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Am J Manag Care. Author manuscript; available in PMC 2016 December 01.
Published in final edited form as:
Am J Manag Care. ; 22(6): e215–e223.
Effects of Physician Payment Reform on Provision of Home
Dialysis
Kevin F. Erickson, MD, MS1,2, Wolfgang C. Winkelmayer, MD, ScD1,3, Glenn M. Chertow,
MD, MPH1, and Jay Bhattacharya, MD, PhD2
1Stanford
University School of Medicine, Division of Nephrology, Department of Medicine, Palo
Alto, CA
Author Manuscript
2Stanford
University School of Medicine, Center for Primary Care and Outcomes Research,
Department of Medicine, Stanford, CA
3Baylor
College of Medicine, Section of Nephrology, Houston, TX
Abstract
Objectives—Patients with end-stage renal disease can receive dialysis at home or in-center. In
2004 the Centers for Medicare and Medicaid Services reformed physician payment for in-center
hemodialysis care from a capitated to a tiered fee-for-service model, augmenting physician
payment for frequent in-center visits. We evaluated whether payment reform influenced dialysis
modality assignment.
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Study Design—Cohort study of patients starting dialysis in the US in the three years before and
after payment reform.
Methods—We conducted difference-in-difference analyses comparing patients with Traditional
Medicare coverage (who were affected by the policy) to others with Medicare Advantage (who
were unaffected by the policy). We also examined whether the policy had a more pronounced
influence on dialysis modality assignment in areas with lower costs of traveling to dialysis
facilities.
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Results—Patients with Traditional Medicare coverage experienced a 0.7% (95% CI 0.2%–1.1%;
p=0.003) reduction in the absolute probability of home dialysis use following payment reform
compared to patients with Medicare Advantage. Patients living in areas with larger dialysis
facilities (where payment reform made in-center hemodialysis comparatively more lucrative for
physicians) experienced a 0.9% (95% CI 0.5%–1.4%; p<0.001) reduction in home dialysis use
following payment reform compared to patients living in areas with smaller facilities (where
payment reform made in-center hemodialysis comparatively less lucrative for physicians).
Conclusions—Transition from a capitated to tiered fee-for-service payment model for dialysis
care resulted in fewer patients receiving home dialysis. This area of policy failure highlights the
importance of considering unintended consequences of future physician payment reform efforts.
Correspondence to: Kevin Erickson, MD, MS, kevine1@stanford.edu, 650-498-7156, Center for Primary Care and Outcomes
Research, Stanford University School of Medicine, 117 Encina Commons, Stanford, CA 94305-6019.
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INTRODUCTION
Pay-for-performance (P4P) initiatives tying payment to performance and value of care have
become a major component of recent healthcare reform efforts. Since the passage of the
Affordable Care Act, and more recently, the repeal of Medicare’s Sustainable Growth Rate,
P4P programs are increasingly targeting physician practices directly.1,2 Lessons from prior
P4P initiatives can help inform the development of future policies applied to both managed
care and fee-for-service settings.
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More than 100,000 persons develop end-stage renal disease (ESRD) every year in the US.3
Due to a shortage of organs available for transplantation, the vast majority receive dialysis.
In-center hemodialysis is the most common modality; home-based peritoneal or
hemodialysis are alternatives that offer more flexibility and lifestyle benefits for some
patients.4–8 Ideally, dialysis modality is chosen after careful consideration of medical
suitability, and shared decision making among patients, loved ones and care providers.9
Evidence suggests that these discussions occur infrequently10, leading many to conclude that
home dialysis therapies are underutilized in the US.1112
It is uncertain whether physicians’ economic incentives influence dialysis modality choice.
