The Comprehensive Primary Care Plus Model and Health Care Spending, Service Use, and Quality.

Importance: Implemented in 18 regions, Comprehensive Primary Care Plus (CPC+) was the largest US primary care delivery model ever tested. Understanding its association with health outcomes is critical in designing future transformation models. Objective: To test whether CPC+ was associated with lower health care spending and utilization and improved quality of care. Design, Setting, and Participants: Difference-in-differences regression models compared changes in outcomes between the year before CPC+ and 5 intervention years for Medicare fee-for-service beneficiaries attributed to CPC+ and comparison practices. Participants included 1373 track 1 (1 549 585 beneficiaries) and 1515 track 2 (5 347 499 beneficiaries) primary care practices that applied to start CPC+ in 2017 and met minimum care delivery and other eligibility requirements. Comparison groups included 5243 track 1 (5 347 499 beneficiaries) and 3783 track 2 (4 507 499 beneficiaries) practices, matched, and weighted to have similar beneficiary-, practice-, and market-level characteristics as CPC+ practices. Interventions: Two-track design involving enhanced (higher for track 2) and alternative payments (track 2 only), care delivery requirements (greater for track 2), data feedback, learning, and health information technology support. Main Outcomes and Measures: The prespecified primary outcome was annualized Medicare Part A and B expenditures per beneficiary per month (PBPM). Secondary outcomes included expenditure categories, utilization (eg, hospitalizations), and claims-based quality-of-care process and outcome measures (eg, recommended tests for patients with diabetes and unplanned readmissions). Results: Among the CPC+ patients, 5% were Black, 3% were Hispanic, 87% were White, and 5% were of other races (including Asian/Other Pacific Islander and American Indian); 85% of CPC+ patients were older than 65 years and 58% were female. CPC+ was associated with no discernible changes in the total expenditures (track 1: $1.1 PBPM [90% CI, -$4.3 to $6.6], P = .74; track 2: $1.3 [90% CI, -$5 to $7.7], P = .73), and with increases in expenditures including enhanced payments (track 1: $13 [90% CI, $7 to $18], P < .001; track 2: $24 [90% CI, $18 to $31], P < .001). Among secondary outcomes, CPC+ was associated with decreases in emergency department visits starting in year 1, and in acute hospitalizations and acute inpatient expenditures in later years. Associations were more favorable for practices also participating in the Medicare Shared Savings Program and independent practices. CPC+ was not associated with meaningful changes in claims-based quality-of-care measures. Conclusions and Relevance: Although the timing of the associations of CPC+ with reduced utilization and acute inpatient expenditures was consistent with the theory of change and early focus on episodic care management of CPC+, CPC+ was not associated with a reduction in total expenditures over 5 years. Positive interaction between CPC+ and the Shared Savings Program suggests transformation models might be more successful when provider cost-reduction incentives are aligned across specialties. Further adaptations and testing of primary care transformation models, as well as consideration of the larger context in which they operate, are needed.

Long-Term Effects of the Comprehensive Primary Care Model on Health Care Spending and Utilization.

BACKGROUND: The Centers for Medicare & Medicaid Services launched the 4-year Comprehensive Primary Care Initiative (CPC Classic) in 2012 and its 5-year successor, CPC Plus (CPC+), in 2017 to test whether improving primary care delivery in five areas-and providing practices with financial and technical support-reduced spending and improved quality. This is the first study to examine long-term effects of a primary care practice transformation model. OBJECTIVE: To test whether long-term primary care transformation-the 4-year CPC Classic and the first 2 years of its successor, CPC+-reduced hospitalizations, emergency department (ED) visits, and spending over 6 years. DESIGN: We used a difference-in-differences analysis to compare outcomes for beneficiaries attributed to CPC Classic practices with outcomes for beneficiaries attributed to comparison practices during the year before and 6 years after CPC Classic began. PARTICIPANTS: The study involved 565,674 Medicare fee-for-service beneficiaries attributed to 502 CPC Classic practices and 1,165,284 beneficiaries attributed to 908 comparison practices, with similar beneficiary-, practice-, and market-level characteristics as the CPC Classic practices. INTERVENTIONS: The interventions required primary care practices to improve 5 care areas and supported their transformation with substantially enhanced payment, data feedback, and learning support and, for CPC+, added health information technology support. MAIN MEASURES: Hospitalizations (all-cause), ED visits (outpatient and total), and Medicare Part A and B expenditures. KEY RESULTS: Relative to comparison practices, beneficiaries in intervention practices experienced slower growth in hospitalizations-3.1% less in year 5 and 3.5% less in year 6 (P < 0.01) and roughly 2% (P < 0.1) slower growth each year in total ED visits during years 3 through 6. Medicare Part A and B expenditures (excluding care management fees) did not change appreciably. CONCLUSIONS: The emergence of favorable effects on hospitalizations in years 5 and 6 suggests primary care transformation takes time to translate into lower hospitalizations. Longer tests of models are needed.

