Association of deprivation with worse outcomes in chronic kidney disease: findings from a hospital-based cohort in the United Kingdom

Association of deprivation and its individual domains on outcomes in people with chronic kidney disease

Background

Due to the high correlation of chronic kidney disease (CKD) with other comorbidities, the sole effect of CKD on deprived people is not clear. In addition, there is a paucity of evidence in the literature linking isolated domains of deprivation to outcomes. This study aimed to examine whether deprivation was associated with adverse outcomes in patients with CKD, independent of cardiometabolic morbidities. Individual domains of deprivation were also evaluated.

Methods

A retrospective study of patients with non-dialysis-dependent CKD (ND-CKD) in the Salford Kidney Study to investigate the association of deprivation with outcomes. The English Indices of Deprivation was used for the comparative analysis of the five quintiles of deprivation. Two propensity score methods were used to attenuate the confounding effect of cardiometabolic morbidities between the least and the most deprived groups.

Results

People living in the least deprived areas (n = 319) had a lower risk of combined outcomes (all-cause mortality and renal replacement therapy) when compared with the most deprived group (n = 813) [hazard ratio (HR) 0.83; 95% confidence interval (CI) 0.71-0.98]. The negative association of deprivation remained after matching but with mixed statistical significance when using different propensity methods (HR 0.85; 95% CI 0.70-1.03 for propensity score matching and HR 0.77; 95% CI 0.61-0.98 for inverse probability weighting). The association of combined outcomes varied across component index of multiple deprivation domains with wide CIs. However, areas with lower scores for education, income and employment were significantly associated with a higher risk.

Conclusions

This study has identified that in people with ND-CKD, unemployment, poor educational attainment and lower household income were associated with poor outcomes. The association of deprivation with adverse outcomes persists despite adjustment for cardiometabolic morbidities.

Social Deprivation and Incidence of Pediatric Kidney Failure in France

Introduction

Approximately 8 per million children and young adults aged < 20 years initiate kidney replacement therapy (KRT) per year in France. We hypothesize that social deprivation could be a determinant of childhood-onset kidney failure. The objective of this study was to estimate the incidence of pediatric KRT in France according to the level of social deprivation.

Methods

All patients < 20 years who initiated KRT from 2010 to 2015 in metropolitan France were included. Data were collected from the comprehensive French registry of KRT French Renal Epidemiology and Information network (REIN). We used a validated ecological index to assess social deprivation, the 2011 French version of the European Deprivation Index (EDI). We estimated the age standardized incidence rates according to the quintiles of EDI using direct standardization and incidence rate ratio using Poisson regression.

Results

We included 672 children with kidney failure (58.6% males, 30.7% with glomerular or vascular disease, 43.3% starting KRT between 11 and 17 years). 38.8% were from the most deprived areas (quintile 5 of EDI). The age standardized incidence rate increased with quintile of EDI, from 5.45 (95% confidence interval [CI] = 4.25-6.64) per million children per year in the least deprived quintile to 8.46 (95% CI = 7.41-9.51) in the most deprived quintile of EDI (incidence rates ratio Q5 vs. Q1 1.53-fold; 95% CI = 1.18-2.01).

Conclusion

This study showed that even in a country with a universal health care system, there is a strong association between the incidence of pediatric KRT and social deprivation showing that social health inequalities appear from KRT initiation. This study highlights the need to look further into social inequalities in the earliest stage of chronic kidney disease (CKD).

Addressing Housing Issues Among People With Kidney Disease: Importance, Challenges, and Recommendations

Kidney disease disproportionately impacts people with low socioeconomic status, and low socioeconomic status is associated with worse outcomes for people with kidney disease. Unstable housing, which includes housing insecurity and homelessness, is increasing due to rising housing costs. There is mounting evidence that unstable housing and other health-related social needs are partially driving worse outcomes for people with low socioeconomic status. In this perspective, we consider the challenges to addressing housing for people with kidney disease, such as difficulty with identification of those with unstable housing, strict eligibility criteria for housing support, inadequate supply of affordable housing, and flaws in communities' prioritization of affordable housing. We discuss ways to tailor management for people experiencing unstable housing with kidney disease, and the importance of addressing safety, trauma, and emotional concerns as a part of care. We identify opportunities for the nephrology community to surmount challenges through increased screening, investment in workforce dedicated to community resource navigation, advocacy for investment in affordable housing, restructuring of communities' prioritization of affordable housing, and conducting needed research. Identifying and addressing housing needs among people with kidney disease is critical to eliminating kidney health disparities.

