Geographic variation in the incidence of treated end-stage renal disease

County-Level Characteristics Associated with Variation in ESKD Mortality in the United States, 2010-2018

Background

Geographic and neighborhood-level factors, such as poverty and education, have been associated with an increased risk for incident ESKD, likelihood of receiving pre-ESKD care, and likelihood of receiving a transplant. However, few studies have examined whether these same factors are associated with ESKD mortality. In this study, we examined county-level variation in ESKD mortality and identified county-level characteristics associated with this variation.

Methods

We identified 1,515,986 individuals (aged 18-84 years) initiating RRT (dialysis or transplant) between 2010 and 2018 using the United States Renal Data System. Among 2781 counties, we estimated county-level, all-cause, age-standardized mortality rates (ASMR) among patients with ESKD. We then identified county-level demographic (e.g., percent female), socioeconomic (e.g., percent unemployed), healthcare (e.g., percent without health insurance), and health behavior (e.g., percent current smokers) characteristics associated with ASMR using multivariable hierarchic linear mixed models and quantified the percentage of ASMR variation explained by county-level characteristics.

Results

County-level ESKD ASMR ranged from 45 to 1022 per 1000 person-years (PY) (mean, 119 per 1000 PY). ASMRs were highest in counties located in the Tennessee Valley and Appalachia regions, and lowest in counties located in New England, the Pacific Northwest, and Southern California. In fully adjusted models, county-level characteristics significantly associated with higher ESKD mortality included a lower percentage of Black residents (-4.94 per 1000 PY), lower transplant rate (-4.08 per 1000 PY), and higher healthcare expenditures (5.21 per 1000 PY). Overall, county-level characteristics explained 19% of variation in ESKD mortality.

Conclusions

Counties with high ESKD-related mortality may benefit from targeted and multilevel interventions that combine knowledge from a growing evidence base on the interplay between individual and community-level factors associated with ESKD mortality.

Emergency department use by patients with end-stage renal disease in the United States

Background

We sought to describe the national characteristics of ED visits by patients with end-stage renal disease (ESRD) in the United States in order to improve the emergency treatment and screening of ESRD patients.

Methods

We analyzed data from 2014 to 2016 ED visits provided by the National Hospital Ambulatory Medical Care Survey. We sampled adult (age ≥ 18 years) ED patients with ESRD. By proportion or means of weighted sample variables, we quantified annual ED visits by patients with ESRD. We investigated demographics, ED resource utilization, clinical characteristics, and disposition of patients with ESRD and compared these to those of patients without ESRD. Logistic regression models were used to estimate the association between these characteristics and ESRD ED visits.

Results

Approximately 722,692 (7.78%) out of 92,899,685 annual ED visits represented ESRD patients. Males were more likely to be ESRD patients than females (aOR: 1.34; 95% CI: 1.09–1.66). Compare to whites, non-Hispanic Blacks were 2.55 times more likely to have ESRD (aOR: 2.55; 95% CI: 1.97–3.30), and Hispanics were 2.68 times more likely to have ESRD (95% CI: 1.95–3.69). ED patients with ESRD were more likely to be admitted to the hospital (aOR: 2.70; 95% CI: 2.13–3.41) and intensive care unit (ICU) (aOR: 2.21; 95% CI: 1.45–3.38) than patients without ESRD. ED patients with ESRD were more likely to receive blood tests and get radiology tests.

Conclusion

We described the unique demographic, socioeconomic, and clinical characteristics of ED patients with ESRD, using the most comprehensive, nationally representative study to date. These patients’ higher hospital and ICU admission rates indicate that patients with ESRD require a higher level of emergency care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00420-8.