Measuring physician practice site characteristics: A comparison of data from SK&A and a practice site survey.

OBJECTIVE: To evaluate the comparability of commercially available practice site data from SK&A with survey data to understand the implications of using SK&A data for health services research. DATA SOURCES: Responses to the Comprehensive Primary Care Plus (CPC+) Practice Survey and SK&A data. STUDY DESIGN: Comparison of CPC + Practice Survey responses to SK&A information for 2698 primary care practice sites. DATA COLLECTION: CPC + Practice Survey data collected through a web-only survey from April through September 2017, and SK&A data purchased in November 2016. PRINCIPAL FINDINGS: Information was similar across data sources, although some discrepancies were common. For example, 56% of practice sites had differences in the reported number of practitioners, and larger sites tended to have larger differences. Among practice sites with 1 practitioner in the survey, only 1.3% had a difference of 3 or more practitioners between the data sources, whereas 63% of practice sites with 11 or more practitioners had a difference of 3 or more practitioners. CONCLUSIONS: Discrepancies between data sources could reflect differences of interpretation when defining practice site characteristics, changes over time in those characteristics, or data errors in either SK&A or the survey. Researchers using SK&A data should consider possible ramifications for their studies.

Participation in the Comprehensive Primary Care Plus Initiative.

PURPOSE: Comprehensive Primary Care Plus (CPC+) is the largest test of primary care payment and delivery reform. This program aims to strengthen primary care via enhanced and alternative payment, data feedback, learning, and health information technology support for practice transformation for more than 3,000 practices. We analyzed participation rates and how CPC+ practices differ from other primary care practices in CPC+ regions. METHODS: We assembled a unique data set describing all US primary care practices and compared primary care practices in CPC+ regions, CPC+ applicants, and CPC+ participants. Among CPC+ participants, we compared across 2 model tracks. RESULTS: Of the primary care practices in CPC+ regions, 22% applied for CPC+ and 15% participated. Practices that applied to CPC+ were diverse, but they were generally larger, more sophisticated electronic health record users, more likely to be owned by a hospital or health system, more likely to have experience with transformation efforts, and more likely to be in urban areas than practices that did not apply. Applicants also generally served slightly healthier and more advantaged Medicare fee-for-service beneficiaries. Differences between practices that applied but did not join CPC+ and CPC+ participants were smaller yet systematic. CONCLUSIONS: Participants in CPC+ are diverse but not representative of all primary care practices, underscoring the need to further engage practices that are small, independent, in rural areas, and lack experience with practice and payment transformation models, as well as the need to extrapolate evaluation results carefully.

Contemporaneous and long-term effects of children's public health insurance expansions on Supplemental Security Income participation.

This study explores the interplay between two important public programs for vulnerable children: Medicaid and the Supplemental Security Income (SSI) program. Children's public health insurance eligibility increased dramatically during the late 1990s with the launch of the Children's Health Insurance Program along with concurrent Medicaid expansions. We use a measure of simulated eligibility as an exogenous source of variation in Medicaid generosity to identify the effects of the eligibility expansions on SSI outcomes. Though increases in eligibility for public health insurance did not affect contemporaneous youth SSI applications or awards on average, expansions in coverage significantly decreased both applications and awards in states where SSI recipients did not automatically receive Medicaid. We attribute the difference in findings to the higher transactions costs associated with entering Medicaid via SSI in such states. In the long-term, increased public insurance eligibility during childhood reduces young adult SSI applications to some extent, consistent with recent findings that Medicaid coverage in youth improves adult health and economic outcomes.

The Impact of a Health Information Technology-Focused Patient-centered Medical Neighborhood Program Among Medicare Beneficiaries in Primary Care Practices: The Effect on Patient Outcomes and Spending.