Income Level and Impaired Kidney Function Among Working Adults in Japan

Importance

Chronic kidney disease (CKD) is a major public health issue, affecting 850 million people worldwide. Although previous studies have shown the association between socioeconomic status and CKD, little is known about whether this association exists in countries such as Japan where universal health coverage has been mostly achieved.

Objective

To identify any association of income-based disparity with development of impaired kidney function among the working population of Japan.

Design, Setting, and Participants

This was a nationwide retrospective cohort study of adults aged 34 to 74 years who were enrolled in the Japan Health Insurance Association insurance program, which covers approximately 40% of the working-age population (30 million enrollees) in Japan. Participants whose estimated glomerular filtration rate (eGFR) had been measured at least twice from 2015 to 2022 were included in the analysis, which was conducted from September 1, 2021, to March 31, 2023.

Exposure

Individual income levels (deciles) in the fiscal year 2015.

Main Outcomes and Measures

Odds ratios were calculated for rapid CKD progression (defined as an annual eGFR decline of more than 5 mL/min/1.73 m2), and hazard ratios, for the initiation of kidney replacement therapy (dialysis or kidney transplant) by income level deciles in the fiscal year 2015.

Results

The study population totaled 5 591 060 individuals (mean [SD] age, 49.2 [9.3] years) of whom 33.4% were female. After adjusting for potential confounders, the lowest income decile (lowest 10th percentile) demonstrated a greater risk of rapid CKD progression (adjusted odds ratio, 1.70; 95% CI, 1.67-1.73) and a greater risk of kidney replacement therapy initiation (adjusted hazard ratio, 1.65; 95% CI, 1.47-1.86) compared with the highest income decile (top 10th percentile). A negative monotonic association was more pronounced among males and individuals without diabetes and was observed in individuals with early (CKD stage 1-2) and advanced (CKD stage 3-5) disease.

Conclusions and Relevance

The findings of this retrospective cohort study suggest that, even in countries with universal health coverage, there may be a large income-based disparity in the risk of rapid CKD progression and initiation of kidney replacement therapy. These findings highlight the importance of adapting CKD prevention and management strategies according to an individual's socioeconomic status, even when basic health care services are financially guaranteed.

Deprivation and chronic kidney disease-a review of the evidence

The relationship between socioeconomic deprivation and health is inequitable. Chronic kidney disease (CKD) is an archetypal disease of inequality, being more common amongst those living in deprivation. The prevalence of CKD is rising driven by an increase in lifestyle-related conditions. This narrative review describes deprivation and its association with adverse outcomes in adults with non-dialysis-dependent CKD including disease progression, end-stage kidney disease, cardiovascular disease and all-cause mortality. We explore the social determinants of health and individual lifestyle factors to address whether patients with CKD who are socioeconomically deprived have poorer outcomes than those of higher socioeconomic status. We describe whether observed differences in outcomes are associated with income, employment, educational attainment, health literacy, access to healthcare, housing, air pollution, cigarette smoking, alcohol use or aerobic exercise. The impact of socioeconomic deprivation in adults with non-dialysis-dependent CKD is complex, multi-faceted and frequently under-explored within the literature. There is evidence that patients with CKD who are socioeconomically deprived have faster disease progression, higher risk of cardiovascular disease and premature mortality. This appears to be the result of both socioeconomic and individual lifestyle factors. However, there is a paucity of studies and methodological limitations. Extrapolation of findings to different societies and healthcare systems is challenging, however, the disproportionate effect of deprivation in patients with CKD necessitates a call to action. Further empirical study is warranted to establish the true cost of deprivation in CKD to patients and societies.

Effect of social deprivation on peritoneal dialysis uptake: A mediation analysis with the data of the REIN registry

BACKGROUND

Social deprivation could act as a barrier to peritoneal dialysis (PD). The objective of this study was to assess the association between social deprivation estimated by the European deprivation index (EDI) and PD uptake and to explore the potential mediators of this association.

METHODS

From the Renal Epidemiology and Information Network registry, patients who started dialysis in 2017 were included. The EDI was calculated based on the patient's address. The event of interest was the proportion of PD 3 months after dialysis initiation. A mediation analysis with a counterfactual approach was carried out to evaluate the direct and indirect effect of the EDI on the proportion of PD.

