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Abstract: SA-PO856

No Independent Relationship Between Socioeconomic Status and CKD Progression in South Korea: Results from the KNOW-CKD Cohort

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Kang, Eunjeong, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Ryu, Hyunjin, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Kang, Minjung, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Hong, Yeji, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Kim, Jayoun, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Ahn, Curie, Seoul National University Hospital, Seoul, Korea (the Republic of)
  • Oh, Kook-Hwan, Seoul National University College of Medicine, Seoul, Korea (the Republic of)
Background

Socioeconomic status (SES) has long been conjectured to be associated with the incidence and progression of chronic kidney disease (CKD). However, prospective studies from Asian data for impact of SES on renal progression were less. We revealed the association between SES and renal progression in CKD patients especially in South Korea where medical insurance is well established.

Methods

Data were collected from the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD, NCT01630486 at http://www.clinicaltrials.gov). SES was characterized based on monthly income which was divided into three strata; ≥$4,500, $1,500-4,000, <$1,500. Patients who underwent baseline tests but did not have follow-up visits thereafter or who did not respond to questionnaires regarding SES were excluded. The outcome was a composite of estimated glomerular filtration rate (eGFR) halving or the onset of end-stage renal disease (ESRD). ESRD was defined as the initiation of maintenance dialysis or kidney transplantation. Cox or time-dependent cox regression analysis were conducted as appropriate. Age, sex, cause of CKD, baseline eGFR by CKD-EPI (cr) equation, hemoglobin, albumin, uric acid, calcium, phosphorus, mean blood pressure, 24hr sodium intake calculated by 24hr urine sodium was included as covariates in multivariable analysis.

Results

Total 1,732 patients were enrolled in this study. Mean age was 52.9 ± 12.0 years and 61.5% were men. Higher monthly income was associated with higher educational attainment (P for trend <0.001). There is an incremental tendency of CKD progression according to lower monthly income level ($1,500 to $4,500, adjusted hazard ratio [HR] 1.55, 95% confidence interval [CI] 0.86-2.77, P=0.144; <$1,500, adjusted HR 1.75, 95% CI 0.93-3.29, P=0.080; ≥$4,500 group as reference), but the statistical significance was not observed, event after the subgroup analysis according to age ≥ 50 years or below.

Conclusion

In the Korean CKD population, there is no definite association between SES classified by monthly income level and renal progression. We speculate that this is because health care accessibility is high regardless of the SES in Korea due to Korean National Health Insurance Service. Further studies are needed to confirm this phenomenon.

Funding

  • Government Support - Non-U.S.