Association of morbid obesity and weight change over time with cardiovascular survival in hemodialysis population.
ABSTRACT In maintenance hemodialysis (MHD) outpatients, a reverse epidemiology is described, ie, baseline obesity appears paradoxically associated with improved survival. However, the association between changes in weight over time and prospective mortality is not known.
Using time-dependent Cox models and adjusting for changes in laboratory values over time, the relation of quarterly-varying 3-month averaged body mass index (BMI) to all-cause and cardiovascular mortality was examined in a 2-year cohort of 54,535 MHD patients from virtually all DaVita dialysis clinics in the United States.
Patients, aged 61.7 +/- 15.5 (SD) years, included 54% men and 45% with diabetes. Time-dependent unadjusted and multivariate-adjusted models, based on quarterly-averaged BMI controlled for case-mix and available time-varying laboratory surrogates of nutritional status, were calculated in 11 categories of BMI. Obesity, including morbid obesity, was associated with better survival and reduced cardiovascular death, even after accounting for changes in BMI and laboratory values over time. Survival advantages of obesity were maintained for dichotomized BMI cutoff values of 25, 30, and 35 kg/m2 across almost all strata of age, race, sex, dialysis dose, protein intake, and serum albumin level. Examining the regression slope of change in weight over time, progressively worsening weight loss was associated with poor survival, whereas weight gain showed a tendency toward decreased cardiovascular death.
Weight gain and both baseline and time-varying obesity may be associated with reduced cardiovascular mortality in MHD patients independent of laboratory surrogates of nutritional status and their changes over time. Morbidly obese patients have the lowest mortality. Clinical trials need to verify these observational findings.
- [show abstract] [hide abstract]
ABSTRACT: An increased level of total plasma homocysteine (tHcy) is a risk factor for poor cardiovascular outcome in the general population. However, a decreased, rather than an increased, tHcy concentration may predict poor outcome in maintenance hemodialysis (MHD) patients, a phenomenon referred to as reverse epidemiology. Associations were examined between tHcy level and markers of malnutrition-inflammation complex syndrome and 12-mo prospective hospitalization and mortality in 367 MHD patients, aged 54.5 +/- 14.7 (mean +/- SD) years, who included 199 men and 55% individuals with diabetes. tHcy was 24.4 +/- 11.8 micro mol/L, and 94% of the patients had hyperhomocysteinemia (tHcy >13.5 micro mol/L). tHcy had weak to moderate but statistically significant bivariate and multivariate correlations with some laboratory markers of nutrition (serum albumin, prealbumin, creatinine, and urea nitrogen) but no significant correlation with serum C-reactive protein or two proinflammatory cytokines (IL-6 and TNF-alpha). During 12 mo of follow-up, 191 MHD patients were hospitalized, 37 died, nine underwent renal transplantation, and 38 transferred out. Hospitalization rates were significantly higher in patients with lower tHcy levels. Mortality rate in the lowest tHcy quartile (17.4%) was significantly higher compared with other three quartiles (6.5 to 9.8%; Kaplan-Meier P = 0.04). Relative risk of death for the lowest tHcy quartile, even after adjustment for case-mix and serum albumin, was 2.27 (95% confidence interval, 1.14 to 4.53; P = 0.02). Hence, tHcy may be a more exclusive nutritional marker in MHD patients with no association with inflammatory measures. Despite a very high prevalence of hyperhomocysteinemia in MHD patients, lower values of tHcy are paradoxically associated with increased hospitalization and mortality. The lowest tHcy quartile confers a twofold increase in risk of death independent of hypoalbuminemia. The nutritional feature of tHcy in MHD patients may explain its reverse association with outcome.Journal of the American Society of Nephrology 02/2004; 15(2):442-53. · 8.99 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: To define relationships among dietary intake and counseling, weight maintenance, and the clinical course of patients infected with the human immunodeficiency virus (HIV). A prospective cohort study in an HIV clinic in a county hospital. HIV-infected patients (68 with and 40 without acquired immunodeficiency syndrome [AIDS]) who had a good performance status and no chronic diarrhea