Research Highlights Impact of SDOH on Veterans With CKD

A pair of abstracts presented at Kidney Week 2020 underscore the relationship between social determinants of health (SDOH) and chronic kidney disease (the CKD) in military populations and the challenges of tracking these factors.

“A growing body of evidence suggests that negative SDOH—or social risks—contribute to socioeconomic and racial disparities in CKD,” researchers wrote.¹ “One mechanism through which social risks appear to produce disease is by impeding access to healthcare.”

Using data from the Military Health System (MHS), researchers assessed CKD disparities in the context of universal health care. All MHS beneficiaries between the ages of 18 and 64 who received care from the MHS from October 2015 through September 2018 were included in the analysis. International Classification of Disease, 10th Revision (ICD-10), codes and/or validated laboratory value-based electronic phenotypes constituted CKD incidence.

The investigators used multivariable logistic regression models to compare the prevalence of CKD by race, rank, and other factors while controlling separately for confounders.

A total of 3,330,893 beneficiaries were included in the analysis, of whom 105,504 (3.2%) had CKD. Confounder-adjusted models showed, “CKD prevalence was statistically elevated in beneficiaries of Black vs White race, lower vs higher rank (as a proxy for socioeconomic status), lower vs higher income, and married vs single status (P <.0001).”

However, associations were mitigated when adjusting for suspected mediators, “indicating the mediators may indeed be on the causal pathway between social risks and CKD,” the researchers wrote. The findings also suggest social factors remain pertinent despite access to universal health care coverage.

In a separate analysis,² investigators found low documentation of SDOH among US veterans and Medicare patients with CKD. In 2015, implementation of ICD-10 codes included new Z-codes to specifically identify SDOH. In this investigation, the researchers “sought to identify differences in SDOH-related Z-code (SDOH-ZC) utilization in Veterans Health Administration and Medicare patients, identifying differences in SDOH-ZC utilization in those with and without CKD.”

The study included a 5% sample of Medicare claims data from 2015 to 2018 and 100% of VA health data amassed during the same time period. SDOH-ZCs were grouped into 17 categories such as employment status, housing, and economic circumstances.

The researchers measured the proportion of claims assigned a SDOH-ZC quarterly across different health care encounters and described by patient demographic and medical characteristics. Code use was then compared between those with CKD and those without.

Analyses revealed:

• SDOH-ZCs appeared more frequently in the VA health system than in Medicare data
• Tobacco use was the most common SDOH-ZC in both the Medicare and VA data
• More SDOH-ZCs were evident in the VA employment, environment, housing and economic, and family circumstances
• Compared to those without CKD, use of SDOH-ZC was higher in individuals with CKD in outpatient settings but lower among those with inpatient visits, observation stays, and emergency department visits

“We observed lower recording of SDOH overall and among those with CKD in health care settings,” the authors concluded. “Additional efforts might consider increasing SDOH documentation to help assess need for social services, which could potentially reduce disparities in health outcomes by socioeconomic status.”

References

1. Norton JM, Grunwald L, Olsen CH, Marks ES, and Koehlmoos TL. Social determinants of CKD in the military health system. Presented at: Kidney Week; October 22-25, 2020. Abstract PO0474
2. Han Y, Yin M, Steffick D, et al. Low documentation of social determinants of health among US veterans and Medicare patients with CKD. Presented at: Kidney Week; October 22-25, 2020. Abstract PO0475