International comparisons indicate that the relative physician payment for patients on home
versus in-center dialysis directly influences the fraction of patients on home dialysis.13 In
the US, higher Medicare payment to dialysis facilities for home therapies associated with the
2011 ESRD Prospective Payment System (“bundling”) coincided with a substantial increase
in the use of peritoneal dialysis.3,14 Yet, surveys of nephrologists suggest that patient
preferences and health are the primary factors considered when recommending a dialysis
modality, rather than economic factors.11,15
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In 2004, in an effort to align economic incentives and encourage high quality care, the
Centers for Medicare and Medicare Services (CMS) transformed payment to physicians
caring for patients receiving dialysis from a capitated to a tiered fee-for-service model
(Appendix Table A1).16 Under the new payment system, which continues to govern
physician dialysis reimbursement, physicians could increase professional fee revenues by
seeing patients receiving in-center hemodialysis four or more times per month. While this
policy was not focused on the delivery of home dialysis care, it may have influenced dialysis
modality decisions by making in-center hemodialysis comparatively more lucrative for some
physicians – physician payment for home dialysis therapy remained capitated and decreased
slightly.17 In this study, we determine whether the transition to a tiered fee-for-service
payment model influenced dialysis modality choices. We hypothesize that patients were less
likely to receive home dialysis following payment reform, and that this decrease was more
pronounced in places where physicians could increase in-center hemodialysis revenues at
lower cost.
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METHODS
Data and patient selection
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We selected patients who started dialysis in the US from January 1, 2001 through December
31st, 2006 – the three years prior to and following physician payment reform. We excluded
patients who received a kidney transplant within 60 days of ESRD onset. We obtained data
on patients’ insurance coverage, home ZIP codes, initial dialysis modality, and information
about dialysis facilities from the United States Renal Data System (USRDS), a national
registry of patients with treated ESRD. We obtained data on patient co-morbidities prior to
ESRD from the CMS Medical Evidence Report (CMS-2728). Due to large number of
missing values for Quételet’s (body mass) index (BMI), hemoglobin, and albumin, we used
multiple imputation to estimate missing values.18–20 Information on population density
came from census-based rural-urban commuting area codes.21 Information on hospital
referral region (HRR) came from the Dartmouth Atlas of Health Care.22
Outcomes and Study Design
The primary study outcome was the initial dialysis modality chosen, as reported by the
nephrologist to CMS. We categorized dialysis modality as in-center hemodialysis or home
dialysis, where home dialysis included home hemodialysis or peritoneal dialysis.
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We used several difference-in-difference models to examine the effect of payment reform on
dialysis modality. Difference-in-difference analysis is an econometric method commonly
used to analyze policy.23 Difference-in-difference analyses separate patients into “treatment”
and “control” groups. The “treatment” group includes patients who were affected by the
policy of interest, while the “control” group includes patients who were not subject to the
policy. Thus, any changes observed in the control group reflect changes in the population
from measures not changed by the policy. The difference in the change of the outcome after
implementation of the policy between the treatment and control groups characterizes the
policy’s effect.
Comparison groups
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We formed comparison groups from two separate cohorts. In an “insurance coverage”
cohort, we selected patients enrolled in either Traditional Medicare as a primary payer or
Medicare Advantage prior to start of dialysis. In this analysis, we included patients 65 or
older at ESRD onset because patients are not permitted to enroll in Medicare Advantage if
ESRD (rather than age) is their qualifying criterion; thus, virtually all patients with ESRD
with Medicare Advantage are 65 or older. We conducted a difference-in-difference analysis
comparing the choice of dialysis modality among patients with Traditional Medicare versus
Medicare Advantage. We chose these groups because payment for services provided to
patients with Traditional Medicare was affected by payment reform, while payment for
services provided to patients with Medicare Advantage was not.
In a “Non-HMO Medicare” cohort, we selected patients with Traditional Medicare as a
primary payer, or waiting for Medicare coverage, at the onset of dialysis. Because the
majority of patients in the US who develop ESRD qualify for Medicare within 90 days of
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ESRD onset, we assumed that patients documented as “waiting” for Medicare would soon
receive it and that physicians would consider the financial implications of treating these
patients as similar to treating patients already covered. In this cohort, we excluded patients
with private insurance since they do not qualify for Medicare until after 30 months of ESRD.
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We previously demonstrated that the frequency of physician (or advanced practice provider)
visits to patients receiving in-center hemodialysis was predominantly related to geographic
and dialysis facility factors, rather than patient clinical characteristics.24 Geographic
measures – such as dialysis facility size and population density – that determine the costs
physicians incur (in resources and time) traveling to visit patients at dialysis facilities have a
substantial influence on visit frequency. All else equal, it is more lucrative for physicians to
see patients in larger dialysis facilities because physicians can collect revenue for more
patient visits after incurring a fixed cost of traveling to a facility. Likewise, it is more
lucrative for physicians to see patients in more densely populated areas due to lower travel
costs to facilities.
