Independent and joint associations of nutritional status indicators with mortality risk among chronic hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS).

OBJECTIVE: To consider the Kidney Disease Outcomes Quality Initiative recommendation of using multiple nutritional measurements for patients on maintenance dialysis, we explored data for independent and joint associations of nutritional indicators with mortality risk among maintenance hemodialysis patients treated in 12 countries. SETTING: Dialysis units in seven European countries, the United States, Canada, Australia, New Zealand, and Japan. MAIN OUTCOME: Mortality risk. METHODS: We conducted a prospective cohort study of 40,950 patients from phases I to III of the Dialysis Outcomes and Practice Patterns Study (1996-2008). Independent and joint effects (interactions) of nutritional indicators (serum creatinine, serum albumin, normalized protein catabolic rate, body mass index [BMI]) on mortality risk were assessed by Cox regression with adjustments for demographics, years on dialysis, and comorbidities. RESULTS: Important variations in nutritional indicators were seen by country and patient characteristics. Poorer nutritional status assessed by each indicator was independently associated with higher mortality risk across regions. Significant multiplicative interactions (each p < or = 0.01) between indicators were also observed. For example, by using patients with serum creatinine 7.5-10.5 mg/dL and BMI 21-25 kg/m(2) as referent, BMI <21 kg/m(2) was associated with lower mortality risk among patients with creatinine >10.5 mg/dL (relative risk = 0.68) but with higher mortality risk among those with creatinine <7.5 mg/dL (relative risk = 1.38). The association of lower albumin concentration with higher mortality risk was stronger for patients with lower BMI or lower creatinine. CONCLUSION: The joint effects of nutritional indicators on mortality indicate the need to use multiple measurements when assessing the nutritional status of hemodialysis patients.

Factors associated with health-related quality of life among hemodialysis patients in the DOPPS.

OBJECTIVE: To identify modifiable factors associated with health-related quality of life (HRQOL) among chronic hemodialysis patients. METHODS: Analysis of baseline data of 9,526 hemodialysis patients from seven countries enrolled in phase I of the Dialysis Outcomes and Practice Patterns Study (DOPPS). Using the Kidney Disease Quality of Life Short Form (KDQOL-SF(TM)), we determined scores for 8 generic scale summaries derived from these scales, i.e., the physical component summary [PCS] and mental component summary [MCS], and 11 kidney disease- targeted scales. Regression models were used to adjust for differences in comorbidities and sociodemographic and treatment factors. The Benjamini-Hochberg procedure was used to correct P-values for multiple comparisons. RESULTS: Unemployment and psychiatric disease were independently and significantly associated with lower scores for all generic and several kidney disease-targeted HRQOL measures. Several other comorbidities, lower educational level, lower income, and hypoalbuminemia were also independently and significantly associated with lower scores of PCS and/or MCS and several generic and kidney disease-targeted scales. Hemodialysis by catheter was associated with significantly lower PCS scores, partially explained by the correlation with covariates. CONCLUSION: Associations of poorer HRQOL with preventable or controllable factors support a greater focus on psychosocial and medical interventions to improve the well-being of hemodialysis patients.

Health-related quality of life and associated outcomes among hemodialysis patients of different ethnicities in the United States: the Dialysis Outcomes and Practice Patterns Study (DOPPS).

BACKGROUND: In the United States, an association between mortality risk and ethnicity has been observed among hemodialysis patients. This study was developed to assess whether health-related quality of life (HRQOL) scores also vary among patients of different ethnic backgrounds. Associations between HRQOL and adverse dialysis outcomes (ie, death and hospitalization) also were assessed for all patients and by ethnicity. METHODS: Data are from the Dialysis Outcomes and Practice Patterns Study for 6,151 hemodialysis patients treated in 148 US dialysis facilities who filled out the Kidney Disease Quality of Life Short Form. We determined scores for three components of HRQOL: Physical Component Summary (PCS), Mental Component Summary (MCS), and Kidney Disease Component Summary (KDCS). Patients were classified by ethnicity as Hispanic and five non-Hispanic categories: white, African American, Asian, Native American, and other. Multiple linear regression models were used to estimate differences in HRQOL scores among ethnic groups, using whites as the referent category. Cox regression models were used for associations between HRQOL and outcomes. Regression models were adjusted for sociodemographic variables, delivered dialysis dose (equilibrated Kt/V), body mass index, years on dialysis therapy, and several laboratory/comorbidity variables. RESULTS: Compared with whites, African Americans showed higher HRQOL scores for all three components (MCS, PCS, and KDCS). Asians had higher adjusted PCS scores than whites, but did not differ for MCS or KDCS scores. Compared with whites, Hispanic patients had significantly higher PCS scores and lower MCS and KDCS scores. Native Americans showed significantly lower adjusted MCS scores than whites. The three major components of HRQOL were significantly associated with death and hospitalization for the entire pooled population, independent of ethnicity. CONCLUSION: The data indicate important differences in HRQOL among patients of different ethnic groups in the United States. Furthermore, HRQOL scores predict death and hospitalization among these patients.

Depression as a predictor of mortality and hospitalization among hemodialysis patients in the United States and Europe.

BACKGROUND: Depression is not uncommon among patients with end-stage renal disease (ESRD) being treated by hemodialysis. We investigated whether risk of mortality and rate of hospitalization may be predicted from physician-diagnosed depression and patients' self-reports of depressive symptoms. METHODS: Data were analyzed from the Dialysis Outcomes and Practice Patterns Study (DOPPS) for randomly selected ESRD patients being treated by hemodialysis in the United States (142 facilities, 2855 patients) and five European countries (101 facilities, 2401 patients). The diagnosis of depression during the past year was abstracted from the medical records. In addition, the patients were asked to indicate how much of their time over the previous four weeks they had felt (1) "so down in the dumps that nothing could cheer you up" and (2) "downhearted and blue." A response of "a good bit,""most," or "all" of the time were classified as depressed. RESULTS: The prevalence of depression was nearly 20%. The relative risks of mortality and hospitalization among depressed (vs. non-depressed), adjusted for time on dialysis, age, race, socioeconomic status, comorbid indicators and country were, respectively: 1.23 and 1.11 for physician-diagnosed depression, 1.48 and 1.15 for the "so down in the dumps" question, and 1.35 and 1.11 for the "downhearted and blue" question (P < 0.05 for all six relative risks). These associations were not significantly different between US and European patients. CONCLUSIONS: Self-reported depression by two simple questions was associated with increased risks of mortality and hospitalization for hemodialysis patients. Future research needs to assess whether early identification and treatment of depression may help to improve quality of life and survival in hemodialysis patients.