Sex Disparities in the Quality of Care for CKD

CKD represents a substantial public health issue for women. The prevalence of CKD among adult women in the United States from the period 2015–2018 was 15.6%.¹ Understanding quality of care for women versus men with CKD is limited. Interpreting comparisons of outcomes of CKD in women versus men is inherently difficult because of numerous differences between them; for example, women tend to have a longer life expectancy than men and thus, may be more likely to develop CKD. In this issue of JASN, Swartling et al.² compare processes of care for CKD in men and women in a large, insured population in Stockholm.

The Centers for Medicare and Medicaid Services is prioritizing evaluation of health care disparities as a critical step in promoting health equity, which the organization defines as “the attainment of the highest level of health for all people, where everyone has a fair and just opportunity to attain their optimal health regardless of race, ethnicity, disability, sexual orientation, gender identity, socioeconomic status, geography, preferred language, or other circumstance.”^3,4 Although comparison of health outcomes in the context of identifying health care disparities is often limited by confounding from patient-specific factors, evaluation of health care processes may provide a clearer reflection of the ways in which systems or providers are perpetuating health inequities. Accordingly, many quality measures focus on process. Donabedian,⁵ in his model of quality of care, identifies process as an integral component of quality along with structure and outcome, stating that “we cannot claim either for the measurement of process or the measurement of outcomes an inherently superior validity compared with the other, since the validity of either flows to an equal degree from the validity of the science that postulates a linkage between the two.” Process measure evaluation is common in the context of quality improvement for kidney failure.⁶ Understanding and addressing disparities in care are critical to promoting health equity for patients with earlier stages of CKD.

Swartling et al.² use data from the Stockholm Creatinine Measurements project derived from a health care provider that provides care to 20%–25% of Sweden’s population. In a retrospective cohort study of adult subjects from 2009 to 2018, serum or plasma creatinine was used to calculate eGFR. Individuals with an eGFR<60 ml/min per 1.73 m² were included in the study cohort (n=227,847). The authors examined components of care processes, including diagnosis, monitoring, and management. The mean eGFR for both men and women was 51 ml/min per 1.73 m², and <10% of individuals had received a diagnosis of CKD at study inclusion (6.9% of men versus 3.4% of women). Over the 18-month follow-up period and across nearly all care measures, women fared worse than men. They were less likely to receive a CKD diagnosis (7.5% for men versus 3.4% for women) and less likely to be referred to a nephrologist, even if they met Kidney Disease Improving Global Outcomes (KDIGO) or regional criteria for referral. Even among those with CKD stages G4 and G5, differences persisted in rates of seeing a nephrologist (for CKD stage G4, 16.4% for men versus 9.5% for women and for CKD stage G5, 29.4% for men versus 20.8% for women). Although the majority of both men and women received a repeat creatinine measurement over the follow-up period (91.1% for men and 87.1% for women), rates of albuminuria measurement were much lower (34.3% for men and 28.1% for women). In terms of management, women were less likely to be started on renin-angiotensin-aldosterone blocking agents and less likely to be started on a statin, although odds ratios did not differ significantly for subgroup analysis of those with coronary disease, diabetes, and prior ischemic stroke.

Swartling et al.² highlight stark disparities in CKD care between men and women. Although these findings were observed in a Swedish population, a previous review by Carrero et al.⁷ highlights numerous disparities in processes and outcomes of care in other countries. The findings of Swartling et al.² were observed despite reporting of eGFR by clinical laboratories in the later years of the study. Larger disparities might be expected if clinical laboratories report only serum creatinine, which is lower in women than in men with the same measured GFR. Critically, these findings were observed in an insured population, thus eliminating reduced access as a potential barrier to quality of care. Among Medicare fee-for-service beneficiaries in the US, men were more likely than women to receive nephrology care for CKD stages G3 and G4.¹ These observations suggest the need for examination of additional system- and provider-based factors that may lead to sex-based disparities in CKD care.

One item that stands out in the work by Swartling et al.² and others is the paucity of measurement of albuminuria, a key component of the detection and risk stratification for CKD. Stempniewicz et al.⁸ found similar disparate rates of creatinine versus albuminuria measurement in the United States; among >500,000 adults with type 2 diabetes receiving primary care across 24 health care organizations, median 1-year testing rates for eGFR and urine albumin-creatinine ratio were 89.5% and 52.9%, respectively. CKD cannot be fully characterized by GFR alone, and thus, increasing rates of albuminuria measurement may be one way to increase the quality and value of CKD care.⁹

A recent KDIGO Controversies Conference has called attention to the disproportionate effect of CKD on socially and economically disadvantaged populations.¹⁰ Recommendations included CKD screening consisting of both eGFR and albuminuria for individuals with comorbid conditions, such as hypertension, diabetes, and cardiovascular disease, as well as those who are considered high risk on the basis of environmental factors, other comorbidities, or genetic risk factors. Ultimately, implementing these processes of care often falls within the purview of primary care physicians who are diagnosing, monitoring, and managing a multitude of health issues, including those specific to women’s health. In order to facilitate early intervention in CKD, the nephrology community has a critical role to play in advocating for and aiding early diagnosis and risk stratification of CKD within primary care using both eGFR and albuminuria so that CKD care is improved—for everyone.

Disclosures

A.S. Levey reports Research Funding: Grants and contracts paid to Tufts Medical Center: NIH,NKF; Contracts to paid to A.S. Levey: AstraZeneca (DSMB for dapagliflozin trials); and Honoraria: Academic medical centers for visiting professorships. A.C. Reaves reports no disclosures.

Funding

A.C. Reaves was supported through the Driscoll Family Fund in Nephrology at Tufts Medical Center.

Author Contributions

A.S. Levey provided supervision; A.C. Reaves wrote the original draft; and A.S. Levey reviewed and edited the manuscript.