Socioeconomic Position and Incidence of Glomerular Diseases

Abstract

Background and objectives Social deprivation is a recognized risk factor for undifferentiated CKD; however, its association with glomerular disease is less well understood. We sought to investigate the relationship between socioeconomic position and the population-level incidence of biopsy-proven glomerular diseases. Design, setting, participants, & measurements In this retrospective cohort study, a provincial kidney pathology database (2000-2012) was used to capture all incident cases of membranous nephropathy (n5392), IgA nephropathy (n5818), FSGS (n5375), ANCA-related GN (ANCA-GN, n5387), and lupus nephritis (n5389) in British Columbia, Canada. Quintiles of area-level household income were used as a proxy for socioeconomic position, accounting for regional differences in living costs. Incidence rates were direct standardized to the provincial population using census data for age and sex and were used to generate standardized rate ratios. For lupus nephritis, age standardization was performed separately in men and women. Results A graded increase in standardized incidence with lower income was observed for lupus nephritis (P,0.001 for trend in both sexes) and ANCA-GN (P50.04 for trend). For example, compared with the highest quintile, the lowest income quintile had a standardized rate ratio of 1.7 (95% confidence interval, 1.19 to 2.42) in women with lupus nephritis and a standardized rate ratio of 1.5 (95% confidence interval, 1.09 to 2.06) in ANCA-GN. The association between income and FSGS was less consistent, in that only the lowest income quintile was associated with a higher incidence of disease (standardized rate ratio, 1.55; 95% confidence interval, 1.13 to 2.13). No significant associations were demonstrated for IgA nephropathy or membranous nephropathy. Conclusions Using population-level data and a centralized pathology database, we observed an inverse association between socioeconomic position and the standardized incidence of lupus nephritis and ANCA-GN.

Social Determinants of Glomerular Disease

“…Alternatively, because socioeconomic position is a surrogate for innumerable individual health behaviors and social and physical environmental factors, drivers of the association between socioeconomic position and glomerular disease risk might differ in Canada compared with in other regions. In particular, universal access to health care in Canada should minimize differences in missed or delayed diagnoses as supported by the broadly similar laboratory values at presentation across socioeconomic groups in the study by Canney et al (9). Accordingly, differences in disease incidence identified in this study are more likely to be explained by differences in health behaviors or social and environmental hazards than by inequitable access to preventative or diagnostic health care services.…”

“…The study by Canney et al (9) in this issue of CJASN represents an important step toward closing this knowledge gap. In their analysis, the investigators identified all biopsies performed in the province of British Columbia, Canada over a 13-year period (2000-2012) using an existing centralized kidney pathology database.…”

“…In the meantime, on the basis of the insights provided by Canney et al (9), clinicians and investigators should have a renewed focus on socioeconomic position when evaluating patients with suspected glomerular disease, determining recruitment populations for clinical trials, or designing observational studies aimed at identifying risk factors for glomerular disease onset. Furthermore, identifying that a socioeconomic disparity exists with respect to risk for glomerular disease incidence only partially addresses socioeconomic disparity questions: studies aiming to identify and target socioeconomic differences in access to specialized nephrology care, receipt of optimal therapies, participation in clinical trials, or achievement of clinical end points are long overdue and should be prioritized in future glomerular disease clinical research efforts.…”

ANCA-associated renal vasculitis is associated with rurality but not seasonality or deprivation in a complete national cohort study

“…[10][11][12][13] Considering socioeconomic factors, several studies have explored a possible link between socioeconomic deprivation and incidence of AAV with mixed results. [14][15][16] We recently demonstrated a twofold increased risk of death in patients with primary glomerulonephritis living in relative socioeconomic deprivation. 17 Chronic kidney disease (CKD) is more common in areas of social deprivation 18 and individuals living in these areas are more likely to progress to ESKD.…”

The Impact of Household Income on Kidney Care

“…I was greatly interested in the findings of a recent study published in this issue of CJASN on socioeconomic status and kidney disease in British Columbia (1). I did in-center hemodialysis for 3 years and saw people from a variety of socioeconomic backgrounds there.…”