RESULTS

Among the 9588 patients included, 1116 patients were on PD; 2894 (30.2%) patients belonged to the most deprived quintile (Q5). PD was associated with age >70 years (odds ratio (OR) 0.79 [95% confidence interval (CI): 0.69-0.91]), male gender (0.85 [95% CI: 0.74-0.97]), cardiovascular disease (OR 0.86 [95% CI: 0.86-1.00]), chronic heart failure (OR 1.34 [95% CI: 1.13-1.58]), active cancer (OR 0.67 [95% CI: 0.53-0.85]) and obesity (OR 0.75 [95% CI: 0.63-0.89]). In the mediation analysis, Q5 had a direct effect on PD proportion OR 0.84 [95% CI: 0.73-0.96]. The effect of Q5 on the proportion of PD was mediated by haemoglobin level at dialysis initiation (OR 0.96 [95% CI: 0.94-0.98]) and emergency start (OR 0.98 [95% CI: 0.96-0.99]).

CONCLUSION

Social deprivation, estimated by the EDI, was associated with a lower PD uptake. The effect of social deprivation was mediated by haemoglobin level, a proxy of predialysis care and emergency start.

Impact of educational level on incident chronic kidney disease during 13 years of follow-up: a prospective cohort study

OBJECTIVES

To examine the association between educational level and chronic kidney disease (CKD) among the Iranian population.

STUDY DESIGN

This is a prospective cohort study conducted in the framework of the Tehran Lipid and Glucose Study.

METHODS

A total of 8173 Iranians (men = 3659) aged ≥20 years were included in the study. CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². The association between educational status and CKD was explored using multivariate Cox proportional regression analyses, adjusted for age, gender, current smoking, marital status, body mass index, waist circumference, baseline eGFR, diabetes, hypertension, physical activity, history of cardiovascular diseases and dyslipidaemia.

RESULTS

During a median follow-up of 13.14 years, 2609 cases of incident CKD were identified; the corresponding incidence rate was 26.35 (range 25.39-27.34) per 1000 person-years. Compared to low educational level, middle and high educational levels showed lower risks for incident CKD in the crude model [hazard ratio (HR) 0.37 (95% confidence interval {CI} 0.34-0.40) and HR 0.40 (95% CI 0.35-0.45), respectively]; however, these HRs changed direction after further adjustment for age and gender [HR 1.26 (95% CI 1.14-1.39) and HR 1.40 (95% CI 1.22-1.61), respectively]. The increased risk of incident CKD for those at higher educational levels remained significant in the fully adjusted model. In addition, results from the gender stratified analyses were in the same direction as those found among the whole study population (P-value for interaction of gender and education >0.8).

CONCLUSIONS

Higher educational levels were associated with incident CKD during more than a decade of follow-up; this finding may be attributed to unhealthy lifestyle behaviours among this population group.

Area Deprivation and Risk of Death and CKD Progression: Long-Term Cohort Study in Patients under Unrestricted Nephrology Care

BACKGROUND

Area deprivation index (ADI) associates with prognosis in non-dialysis CKD. However, no study has evaluated this association in CKD patients under unrestricted nephrology care.

METHODS

We performed a long-term prospective study to assess the role of deprivation in CKD progression and mortality in stage 1-4 CKD patients under regular nephrology care, living in Naples (Italy). We used ADI calculated at census block levels, standardized to mean values of whole population in Naples, and linked to patients by georeference method. After 12 months of "goal-oriented" nephrology treatment, we compared the risk of death or composite renal outcomes (end-stage kidney disease or doubling of serum creatinine) in the tertiles of standardized ADI. Estimated glomerular filtration rate (eGFR) decline was evaluated by mixed effects model for repeated eGFR measurements.

RESULTS

We enrolled 715 consecutive patients (age: 64 ± 15 years; 59.1% males; eGFR: 49 ± 22 mL/min/1.73 m2). Most (75.2%) were at the lowest national ADI quintile. At referral, demographic, clinical, and therapeutic features were similar across ADI tertiles; after 12 months, treatment intensification allowed better control of hypertension, proteinuria, hypercholesterolaemia, and anaemia with no difference across ADI tertiles. During the subsequent long-term follow-up (10.5 years [interquartile range 8.2-12.6]), 166 renal events and 249 deaths were registered. ADI independently associated with all-cause death (p for trend = 0.020) and non-cardiovascular (CV) mortality (p for trend = 0.045), while CV mortality did not differ (p for trend = 0.252). Risk of composite renal outcomes was similar across ADI tertiles (p for trend = 0.467). The same held true for eGFR decline (p for trend = 0.675).

CONCLUSIONS

In CKD patients under regular nephrology care, ADI is not associated with CKD progression, while it is associated with all-cause death due to an excess of non-CV mortality.