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Using the Non-HMO Medicare cohort, we conducted two difference-in-difference analyses
to determine whether changes in the choice of dialysis modality following payment reform
varied geographically depending upon how costly it was for physicians to see patients more
frequently. While the small decrease in physician payment for home dialysis was similar
across all geographic regions, the change in physician payment for in-center hemodialysis
after 2004 varied geographically. Physicians practicing in areas where the cost of more
frequent visits was lower had an opportunity to increase their professional fee revenues after
payment reform by assigning more patients to in-center hemodialysis. In contrast, physicians
practicing in areas where it was too costly to visit patients four times per month would have
experienced little or no increase in professional fee revenues by assigning patients to incenter hemodialysis. We used the two geographic characteristics previously found to be
associated with visit frequency, and therefore the relative gain in professional fee revenue
from in-center hemodialysis – dialysis facility size and population density – to determine if
changes in physician payment influenced dialysis modality choice.
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We averaged dialysis facility size across the HRR where patients lived. We calculated
dialysis facility size from the average number of patients receiving in-center hemodialysis
documented in annual facility surveys in the three years prior to payment reform. We
divided HRRs into quintiles based on their average facility size and assessed the proportion
of prevalent in-center patients seen four or more times per month (and associated changes in
revenues) in the three years following payment reform within each quintile. We observed
that the proportion of patients with four or more visits per month was smallest in the lowest
mean facility size quintile. Consequently, we categorized HRRs in the lowest quintile of
mean facility size as areas with “smaller facilities.”
We dichotomized population density into “small town/rural” and “non-small town/rural.”
The differences in visit frequency across population density category were small relative to
differences across dialysis facility size (Appendix Table A2).
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Statistical methods
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Due to large population size, we used a 10% standardized difference as a marker of
heterogeneity when comparing differences in characteristics between treatment groups.25 In
all difference-in-difference analyses, we used logistic regression to estimate odds ratios
(OR) and corresponding 95% confidence intervals (CI). We controlled for regional
differences in population density and dialysis facility size, as well as patient age, sex, race,
ethnicity, and medical comorbidities listed in Table 1.26 We did not adjust for dialysis
facility characteristics, since the facility where a patient receives dialysis is often a
consequence of dialysis modality choice. An interaction term between binary variables
representing the start of dialysis before versus after payment reform, and whether patients
were in the “treatment” or “control” group, estimated the effect of the policy on the odds of
dialysis modality choice for each comparison.
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We used our logistic regression estimates to determine the effect of physician reimbursement
reform on the absolute probability of home dialysis use. For each patient in the relevant
cohort, we calculated four predicted probabilities of home dialysis use assuming he was in
each comparison group both before and after the policy. We used these predicted
probabilities to calculate a difference-in-difference estimate of the policy effect for each
patient. (See appendix) We averaged the individual policy effect estimates over all patients,
and used the delta method to calculate standard errors and 95% confidence intervals around
average predicted probability estimates.
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In a secondary analysis, we explored how different patients were affected by the policy. We
separated selected categories of patients by dialysis facility size comparison group. For each
patient category, we determined the unadjusted change in proportion of patients assigned to
home dialysis following payment reform stratified by dialysis facility size.
RESULTS
The cohort of patients with Traditional Medicare and Medicare Advantage (insurance
coverage cohort) included 241,111 patients. Before payment reform, 18,754 (16.5%) and
94,615 (83.5%) of patients had Medicare Advantage and Traditional Medicare, respectively,
compared to 22,473 (17.6%) and 105,269 (82.4%) after the reform. Among patients with
Traditional Medicare, 5.8% and 5.0% of patients were assigned to home dialysis before and
after payment reform, respectively. Corresponding figures for patients with Medicare
Advantage were 4.5% and 4.3%. Patient characteristics, were similar across insurance
category, except more patients with Medicare Advantage were Hispanic and fewer lived in
rural areas and small towns. (Table 1)
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The cohort of patients with Traditional Medicare or waiting for Medicare coverage (NonHMO Medicare cohort) included 389,526 patients. Before payment reform, 19,685 (10.8%)
and 163,415 (89.2%) of patients lived in areas with smaller and larger facilities, respectively,
compared to 21,840 (10.6%) and 184,586 (89.4%) after the reform. Among patients living in
areas with smaller facility sizes, 6.7% were assigned to home dialysis both prior to and
following payment reform. Among patients living in areas with larger facility sizes, 6.5%
were assigned to home dialysis prior to payment reform compared to 5.5% following
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payment reform. There were no significant differences in co-morbidities among patients
receiving dialysis in areas with different facility sizes, while more whites and American
Indians lived in areas with smaller facilities, and more blacks and Hispanics lived in areas
with larger facilities. Smaller facilities were more likely to be in rural areas and small towns.
