czech Registry] (N=4 004) % (p.m.p/year)
Serbian Registry] (N=1 626) % (p.m.p/year)
Period 1 (N=304) % (p.m.p/year)
Period 2 (N= 210) % (p.m.p/year)
Overall (N= 514) % (p.m.p/year)
Incidence of different forms of primary glomerulonephritis
MPGN % (p.m.p/year)
MesGN % (p.m.p/year)
MN % (p.m.p/year)
CGN % (p.m.p/year)
FSGS % (p.m.p/year)
MCD % (p.m.p/year)
Iasi, Romania (1995–2010)
Period 1, N=172
Period 2, N=116
CRRB, N= 2333
SRRB, N=955; <60 years (%)
SRRB, N=87; ≥60 years (%)
SRRB, N=1042; all ages (renal biopsies/per million population (p.m.p.)/year)
Correlations between histological diagnoses and clinical presentations
Nephrotic syndrome (%)
Nephritic syndrome (%)
Dysgammaglobulinaemia associated GN
Infectious disease associated GN
Others (metabolic, hereditary, etc.)
Serum creatinine and proteinuria in primary glomerulonephritis
Serum creatinine, mg/dl
Incidence of different types of secondary glomerulonephritis
IRRB N = 2348
CRRB N = 990
SRRB, N = 373; <60 years (%)
SRRB, N = 29; ≥60 years (%)
SRRB, N = 402; all ages (p.m.p/year)
Period 1 N = 98
Period 2 N = 82
Overall N = 180
Others (Goodpasture’s syndrome, rheumatoid arthritis, etc.)
Infectious diseases associated GN
Others (metabolic, hereditary, etc.)
Macroscopic hematuria was the most frequent complication of renal biopsies, encountered in 5.2% of patients. Blood transfusions were administered in only 0.9% of cases, but no surgical or radiological interventions for bleeding were necessary.
This study provides comprehensive information about the spectrum of biopsy-proven GN in the past 16 years in our center. Additionally, we compared our findings to those reported by the Italian, the Serbian and the Czech renal biopsy registries. The Italian registry is representative for the Western Europe and the Czech and Serbian registries much more related, from the geographical and economical point of view, with our report. The biopsy frequency is significantly lower than that of the mentioned registries, and that could be explained by the lower addressability to health care providers, at least in initial, non-symptomatic disease. This conservative approach could also be a consequence of the opinion of a part of the physicians to perform a biopsy only when they felt that the pathology could alter the therapy or when patients had signs of progressive renal disease.
The main findings of our study, in comparison with other European reports are: (a) a similar frequency but with a lower incidence of primary and secondary GN, (b) a higher frequency of MPGN, but with a clear descending trend over the past 16 years, (c) a lower incidence of primary MN, but with an ascending trend over the past 16 years, (d) a higher and steady frequency of infectious disease-associated GN.
The most frequent clinical presentation was NS, followed by AKI, ANS, and AUA. These data were in contrast with the reports from Western Europe, where the most common clinical indications for kidney biopsy were AUA [1, 17]. However, when comparing the data from 1995–2004 with those from 2005–2010, we found a similar trend as in the Western registries [18, 19], with less patients having AKI [19.06% vs 8.7%]. Similarly to other reports [18, 19], NS was seen in about 10% of FSGS and 25% of MN cases. Significant differences from all other reports were found for MPGN and MCD [18–21].
For the last 16 years, MPGN (primary and secondary) has remained the first cause of NS in North-Eastern Romania. This feature has been described in other centers in Romania, as well . A possible explanation might be the high prevalence of infectious diseases in our country, such as viral B and C hepatitis and streptococcal infections [22, 23]. However, from 1995 to 2010, the incidence of MPGN in our center has continuously declined. Such a trend was previously reported in countries like France, where a decline in the incidence of rheumatic fever was associated with a parallel decline in the incidence of MPGN and post-streptococcal GN . It seems that the epidemiology of MPGN is strongly related to socio-economic conditions and that improvements in incomes, social and health care status are associated with a decrease in the incidence of MPGN . These advances have been significant in Romania after 1989, as well as in other Eastern European countries [8, 24].
According to our data, MN was the second cause of NS, followed by FSGS and MesGN (including IgAN). The increasing prevalence of FSGS in our center is comparable to that seen in previous decades in the USA, where FSGS has now become the most common cause of NS [25, 26]. On the other hand, in our study MesGN was the first cause of AUA.
Acute kidney injury was the most common clinical presentation of patients with VAS and CGN. We found that 11.1% of primary GN were CGN and almost one-third of all cases with AKI had CGN. These data are similar to the Italian registry , where CGN were found in 34.1% of cases presenting with AKI.
Our study has several limitations. We analyzed retrospectively only patients from a single centre, but the “Dr. C.I. Parhon” University Hospital is the only reference centre for the entire North-Eastern region of Romania (six counties, over 4.75 million inhabitants). The economy of this region is mainly agricultural with the regional gross domestic product per capita being the lowest in Romania (€ 7 200 in 2008), at about two-thirds of the national average and this could explain the lower addressability to health care providers, at least in initial, non-symptomatic disease. Corroborated with a conservative approach, this lead to a lower biopsy frequency with a relatively low number of patients included in our study. Finally, although we performed immunohistology in all biopsies, the C3 staining was available only from 2009, thus preventing the analysis of different subtypes of GNMP.
Nephrotic syndrome was the indication for renal biopsy in more than 50% of cases in our center. Membranoproliferative GN has remained the most common type of primary GN, whereas immune-mediated diseases (LN and VAS) were the main causes of secondary GN. Serious complications of renal biopsy were rare.
We believe that our data represent an important contribution to the epidemiology of kidney diseases in Europe.
We have no acknowledgements to declare.
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