Deprivation and kidney disease-a predictor of poor outcomes

There is a growing body of evidence for the role of deprivation in a broad spectrum of diseases including renal disease. Deprivation has been demonstrated to be associated with poorer outcomes across a range of renal diseases including acute kidney injury (AKI), chronic kidney disease and transplantation. In this issue of Clinical Kidney Journal, Hounkpatin et al. describe the association of socioeconomic deprivation with incidence, mortality and resolution of AKI in a large UK cohort. Investigating deprivation as a factor influencing either incidence or outcome of disease is challenging due to variations in measures of deprivation used and other confounding factors that may be contributing to the observed differences. In this editorial, we review the current literature examining the role of deprivation in renal disease.

Socioeconomic disadvantage and the risk of advanced chronic kidney disease: results from a cohort study with 1.4 million participants

Background

Several studies have investigated the effect of socioeconomic deprivation on cardiovascular disease (CVD) and diabetes; less is known about its effect on chronic kidney disease (CKD). We aimed to measure the association between deprivation, CKD Stages 4–5 and end-stage renal disease (ESRD) in a general population sample.

Methods

This observational study examined 1 405 016 participants from the English Clinical Practice Research Datalink (2000–14), linked to hospital discharge data and death certification. Deprivation was assessed according to the participant’s postcode. Cox models were used to estimate hazard ratios (HRs) for CKD Stages 4–5 and ESRD, adjusting for age and sex, and additionally for smoking status, body mass index, diabetes, systolic blood pressure, prior CVD and estimated glomerular filtration rate (eGFR) at baseline.

Results

During 7.5 years of median follow-up, 11 490 individuals developed CKD Stages 4–5 and 1068 initiated ESRD. After adjustment for age and sex, the HRs and confidence interval (CI) comparing those in the 20% most deprived of the population to the 20% least deprived were 1.76 (95% CI 1.68–1.84) and 1.82 (95% CI 1.56–2.12) for CKD Stages 4–5 and ESRD, respectively. Further adjustment for known risk factors and eGFR substantially attenuated these HRs. Adding our results to all known cohort studies produced a pooled relative risk of 1.61 (95% CI 1.42–1.83) for ESRD, for comparisons between highest to lowest categories of deprivation.

Conclusion

Socioeconomic deprivation is independently associated with an increased hazard of CKD Stages 4–5 and ESRD, but in large part may be mediated by known risk factors.

Associations between access to healthcare, environmental quality, and end-stage renal disease survival time: Proportional-hazards models of over 1,000,000 people over 14 years

Prevalence of end-stage renal disease (ESRD) in the US increased by 74% from 2000 to 2013. To investigate the role of the broader environment on ESRD survival time, we evaluated average distance to the nearest hospital by county (as a surrogate for access to healthcare) and the Environmental Quality Index (EQI), an aggregate measure of ambient environmental quality composed of five domains (air, water, land, built, and sociodemographic), at the county level across the US. Associations between average hospital distance, EQI, and survival time for 1,092,281 people diagnosed with ESRD between 2000 and 2013 (age 18+, without changes in county residence) from the US Renal Data System were evaluated using proportional-hazards models adjusting for gender, race, age at first ESRD service date, BMI, alcohol and tobacco use, and rurality. The models compared the average distance to the nearest hospital (<10, 10-20, >20 miles) and overall EQI percentiles [0-5), [5-20), [20-40), [40-60), [60-80), [80-95), and [95-100], where lower percentiles are interpreted as better EQI. In the full, non-stratified model with both distance and EQI, there was increased survival for patients over 20 miles from a hospital compared to those under 10 miles from a hospital (hazard ratio = 1.14, 95% confidence interval = 1.12-1.15) and no consistent direction of association across EQI strata. In the full model stratified by average hospital distance, under 10 miles from a hospital had increased survival in the worst EQI strata (median survival 3.0 vs. 3.5 years for best vs. worst EQI, respectively), however for people over 20 miles from a hospital, median survival was higher in the best (4.2 years) vs worst (3.4 years) EQI. This association held across different rural/urban categories and age groups. These results demonstrate the importance of considering multiple factors when studying ESRD survival and future efforts should consider additional components of the broader environment.

Socioeconomic status and risk of kidney dysfunction: the Atherosclerosis Risk in Communities study

Background

There is strong evidence of an association between socioeconomic status (SES) and end-stage renal disease (ESRD). However, the association of SES with the risk of chronic kidney disease (CKD) and the rate of change in kidney function is unclear.