(Table 2)
Applying a difference-in-difference regression model, patients with Traditional Medicare
coverage (who were affected by the policy) experienced a 12% (95% CI, 2%–21%)
reduction in the odds of home dialysis following payment reform when compared to patients
with Medicare Advantage (who were not affected by the policy). (Appendix Table A3) This
corresponds to a 0.7% (95% CI 0.2%–1.1%; p=0.003) reduction in the average absolute
probability of home dialysis use following payment reform among patients with Traditional
Medicare compared to patients with Medicare Advantage. (Table 3)
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Patients living in areas with larger dialysis facilities (where physicians could increase
revenues from in-center dialysis at lower cost) experienced a 16% reduction in the odds of
provision of home dialysis (95% CI, 8%–22%) compared to patients living in areas with
smaller facilities (where it was less lucrative to visit patients receiving in-center dialysis).
(Appendix Table A4) This corresponds to a 0.9% (95% CI 0.5%–1.4%; p<0.001) reduction
in the average absolute probability of home dialysis use following payment reform among
patients living in areas with larger facilities compared to patients living in areas with smaller
facilities. (Table 3) Figure 1 illustrates the unadjusted change in modality choice among
patients residing in areas with different dialysis facility sizes. There was no significant effect
of the policy in our analysis of population density.
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Nearly all patient groups living in areas with larger facilities were less likely to receive home
dialysis following physician payment reform. Among patients living in areas with smaller
facilities, women, whites, patients with hemoglobin >10.5 g/dL, and immobile patients
appeared more likely to receive home dialysis following payment reform. (Figure 2)
DISCUSSION
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We found that the 2004 Medicare reform to physician dialysis visit payments led to a
reduction in use of home dialysis. Patients who were most affected by the policy, either
because they were insured by Traditional Medicare or because they lived in areas where
physicians could increase in-center hemodialysis revenues at lower cost, experienced nearly
a 1% absolute reduction in the probability of receiving home dialysis compared to patients
who were unaffected (or less affected) by the policy. More specifically, approximately 8 out
of every 1,000 patients initiating dialysis who were affected by the policy received in-center
hemodialysis rather than home dialysis as a result of the policy. The payment policy
appeared to have influenced dialysis modality choice for nearly all patient groups, regardless
of sex, race, ethnicity, or overall health.
According to statements from CMS, the 2004 physician payment reform was designed to
align economic incentives and improve the quality of dialysis care.27 In the discourse
leading up to the policy’s enactment, there was no mention of how the reform might
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influence dialysis modality decisions. Since the policy was enacted, some physicians have
expressed concern that the policy created a financial incentive to place some patients on incenter hemodialysis rather than home hemodialysis or peritoneal dialysis.28 Yet, surveys of
nephrologists in the US suggest that economic factors do not play an important role in
dialysis modality selection.11,15 Our findings indicate that economic incentives have had a
substantial effect on physicians’ decisions regarding dialysis modality, and that payment
reform had the unintended consequence of leading fewer patients to home dialysis. Since the
choice of dialysis modality is central to patients’ quality of life, independence, and
healthcare costs, a reduction in the use of home dialysis can be seen as a failure of the
policy.8,29,30 Recently, reform to Medicare dialysis facility reimbursement (the 2011 ESRD
PPS) encourages greater use of home dialysis, and has coincided with a trend back towards
greater use of peritoneal dialysis.3,14
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Pay-for-performance (P4P) initiatives have been proposed as a solution to problems in
healthcare by encouraging the delivery of high-value care.31,32 Small trials and
demonstration projects suggest that P4P initiatives may lead to high-quality care.33,34 Yet,
the overall efficacy of P4P programs remains uncertain, and a number of studies have
demonstrated important unintended consequences.35 Due to mandates from the Patient
Protection and Affordable Care Act, CMS plans to expand the scope of its P4P initiative on
a national scale with a program directed at physician payments deemed the Physician Valuebased Payment Modifier.36 The recent repeal of Medicare’s Sustainable Growth Rate