Mapping end-stage renal disease (ESRD): spatial variations on small area level in northern France, and association with deprivation

BACKGROUND

Strong geographic variations in the incidence of end-stage renal disease (ESRD) are observed in developed countries. The reasons for these variations are unknown. They may reflect regional inequalities in the population's sociodemographic characteristics, related diseases, or medical practice patterns. In France, at the district level, the highest incidence rates have been found in the Nord-Pas-de-Calais region. This area, with a high population density and homogeneous healthcare provision, represents a geographic situation which is quite suitable for the study, over small areas, of spatial disparities in the incidence of ESRD, together with their correlation with a deprivation index and other risk factors.

METHODS

The Renal Epidemiology and Information Network is a national registry, which lists all ESRD patients in France. All cases included in the Nord-Pas-de-Calais registry between 2005 and 2011 were extracted. Adjusted and smoothed standardized incidence ratio (SIR) was calculated for each of the 170 cantons, thanks to a hierarchical Bayesian model. The correlation between ESRD incidence and deprivation was assessed using the quintiles of Townsend index. Relative risk (RR) and credible intervals (CI) were estimated for each quintile.

RESULTS

Significant spatial disparities in ESRD incidence were found within the Nord-Pas-de-Calais region. The sex- and age-adjusted, smoothed SIRs varied from 0.66 to 1.64. Although no correlation is found with diabetic or vascular nephropathy, the smoothed SIRs are correlated with the Townsend index (RR: 1.18, 95% CI [1.00-1.34] for Q2; 1.28, 95% CI [1.11-1.47] for Q3; 1.30, 95% CI [1.14-1.51] for Q4; 1.44, 95% CI [1.32-1.74] for Q5).

CONCLUSION

For the first time at this aggregation level in France, this study reveals significant geographic differences in ESRD incidence. Unlike the time of renal replacement care, deprivation is certainly a determinant in this phenomenon. This association is probably independent of the patients' financial ability to gain access to healthcare.

State medicaid coverage, ESRD incidence, and access to care

The proportion of low-income nonelderly adults covered by Medicaid varies widely by state. We sought to determine whether broader state Medicaid coverage, defined as the proportion of each state's low-income nonelderly adult population covered by Medicaid, associates with lower state-level incidence of ESRD and greater access to care. The main outcomes were incidence of ESRD and five indicators of access to care. We identified 408,535 adults aged 20-64 years, who developed ESRD between January 1, 2001, and December 31, 2008. Medicaid coverage among low-income nonelderly adults ranged from 12.2% to 66.0% (median 32.5%). For each additional 10% of the low-income nonelderly population covered by Medicaid, there was a 1.8% (95% confidence interval, 1.0% to 2.6%) decrease in ESRD incidence. Among nonelderly adults with ESRD, gaps in access to care between those with private insurance and those with Medicaid were narrower in states with broader coverage. For a 50-year-old white woman, the access gap to the kidney transplant waiting list between Medicaid and private insurance decreased by 7.7 percentage points in high (>45%) versus low (<25%) Medicaid coverage states. Similarly, the access gap to transplantation decreased by 4.0 percentage points and the access gap to peritoneal dialysis decreased by 3.8 percentage points in high Medicaid coverage states. In conclusion, states with broader Medicaid coverage had a lower incidence of ESRD and smaller insurance-related access gaps.

The increase in renal replacement therapy (RRT) incidence has come to an end in Sweden-analysis of variations by region over the period 1991-2010

BACKGROUND

Renal replacement therapy (RRT) incidence has increased significantly in Sweden during the past decades. This study analyses variations in time and regional trends in RRT incidence in Sweden, adjusted for age and gender, focusing on the impact change in incidence during the last decade.

METHODS

Using data from the Swedish Renal Registry (SRR) (21 counties in Sweden, total population 9 million), we identified all incident subjects starting RRT from 1991 through 2010. Only individuals alive following 90 days of RRT start were included. Gender- and age-specific standardized RRT incidences on an annual and regional basis were calculated, and differences between counties and variations over time were examined. We compared the overall age and gender-adjusted RRT incidence rates for Sweden by calendar year. Furthermore, we also calculated the age and gender-adjusted RRT incidence in each county during two time periods (1991-1999 versus 2000-2010).