Methods

A cohort of 14 086 participants with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 at baseline in the Atherosclerosis Risk in Communities study (1987–89) were studied. The association of annual household income, educational attainment and neighborhood deprivation with incident ESRD, incident CKD and change in eGFR using four measurements over ∼23 years was assessed.

Results

A total of 432 participants developed ESRD and 3510 developed CKD over a median follow-up time of ∼23 years. After adjustment for demographics and baseline eGFR, the hazard ratio (HR) for incident ESRD compared with the high-income group was 1.56 [95% confidence interval (CI) 1.22–1.99 in the medium-income group and 2.30 (95% CI 1.75–3.02) in the low-income group (P-trend < 0.001), and for CKD was 1.10 (95% CI 1.01–1.20) in the medium-income group and 1.30 (95% CI 1.17–1.44) in the low-income group (P-trend < 0.001). After full adjustments, the HR for ESRD was 1.33 (95% CI 1.03–1.70) in the medium-income group and 1.50 (95% CI 1.14–1.98) in the low-income group (P-trend = 0.003) and for CKD was 1.01 (95% CI 0.92–1.10) in the medium-income group and 1.04 (95% CI 0.93–1.16) in the low-income group (P-trend = 0.50). The eGFR decline was 5% and 15% steeper in the medium- and low-income groups, respectively, after full adjustment (P-trend < 0.001). Results were similar, with lower educational attainment and higher neighborhood deprivation being associated with adverse outcomes.

Conclusions

SES (annual household income, educational attainment or neighborhood deprivation) was associated not only with ESRD risk but also with eGFR decline, although the association with CKD appeared weaker.

Associations between socioeconomic status and chronic kidney disease: a meta-analysis

BACKGROUND

Socioeconomic status (SES) has long been conjectured to be associated with the incidence and progression of chronic kidney disease (CKD), but few studies have examined this quantitatively. This meta-analysis aims to fill this gap.

METHODS

A systematic literature review was performed using Medline and EMBASE to identify observational studies on associations between SES and incidence and progression of CKD, published between 1974 and March 2017. Individual results were meta-analysed using a random effects model, in line with Meta-analysis of Observational Studies in Epidemiology guidelines.

RESULTS

In total, 43 articles met our inclusion criteria. CKD prevalence was associated with several indicators of SES, particularly lower income (OR 1.34, 95% CI (1.18 to 1.53), P<0.001; I²=73.0%, P=0.05); lower education (OR 1.21, 95% CI (1.11 to 1.32), P<0.001; I²=45.20%, P=0.034); and lower combined SES (OR 2.18, 95% CI (1.64 to 2.89), P<0.001; I²=0.0%, P=0.326). Lower levels of income, occupation and combined SES were also significantly associated with progression to end-stage renal disease (risk ratio (RR) 1.24, 95% CI (1.12 to 1.37), P<0.001; I²=66.6%, P=0.006; RR 1.05, 95% CI (1.01 to 1.09), P=0.012; I²=0.0%, P=0.796; and RR 1.39, 95% CI (1.09 to 1.79), P=0.009; I²=74.2%, P=0.009). Subgroup analyses generally confirmed these results, except in a few cases, such as an inverse association related to particular socioeconomic backgrounds and where results were adjusted by more disease-related risk factors.

CONCLUSION

Lower income was most closely associated with prevalence and progression of CKD, and lower education was significantly associated with its prevalence. Evidence for other indicators was inconclusive.

Estimating the risk of bladder and kidney cancer from exposure to low-levels of arsenic in drinking water, Nova Scotia, Canada

Arsenic in drinking water impacts health. Highest levels of arsenic have been historically observed in Taiwan and Bangladesh but the contaminant has been affecting the health of people globally. Strong associations have been confirmed between exposure to high-levels of arsenic in drinking water and a wide range of diseases, including cancer. However, at lower levels of exposure, especially near the current World Health Organization regulatory limit (10μg/L), this association is inconsistent as the effects are mostly extrapolated from high exposure studies. This ecological study used Bayesian inference to model the relative risk of bladder and kidney cancer at these lower concentrations-0-2μg/L; 2-5μg/L and; ≥5μg/L of arsenic-in 864 bladder and 525 kidney cancers diagnosed in the study area, Nova Scotia, Canada between 1998 and 2010. The model included proxy measures of lifestyle (e.g. smoking) and accounted for spatial dependencies. Overall, bladder cancer risk was 16% (2-5μg/L) and 18% (≥5μg/L) greater than that of the referent group (<2μg/L), with posterior probabilities of 88% and 93% for these risks being above 1. Effect sizes for kidney cancer were 5% (2-5μg/L) and 14% (≥5μg/L) above that of the referent group (<2μg/L), with probabilities of 61% and 84%. High-risk areas were common in southwestern areas, where higher arsenic-levels are associated with the local geology. The study suggests an increased bladder cancer, and potentially kidney cancer, risk from exposure to drinking water arsenic-levels within the current the World Health Organization maximum acceptable concentration.