formula calls for additional programs directed at physician payment.2 Because it was, in
part, designed to improve the quality of care, the 2004 physician payment reform is an early
example of a national P4P program directed at physician behavior. Despite evidence that
more frequent hemodialysis visits are associated with some favorable health outcomes,37–40
policy analyses have failed to demonstrate any benefit and suggest that healthcare costs
increased.41,42
Our findings appear to contrast with physician surveys indicating that economic factors do
not influence dialysis modality decisions. However, these seemingly disparate findings can
be reconciled. For a given physician, or group of physicians practicing in geographic
proximity, the net financial reward from in-center versus home dialysis is a function of
facility sizes and insurance composition (i.e., the fraction of patients with Traditional
Medicare versus Medicare Advantage) among other factors. To the extent that dialysis
facility characteristics and patients with Medicare Advantage are clustered geographically,
regional differences in practice patterns may reflect underlying economic incentives even if
individual physicians do not base their dialysis modality recommendations on economic
grounds.
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This study has several limitations. Although we use “control” groups for comparison and
multivariable adjustment to reduce the potential for bias, we cannot fully exclude the
possibility that unobserved factors differentially affected changes in modality choice across
comparison groups. For example, unobserved changes over time in patients’ suitability for
home dialysis, willingness to administer dialysis at home, or preparation for dialysis that
differentially affected one comparison group could lead to bias. Additionally, the relative
financial gain for physicians of in-center versus home dialysis care may have influenced
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dialysis modality decisions for some patients receiving Medicare Advantage through a
“spillover” effect, leading us to underestimate the effect of payment reform. Finally, small
variation in visit frequency associated with nephrologist and geographic density may have
prevented us from observing significant effects of these factors on dialysis modality choice.
In conclusion, we found that national physician payment reform enacted by CMS in 2004 in
an effort to encourage more frequent face-to-face dialysis visits and improve the quality of
care resulted in an unintended consequence of relatively fewer patients choosing home
dialysis. The tiered fee-for-service payment system enacted in 2004 continues to govern
physician reimbursement for dialysis care, and consequently, may continue to discourage
home dialysis use in certain patient populations. These findings highlight both an area of
policy failure and the importance of considering unintended consequences of future efforts
to reform physician payment.
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Supplementary Material
Refer to Web version on PubMed Central for supplementary material.
Acknowledgments
Author Access to Data: This work was conducted under a data use agreement between Dr. Winkelmayer and the
National Institutes for Diabetes and Digestive and Kidney Diseases (NIKKD). An NIDDK officer reviewed the
manuscript and approved it for submission. The data reported here have been supplied by the United States Renal
Data System (USRDS). The interpretation and reporting of these data are the responsibility of the author(s) and in
no way should be seen as an official policy or interpretation of the U.S. government.
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Funding: F32 HS019178 from AHRQ (Dr. Erickson); DK085446 (Dr. Chertow); Dr. Winkelmayer receives research
and salary support through the endowed Gordon A. Cain Chair in Nephrology at Baylor College of Medicine. Dr.
Bhattacharya would like to thank the National Institute on Aging for support for his work on this paper (R37
150127-5054662-0002).
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40. Erickson KF, Mell M, Winkelmayer WC, Chertow GM, Bhattacharya J. Provider Visits and Early
Vascular Access Placement in Maintenance Hemodialysis. Journal of the American Society of
Nephrology. 2014 2014(Published ahead of print).
41. Erickson KF, Winkelmayer WC, Chertow GM, Bhattacharya J. Medicare Reimbursement Reform
for Provider Visits and Health Outcomes in Patients on Hemodialysis. Forum for Health
Economics & Policy. 2014; 0(0):1558–9544.
42. Mentari EK, DeOreo PB, O'Connor AS, Love TE, Ricanati ES, Sehgal AR. Changes in Medicare
reimbursement and patient-nephrologist visits, quality of care, and health-related quality of life.