BACKGROUND: The Center for Medicare & Medicaid Innovation (CMMI) tests new models of paying for or delivering health care services and expands models that improve health outcomes while lowering medical spending. CMMI gave TransforMED, a national learning and dissemination contractor, a 3-year Health Care Innovation Award (HCIA) to integrate health information technology systems into physician practices. This paper estimates impacts of TransforMED's HCIA-funded program on patient outcomes and Medicare parts A and B spending. RESEARCH DESIGN: We compared outcomes for Medicare fee-for-service (FFS) beneficiaries served by 87 treatment practices to outcomes for Medicare FFS beneficiaries served by 286 matched comparison practices, adjusting for differences in outcomes between the 2 groups during a 1-year baseline period. We estimated impacts in 3 evaluation outcome domains: quality-of-care processes, service use, and spending. RESULTS: We estimated the program led to a 7.1% reduction in inpatient admissions and a 5.7% decrease in the outpatient emergency department visits. However, there was no evidence of statistically significant effects in outcomes in either the quality-of-care processes or spending domains. CONCLUSIONS: These results indicate that TransforMED's program reduced service use for Medicare FFS beneficiaries, but also show that the program did not have statistically significant favorable impacts in the quality-of-care processes or spending domains. These results suggest that providing practices with population health management and cost-reporting software-along with technical assistance for how to use them-can complement practices' own patient-centered medical home transformation efforts and add meaningfully to their impacts on service use.

Impact of Enroll America on the Number of Individuals Covered through the Federally Facilitated Marketplace.

OBJECTIVE: To assess the impact of Enroll America's field outreach activities on the number of individuals enrolled in Marketplace coverage during the first open enrollment period. DATA SOURCES/STUDY SETTING: Marketplace enrollment for the initial open enrollment period linked with data on Enroll America's field activities and baseline local-area demographic, economic, and health services characteristics. STUDY DESIGN: We used a quasi-experimental design, comparing Marketplace enrollment during the first open enrollment period in local areas drawn from Enroll America field states to a comparison group of local areas drawn from states that were not served by Enroll America's field effort, but that otherwise match up well with Enroll America states. PRINCIPAL FINDINGS: We find evidence of a large, positive effect of Enroll America's field outreach on Marketplace enrollment in non-Medicaid expansion states. Across model specifications, the Enroll America effects on Marketplace enrollment ranged between 10 and 15 percent, with most estimates statistically significant at the 5 percent level. CONCLUSIONS: Enroll America played an important role in the success of individual states' efforts to boost Marketplace enrollment. Enroll American's evidence-driven, grassroots approach could serve as a model for others interested in conducting similar outreach campaigns for Affordable Care Act-related coverage.

Program Churning and Transfers Between Medicaid and CHIP.

OBJECTIVE: In the 10 states that are the focus of the Children's Health Insurance Program Reauthorization Act of 2009 evaluation, we analyze in detail the states' recent progress in retaining children in public coverage and public coverage churning. METHODS: We used administrative data spanning a five-and-a-half-year period collected from 10 study states-Alabama, California, Florida, Louisiana, Michigan, New York, Ohio, Texas, Utah, and Virginia-to analyze the extent to which children return to the same program a short time after disenrollment and the extent to which transfers between Medicaid and Children's Health Insurance Program (CHIP) lead to public coverage gaps. RESULTS: Our analysis yielded 3 key findings. First, many children moved between Medicaid and CHIP; while most transitioned seamlessly, coverage gaps occurred for as many as 40%, depending on the type of transition. Second, churning continued to be a concern for public coverage programs, with approximately 21% of Medicaid disenrollees and 10% of separate CHIP disenrollees returning to the same program within 7 months. Third, we found sizable differences in rates of program churning and nonseamless program transfers across the 10 study states. CONCLUSIONS: Notable variation existed across programs and states, which persisted over the period in public program churning. These results suggest the need for continued efforts to simplify renewal processes, particularly in state Medicaid programs, along with the adoption of processes that improve coordination across programs and policies that simplify these transfers.

Stability of children's insurance coverage and implications for access to care: evidence from the Survey of Income and Program Participation.

Even as the number of children with health insurance has increased, coverage transitions--movement into and out of coverage and between public and private insurance--have become more common. Using data from 1996 to 2005, we examine whether insurance instability has implications for access to primary care. Because unobserved factors related to parental behavior and child health may affect both the stability of coverage and utilization, we estimate the relationship between insurance and the probability that a child has at least one physician visit per year using a model that includes child fixed effects to account for unobserved heterogeneity. Although we find that unobserved heterogeneity is an important factor influencing cross-sectional correlations, conditioning on child fixed effects we find a statistically and economically significant relationship between insurance coverage stability and access to care. Children who have part-year public or private insurance are more likely to have at least one doctor's visit than children who are uninsured for a full year, but less likely than children with full-year coverage. We find comparable effects for public and private insurance. Although cross-sectional analyses suggest that transitions directly between public and private insurance are associated with lower rates of utilization, the evidence of such an effect is much weaker when we condition on child fixed effects.