A multicenter cohort study of potential living kidney donors provides predictors of living kidney donation and non-donation

This multicenter prospective potential living kidney donor cohort study investigated which sociodemographic and other factors predict progression to living kidney donation or donor withdrawal as little is known on this topic. Therefore, we examined data on individuals undergoing living donor assessment at seven hospitals in the United Kingdom. Multivariable logistic regression was used to explore the relationships between donor and recipient characteristics and likelihood of kidney donation. A total of 805 individuals presented for directed donation to 498 intended recipients, of which 112 received a transplant from a living donor. Potential donors were less likely to donate if their intended recipient was female rather than male with an odds ratio of 0.60, a friend rather than relative 0.18, or had renal failure due to a systemic disease rather than another cause 0.41. The most socioeconomically deprived quintile was less likely to donate than the least 0.49, but the trend with deprivation was consistent with chance. Higher body mass index was associated with a lower likelihood of donation (odds ratio per each kg/m² increase, 0.92). Younger potential donors (odds ratio per each year increase 0.97), those of nonwhite ethnicity 2.98, and friend donors 2.43 were more likely to withdraw from work-up. This is the first study in the United Kingdom of potential living kidney donors to describe predictors of non-donation. Qualitative work with individuals who withdraw might identify possible ways of supporting those who wish to donate but experience difficulties doing so.

A comparative study of renal care in Brazil and Mexico: hemodialysis treatment from the perspective of ESRD sufferers

Renal replacement therapy is the indicated treatment for individuals with chronic kidney disease (CKD) to survive. However, not all sick people have access to the same treatment. This study compares renal care in two developing countries with different health systems. Specifically, it explores hemodialysis treatment from the perspective of low-income individuals. A qualitative, comparative study was performed in Brazil and Mexico. Using purposive sampling, the research was based on open-ended interviews with nineteen participants with kidney failure undergoing hemodialysis treatment in public hospitals and ten relatives. According to our results, Brazilian participants perceived hemodialysis care as satisfactory because of health personnel courtesy as well as free access to dialysis treatment, prescription drugs, hospitalization and transportation. However, they reported deficiencies in the care they were receiving due to shortages of specialists, prescription drugs, laboratory tests and transportation. Mexican participants, in contrast, highlighted the catastrophic costs of medical care because they had no free access to renal therapy, nor adequate financial resources. Our findings suggest that low-income Brazilian CKD sufferers experience renal care differently, as they are more satisfied and face less obstacles with hemodialysis compared with those of Mexico. More studies on the topic are needed.

Small-area spatio-temporal analyses of bladder and kidney cancer risk in Nova Scotia, Canada

BACKGROUND

Bladder and kidney cancers are the ninth and twelfth most common type of cancer worldwide, respectively. Internationally, rates vary ten-fold, with several countries showing rising incidence. This study describes the spatial and spatio-temporal variations in the incidence risk of these diseases for Nova Scotia, a province located in Atlantic Canada, where rates for bladder and kidney cancer exceed those of the national average by about 25% and 35%, respectively.

METHODS

Cancer incidence in the 311 Communities of Nova-Scotia was analyzed with a spatial autoregressive model for the case counts of bladder and kidney cancers (3,232 and 2,143 total cases, respectively), accounting for each Community's population and including variables known to influence risk. A spatially-continuous analysis, using a geostatistical Local Expectation-Maximization smoothing algorithm, modeled finer-scale spatial variation in risk for south-western Nova Scotia (1,810 bladder and 957 kidney cases) and Cape Breton (1,101 bladder, 703 kidney).

RESULTS

Evidence of spatial variations in the risk of bladder and kidney cancer was demonstrated using both aggregated Community-level mapping and continuous-grid based localized mapping; and these were generally stable over time. The Community-level analysis suggested that much of this heterogeneity was not accounted for by known explanatory variables. There appears to be a north-east to south-west increasing gradient with a number of south-western Communities have risk of bladder or kidney cancer more than 10% above the provincial average. Kidney cancer risk was also elevated in various northeastern communities. Over a 12 year period this exceedance translated in an excess of 200 cases. Patterns of variations in risk obtained from the spatially continuous smoothing analysis generally mirrored those from the Community-level autoregressive model, although these more localized risk estimates resulted in a larger spatial extent for which risk is likely to be elevated.

