Thomas J. Arneson

Propensity-Matched Mortality Comparison of Incident Hemodialysis and Peritoneal Dialysis Patients

Contemporary comparisons of mortality in matched hemodialysis and peritoneal dialysis patients are lacking. We aimed to compare survival of incident hemodialysis and peritoneal dialysis patients by intention-to-treat analysis in a matched-pair cohort and in subsets defined by age, cardiovascular disease, and diabetes. We matched 6337 patient pairs from a retrospective cohort of 98,875 adults who initiated dialysis in 2003 in the United States. In the primary intention-to-treat analysis of survival from day 0, cumulative survival was higher for peritoneal dialysis patients than for hemodialysis patients (hazard ratio 0.92; 95% CI 0.86 to 1.00, P = 0.04). Cumulative survival probabilities for peritoneal dialysis versus hemodialysis were 85.8% versus 80.7% (P < 0.01), 71.1% versus 68.0% (P < 0.01), 58.1% versus 56.7% (P = 0.25), and 48.4% versus 47.3% (P = 0.50) at 12, 24, 36, and 48 months, respectively. Peritoneal dialysis was associated with improved survival compared with hemodialysis among subgroups with age <65 years, no cardiovascular disease, and no diabetes. In a sensitivity analysis of survival from 90 days after initiation, we did not detect a difference in survival between modalities overall (hazard ratio 1.05; 95% CI 0.96 to 1.16), but hemodialysis was associated with improved survival among subgroups with cardiovascular disease and diabetes. In conclusion, despite hazard ratio heterogeneity across patient subgroups and nonconstant hazard ratios during the follow-up period, the overall intention-to-treat mortality risk after dialysis initiation was 8% lower for peritoneal dialysis than for matched hemodialysis patients. These data suggest that increased use of peritoneal dialysis may benefit incident ESRD patients.

Survival in Daily Home Hemodialysis and Matched Thrice-Weekly In-Center Hemodialysis Patients

Frequent hemodialysis improves cardiovascular surrogates and quality-of-life indicators, but its effect on survival remains unclear. We used a matched-cohort design to assess relative mortality in daily home hemodialysis and thrice-weekly in-center hemodialysis patients between 2005 and 2008. We matched 1873 home hemodialysis patients with 9365 in-center patients (i.e., 1:5 ratio) selected from the prevalent population in the US Renal Data System database. Matching variables included first date of follow-up, demographic characteristics, and measures of disease severity. The cumulative incidence of death was 19.2% and 21.7% in the home hemodialysis and in-center patients, respectively. In the intention-to-treat analysis, home hemodialysis associated with a 13% lower risk for all-cause mortality than in-center hemodialysis (hazard ratio [HR], 0.87; 95% confidence interval [95% CI], 0.78-0.97). Cause-specific mortality HRs were 0.92 (95% CI, 0.78-1.09) for cardiovascular disease, 1.13 (95% CI, 0.84-1.53) for infection, 0.63 (95% CI, 0.41-0.95) for cachexia/dialysis withdrawal, 1.06 (95% CI, 0.81-1.37) for other specified cause, and 0.59 (95% CI, 0.44-0.79) for unknown cause. Findings were similar using as-treated analyses. We did not detect statistically significant evidence of heterogeneity of treatment effects in subgroup analyses. In summary, these data suggest that relative to thrice-weekly in-center hemodialysis, daily home hemodialysis associates with modest improvements in survival. Continued surveillance should strengthen inference about causes of mortality and determine whether treatment effects are homogeneous throughout the dialysis population.

Estimated number of prevalent cases of metastatic bone disease in the US adult population.