Health insurance and access to care among welfare leavers.

This analysis explores the effects of the 1996 welfare reform on health insurance coverage and access to care among former recipients of cash aid. Using panel data from the Women's Employment Study, which conducted five interviews between 1997 and 2003 in one Michigan county, we find that 25% of welfare leavers lacked health insurance coverage in fall 2003. Uninsured adults were significantly more likely than others to report that they could not afford a medical or dental visit during the year prior to the 2003 interview. Fixed-effect logistic regression analysis indicates that women who had been off the welfare rolls for at least 12 months (the duration of transitional Medicaid) were significantly more likely to be uninsured than women who had made more recent welfare exits, and were significantly more likely to report financial obstacles to the receipt of medical and dental care.

The association between maltreatment and obesity among preschool children.

OBJECTIVE: To determine whether child maltreatment is associated with obesity in preschool children. METHODS: Data were obtained from the Fragile Families and Child Wellbeing Study, a birth cohort study of 4898 children born between 1998 and 2000 in 20 large US cities. At 3 years of age, 2412 of these children had their height and weight measured, and mothers answered items on the Parent-Child Conflict Tactics Scales about three types of child maltreatment--neglect, corporal punishment, and psychological aggression. The frequency of each type of maltreatment behavior in the prior year was analyzed using categories--ever/never for neglect and quintiles for the other two types of maltreatment. Child obesity was defined as measured body mass index (kg/m(2)) > or =95th percentile. RESULTS: Eighteen percent of the children were obese, and the prevalence of any episode of neglect, corporal punishment, and psychological aggression was 11%, 84%, and 93%, respectively. The odds of obesity were increased in children who had experienced neglect (odds ratio 1.56, 95% confidence interval, 1.14-2.14), after controlling for the income and number of children in the household, the mothers' race/ethnicity, education, marital status, body mass index, prenatal smoking, and age, and the children's sex and birth weight. Neither the frequency of corporal punishment nor psychological aggression was associated with an increased risk of obesity. CONCLUSIONS: In a sample of preschool children from 20 large US cities, maternal self-report of neglectful behavior was associated with an increased risk of childhood obesity, after controlling for birth weight, maternal obesity, and multiple socioeconomic factors.

The co-occurrence of smoking and a major depressive episode among mothers 15 months after delivery.

OBJECTIVE: To examine the association between maternal smoking 15 months after delivery and the occurrence of a major depressive episode in the prior 12 months. METHODS: Data were obtained from the Fragile Families and Child Wellbeing Study, a birth cohort study. In 20 U.S. cities, 4898 mothers were surveyed at delivery in the years 1998 to 2000. In a survey 15 months later, 4353 (89%) of the mothers reported their smoking behavior and symptoms of a major depressive episode during the prior 12 months. RESULTS: At the follow-up survey, 26.6% of mothers reported that they were current smokers and 13.6% reported that they had symptoms of a major depressive episode during the prior 12 months. After adjusting for sociodemographic characteristics, the prevalence (95% confidence interval) of a major depressive episode was higher among smokers than nonsmokers: 17.7% (15.7%, 19.8%) vs. 12.1% (10.9%, 13.3%). Smoking was also more common among mothers with a major depressive episode than in those without one: 34.0% (30.6%, 37.4%) vs. 25.5% (24.1%, 26.8%). CONCLUSION: Smoking and depression often co-occur among mothers with infants. This suggests that these conditions should not be diagnosed or treated in isolation from each other and that the care of mothers and children should be integrated.

Food insecurity and the risks of depression and anxiety in mothers and behavior problems in their preschool-aged children.