CONCLUSIONS

Modelling the spatio-temporal distribution of disease risk enabled the quantification of risk relative to expected background levels and the identification of high risk areas. It also permitted the determination of the relative stability of the observed patterns over time and in this study, pointed to excess risk potentially driven by exposure to risk factors that act in a sustained manner over time.

Serum phosphate and social deprivation independently predict all-cause mortality in chronic kidney disease

Background

Hyperphosphataemia is linked to cardiovascular disease and mortality in chronic kidney disease (CKD). Outcome in CKD is also affected by socioeconomic status. The objective of this study was to assess the associations between serum phosphate, multiple deprivation and outcome in CKD patients.

Methods

All adult patients currently not on renal replacement therapy (RRT), with first time attendance to the renal outpatient clinics in the Glasgow area between July 2010 and June 2014, were included in this prospective study. Area socioeconomic status was assessed as quintiles of the Scottish Index of Multiple Deprivation (SIMD). Outcomes were all-cause and cardiovascular mortality and commencement of RRT.

Results

The cohort included 2950 patients with a median (interquartile range) age 67.6 (53.6–76.9) years. Median (interquartile range) eGFR was 38.1 (26.3–63.5) ml/min/1.73 m², mean (±standard deviation) phosphate was 1.13 (±0.24) mmol/L and 31.6 % belonged to the most deprived quintile (SIMD quintile I). During follow-up 375 patients died and 98 commenced RRT. Phosphate ≥1.50 mmol/L was associated with all-cause (hazard ratio (HR) 2.51; 95 % confidence interval (CI) 1.63-3.89) and cardiovascular (HR 5.05; 95 % CI 1.90–13.46) mortality when compared to phosphate 0.90–1.09 mmol/L in multivariable analyses. SIMD quintile I was independently associated with all-cause mortality. Phosphate did not weaken the association between deprivation index and mortality, and there was no interaction between phosphate and SIMD quintiles. Neither phosphate nor SIMD predicted commencement of RRT.

Conclusions

Multiple deprivation and serum phosphate were strong, independent predictors of all-cause mortality in CKD and showed no interaction. Phosphate also predicted cardiovascular mortality. The results suggest that phosphate lowering should be pursued regardless of socioeconomic status.

Impact of Educational Attainment on Health Outcomes in Moderate to Severe CKD

Background

The inverse association between educational attainment and mortality is well established, but its relevance to vascular events and renal progression in a population with chronic kidney disease (CKD) is less clear. This study aims to determine the association between highest educational attainment and risk of vascular events, cause-specific mortality, and CKD progression.

Study Design

Prospective epidemiologic analysis among participants in the Study of Heart and Renal Protection (SHARP), a randomized controlled trial.

Setting & Participants

9,270 adults with moderate to severe CKD (6,245 not receiving dialysis at baseline) and no history of myocardial infarction or coronary revascularization recruited in Europe, North America, Asia, Australia, and New Zealand.

Predictor

Highest educational attainment measured at study entry using 6 levels that ranged from “no formal education” to “tertiary education.”

Outcomes

Any vascular event (any fatal or nonfatal cardiac, cerebrovascular, or peripheral vascular event), cause-specific mortality, and CKD progression during 4.9 years’ median follow-up.

Results

There was a significant trend (P < 0.001) toward increased vascular risk with decreasing levels of education. Participants with no formal education were at a 46% higher risk of vascular events (relative risk [RR], 1.46; 95% CI, 1.14-1.86) compared with participants with tertiary education. The trend for mortality across education levels was also significant (P < 0.001): all-cause mortality was twice as high among those with no formal education compared with tertiary-educated individuals (RR, 2.05; 95% CI, 1.62-2.58), and significant increases were seen for both vascular (RR, 1.84; 95% CI, 1.21-2.81) and nonvascular (RR, 2.15; 95% CI, 1.60-2.89) deaths. Lifestyle factors and prior disease explain most of the excess mortality risk. Among 6,245 participants not receiving dialysis at baseline, education level was not significantly associated with progression to end-stage renal disease or doubling of creatinine level (P for trend = 0.4).

Limitations

No data for employment or health insurance coverage.

Conclusions

Lower educational attainment is associated with increased risk of adverse health outcomes in individuals with CKD.