Background The prevalence of metastatic bone disease in the US population is not well understood. We sought to estimate the current number of US adults with metastatic bone disease using two large administrative data sets. Methods Prevalence was estimated from a commercially insured cohort (ages 18–64 years, MarketScan database) and from a fee-for-service Medicare cohort (ages ≥65 years, Medicare 5% database) with coverage on December 31, 2008, representing approximately two-thirds of the US population in each age group. We searched for claims-based evidence of metastatic bone disease from January 1, 2004, using a combination of relevant diagnosis and treatment codes. The number of cases in the US adult population was extrapolated from age- and sex-specific prevalence estimated in these cohorts. Results are presented for all cancers combined and separately for primary breast, prostate, and lung cancer. Results In the commercially insured cohort (mean age = 42.3 years [SD = 13.1]), we identified 9505 patients (0.052%) with metastatic bone disease. Breast cancer was the most common primary tumor type (n = 4041). In the Medicare cohort (mean age = 75.6 years [SD = 7.8]), we identified 6427 (0.495%) patients with metastatic bone disease. Breast (n = 1798) and prostate (n = 1862) cancers were the most common primary tumor types. We estimate that 279,679 (95% confidence interval: 274,579–284,780) US adults alive on December 31, 2008, had evidence of metastatic bone disease in the previous 5 years. Breast, prostate, and lung cancers accounted for 68% of these cases. Conclusion Our findings suggest that approximately 280,000 US adults were living with metastatic bone disease on December 31, 2008. This likely underestimates the true frequency; not all cases of metastatic bone disease are diagnosed, and some diagnosed cases might lack documentation in claims data.

Who Should Be Targeted for CKD Screening? Impact of Diabetes, Hypertension, and Cardiovascular Disease

To address the highly complex interrelated nature of chronic kidney disease (CKD) and diabetes, hypertension, and cardiovascular disease, we examined CKD prevalence by the predictive effect of demographic factors, comorbid conditions, and CKD risk factors by using National Health and Nutrition Examination Survey (NHANES) 1999-2004 data. NHANES is a nationally representative cross-sectional series of surveys with a complex stratified multistage sampling design. NHANES 1999-2004 participants (n = 15,332; age > or = 20 years) were interviewed in their homes and asked to participate in standardized medical examinations in mobile centers and provide samples for laboratory tests. Weighted logistic regression modeling was used to assess the importance of individual CKD risk factors. Multiple logistic regressions were performed on patient cohorts, with increasing levels of CKD severity defined by means of estimated glomerular filtration rate. A branching diagram was constructed to address the distribution of CKD grouped by diabetes, hypertension, and cardiovascular disease status. CKD prevalence increases with age (39.2% for age > or = 60 years). For ages 20 to 59 years, CKD prevalence was greater for participants with diabetes (33.8%) than for those without diabetes (8.2%) and for participants with both diabetes and hypertension (43%) than for diabetic participants without hypertension (25.5%) or nondiabetic participants with hypertension (15.2%). The prevalence was 6.8% for nondiabetic participants without hypertension. Effects of cardiovascular disease are less dramatic when hypertension and diabetes are considered. A CKD screening approach targeting individuals 60 years and older or those with diabetes or hypertension likely would be useful from a public health standpoint.

Hospital Treatment for Fluid Overload in the Medicare Hemodialysis Population

BACKGROUND AND OBJECTIVES Fluid overload in hemodialysis patients sometimes requires emergent dialysis, but the magnitude of this care has not been characterized. This study aimed to estimate the magnitude of fluid overload treatment episodes for the Medicare hemodialysis population in hospital settings, including emergency departments. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Point-prevalent hemodialysis patients were identified from the Centers for Medicare and Medicaid Renal Management Information System and Standard Analytical Files. Fluid overload treatment episodes were defined by claims for care in inpatient, hospital observation, or emergency department settings with primary discharge diagnoses of fluid overload, heart failure, or pulmonary edema, and dialysis performed on the day of or after admission. Exclusion criteria included stays >5 days. Cost was defined as total Medicare allowable costs for identified episodes. Associations between patient characteristics and episode occurrence and cost were analyzed. RESULTS For 25,291 patients (14.3%), 41,699 care episodes occurred over a mean follow-up time of 2 years: 86% inpatient, 9% emergency department, and 5% hospital observation. Heart failure was the primary diagnosis in 83% of episodes, fluid overload in 11%, and pulmonary edema in 6%. Characteristics associated with more frequent events included age <45 years, female sex, African-American race, causes of ESRD other than diabetes, dialysis duration of 1 to 3 years, fewer dialysis sessions per week at baseline, hospitalizations during baseline, and most comorbid conditions. Average cost was

Trends in Hip Fracture Rates in US Hemodialysis Patients, 1993-2010

6,372 per episode; total costs were approximately

The association of pneumococcal vaccination with hospitalization and mortality in hemodialysis patients

266 million. CONCLUSIONS Among U.S. hemodialysis patients, fluid overload treatment is common and expensive. Further study is necessary to identify prevention opportunities.

