Prospective payment system and racial/ethnic disparities: a national retrospective observational study in anaemia complication among end-stage renal disease patients in the US

Background A series of policy changes in 2011 altered reimbursement arrangements and guidance on use of erythropoiesis-stimulating agents for end-stage renal disease (ESRD) patients with anaemia in the US. While the policy changes were principally directed at care delivered in an outpatient setting, these had the potential to affect inpatient care also. This study used HCUP-NIS data (2008–2016) to examine trends in recorded anaemia among ESRD hospitalizations and analyse disparities in inpatient outcomes among ethnic groups following policy changes. Methods The International Classification of Diseases codes were used to identify ESRD admissions, recorded anaemia due to chronic kidney disease (CKD), and to generate an age-adjusted Deyo-Charlson comorbidity index. Linear splines with a knot placed at the time point of policy changes and multivariable logistic regression were used to examine the likelihood of recorded anaemia, adjusted for a range of socio-demographic and clinical covariates. Difference-in-difference analyses investigated the impact of policies on recorded anaemia. Other outcomes included hospital cost, mortality and place of discharge. Results The percentage of inpatient episodes with recorded anaemia arising from CKD increased from 26.2% in 2008 to 50.0% in 2016. Anaemia was more likely to be recorded as a complication of ESRD among minority ethnic groups and Native American admissions, in particular, (OR 1.20, 95%CI 1.15–1.25) relative to White American admissions; and these disparities widened following changes to reimbursement. Minorities were less likely to die in hospital and to be discharged to another healthcare facility, and (with the exception of Black American admissions) they were more expensive to treat. Conclusions Our findings provide evidence of an increase in recorded anaemia consistent with a shift of patients from outpatient to inpatient settings in the wake of changes to reimbursement enacted in 2011. In addition, the study highlights the existence of ethnic disparities that widened after the policy initiated reimbursement changes.