RESULTS

There were 20 172 new subjects treated with RRT between January 1991 and December 2010. The most common cause of end-stage renal disease (ESRD) was diabetes (24%) and hypertension/renal vascular disease (19%), followed by glomerulonephritis (16%). Sixty-four percent of new patients were male; the median age when commencing RRT was 66 years (10-90 percentiles; 39-80). The overall standardized RRT incidence reached its peak in 2000, and slowly decreased thereafter. A decrease in RRT incidence was observed over the study period in eight regions. The standardized RRT incidence varied between the different counties, from 0.82 to 1.19.

CONCLUSIONS

Adjusted for demographic changes in the population, an overall decrease in RRT incidence was observed from the year 2000 onwards-suggesting that the previously reported steady increase in RRT incidence is coming to an end in Sweden. Noteworthy differences were found between counties and in 8 out of 21 counties, a decreased incidence of RRT was found. Further studies need to identify the factors that contribute to this decrease.

Geographic variation in CKD prevalence and ESRD incidence in the United States: results from the reasons for geographic and racial differences in stroke (REGARDS) study

BACKGROUND

It is not known whether geographic differences in the prevalence of chronic kidney disease exist and are associated with end-stage renal disease (ESRD) incidence rates across the United States.

STUDY DESIGN

Cross-sectional and ecologic.

SETTING & PARTICIPANTS

White (n = 16,410) and black (n = 11,109) participants from across the continental United States in the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

PREDICTOR

Geographic region, defined by the 18 networks of the US ESRD Network Program.

OUTCOMES & MEASUREMENTS

Albuminuria, defined as albumin-creatinine ratio ≥30 mg/g, and decreased estimated glomerular filtration rate (eGFR), defined as <60 mL/min/1.73 m(2), were measured in the REGARDS Study. ESRD incidence rates were obtained from the US Renal Data System.

RESULTS

For whites, the network-specific prevalence of albuminuria ranged from 8.4% (95% CI, 3.3%-13.5%) in Network 15 to 14.8% (95% CI, 8.0%-21.6%) in Network 3, and decreased eGFR ranged from 4.3% (95% CI, 2.0%-6.6%) in Network 4 to 16.7% (95% CI, 12.7%-20.7%) in Network 7. For blacks, the prevalence of albuminuria ranged from 12.1% (95% CI, 8.7%-15.5%) in Network 5 to 26.5% (95% CI, 16.7%-36.3%) in Network 4, and decreased eGFR ranged from 6.7% (95% CI, 5.0%-8.4%) in Network 17/18 to 13.4% (95% CI, 7.8%-19.1%) in Network 12. Spearman correlation coefficients for the prevalence of albuminuria and decreased eGFR with network-specific ESRD incidence rates were 0.49 and 0.24, respectively, for whites and 0.29 and 0.25, respectively, for blacks.

LIMITATIONS

There were few cases of albuminuria and decreased eGFR in some geographic regions.

CONCLUSIONS

In the United States, substantial geographic variations in the prevalence of albuminuria and decreased eGFR exist, but were correlated only modestly with ESRD incidence, suggesting the chronic kidney disease burden may not explain the geographic variation in ESRD incidence.

Regional and social inequalities in chronic renal replacement therapy in Denmark

BACKGROUND

The incidence of chronic renal replacement therapy (RRT) varies markedly between Danish nephrology centres. The aim of the present study was to establish if there is regional and social variation in the incidence of chronic RRT in Denmark when analysed according to patient residence. The importance of diabetic nephropathy and patients aged 70 years or older was also studied.

METHODS

Incident patients on chronic RRT in the period 1995-2006 were identified in the Danish National Registry on Regular Dialysis and Transplantation. Information on residence, income, educational status and ethnic origin was obtained from Statistics Denmark. Rates of incident RRT patients were standardized for regional differences of sex and age as well as income, educational status and ethnic origin. Poisson regression was used when comparing rates.

