We conducted a retrospective cohort study of Medicare fee-for-service beneficiaries aged >65 years who underwent RA stent placement for atherosclerotic RAS between January 1, 2016, and December 31, 2020. The age criterion ensured at least 1 year of baseline Medicare enrollment for comorbidity ascertainment. Patients were included if they had a diagnosis code for RA stenosis in combination with a procedural code for RA angioplasty with stenting ( Figure 1 ). Patients required a diagnosis of atherosclerotic RAS, unlike our prior study where all patients who underwent RA stenting procedures were included. Patients were identified using ICD-10-CM diagnosis code I70.1 (atherosclerotic RA stenosis) and concurrent procedural codes for renal stenting: 36251, 36252, 36253, 36254, and inpatient procedures using ICD-10-PCS codes. Missing data were minimal for key demographic variables (age, sex, race, region) and no imputation methods were employed given the minimal missing data in this claims-based analysis. Comorbidities were determined using the CMS Chronic Conditions Warehouse algorithms, which incorporate diagnostic and procedural claims over a 1-year lookback window. All patients had complete follow-up for vital status through Medicare enrollment records. For temporal utilization trends, we included all 45, 202 identified RA stenting procedures (2016–2020). For baseline and outcome analyses, we restricted to 19,130 patients meeting full ARAS inclusion criteria.

Exclusion criteria. FFS, fee for service; CKD, chronic kidney disease, CV, cardiovascular disease; HTN, hypertension.

The primary exposures in this study were race, dual Medicare-Medicaid enrollment status, and geographic region ( Supplementary Table 1 ). Race was self-reported in Medicare claims and categorized as White, Black, or Other, with the Other category encompassing Asian, Hispanic, Native American, mixed, or unknown race/ethnicity. Geographic region was determined based on U.S. Census classifications and categorized as Northeast, Midwest, South, or West according to the location of the hospital where the procedure was performed. Dual enrollment status was used as a surrogate for low socioeconomic status, as individuals who are dually eligible for Medicare and Medicaid are typically aged 65 or older or have qualifying disabilities with low monthly incomes depending on the specific Medicare Savings Program. Baseline demographics, including age, sex, and self-reported race (categorized as Black, White, or Other [including Asian, Hispanic, North American Native, and Mixed/Unknown]), were assessed at the time of the index procedure. Institutional characteristics, including hospital region, were linked from the 2016 American Hospital Association Annual Survey.

The primary outcomes for this study were procedural utilization over time and cardiovascular events: a composite of stroke, myocardial infarction, and congestive heart failure (CHF) hospitalization. Secondary outcomes included repeat RA stenting, dialysis initiation, hospital admission for hypertensive crisis, rehospitalization after index procedure and all-cause mortality. We defined the index procedure as the first qualifying renal-artery stenting event during the study period; subsequent procedures were treated as follow-up events. Patients who did not experience the outcome of interest were censored at the first occurrence of either the last date of consecutive Medicare FFS coverage or the last study follow-up date where data were available (December 31, 2020). All outcomes were compared between exposure groups.

Continuous variables were reported using means and categorical data were summarized by percentages. Differences in baseline demographics and clinical presentation were evaluated using χ 2 tests for categorical variables and generalized linear model for continuous variables and were stratified for the whole cohort and by region, race and dual status.

For each of the exposure groups, time-to-event analyses were used to estimate the cumulative incidence of outcomes. All-cause mortality was estimated using Kaplan–Meier methods. For nonfatal outcomes, Cumulative Incidence Functions were used to estimate cumulative incidences. Hazard ratios (HRs) for each outcome were estimated using Cox proportional hazard regression for mortality and Cox regression with subdistribution hazard ratios using the Fine–Gray approach for other outcomes, accounting for the competing risk of death. Models were constructed both unadjusted and adjusted for prespecified characteristics based on clinical relevance, including demographic variables (age, sex, race), dual enrollment in Medicare and Medicaid, and prevalent clinical comorbidities (chronic kidney disease, diabetes, heart failure, hyperlipidemia, hypertension, ischemic heart disease, stroke, obesity, peripheral artery disease, tobacco use disorder, and indication for RA stenting). Region was included as a covariate in all models to account for geographic variation. All analyses were performed using SAS version 9.4 (SAS Institute, Cary, NC), and a 2-sided p value < 0.05 was considered statistically significant. This study was approved by the Institutional Review Board at Beth Israel Deaconess Medical Center and was conducted using deidentified Medicare claims data; informed consent was not required.

A total of 45,202 Medicare beneficiaries underwent RA stenting between 2016 and 2020. Procedural volumes declined by 41.1% between 2016 and 2020 (11,153 to 6,565 procedures). Declines were observed across all racial groups, with a 41.5% decrease among White patients, a 43.9% decrease among Black patients, and a 29.9% decrease among patients classified as Other race ( Figure 2 ).

Annual volumes of renal artery stent placement.

Overall, the cohort of patients who underwent RA stenting with a diagnosis of ARAS had a mean age of 76 years and 59% were women. Diabetes was present in 50% of patients, heart failure in 49%, chronic kidney disease in 84%, ischemic heart disease in 81%, peripheral artery disease in 82%, and stroke or TIA in 27%.

