Influence of Body Mass Index on the Association of Weight Changes with Mortality in Hemodialysis Patients

Abstract

SummaryBackground and Objectives A high body mass index (BMI) is associated with lower mortality in patients undergoing hemodialysis. Short-term weight gains and losses are also related to lower and higher mortality risk, respectively. The implications of weight gain or loss may, however, differ between obese individuals and their nonobese counterparts. Results Among 6296 patients with complete data, 1643 died. At study entry, 42% of patients had a normal weight (BMI, 20-25 kg/m 2 ), 11% were underweight, 31% were overweight, and 16% were obese (BMI $30 kg/m 2 ). Weight loss or gain (,1% or .1% of body weight) was strongly associated with higher rates of mortality or survival, respectively. After stratification by BMI categories, this was true in nonobese categories and especially in underweight patients. In obese patients, however, the association between weight loss and mortality was attenuated (hazard ratio, 1.28 [95% confidence interval (CI), 0.74 to 2.14]), and no survival benefit of gaining weight was seen (hazard ratio, 0.98 [95% CI, 0.59 to 1.62]).Conclusions Assuming that these weight changes were unintentional, our study brings attention to rapid weight variations as a clinical sign of health monitoring in hemodialysis patients. In addition, a patient's BMI modifies the strength of the association between weight changes with mortality.

Association of Body Weight Changes With Mortality in Incident Hemodialysis Patients

“…A few prior studies have examined the association of weight change over time on dialysis with mortality outcomes, but have focused solely on the first few months after dialysis initiation [19][20][21][22][23]. Kalantar-Zadeh et al [19] explored the impact of changes in weight by examining the regression slope of changes in weight over time on all-cause and cardiovascular mortality in Table 3.…”

“…However, most literature on obesity in ESRD has examined the association of baseline BMI levels ascertained at a single point in time with future outcomes, which offer limited insight into how changes in weight over time impact outcomes in dialysis patients. Recent large observational studies on changes in weight over time on dialysis have also indicated that weight gain, mostly in the first 6 months after starting dialysis, is associated with better survival, whereas weight loss harbors a higher death risk [19][20][21][22][23]. Trends in weight change after starting dialysis have not yet been characterized in these studies.…”

Body Composition and Its Clinical Outcome in Maintenance Hemodialysis Patients

“…However, one of the limitations is that potential reasons of weight change could not be identified due to its observational nature, making confounded by intercurrent health status likely as more spontaneous weight loss among sicker patients. The Current Management of Secondary Hyperparathyroidism: A Multicenter Observational Study (COSMOS) [28] also evaluated the implication of weight loss and gain among obese patients undergoing hemodialysis and their nonobese counterparts. Assuming that weight changes were unintentional, weight loss (<1% of dry weight at baseline) was significantly associated with increased rate of mortality, whereas weight gain (>1%) was strongly associated with higher survival compared with stable weight (±1%).…”

Retarding Chronic Kidney Disease (CKD) Progression: A Practical Nutritional Approach for Non-Dialysis CKD

“…Unintentional weight loss is a common feature of all nutritional screening tools applied in clinical practice. Also in CKD, unintentional weight losses in a short period of time, even if only a couple of kilograms, is associated with risk of adverse outcomes (40,41).…”