Survival of Balkan endemic nephropathy patients

Progression of Kidney Damage in Balkan Endemic Nephropathy: A 15-Year Follow-Up of Patients with Kidney Biopsy Examination

Progression of kidney damage was studied in 18 patients with Balkan endemic nephropathy (BEN), with a mean 15-year follow-up after renal biopsy. According to kidney function, estimated by 99mTc-DTPA clearance, patients were divided into three groups: with apparently normal kidney function (clearance 103.5+/-21.3 mL/min/1.73 m2), with incipient renal failure (clearance 65.5 +/- 11.3), and with advanced renal failure (clearance 28.0+/-6.2). The mean yearly decrease of glomerular filtration rate was 2.74 mL/min. In two patients, an increase of kidney function was recorded. Six patients become dialysis dependent, two from the group with incipient renal failure, but all four from the group with advanced renal failure. Three patients died after 8 to 12 years of follow-up, one from causes unrelated to kidney disease and two from end-stage renal failure. This study has shown that BEN is characterized by a slow course and prolonged evolution, modified by medical supervision and treatment.

Balkan Endemic Nephropathy is Still Present in the Kolubara Region, Serbia

BACKGROUND

Almost 50 years ago Balkan Endemic Nephropathy (BEN) was first described in Serbia in the village of Sopić where the first field examination was carried out in 1971. Our aim was to find out whether BEN is still present in this region.

METHODS

Prevalence data on BEN from a field examination run in 1971 were compared with the results of a cross-sectional study conducted in the same village in 1992. In addition, every new case of the disease diagnosed between 1971 and 1992 was recorded retrospectively. The prospective study included 50 members of five BEN families randomly selected from 28 BEN families registered in the village Sopić in 1992. The objective survey and examination of global and tubular kidney function was carried out in all examined persons once yearly in 1998, 1999, and 2000.

RESULTS

The overall prevalence of BEN was 6.4% in 1971 and 8.9% in 1992. In the period of 21 years, 161 new BEN patients were detected in 28 families in which the disease had already been recorded. No new family affected by BEN and none of the new patients in 47 families registered previously as nonaffected were discovered. In the prospective study of five BEN families, three new BEN cases were discovered among 50 members, and two patients fulfilled criteria for BEN-suspected ones.

CONCLUSION

Balkan Endemic Nephropathy (BEN) is still present in the village of Sopić, but the clinical course of the disease became more protracted over time. New cases of BEN appeared only in the affected families.

One-year follow-up of renal function in endemic nephropathy families

Introduction. Endemic nephropathy is familial, chronic tubulointerstitial disease with an insidious onset and asymptomatic, slow progressive course. Objective. The present study was undertaken with the aim to find out whether new persons with renal disorders can be detected among members of endemic families in the village of Sopic (Kolubara River region, Serbia). Methods. The study involved 44 members of five endemic families without history of renal disorders. Objective survey and laboratory analyzes that enabled determination of kidney functions (creatinine clearance, proteinuria, urine specific gravity and osmolality, fractional sodium excretion (FENa), the rate of tubular phosphate reabsorption (TRP), urine N-acetil-D-glycosaminidase and intestinal alkaline phosphatase) were done in all examined persons three times during the 6-month intervals. Results. At the first examination, hypertension was detected in 23 (52%) person, decreased creatinine clearance in two and proteinuria in 10 persons included in the study. In addition, proteinuria and tubular disorders were detected in 6, hypertension, proteinuria and/or tubular disorders in 9 persons. The analysis of the results obtained by three check-ups undertaken during one year showed that proteinuria and tubular disorders appeared intermittently in half of the examined endemic family members. All persons with detected renal disorders required further examination in order to establish accurate diagnosis of renal disease. Conclusion. Three check-ups performed at six-month intervals in the members of five endemic families detected various renal disorders including renal hypofunction. Regular systematic check-ups of endemic families could enable early detection of the disease and early initiation of measures for slowing down chronic renal disease progression.

Hemodialysis treatment in patients with Balkan endemic nephropathy: an epidemiological study

AIM

To analyze hemodialysis (HD) treatment of patients with Balkan endemic nephropathy (BEN) from five endemic villages in the South Morava Region of Serbia. Analyses of patterns of incidence may generate hypotheses about the underlying causes of BEN, and prevalence data provide information on the current and likely future burden on health services for managing BEN.

METHODS

A total of 143 end-stage kidney disease patients (ESKD) with BEN were admitted to the renal replacement program from 1974 to 2004: 121 to HD, 15 peritoneal dialysis, and 7 kidney transplantation. As a control group, 117 patients with other kidney disease (chronic pyelonephritis, glomerulonephritis, and ischemic nephropathy) admitted to HD at the time of BEN patients and matched by age and gender were studied.

RESULTS

Most of the BEN patients (93.4%) treated by HD were born from 1917 to 1941. The majority of patients (79.3%) started HD from 1977 to 1991 (period of 15 years). The mean age of BEN patients starting HD treatment was 49.1 years in the period from 1974 to 1978, and increased steadily in the following years, being 72.5 years in the last period of study (2004-2006) The mean survival time of BEN males was 4.70 (95% CI 3.66-5.75) and for females was 5.02 (95% CI 1.47-4.53). Difference between males and females was not statistically significant (log rank 0.14, p = 0.7, P > 0.5). Mean survival times of 4.84 (95% CI 3.97-5.70) in BEN patients and 3.1 (95% CI 2.78-3.84) in other kidney disease patients were found. Difference between BEN patients and controls was statistically significant (log rank 8.38, p = 0.0038, P < 0.01).