From potential donor to actual donation: does socioeconomic position affect living kidney donation? A systematic review of the evidence

Evidence from Europe, Australia and the United States demonstrates that socioeconomically deprived individuals with advanced chronic kidney disease are less likely to receive a living kidney transplant compared with less deprived individuals. This systematic review focuses on how socioeconomic position (SEP) may influence hypothetical and actual living kidney donors and where appropriate, summarizes the quantitative evidence.In the general population, a higher SEP appears to be associated with an increased 'hypothetical' willingness to be a living kidney donor but with marked heterogeneity in the absolute differences (I = 95.9%, P < 0.001). In a commercial setting, lower SEP motivates people to donate. Outside of this setting, there is no evidence of discordance in the SEP of donors and recipients that would suggest undisclosed financial exchange. There is evidence for a complex interaction between SEP and other variables, such as ethnicity, sex, and the national economic climate. Some evidence suggests that measures to remove financial disincentives to donation are associated with an increase in living donation rates. Future research needs to study how SEP impacts the potential donor population from willingness to donate, progression through donor assessment to actual donor nephrectomy.

Low income, community poverty and risk of end stage renal disease

BACKGROUND

The risk of end stage renal disease (ESRD) is increased among individuals with low income and in low income communities. However, few studies have examined the relation of both individual and community socioeconomic status (SES) with incident ESRD.

METHODS

Among 23,314 U.S. adults in the population-based Reasons for Geographic and Racial Differences in Stroke study, we assessed participant differences across geospatially-linked categories of county poverty [outlier poverty, extremely high poverty, very high poverty, high poverty, neither (reference), high affluence and outlier affluence]. Multivariable Cox proportional hazards models were used to examine associations of annual household income and geospatially-linked county poverty measures with incident ESRD, while accounting for death as a competing event using the Fine and Gray method.

RESULTS

There were 158 ESRD cases during follow-up. Incident ESRD rates were 178.8 per 100,000 person-years (105 py) in high poverty outlier counties and were 76.3 /105 py in affluent outlier counties, p trend=0.06. In unadjusted competing risk models, persons residing in high poverty outlier counties had higher incidence of ESRD (which was not statistically significant) when compared to those persons residing in counties with neither high poverty nor affluence [hazard ratio (HR) 1.54, 95% Confidence Interval (CI) 0.75-3.20]. This association was markedly attenuated following adjustment for socio-demographic factors (age, sex, race, education, and income); HR 0.96, 95% CI 0.46-2.00. However, in the same adjusted model, income was independently associated with risk of ESRD [HR 3.75, 95% CI 1.62-8.64, comparing the <$20,000 income group to the >$75,000 group]. There were no statistically significant associations of county measures of poverty with incident ESRD, and no evidence of effect modification.

CONCLUSIONS

In contrast to annual family income, geospatially-linked measures of county poverty have little relation with risk of ESRD. Efforts to mitigate socioeconomic disparities in kidney disease may be best appropriated at the individual level.

Effects of a self-management program on patients with early-stage chronic kidney disease: a pilot study

BACKGROUND

Without intervention, renal function deteriorates in patients with chronic kidney disease (CKD).

AIM

This pilot study aimed to develop a self-management education program based on self-regulation theory and to evaluate its effects on self-efficacy, self-management behavior, and CKD progression among patients with early-stage CKD.

METHODS

In this single-group, pretest-posttest, repeated-measures, longitudinal study, participants underwent baseline pretesting (T0) and posttesting at 3 (T1), 6 (T2), and 12 (T3) months after a 5-week group-session self-management program.

RESULTS

Self-efficacy increased significantly at T2 (χ(2)=8.97, p=.02) and T3 (χ(2)=10.71, p=.01) compared with T0, but self-management behavior did not. A marginally significant decrease in serum creatinine levels was observed from T0 to T3 (χ(2)=6.29, p=.07) but estimated glomerular filtration rates remained stable throughout the 12-month period.

CONCLUSIONS

The results of this empirical study suggest that the theory-based intervention is feasible and has potential efficacy in retarding CKD progression.

Influence of race, ethnicity and socioeconomic status on kidney disease

Low socioeconomic status (SES) influences disease incidence and contributes to poor health outcomes throughout an individual's life course across a wide range of populations. Low SES is associated with increased incidence of chronic kidney disease, progression to end-stage renal disease, inadequate dialysis treatment, reduced access to kidney transplantation, and poor health outcomes. Similarly, racial and ethnic disparities, which in the USA are strongly associated with lower SES, are independently associated with poor health outcomes. In this Review, we discuss individual-level and group-level SES factors, and the concomitant role of race and ethnicity that are associated with and mediate the development of chronic kidney disease, progression to end-stage renal disease and access to treatment.