Chronic kidney disease and socio-economic status: a cross sectional study

ABSTRACT

Objective: This cross-sectional study investigated the relationship between individual-level markers of disadvantage, renal function and cardio-metabolic risk within an Indigenous population characterised by a heavy burden of chronic kidney disease and disadvantage.

Design: Using data from 20 Indigenous communities across Australia, an aggregate socio-economic status (SES) score was created from individual-level socio-economic variables reported by participants. Logistic regression was used to assess the association of individual-level socio-economic variables and the SES score with kidney function (an estimated glomerular function rate (eGFR) cut-point of <60 ml/min/1.73 m²) as well as clinical indicators of cardio-metabolic risk.

Results: The combination of lower education and unemployment was associated with poorer kidney function and higher cardio-metabolic risk factors. Regression models adjusted for age and gender showed that an eGFR < 60 ml/min/1.73 m² was associated with a low socio-economic score (lowest vs. highest 3.24 [95% CI 1.43–6.97]), remote living (remote vs. highly to moderately accessible 3.24 [95% CI 1.28–8.23]), renting (renting vs. owning/being purchased 5.76[95% CI 1.91–17.33]), unemployment (unemployed vs employed 2.85 [95% CI 1.31–6.19]) and receiving welfare (welfare vs. salary 2.49 [95% CI 1.42–4.37]). A higher aggregate socio-economic score was inversely associated with an eGFR < 60 ml/min/1.73 m² (0.75 [95% CI 063–0.89]).

Conclusion: This study extends upon our understanding of associations between area-level markers of disadvantage and burden of end stage kidney disease amongst Indigenous populations to a detailed analysis of a range of well-characterised individual-level factors such as overall low socio-economic status, remote living, renting, unemployment and welfare. With the increasing burden of end-stage kidney disease amongst Indigenous people, the underlying socio-economic conditions and social and cultural determinants of health need to be understood at an individual as well as community-level, to develop, implement, target and sustain interventions.

KEYWORDS:

• Chronic kidney disease
• aboriginal and torres strait islander peoples
• indigenous peoples
• socio-economic status
• disadvantage

Acknowledgements

The authors gratefully acknowledge the support of eGFR study participants, study staff, and partner organisations and the eGFR Study Investigators not included as co-authors on this manuscript: G Jerums, R MacIsaac, L Ward, M Thomas, A Sinha, R McDermott, G Jones, A Ellis, LS Piers, K Warr, S Cherian, W Majoni. We thank Dr. Kevin Warr and Dr. William Majoni for facilitating participant recruitment at the sites of their employing organisation and Loyla Leysley, Sian Graham, Mary Ward, and Joseph Fitz for assistance with follow-up in their communities. The authors also acknowledges the support and mentorship of Kevin Rowley for RR. Thank you to Melbourne Pathology for providing the technical support in the enzymatic creatinine analysis and Roche Diagnostics for supplying the enzymatic creatinine reagent kit for this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Wendy Hoy http://orcid.org/0000-0002-8405-1539

Additional information

Funding

The eGFR Study was funded by the Australian National Health and Medical Research Council (NHMRC), Project [grants number 545202] and [grant number 1021460] and NHMRC Program [grant number 631947], Kidney Health Australia, Colonial Foundation Trust, Rebecca L Cooper Medical Research Foundation and SeaSwift, Thursday Island. LMB was supported by NHMRC Fellowship [grant number 605837] and NHMRC Practitioner Fellowship [grant number 1078477]; JH by NHMRC Scholarship [grant number 490348] and NHMRC Fellowship [grant number 1092576]; PL by NHMRC Scholarship [grant number 1038529]; Cass by NHMRC Principal Research Fellowship [grant number 1027204]; RR was supported by a fellowship with a NHMRC Program [grant number 631947] and acknowledges the support and mentorship of Kevin Rowley; Hoy by an NHMRC Australia Fellowship [grant number 511081]; and AB a Charles and Sylvia Viertel Charitable Foundation Senior Medical Research Fellowship. The views expressed in this publication are those of the authors and do not reflect the views of the NHMRC. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.