RESULTS

Age- and sex-standardized incident chronic RRT rates among individuals with low income or short educational level were higher (P < 0.0001) compared to other groups. Also, standardized rates of patients in total and patients aged 70 years or older were higher in the catchment areas of the nephrology centres located in the two largest cities than for patients with residence in other areas of the country (P < 0.0001). Standardizing for regional differences of ethnic origin did not change the rates. The incident chronic RRT rate caused by diabetic nephropathy was higher for patients with residence in the catchment area of the nephrology centre in the largest city [49 per million people (p.m.p.) (95% CI = 40-57 p.m.p.)] compared to the catchment area of the nephrology centre located in the second largest city [31 (95% CI = 26-37 p.m.p.)] and other areas [29 p.m.p. (95% CI = 26-31 p.m.p.)] in 2001-06. When standardizing for differences in income among the 30-69-year-old persons, the rate of patients with residence in the catchment area of the nephrology centre located in the largest city decreased but was still higher than in other regions (P = 0.0003).

CONCLUSIONS

There are marked socio-economic and regional differences in rates of incident RRT patients. The rates of incident RRT patients are highest in the catchment areas of the two largest nephrology centres and this may be partly explained by a higher frequency of end-stage diabetic nephropathy and a new treatment programme targeting frail, mainly elderly, patients.

Proposal for mapping renal failure in Japan and its application for strategy to arrest endstage renal disease

Remarkable regional differences in the annual incidence of endstage renal disease (ESRD) was found within Japan, which has a relatively homogeneous ethnic composition. In addition, there existed no regional difference in the incidence of ESRD due to polycystic kidney disease, the major genetic disorder of the kidneys. These findings suggest that the presence of factors other than genetic disposition contribute to the differences. On the other hand, there were similar regional variations in the incidences of ESRD between two causes of ESRD: chronic glomerulonephritis and diabetic nephropathy. Because it is unlikely that the regional distribution of underlying disease incidence and the disease-specific progression rate would be similar for two different causes, this observation suggests that factors governing the progression rate, which operate commonly for all causes of ESRD but differ among regions, may play an important role in generating the regional differences. Finally, we examined regional differences in the amounts of inhibitors of the renin-angiotensin system used, especially angiotensin-converting enzyme (ACE) inhibitors, in our search for an explanation of the regional differences in ESRD dynamics. Among antihypertensive agents examined, only ACE inhibitors were negatively correlated with the annual incidence of ESRD. The renal protective effects of ACE inhibitors have been established by results with animal models of progressive nephropathy and by large-scale clinical trials. Our epidemiological results for Japan as a whole show the same protective effects still more convincingly from a different approach. It is not completely clear yet at present, however, how regional variations in the incidence of ESRD are generated. If we could identify in future the factors that contribute to the regional differences, strategies for the treatment of renal disease will become available from different angles. Thus, much effort will be encouraged for the further analysis of regional differences in ESRD dynamics.

Different regional dynamics of end-stage renal disease in Japan by different causes

BACKGROUND

We recently showed that there were clear regional differences in the dynamics of end-stage renal disease (ESRD) within Japan, which has an ethnically homogenous population. We speculate on the reason for these regional differences by correlating the regional distributions in the incidence of ESRD due to each of the following individual causes of ESRD: chronic glomerulonephritis (CGN), diabetic nephropathy (DMN) and polycystic kidney disease (PKD).

METHODS

The number of ESRD patients entering maintenance dialysis therapy due to individual causes of renal disease in each prefecture was reported annually for a 6-year period by the Japanese Society for Dialysis Therapy. After combining data from several prefectures into 11 geopolitical regions in Japan, the mean annual incidence of ESRD across the 11 regions was correlated among the three causes of ESRD.

RESULTS

There were significant regional differences in the incidence of ESRD due to CGN (P<0.0001) and DMN (P=0.0015), the distributions of which were similar to each other across the 11 regions. In contrast, no regional differences were found in the incidence of ESRD due to PKD (P=0.6) as the major genetic disorder of the kidneys, suggesting that genetic backgrounds are relatively uniform throughout Japan. The regional distributions due to PKD were not correlated with those due to other causes: CGN and DMN.