American Journal of Kidney Diseases. 2005 Oct; 46(4):621–627. [PubMed: 16183416]
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Take Away Points
In 2004, the Centers for Medicare and Medicaid Services reformed physician payment
for in-center hemodialysis care from a capitated to tiered fee-for-service model,
augmenting physician payment for frequent in-center visits. This policy may have
influenced home dialysis use by making in-center dialysis more lucrative for some
physicians. We compared home dialysis use among patients differentially affected by the
policy.
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•
Patients most affected by the policy experienced nearly a 1% reduction
in the absolute probability of home dialysis use following payment
reform.
•
Our findings indicate that transition to fee-for-service payment for
dialysis had the unintended consequence of reducing home dialysis use.
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Figure 1. Dialysis Modality Assignment over Time in Areas with Small versus Larger Dialysis
Facilities
Note: Dashed line represents the reimbursement reform proposed rule; solid line represents
the final rule. Probabilities are unadjusted. A plot of probabilities adjusted for covariates
from our primary regression model is not substantively different.
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Erickson et al.
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Figure 2. Change in Dialysis Modality Following Payment Reform by Dialysis Facility Sizes and
Selected Patient Characteristics
Note: bre a statistically significant difference (p<0.01) in the change in use of home dialysis
between areas with large and smaller facilities. Analyses are unadjusted.
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Exhibit 1
Pre-Reimbursement Reform
Am J Manag Care. Author manuscript; available in PMC 2016 December 01.
Medicare
Advantage
Traditional
Medicare
(n=18,754)
(n=94,615)
Age - years
75.2
75.2
Male - %
53.4
50.4
std
diff
Post-Reimbursement Reform
Medicare
Advantage
Traditional
Medicare
std
diff
(n=22,473)
(n=105,269)
0.4
75.6
75.5
1.1
6.0
54.3
52.4
3.9
Erickson et al.
Baseline Characteristics of “Insurance Coverage” Cohort:
Demographic
American Indian - %
0.3
0.9
7.4
0.3
0.8
7.2
Black - %
20.8
22.4
3.7
22.4
21.2
2.8
White - %
73.7
73.8
0.3
72.3
74.8
5.6
Other race - %
5.2
3.0
11.4
5.0
3.1
9.8
Hispanic ethnicity - %
12.3
7.5
16.5
12.7
7.9
16.1
Diabetes - %
49.3
50.9
3.2
52.6
51.8
1.6
Coronary disease - %
34.6
38.0
6.9
31.1
34.8
7.9
Comorbidities
Cancer - %
8.0
8.8
2.9
9.0
10.1
3.7
Heart failure - %
37.0
40.6
7.3
39.8
42.0
4.5
Pulmonary disease - %
9.0
11.0
6.7
10.1
12.4
7.3
Cerebrovascular disease - %
11.2
12.5
4.2
11.5
12.4
2.8
Peripheral vascular disease - %
15.9
18.7
7.4
16.3
19.0
7.0
Hemoglobin - g/dl±
10.2
10.1
2.8
10.3
10.3
1.9
Serum albumin g/dl±
3.2
3.2
8.0
3.2
3.2
8.6
BMI kg/m2±
26.2
26.5
4.7
27.1
27.2
0.5
Smoking history - %
2.6
3.2
3.7
2.9
3.6
3.9
Immobility - %
4.1
5.0
4.4
6.5
7.3
3.2
Drug or alcohol use - %
0.6
0.7
1.3
0.6
0.7
0.8
Rural or small town
2.3
12.3
37.2
3.8
12.3
30.8
Area with larger facilities
93.5
88.5
20.9
92.3
88.6
14.0
Geographic
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Note: 1,946 patients were excluded from this analysis because their zip codes could not be linked to hospital referral regions.
±
Among patients included in the analysis, hemoglobin was missing in 8.4% of the population; serum albumin was missing in 25% of the population; BMI was missing in 1.1% of the population. 0.1% of
patients had missing values for either age, sex, drug or alcohol abuse, or population density. All missing values were imputed.
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Table 2
Am J Manag Care. Author manuscript; available in PMC 2016 December 01.