Patient characteristics varied by race, dual enrollment status, and geographic region. Compared to White patients, Black patients were more frequently female (70.0% vs 58.6%; p < 0.001), younger (74.8 vs 76.1 years; p < 0.001), and more likely to be dually enrolled in Medicare and Medicaid (28.7% vs 9.2%; p < 0.001). They also had higher rates of diabetes (67.8% vs 48.5%), heart failure (58.4% vs 48.0%), and stroke (30.5% vs 26.5%; p < 0.001), but were less likely to have atrial fibrillation (15.4% vs 23.3%; p < 0.001). Patients in the “Other” race category had elevated rates of diabetes (65.6%), chronic kidney disease (82.3%), and stroke (21.4%) (p < 0.001 for all).

Compared to Medicare only patients, dual-enrolled patients were more often female (73.8% vs 57.2%) and had a higher burden of diabetes (63.7% vs 48.6%), heart failure (62.8% vs 46.8%), chronic kidney disease (87.2% vs 83.8%), dementia (20.4% vs 10.9%), obesity (37.0% vs 31.9%), and stroke (31.0% vs 25.9%) (p < 0.001 for all).

Regional variation was less pronounced. The South had the highest proportion of Black patients (6.3%) and the greatest prevalence of diabetes (51.1%), heart failure (48.6%), and ischemic heart disease (82.9%) (p < 0.001). The Northeast had the highest rate of atrial fibrillation (24.3%) (p < 0.001) ( Table 1 ).

Table 1

Baseline characteristics

Characteristic	White (N = 17,249)	Black (N = 1,069)	Other (N = 812)	p (Race)	Medicare only (N = 16,932)	Dual eligible (N = 2,198)	p (Dual)	Northeast (N = 1,786)	Midwest (N = 4,384)	South (N = 10,450)	West (N = 2,252)	p (region) *
Age, mean ± SD (yrs)	76.1 ± 6.4	74.8 ± 6.7	74.9 ± 6.5	< 0.001	76.1 ± 6.4	74.9 ± 6.5	< 0.001	76.1 ± 6.5	76.2 ± 6.5	75.9 ± 6.3	76.2 ± 6.5	0.061
Female (%)	58.6	70	54.8	< 0.001	57.2	73.8	< 0.001	58.6	58.6	59.6	58.7	0.587
Race (%)				< 0.001			< 0.001					< 0.001
White	100	0	0		92.5	71.9		90.4	92.5	89.9	87.2
Black	0	100	0		4.5	14		4.4	5.7	6.3	2.4
Other	0	0	100		3.0	14.1		5.2	1.8	3.7	10.3
Dual enrollment (%)	9.2	28.7	38.2	< 0.001	0	100	< 0.001	13.7	11.2	10.7	14.3	< 0.001
Region (%)				< 0.001			< 0.001					< 0.001
Northeast	9.5	7.6	11.7		9.2	11.2		100	0	0	0
Midwest	23.8	23.8	9.9		23.3	22.6		0	100	0	0
South	55.2	63.4	49.1		55.9	51.4		0	0	100	0
West	11.5	5.3	29.3		11.6	14.8		0	0	0	100
Resistant hypertension (%)	38.2	40	36.7	0.314	37.4	44.3	< 0.001	52.6	36.6	36.2	38.7	< 0.001
Chronic kidney disease (%)	84	88.5	82.3	< 0.001	83.8	87.2	< 0.001	89.6	81.4	83.8	86.5	< 0.001
Heart failure (%)	48	58.4	49.9	< 0.001	46.8	62.8	< 0.001	54	47	48.6	48	< 0.001
Diabetes (%)	48.5	67.8	65.6	< 0.001	48.6	63.7	< 0.001	56.4	46.7	51.1	48.3	< 0.001
Hypertension (%)	98.8	99.2	97.9	0.047	98.7	99.4	0.003	98.7	98.6	98.9	98.3	0.07
Ischemic heart disease (%)	81.2	84.1	83	0.028	80.6	87.3	< 0.001	81.7	80.2	82.9	76.4	< 0.001
Peripheral artery disease (%)	81.9	82.1	78.1	0.023	81.3	84.9	< 0.001	85.9	80.8	80.9	84.7	< 0.001
Atrial fibrillation (%)	23.3	15.4	14.4	< 0.001	22.6	21.5	0.241	24.3	22.7	22.6	20.6	0.041
Stroke/TIA (%)	26.5	30.5	21.4	< 0.001	25.9	31	< 0.001	27.8	25.3	26.8	26.7	0.179
COPD (%)	44.1	39.9	33.1	< 0.001	41.6	57.9	< 0.001	42.5	45.4	43.8	38.7	< 0.001
Obesity (%)	32.2	40.9	26.5	< 0.001	31.9	37	< 0.001	34.5	31.2	33.5	27.9	< 0.001

Only gold members can continue reading. Log In or Register to continue

Share this:

• X
• Facebook

Related

Related posts:

1. Prevalence, Predictors and Clinical Outcomes of Percutaneous Coronary Intervention For In-Stent Restenosis versus De Novo Coronary Artery Disease
2. Cardiac Rehabilitation for Coronary Artery Disease: Gaps, Digital Models, and the Future of Personalized Prevention
3. Evaluating the Accessibility of Transcatheter and Surgical Aortic Valve Replacement Across the US Via Driving-Times
4. Artificial Intelligence as a Prognostic Tool in Cardiac Amyloidosis: A Review

Stay updated, free articles. Join our Telegram channel

Join