Association Between Nephrologist Ownership of Dialysis Facilities and Clinical Outcomes

Abstract

Importance: Ownership of US dialysis facilities presents a financial conflict of interest for nephrologists, who may change their clinical practice to improve facility profitability.

Objective: To investigate the association between nephrologist ownership of freestanding dialysis facilities and clinical outcomes.

Design, setting, and participants: This cross-sectional study was conducted using US Renal Data System data linked to a data set of freestanding nonpediatric dialysis facility owners. Participants were a sample of all adults with fee-for-service Medicare receiving dialysis for end-stage kidney disease from January 2017 to November 2017 at included facilities. Data were analyzed from April 2020 through August 2022.

Exposures: Outcomes associated with nephrologist ownership were assessed using a difference-in-differences analysis comparing the difference in outcomes between patients treated by nephrologist owners and patients treated by nonowners within facilities owned by nephrologists after accounting for differences in patient outcomes between nephrologist owners and nonowners in other facilities.

Main outcomes and measures: Outcomes plausibly associated with nephrologist ownership were evaluated: (1) treatment volumes (missed treatments and transplant waitlist status); (2) erythropoietin-stimulating agent (ESA) use and related outcomes (anemia, defined as hemoglobin level <10 g/dL, and blood transfusions), (3) quality metrics (mortality, hospitalizations, 30-day readmissions, hemodialysis adequacy, arteriovenous fistula use, and hemodialysis catheter use for ≥3 months), and (4) home dialysis use.

Results: A cohort of 251 651 patients (median [IQR] age, 66 [46-85] years; 112 054 [44.5%] women; 9765 Asian [3.9%], 86 837 Black [34.5%], and 148 617 White [59.1%]; 38 938 Hispanic [15.5%]) receiving dialysis for end-stage kidney disease were included. Patient treatment by nephrologist owners at their owned facilities was associated with a 2.4 percentage point (95% CI, 1.1-3.8 percentage points) higher probability of home dialysis, a 2.2 percentage point (95% CI, 3.6-0.7 percentage points) lower probability of receiving an ESA, and no significant difference in anemia or blood transfusions. Patient treatment by nephrologist owners at their owned facilities was not associated with differences in missed treatments, transplant waitlisting, mortality, hospitalizations, 30-day readmissions, hemodialysis adequacy, or fistula or long-term dialysis catheter use.

Conclusions and relevance: This cross-sectional cohort study found that nephrologist ownership was associated with increased home dialysis use, decreased ESA use, and no change in anemia or blood transfusions.

Figure 1.. Study Flow Chart

FFS indicates fee for service.

Figure 2.. Association Between Nephrologist Ownership of Dialysis Facility and Outcomes

Positive values indicate that ownership was associated with increased rates of the outcome. Associations were estimated using a difference-in-differences approach with linear regression of each outcome on the interaction between whether the nephrologist was an owner and whether the facility was owned by that nephrologist. Singleton observations by nephrologist-facility pair were excluded. Data source was author analysis of patient-level data from the US Renal Data System (Consolidated Renal Operations in a Web-Enabled Network data combined with Medicare claims) linked to facility-level data from the Centers for Medicare & Medicaid Services Medicare Provider Enrollment, Chain, and Ownership System database. To convert hemoglobin to grams per liter, multiply by 10.0. A, Results are adjusted only for nephrologist- and facility-level fixed effects. P values were not supplied because of multiple hypothesis testing and because P values were adjusted only in the primary, adjusted analysis. B, Results are adjusted for patient characteristics, with nephrologist- and facility-level fixed effects. P values are adjusted using a correction proposed by Benjamini et al (an outcome is significant if the adjusted P < .05). When the number of observations differed from the final data set, it was because the outcome was missing or not relevant to that patient (eg, patients undergoing peritoneal dialysis were excluded from fistula and catheter outcomes). Abbreviations: ESA indicates erythropoietin-stimulating agent; HD, hemodialysis; Kt/V, a measure of dialysis adequacy.

Figure 3.. Association of Nephrologist Ownership of Dialysis Facility With Outcomes by Profit Status

Positive values indicate that ownership was associated with increased rates of the outcome. Associations were estimated using a difference-in-differences approach with linear regression of each outcome on interactions among whether the nephrologist was an owner, whether the facility was owned by that nephrologist, and the profit status of the dialysis facility. Results are adjusted for patient characteristics, with nephrologist- and facility-level fixed effects. Data source was author analysis of patient-level data from the US Renal Data System (Consolidated Renal Operations in a Web-Enabled Network data combined with Medicare claims) linked to facility-level data from the Centers for Medicare & Medicaid Services Medicare Provider Enrollment, Chain, and Ownership System database. ESA indicates erythropoietin-stimulating agent; HD, hemodialysis; Kt/V, a measure of dialysis adequacy; LDO, large dialysis organization.