were assessed at entry to the study and after 6 months. The following assessments were made: energy and nutrient intake based on 7-day food records, anthropometric measurements, immunologic function as lymphocyte T-cell subpopulations (ratio of CD4 to CD8), and serum cholesterol level. Patients were monitored to determine clinical outcome. All patients received standardized dietary counseling designed to address identified intake deficiencies and maintain body weight. Changes in energy and nutrient intake, body weight, and clinical outcome (ie, time to AIDS-defining illness and overall survival time). Group differences (HIV group vs AIDS group) were sought using chi 2 analyses and Student's t test. A multivariate regression model was used to determined the best predictors of clinical outcome. At baseline, total energy intake (based on 30 kcal/kg usual body weight) was adequate in both HIV and AIDS patients (101 +/- 4% and 103 +/- 5% [mean +/- standard deviation] of need, respectively). Despite dietary counseling and continued maintenance of energy intake, body weight, serum cholesterol level, and CD4 level progressively decreased. Consequently, saturated fat intake was found to be inversely related (P < .01) to serum cholesterol level. Clinical outcome (after 3.5 years) was associated with baseline ratio of CD4 to CD8 (P < .001), weight (P < .01), and serum cholesterol level (P < .001). Multivariate analysis related ratio of CD4 to CD8 (P < .001) and weight maintenance (P < .001) to favorable outcome in the final model. Weight loss in patients with HIV infection is independently prognostic of clinical outcome, and development of hypocholesterolemia is not favorable for clinical outcome. Because weight loss progresses despite conventional dietary counseling to identify energy need, interventions earlier in the disease course should be considered along with increased target levels for energy intake.Journal of the American Dietetic Association 04/1995; 95(4):428-32; quiz 433-5. · 3.80 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: We examined the value of transferrin concentrations in estimating nutritional status as determined by the subjective global assessment (SGA) score. Fifty-nine hemodialysis patients (37 men and 22 women, aged 59+/-16 years, dialyzed for 3.6+/-3.9 years) were selected by predetermined criteria. All received erythropoietin (EPO) and oral iron therapy. SGA evaluation was conducted twice by both a dietitian and a physician. Serum iron, total iron-binding capacity (TIBC; which is linearly correlated with transferrin), transferrin saturation ratio, ferritin, albumin, total protein, and cholesterol were measured. Twenty-seven (46%) patients were well nourished (group A), 20 (34%) were moderately nourished (group B), and 12 (20%) were poorly nourished (group C) according to the SGA. TIBC values were 276+/-47 mg/dL, 217+/-54 mg/dL, and 176+/-41 mg/dL, respectively (P < 0.00001), and thus directly correlated with the state of nutrition. The relationship between TIBC and nutritional status was independent of age and number of years on hemodialysis. Serum ferritin values were 104+/-93 ng/mL, 161+/-154 ng/mL, and 363+/-305 ng/mL, respectively (P < 0.0003), and thus inversely correlated with the state of nutrition. Transferrin saturation ratios were slightly higher in the severely malnourished patients. The number of years on dialysis were a determinant of nutritional status. These values were 2.4+/-2.4 years for group A, 3.9+/-4.0 years for group B, and 5.7+/-3.9 years for group C (P < 0.05). The average age of the poorly nourished patients was 10 years older than the well-nourished patients. Serum iron values were lower but transferrin saturation ratios were higher in the severely malnourished patients. The required EPO doses were higher in the poorly nourished patients. We suggest that transferrin values are superior to other laboratory tests in assessing nutrition and will supplement SGA criteria. Serum ferritin may be useful as a predictor of illness. Older patients who have been on dialysis longer warrant special concern. Malnutrition may be an indicator of EPO resistance in dialysis patients. Finally, since a decreased TIBC level in poorly nourished patients may erroneously increase the transferrin saturation ratio, our findings may have implications in making the diagnosis and treatment of anemia and iron deficiency in malnourished dialysis patients.American Journal of Kidney Diseases 02/1998; 31(2):263-72. · 5.29 Impact Factor