Effects of Monthly Dose and Regular Dosing of Intravenous Active Vitamin D Use on Mortality Among Patients Undergoing Hemodialysis

BACKGROUND Changes in mineral and bone disorder treatment patterns and demographic changes in the dialysis population may have influenced hip fracture rates in US dialysis patients in 1993-2010. STUDY DESIGN Retrospective follow-up study analyzing trends over time in hospitalized hip fracture rates. SETTING & PARTICIPANTS Using Medicare data, we created 2 point-prevalent study cohorts for each study year. Hemodialysis cohorts included patients with Medicare as primary payer receiving hemodialysis in the United States on January 1 of each year; non-end-stage renal disease (ESRD) cohorts included Medicare beneficiaries 66 years or older on January 1 of each year. FACTORS Age, sex, race, primary cause of ESRD, dual Medicare/Medicaid enrollment status, comorbid conditions. OUTCOMES Hip fracture rates. MEASUREMENTS Unadjusted hip fracture rates measured using number of events per 1,000 person-years in each year, then adjusted for patient characteristics. Poisson models estimated strata-specific event rates. RESULTS The observed number of first hospitalized hip fracture events and the adjusted hip fracture rate increased steadily from 1993 (831 events; 11.9/1,000 person-years), peaked in 2004 (3,256 events; 21.9/1,000 person-years), and decreased through 2010 (2,912 events; 16.6/1,000 person-years). The trend for the subset of hemodialysis patients 66 years or older was similar to the trend for the full hemodialysis cohort; however, it differed markedly in magnitude and pattern from the non-ESRD Medicare cohort, for which rates were substantially lower and slowly decreasing since 1996. LIMITATIONS Unable to provide causal explanations for observed changes; hip fractures identified through inpatient episodes; results do not describe hemodialysis patients without Medicare Parts A and B; laboratory values unavailable in the Medicare data set. CONCLUSIONS Temporal trends in hip fracture rates among Medicare hemodialysis patients differ markedly from the steadily decreasing trend in non-ESRD Medicare beneficiaries, showing a relatively rapid increase until 2004 and relatively rapid decrease thereafter. Further research is needed to define associated factors.

Trends in Patient Characteristics and First-Year Medical Costs of Older Incident Hemodialysis Patients, 1995-2005

BACKGROUND Few studies have examined the effectiveness of pneumococcal vaccination (alone or with influenza vaccination) in improving hemodialysis patient outcomes. We aimed to describe vaccination rates between 2003-2005 and to study the effects on outcomes. METHODS For 118,533 prevalent patients who initiated hemodialysis ≥90 days before 1 November 2003, had Medicare Part A and Part B and were aged ≥18 years, and alive through 31 October 2005, Cox proportional hazards models were used to assess pneumococcal vaccination effects on subsequent hospitalization and mortality, adjusting for demographics and comorbidity. RESULTS The 21% of patients who received vaccinations were older; a higher proportion were white, with diabetes as cause of end-stage renal disease and more comorbidity. Pneumococcal vaccination was associated with a statistically significant decreased mortality hazard [hazard ratio (HR) 0.94, 95% confidence interval (CI) 0.90-0.98], cardiac death (HR 0.91, 95% CI 0.85-0.97) and hospitalization for bacteremia/viremia/septicemia (HR 0.95, 95% CI 0.91-1.00). The mortality hazard was 0.73 (95% CI 0.68-0.78) for patients who received pneumococcal and influenza vaccinations. CONCLUSIONS The small but significant association between pneumococcal vaccination and lower mortality risk was seen despite factors associated with poor outcomes in patients most likely to be vaccinated. Pneumococcal and influenza vaccines may have beneficial synergistic effects. Hemodialysis patients may benefit from revaccination more frequently than the recommended 5-year intervals.

Comparison of methodologies to characterize haemoglobin variability in the US Medicare haemodialysis population

Study Objectives. To determine if apparent protective mortality benefits of intravenous active vitamin D in patients undergoing hemodialysis extend across all groups defined by dialysis duration; if higher monthly dose and dosing regularity are associated with reduced mortality; and if intravenous active vitamin D use is associated with reduced cardiovascular, infectious, and cancer‐related mortality.