OBJECTIVES: We sought to determine if the prevalence of depression and anxiety in mothers and the prevalence of behavior problems in preschool-aged children are more common when mothers report being food insecure. METHODS: A cross-sectional survey of 2870 mothers of 3-year-old children was conducted in 2001-2003 in 18 large US cities. On the basis of the adult food-security scale calculated from the US Household Food Security Survey Module, mothers were categorized into 3 levels: fully food secure, marginally food secure, and food insecure. The 12-month prevalence in mothers of a major depressive episode and generalized anxiety disorder was assessed by the Composite International Diagnostic Interview-Short Form. A child behavior problem in > or = 1 of 3 domains (aggressive, anxious/depressed, or inattention/hyperactivity) was based on the Child Behavior Checklist. RESULTS: Seventy-one percent of the respondents were fully food secure, 17% were marginally food secure, and 12% were food insecure. After adjustment for sociodemographic factors plus maternal physical health, alcohol use, drug use, prenatal smoking, and prenatal physical domestic violence, the percentage of mothers with either major depressive episode or generalized anxiety disorder increased with increasing food insecurity: 16.9%, 21.0%, and 30.3% across the 3 levels. Among children, after further adjustment for maternal major depressive episode and generalized anxiety disorder, the percentage with a behavior problem also increased with increasing food insecurity: 22.7%, 31.1%, and 36.7%. CONCLUSIONS: Mental health problems in mothers and children are more common when mothers are food insecure, a stressor that can potentially be addressed by social policy.

Obesity among US urban preschool children: relationships to race, ethnicity, and socioeconomic status.

OBJECTIVES: To determine whether there are racial/ethnic differences in the prevalence of obesity among preschool children and to determine whether these differences are explained by socioeconomic factors. DESIGN: Cross-sectional assessment. SETTING: Twenty large US cities, from 2001 to 2003. PARTICIPANTS: Of the 4898 children enrolled at birth in the Fragile Families and Child Well-being Study, we analyzed data for the 2452 who, at the age of 3 years, had their height and weight measured during a maternal survey. MAIN EXPOSURES: Three socioeconomic indicators were the main exposures-maternal education, household income, and children's food security status, as assessed by the US Household Food Security Survey Module. MAIN OUTCOME MEASURE: Obesity, defined as a body mass index at the 95th percentile or higher for age and sex. RESULTS: Of the mothers, 41.0% had education beyond high school, 52.9% of households had an income above the federal poverty threshold, and 79.5% of the children were food secure. The prevalence of obesity was 25.8% among Hispanics (any race), 16.2% among blacks, and 14.8% among whites. Compared with whites, the odds of obesity were significantly higher in Hispanics (odds ratio, 2.00; 95% confidence interval, 1.46-2.73), but not in blacks (odds ratio, 1.10; 95% confidence interval, 0.82-1.48). Neither of these odds ratios changed meaningfully after adjusting for all 3 socioeconomic indicators (Hispanics: odds ratio, 1.86 [95% confidence interval, 1.33-2.60]; and blacks: odds ratio, 1.07 [95% confidence interval, 0.78-1.47]). CONCLUSION: In a sample of preschool children drawn from 20 large US cities, the high prevalence of obesity among Hispanics relative to blacks or whites was not explained by racial/ethnic differences in maternal education, household income, or food security.

Maternal mental health, substance use, and domestic violence in the year after delivery and subsequent behavior problems in children at age 3 years.

CONTEXT: Mental health disorders, substance use, and domestic violence often occur together. However, studies examining the impact of these conditions in mothers on the well-being of their children have focused only on isolated conditions. OBJECTIVE: To examine the cumulative effect of maternal mental health disorders, substance use, and domestic violence on the risk of behavior problems in young children. DESIGN: A birth cohort (1998-2000) followed up to age 3 years. SETTING: Eighteen large US cities. PARTICIPANTS: At 3 years, 2756 (65%) were followed up from the population-based birth cohort of 4242. Thirty-six percent had annual incomes below the poverty threshold. MAIN OUTCOME MEASURES: One year after delivery, mothers were asked questions about conditions in 3 categories: (1) mental health (major depressive episode and generalized anxiety disorder), (2) substance use (smoking, binge drinking, and illicit drug use), and (3) domestic violence (emotional and physical). At 3 years, mothers completed questions from the Child Behavior Checklist. RESULTS: Fifty percent of mothers had a condition in at least 1 of the 3 categories. The prevalence of child behavior problems increased with the number of categories (0, 1, 2, or 3) in which the mother reported a condition: respectively, 7%, 12%, 17%, and 19% for aggression (P<.001); 9%, 14%, 16%, and 27% for anxious/depressed (P<.001); and 7%, 12%, 15%, and 19% for inattention/hyperactivity (P<.001). This graded risk persisted after adjustment for sociodemographic and prenatal factors and for paternal mental health and substance use. CONCLUSIONS: The risk of child behavior problems increased with the number of areas--mental health, substance use, or domestic violence--in which the mother reported difficulties. Preventing behavior problems in young children requires family-oriented strategies that address the needs of both parents and their children.

Chronic illness, treatment choice and workforce participation.