CONCLUSION

The population of endemic villages around the South Morava River admitted to HD treatment after 1974 was exposed to environmental toxicant(s) from 1917 to 1941. The most intense effect of environmental exposure was in that period, with ESKD in patients in their forties. The exposure to environmental toxicants has diminished, so ESKD of BEN has become less frequent and manifested in the older age, mean 72.5 in the period from 2004 to 2006. Different type of exposure was registered in some other endemic regions in Serbia and abroad.

Decreasing incidence of urothelial cancer in a Balkan endemic nephropathy region in Serbia. A surgery based study from 1969 to 1998

The incidence of upper urothelial tumors (UUT) and bladder tumors associated to Balkan endemic nephropathy (BEN) in the region of South Morava River in Serbia, in the 30-year period, was studied. A total of 575 urothelial neoplasms during 10-year period (1989-1998) was analyzed and compared to 659 urothelial neoplasms in the period from 1969 to 1988. UUT had 11.2-fold increased incidence in endemic than in nonendemic areas, however, this was far less than in the period from 1969 to 1988, when they were 57.1 times more frequent. Bladder tumors were 2.3 times more frequent in endemic than in nonendemic areas, but 11.9 times in the previous study from 1969 to 1988. Neoplasms from the area of BEN, regardless of their location, were not histologically different from the neoplasms out of endemic areas. Similarly to the previous reports that BEN looks like a disease that disappears, this is demonstrated also for urothelial tumors, which are the most frequent associated diseases.

Detection of renal dysfunctions in family members of patients with Balkan endemic nephropathy

BACKGROUND/AIM

Recent studies have questioned whether new cases of Balkan endemic nephropathy (BEN) are occurring. The aim of the present study was to find out whether new members with renal dysfunctions can be identified among family members of BEN patients from the Kolubara region.

METHODS

The study included 47 family members of 5 BEN patients on hemodialysis (HD) and 17 members of 3 non-BEN patients on HD. Their medical and epidemiological histories were taken, an objective survey made, and all persons were examined for global and tubular kidney function.

RESULTS

Seven BEN family members (2 with previously known BEN) had creatinine clearance (Ccr) below the 75th percentile rank according to sex and age. All non-BEN family members had normal Ccr and no evidence of previous renal disorders. Hypertension was found in 20 (43%) BEN and 6 (35%) non-BEN family members. No significant differences in the frequency of renal function disorders (proteinuria, alpha1-microglobulinuria, urine specific gravity, osmolality, functional excretion of sodium, tubular phosphate resorption) or anemia were found between the groups. Renal disorders were detected in 18 BEN family members without previously detected disease, 3 of whom fulfilled criteria for a diagnosis of BEN and another 2 for BEN-suspected persons.

CONCLUSION

New cases of BEN are still arising among the affected families in the Kolubara region.

Urinary neopterin concentrations in patients with Balkan endemic nephropathy (BEN)

BACKGROUND

Balkan endemic nephropathy (BEN) is of great clinical importance in restricted areas of Bulgaria, Serbia, Croatia, Bosnia, Herzegovina, and Romania, since the etiology of BEN is still unknown.

METHODS

In urine samples from 48 patients (41 females and 7 males, aged 65.6 +/- 6.87 years) with BEN living in an endemic area of Vratza district, Bulgaria, neopterin concentrations were measured by high-pressure liquid chromatography (HPLC) and compared with other clinical and laboratory investigations, including creatinine, hemoglobin, and erythrocyte sedimentation rates (ESRs).

RESULTS

Urinary neopterin concentrations were 263 +/- 128 (mean +/- SD; range, 78 to 786 micromol/mol creatinine), 24 (50%) of BEN patients presented with increased concentrations as compared to the established normal ranges. Average ESRs were increased (1 hour, 29.0 +/- 14.7 mm/hour) and hemoglobin was decreased (109.3 +/- 16.4 g/L). Hemoglobin correlated inversely with ESRs (rs = -0.787 and -0.780) and creatinine concentrations (r = -0.690, all P < 0.001), but not with neopterin concentrations. Neopterin concentrations also did not correlate with serum creatinine levels. There existed an age relationship of ESR, creatinine, and hemoglobin, but not of neopterin. Neopterin concentrations were slightly lower in five females with low titers of antibodies against local B1 hantavirus strain (P < 0.05).

CONCLUSION

The findings can support an immune-mediated inflammatory process in the pathogenesis of BEN only in a subgroup of patients.

Balkan endemic nephropathy in Vratza, Bulgaria, 1964-1987: an epidemiologic analysis of population-based disease registers

Balkan Endemic Nephropathy (BEN), first described in 1956 in Vratza region, Bulgaria, may result from prolonged, chronic exposure to environmental toxicants, but the underlying etiologic factors remain elusive. There has been no recent systematic characterization of the epidemiology of this disease. Recently, it has been suggested that the incidence of the disease is decreasing. We therefore abstracted data from registers of patients in 21 affected villages and the town of Vratza, Bulgaria maintained from 1964 through 1987. In 1964, the prevalence of BEN was 6.0 per 1000 inhabitants; among residents of the affected villages, the prevalence was 12.3 per 1000. From 1965 to 1975 the incidence rate was 0.7 per 1,000 person-years, and from 1976 to 1987 the incidence rate was 0.3 per 1,000 person-years (rate ratio 0.43; p < 0.001). Incidence was much lower in Vratza town; among residents of affected villages, the period-specific rates were 1.7 and 0.8 per 1,000 per year, respectively (rate ratio 0.47; p < 0.01). These trends were consistent across all villages for which registers were maintained. Median survival following registration increased from 2.0 to 5.0 years over the same period (p < 0.001). BEN appears to be decreasing in incidence in this region.