CONCLUSION

Risk factors common to nephropathy progression, rather than an underlying disease incidence and genetic predisposition, might contribute to regional differences in the overall ESRD incidence in Japan. Other possibilities such as the prevalence of underlying diseases, and acceptance or rejection rates into treatment programmes must be considered further for better explanations.

Epidemiology and risk factors for chronic kidney disease

Kidney disease is highly prevalent in the United States population and groups at high risk for increased prevalence of CKD include individuals with a family history of ESRD, diabetes, hypertension, and cardiovascular disease. Despite the increased risk of ESRD observed for blacks compared with whites, racial disparities in the prevalence of kidney disease have not been consistently demonstrated in the United States population. Although the reasons for discrepancy in risk of ESRD and CKD have not been established, clinicians should be aware that more rapid progression of CKD among blacks is a possible explanation for this observation and that closer monitoring and intensive care of risk factors associated with progressive renal injury is warranted for blacks with CKD and in other high-risk groups. Therapeutic interventions that delay or prevent progressive kidney disease are well established and incorporated into widely disseminated clinical practice guidelines. These interventions include aggressive blood pressure control with agents that block the renin-angiotensin system, reduction of dietary protein to recommended levels for the American diet, weight loss, smoking cessation, and control of hyperlipidemia. These interventions also reduce the risk of cardiovascular disease and should be regarded as essential components of care of CKD. Achieving high levels of medically appropriate care of CKD patients and reduction in risk of progression to ESRD may be delayed by barriers created by individual and regional poverty.

Regional variation in end-stage renal disease

Regional variations in end-stage renal disease have been found within a country, even within a race. Since diabetic nephropathy is the leading cause of end-stage renal disease in developed countries, first of all, regional differences in diabetic nephropathy must be considered. Although the incidence of end-stage renal disease due to diabetic nephropathy has been found to differ among different areas within a country, there are no data on regional variations in the incidence of type II diabetes or diabetic nephropathy without renal failure. Such regional variations could hardly be explained by local differences in gene pools alone, which suggests an important role of environmental factors. It is not clear at present how regional variations in the incidence of end-stage renal disease are generated. If we can identify the factors that contribute to the regional differences, we can take these into account in future treatment strategies for renal disease. Thus, much effort is required in further analysis of regional differences in end-stage renal disease dynamics.

Hypertension-related morbidity and mortality in the southeastern United States

Stroke mortality is higher in the Southeast compared with other regions of the United States. The prevalence of hypertension is also higher (black men = 35%, black women = 37.7%, white men = 26.5%, white women = 21.5%), and the proportion of patients whose hypertension is being controlled is poor, especially in white and black men. The prevalence of hypertension-related complications other than stroke is also higher in the Southeast. The five states with the highest death rates for congestive heart failure are all in the southern region. Of the 15 states with the highest rates of end-stage renal disease, 10 are in the Southeast. Obesity is very prevalent (24% to 28%) in the Southeast. Although Michigan tops the ranking for all states, 6 of the top 15 states are in the Southeast, as are 7 of the 10 states with the highest reported prevalence regarding no leisure-time physical activity. Similar to other areas of the United States, dietary sodium and saturated fat intake are high in the Southeast; dietary potassium intake appears to be relatively low. Other factors that may be associated with the high prevalence, poor control, and excess morbidity and mortality of hypertension-related complications in the Southeast include misperceptions of the seriousness of the problem, the severity of the hypertension, lack of adequate follow-up, reduced access to health care, the cost of treatment, and possibly, low birth weights. The Consortium of Southeastern Hypertension Control (COSEHC) is a nonprofit organization created in 1992 in response to a compelling need to improve the disproportionate hypertension-related morbidity and mortality throughout this region. The purpose of this position paper is to summarize the data that document the problem, the consequences, and possible causative factors.