Choices with respect to labor force participation and medical treatment are increasingly intertwined. Technological advances present patients with new choices and may facilitate continued employment for the growing number of chronically ill individuals. We examine joint work/treatment decisions of end stage renal disease patients, a group for whom these tradeoffs are particularly salient. Using a simultaneous equations probit model, we find that treatment choice is a significant predictor of employment status. However, the effect size is considerably smaller than in models that do not consider the joint nature of these choices.

Design and analysis of unit cost estimation studies: How many hospital diagnoses? How many countries?

We evaluated three questions that commonly arise when unit costing exercises for multinational trials are conducted: (1). In countries where investigators plan to collect hospital unit cost estimates for a selected set of diagnoses, how should one estimate unit costs for the remaining diagnoses observed in the trial for which cost data were not collected? (2). For how many hospital diagnoses should estimates be obtained? (3). For how many countries should they be obtained? We addressed these questions using unit cost data collected in four western European countries and three relative value measures from the US Medicare diagnosis-related group (DRG) payment system. We found that the arithmetic mean length of stay from the US DRG payment system was a good predictor of unit costs in four countries in Europe. We also found that the imputation error decreased as the number of hospital diagnoses and countries sampled increased, but that the rate of reduction in error shrank. Finally, we found that - given the existence of a reliable method for cost imputation - from a pure information standpoint, it is better to obtain estimates for fewer hospital diagnoses from more countries than the reverse.

Economic evaluation of the randomized aldactone evaluation study (RALES): treatment of patients with severe heart failure.

PURPOSE: To use data from the Randomized Aldactone Evaluation Study (RALES) to compare clinical outcomes and costs as part of the assessment of the economic implications of spironolactone treatment of advanced heart failure. METHODS: RALES was a randomized, double-blinded, placebo-controlled trial that enrolled participants who had severe heart failure and a left ventricular ejection fraction of no more than 35% and who were receiving standard therapy, including an angiotensin-converting enzyme inhibitor, a loop diuretic, and, in some cases, digoxin. We used a decision analytic model that incorporated data from participants in RALES as well as cost data from five countries that participated in the study. Costs were calculated for nonfatal hospitalizations, ambulatory care, spironolactone therapy, and death. The primary health outcome was quality-adjusted life-years saved (QALYS). Outcomes were evaluated for the first 35 months of observation in RALES. RESULTS: Spironolactone therapy during the first 35 months of follow-up in RALES increased quality-adjusted survival time (0.13 QALYS, 95% CI, 0.07 to 0.18) without increasing costs ($713 savings, 95% CI, $2,123 savings to $783 in costs). Spironolactone therapy either dominated placebo or had a ratio of cost per QALYS that was unlikely to exceed $20,300. These results were robust in both one-way and multiway sensitivity analyses. CONCLUSIONS: Even after implementation of current clinical guidelines, addition of spironolactone therapy provides an opportunity to further reduce the large clinical and economic burden of patients with heart failure.

Predictors of loss of residual renal function among new dialysis patients.

Residual renal function (RRF) in end-stage renal disease is clinically important as it contributes to adequacy of dialysis, quality of life, and mortality. This study was conducted to determine the predictors of RRF loss in a national random sample of patients initiating hemodialysis and peritoneal dialysis. The study controlled for baseline variables and included major predictors. The end point was loss of RRF, defined as a urine volume <200 ml/24 h at approximately 1 yr of follow-up. The adjusted odds ratios (AOR) and P values associated with each of the demographic, clinical, laboratory, and treatment parameters were estimated using an "adjusted" univariate analysis. Significant variables (P < 0.05) were included in a multivariate logistic regression model. Predictors of RRF loss were female gender (AOR = 1.45; P < 0.001), non-white race (AOR = 1.57; P = <0.001), prior history of diabetes (AOR = 1.82; P = 0.006), prior history of congestive heart failure (AOR = 1.32; P = 0.03), and time to follow-up (AOR = 1.06 per month; P = 0.03). Patients treated with peritoneal dialysis had a 65% lower risk of RRF loss than those on hemodialysis (AOR = 0.35; P < 0.001). Higher serum calcium (AOR = 0.81 per mg/dl; P = 0.05), use of an angiotensin-converting enzyme inhibitor (AOR = 0.68; P < 0.001). and use of a calcium channel blocker (AOR = 0.77; P = 0.01) were independently associated with decreased risk of RRF loss. The observations of demographic groups at risk and potentially modifiable factors and therapies have generated testable hypotheses regarding therapies that may preserve RRF among end-stage renal disease patients.