Pre-Reimbursement Reform
Post-Reimbursement Reform
Larger
Facility
Small
Facility
Larger
Facility
Small
Facility
(n=163,415)
(n=19,685)
(n=184,586)
(n=21,840)
Age – years
62.8
64.0
7.4
63.0
64.1
7.4
Male - %
53.4
54.2
1.7
55.1
55.0
0.1
std
diff
std
diff
Erickson et al.
Baseline Characteristics of Dialysis Facility Size Comparison in the “Non-HMO Medicare” Cohort.
Demographic
American Indian - %
1.1
3.1
14.2
1.0
3.1
14.4
Black - %
31.8
19.4
29.7
31.0
18.9
29.3
White - %
63.3
76.1
25.5
64.0
76.5
25.0
Other race - %
3.9
1.4
15.8
4.0
1.5
15.2
Hispanic ethnicity - %
11.5
2.8
34.3
12.1
3.1
35.0
Diabetes - %
51.9
50.1
3.8
53.1
52.2
1.9
Coronary disease - %
27.7
31.5
8.3
25.1
29.2
9.2
Comorbidities
Cancer - %
6.0
6.8
3.5
6.8
7.9
4.5
Heart failure - %
32.4
33.7
2.8
33.8
35.3
3.1
Pulmonary disease - %
7.8
9.9
7.2
8.8
11.1
7.7
Cerebrovascular disease - %
9.6
11.0
4.5
9.7
10.9
3.8
Peripheral vascular disease - %
14.3
17.9
9.7
14.6
18.0
9.3
Hemoglobin - g/dl±
9.9
10.1
9.4
10.1
10.2
9.7
Serum albumin g/dl±
3.1
3.1
1.6
3.1
3.2
4.7
BMI kg/m2±
27.6
27.9
4.3
28.3
28.6
4.0
Smoking history - %
5.1
6.6
6.2
5.9
7.3
5.8
Immobility - %
3.9
3.9
0.3
5.6
5.2
1.5
Drug or alcohol use - %
1.9
1.5
2.8
2.2
1.9
2.2
9.7
27.2
43.0
9.8
27.0
42.3
Geographic
Rural or small town
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Note: 2,402 patients were excluded from this analysis because their zip codes could not be linked to hospital referral regions. This cohort differs from the group of patients with Traditional Medicare
coverage in the “Insurance Coverage” cohort in two ways. First, it includes patients of all ages at onset of dialysis. Second, it includes patients documented as “waiting” for Medicare coverage at the onset of
dialysis.
Erickson et al.
±
Among patients included in the analysis, a total of 8.4% had missing hemoglobin; 25% missing serum albumin, and; 1.1% missing BMI. 0.1% of patients had missing values for either age, drug or alcohol
abuse, or population density. All missing values were imputed.
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Table 3
Erickson et al.
Average Probability of Home Dialysis from Regression Models:
Insurance Coverage Comparison Groups
Medicare Advantage
Am J Manag Care. Author manuscript; available in PMC 2016 December 01.
Prior to reimbursement reform
Traditional Medicare
probability of
home dialysis
LCI
UCI
probability of
home dialysis
LCI
UCI
4.5
4.2
4.8
5.8
5.7
6.0
Following reimbursement reform
4.2
4.0
4.5
4.9
4.8
5.1
Difference following reform
−0.2
−0.6
0.1
−0.9
−1.1
−0.7
Policy Effect (%)
LCI
UCI
0.7
0.2
1.1
Difference-in-difference estimate*
Dialysis Facility Size Comparison Groups
Areas with small facilities
Prior to reimbursement reform
‡
LCI
5.8
5.5
Areas with larger facilities
UCI
probability of
home dialysis
LCI
UCI
6.2
6.6
6.5
6.7
Following reimbursement reform
5.8
5.5
6.1
5.6
5.5
5.7
Difference following reform
−0.1
−0.5
0.3
−1.0
−1.2
−0.8
Policy Effect (%)
LCI
UCI
0.9
0.5
1.4
Difference-in-difference estimate‡
*
probability of
home dialysis
p=0.003
p<0.001
Note: UCI and LCI are the upper and lower bounds of the 95% confidence interval, respectively. An examination of the sensitivity of our findings to possible geographic clustering in dialysis modality
choice using generalized estimating equation models was not substantially different from our primary study results. (Table A5)
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