Financial effect of clinical decisions: case study of a dialysis center

The purpose of this study was to specify the financial effect of clinical decisions in a dialysis center. A consecutive sample of 14,343 outpatient hemodialysis treatments (OHD), 16,111 continuous ambulatory peritoneal dialysis (CAPD), and 4,513 chronic cycler-assisted peritoneal dialysis (CCPD) days of treatment was analyzed. An activity-based cost calculation method was applied to the analysis of alternative treatments (service bundles). The weekly cost of OHD was higher ($338 versus $241/$242), and the contribution margin (reimbursement minus total cost) of CAPD/CCPD was much greater ($.48 versus $148/$147 per patient week). Clinical decision-making had an influence on less than 6.8% of OHD and 45.4%/46.6% of CAPD/CCPD related expenses. In comparison to activity-based cost calculation, conventional methods overestimated the overhead expense of CAPD by 3-48%. This study documented that most cost control opportunities reside in the usual process of care and less can be influenced by a direct interference with the patient-physician contacts. Paying for 1 week of renal replacement (capitation) could simplify the process of reimbursement and cost tracking.

Socioeconomic status and end-stage renal disease in the United States

The incidence of treated end-stage renal disease (ESRD) varies markedly according to age, race, sex, and geographic characteristics of the population. We asked whether some of the variability in the incidence of treated ESRD (t-ESRD) was associated with differences in socioeconomic status and whether socioeconomic status could explain some of the effects of race on t-ESRD incidence. Demographic characteristics of incident cases of t-ESRD from the years 1983 to 1988 were obtained from the U.S. Renal Data System, which registers most treated cases of ESRD. The average race specific, per capita income of the county of residence, as determined from the Bureau of Health Professions Area Resource File, was used as a surrogate measure of socioeconomic status. the incidence of t-ESRD for individuals < 60 years of age was modeled as a log-linear function of socioeconomic and demographic factors, including age, sex, the urban fraction of the county of residence, and the census geographic region. For both Whites and Blacks, the incidence of t-ESRD was higher for males and older age groups, as expected. In general, the incidence of t-ESRD was inversely related to income level. For Whites, the relative risk was 1.21 for income of $0 to 10.000, 1.11 for $10,000 to 15,000, 1.00 for $15,000 to 20,000 (reference), 0.89 for $20,000 to 25,000, and 0.77 for income > $25,000. For Blacks, the relative risk was 1.10 for income of $0 to 10,000, 1.20 for $10,000 to 15,000, 1.00 for $15,000 to 20,000 (reference), 0.81 for $20,000 to 25,000, and 0.69 for income > $25,000.(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of low incidence of treated end-stage renal disease among the elderly

We present US county-level maps of the 1983 to 1988 incidence of treated end-stage renal disease (ESRD) among white and nonwhite persons 65 years of age and older (N = 66,129). Recent statistical advances permit the investigation of geographical patterns of unusually low disease incidence. Our maps highlight those US counties which have been determined to have rates of ESRD treatment incidence that are low relative to those of all counties, revealing several interesting geographic patterns. For whites, low rates are found in the Northwest, the Midwest, and the South. Nonwhite rates are seen to be low primarily in the South and Alaska. Low treatment incidence could be due to a combination of (1) low true incidence, (2) lack of access to health care services, (3) insufficient diagnosis and referral, and (4) patients' reluctance to accept ESRD therapy, due to cultural or personal concerns. A state-level regression of elderly rates on those aged 40 to 64 years indicates the variation in treatment incidence among the elderly may be due to factors other than variation in true incidence, which the middle-aged rates reflect more closely. Residual analysis corroborates the visual impression of the maps of low ESRD treatment incidence in several southern states, where referral to dialysis may be as much as 40% lower than the national level. Further research on factors contributing to low treatment incidence, including competing risks, regional lags relative to the national trend to dialyze more elderly patients, and lack of access to health care resources, is indicated.