Our results, based on national data of renal dialysis in the national health system, estimated to cover 85% of Brazilian patients in dialysis, illustrate the growing importance of ESRD in Brazil. From 2000 to 2012, the prevalence of ESRD receiving dialysis increased by 46.8%, an average of 3.6% per year, and the incidence by 20%, an average of 1.8% per year. By 2011, the most recent year with complete ascertainment, a total of 521.4 cases pmp existed, of which 113.4 cases pmp had initiated treatment that year.
To date, considerable uncertainty has existed as to incidence and prevalence of patients with ESRD undergoing dialysis in Brazil. Frequently cited data have come from an annual query of the Brazilian Nephrology Society to its members. However, as reporting through this query is voluntary and incomplete, with only 55% of dialysis centers responding in 2011, uncertainty regarding the exact numbers remains. In fact, our APAC prevalence estimate for 2011 (521 pmp), is greater than the Society’s (475 pmp) . The true difference is even greater, as APAC covers only publically financed treatment, roughly 85% of all dialysis, and our analyses excluded patients on dialysis for less than 3 months . Further, in terms of estimating total cases of ESRD, neither the frequencies here reported, nor those of the Brazilian Nephrology Society include patients who die of ESRD before receiving renal replacement therapy or patients undergoing transplantation without previous dialysis for at least three months.
In any event, by international comparison, a massive number of patients receive dialysis in Brazil. Grassmann et al, in their global overview of ESRD, placed Brazil among countries with the greatest number of patients receiving such treatment in 2004 . The U.S. Renal Data System (USRDS), which estimated a prevalence of renal dialysis of 679 pmp in 2011 for Brazil, ranked the country third in the world for that year in terms of numbers of patients undergoing dialysis .
This position is in large part due to the size of the population, as prevalence rates are at the low end of the spectrum shown in the USRDS’s international comparisons. Approximately half of the countries listed by the USRDS, in general high income countries, had prevalence rates of >1000 pmp. The relatively lower prevalence in Brazil may well reflect remaining problems of access to therapy. According to a recent publication of the Latin American Dialysis and Renal Transplant Registry (RLDTR), prevalence and incidence are increasing across the region. Several South American countries have dialysis prevalence in 2008 - Argentina (620 pmp) Chile (852 pmp) and Uruguay (825 pmp) - greater than those we report (459 pmp) for that year, with the overall prevalence for the region (461 pmp) being quite similar to ours . Of note, however, these comparisons are not adjusted for age, and many of the countries with higher rates of dialysis, especially the high income countries, have a more elderly population. The prevalence of ESRD treated by dialysis in Brazil is likely to continue to increase, since the transplantation rate is around 26 pmp/year in Brazil and crude mortality is lower than 20% .
In terms of modality of dialysis, only 10%, of publically financed patients are currently receiving peritoneal dialysis. The fraction so treated varies tremendously across countries, with most countries having a frequency of peritoneal dialysis not too different from that of Brazil .
The discrete increase in the incidence of patients receiving dialysis from 2001 to 2012 was present in all regions of the country, though less so in the southeast and south, and may reflect growing access to treatment. The increase was greater in women and in the older age strata, where diabetes and hypertension present as the principal causes of ESRD. A notably larger increase in this age group was also reported in Canada a decade ago . More recent series in the in the U.S. noted a larger increase in the 45 to 64 year age range .
The analysis of the underlying cause of ESRD in APAC is limited by the high percentage (42.3%) of diagnoses listed as indeterminate, the percentage being as high as 80% among native Brazilian patients. Among specific diagnoses listed, hypertension (20.4%) was the principal cause, followed by diabetes (12%) and then by glomerulonephritis (7.7%). These results are similar to those reported for the period of 2000-2004 by Cherchiglia et al. . The pattern of hypertension and diabetes as predominant causes is typical of high and medium income countries, with variations in the relative positions of hypertension and diabetes. In contrast, glomerulonephritis is the more prevalent cause of ESRD in low income countries, comprising 25-35% of causes. Diabetes has been cited as the cause of ESRD in 9.1 to 29.9% of patients in different countries in the developing world, and hypertension in 13 to 21% . The USRDS report shows a quite variable proportion, from 15 to 60%, of diabetes as a cause across surveyed countries . Given the multicausal nature of ESRD, it is to be expected that diabetes and hypertension frequently overlap in the causal process, and this uncertainty may explain, in part, the high frequency of indeterminate cause listed in the APAC system.
Data on race/color of dialyzed patients, to our knowledge, have not been previously published in Brazil. Reported patient race/color, after redistribution of those lacking information uniformly across the race/color categories, is predominantly white (52%), followed by brown (35%), black (11%), Asian (0.9%) and native Brazilian (0.2%). These proportions are similar to the self-declared information on race/color presented in the 2010 census: white 47.7%, brown 43.1%, black 7.6%, Asian 1.0% and native Brazilian 0.4% .
The major strength of our study is that the database created permits analysis of a consistent series of several years of all publically-financed dialysis in Brazil, instead of relying on non-representative sampling with incomplete reporting. Aside from serving as the basis for the results here reported, this database will permit future analyses, including economic ones and those related to assessment of disease burden.
Limitations to these results merit a brief discussion. As APAC does not adequately estimate the prevalence and incidence of renal transplantation, caution is required in using these data to estimate the total number of patients receiving renal replacement therapy in Brazil, and further work is necessary to achieve estimates of ESRD incidence and prevalence. In this regard, approximately 28.4 patientspmp received a renal transplant in Brazil in 2012 . As the majority of these were receiving dialysis for more than 3 months prior to receiving their transplant, underestimation of incidence of ESRD receiving renal replacement therapy is likely to be small.
Another important limitation relates to the coding of the underlying cause of renal failure, as previously noted. Similarly, though the introduction of reporting race/color of patients is an important advance, the high frequency of missing data limit precision in the reporting of this characteristic.
In summary, these analyses demonstrate the importance of the APAC system as a source for surveillance of the treatment of ESRD in Brazil. Assuming current incidence rates and lethality, the trends here presented indicate that the total number of cases needing publically financed renal dialysis will increase considerably. Given that renal replacement therapies have been reported to represent 8% of the total budget of the Ministry of Health, the projected increase will demand adequate planning of resources .
In terms of surveillance, continued analysis of the APAC system can provide important findings for public policies regarding the prevention, control and treatment of ESRD at local, regional and national levels. Actions and more detailed investigations should be undertaken to further qualify available data, especially with respect to the underlying causes of ESRD in Brazil. In this regard, the Brazilian Society of Nephrology has joined with the Ministry of Health in stimulating and supporting the adoption of effective measures for the surveillance, prevention, treatment and management of kidney disease in order to reduce its impact in terms of population health. The main goals within this effort are to increase awareness of risk factors for chronic kidney disease and of the importance of its complications .