Dietary Potassium Intake and Mortality in a Prospective Hemodialysis Cohort.

OBJECTIVES: Among hemodialysis patients, clinical practice guidelines recommend dietary potassium restriction given concerns about potential hyperkalemia leading to malignant arrhythmias and mortality. However, there are sparse data informing recommendations for dietary potassium intake in this population. We thus sought to examine the relationship between dietary potassium intake and death risk in a prospective cohort of hemodialysis patients. DESIGN AND METHODS: Among 415 hemodialysis patients from the prospective "Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease" cohort recruited across 16 outpatient dialysis clinics, information regarding dietary potassium intake was obtained using Food Frequency Questionnaires administered over October 2011 to March 2015. We first examined associations of baseline dietary potassium intake categorized as tertiles with mortality risk using Cox regression. We then examined clinical characteristics associated with low dietary potassium intake (defined as the lowest tertile) using logistic regression. RESULTS: In expanded case-mix Cox analyses, patients whose dietary potassium intake was in the lowest tertile had higher mortality (ref: highest tertile) (adjusted hazard ratio 1.74, 95% confidence interval 1.14-2.66). These associations had even greater magnitude of risk following adjustment for laboratory and nutritional covariates (adjusted hazard ratio 2.65, 95% confidence interval 1.40-5.04). In expanded case-mix restricted cubic spline analyses, there was a monotonic increase in mortality risk with incrementally lower dietary potassium intake. In expanded case-mix logistic regression models, female sex; higher serum bicarbonate; and lower dietary energy, protein, and fiber intake were associated with low dietary potassium intake. CONCLUSIONS: In a prospective cohort of hemodialysis patients, lower dietary potassium intake was associated with higher mortality risk. These findings suggest that excessive dietary potassium restriction may be deleterious in hemodialysis patients, and further studies are needed to determine the optimal dietary potassium intake in this population.

Dialysis symptom index burden and symptom clusters in a prospective cohort of dialysis patients.

BACKGROUND: Dialysis patients experience a high symptom burden, which may adversely impact their quality of life. Whereas other specialties emphasize routine symptom assessment, symptom burden is not well-characterized in dialysis patients. We sought to examine the prevalence and severity of unpleasant symptoms in a prospective hemodialysis cohort. METHODS: Among 122 hemodialysis patients from the prospective Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease (CKD) study, CKD-associated symptoms were ascertained by the Dialysis Symptom Index, a validated survey assessing symptom burden/severity (with higher scores indicating greater symptom severity), over 6/2020-10/2020. We examined the presence of (1) individual symptoms and symptom severity scores, and (2) symptom clusters (defined as ≥ 2 related concurrent symptoms), as well as correlations with clinical characteristics. RESULTS: Symptom severity scores were higher among non-Hispanic White and Hispanic patients, whereas scores were lower in Black and Asian/Pacific Islander patients. In the overall cohort, the most common individual symptoms included feeling tired/lack of energy (71.3%), dry skin (61.5%), trouble falling asleep (44.3%), muscle cramps (42.6%), and itching (42.6%), with similar patterns observed across racial/ethnic groups. The most prevalent symptom clusters included feeling tired/lack of energy + trouble falling asleep (37.7%); trouble falling asleep + trouble staying asleep (34.4%); and feeling tired/lack of energy + trouble staying asleep (32.0%). Lower hemoglobin, iron stores, and dialysis adequacy correlated with higher individual and overall symptom severity scores. CONCLUSION: We observed a high prevalence of unpleasant symptoms and symptom clusters in a diverse hemodialysis cohort. Further studies are needed to identify targeted therapies that ameliorate symptom burden in CKD.

The Impact of Race and Ethnicity Upon Health-Related Quality of Life and Mortality in Dialysis Patients.

RATIONALE & OBJECTIVE: Health-related quality of life (HRQoL) has been recognized as a strong predictor of mortality among hemodialysis patients. However, differences in the association of HRQoL with survival across diverse racial/ethnic groups have not been well studied in this population. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: We examined the relationship between HRQoL and mortality in a prospective cohort of racially/ethnically diverse hemodialysis patients recruited from 18 outpatient dialysis units during 2011 to 2016. EXPOSURE: Using the 36-Item Short Form Health Survey (SF-36) administered every 6 months, HRQoL was ascertained by 36 questions summarized as 2 Physical and Mental Component and 8 subscale scores. OUTCOME: All-cause mortality. ANALYTICAL APPROACH: Associations of time-varying SF-36 scores with mortality were estimated using Cox models in the overall cohort and within racial/ethnic subgroups. RESULTS: Among 753 hemodialysis patients who met eligibility criteria, expanded case-mix analyses showed that the lowest quartiles of time-varying Physical and Mental Component scores were associated with higher mortality in the overall cohort (reference: highest quartile): adjusted HRs, 2.30 (95% CI, 1.53-3.47) and 1.54 (95% CI, 1.05-2.25), respectively. In analyses stratified by race/ethnicity, the lowest quartile of Physical Component scores was significantly associated with higher mortality across all groups: adjusted HRs, 2.64 (95% CI, 1.31-5.29), 1.84 (95% CI, 1.01-3.38), and 3.18 (95% CI, 1.13-8.91) for Hispanic, African American, and other race/ethnicity patients, respectively. The lowest quartile of time-varying physical functioning, role limitations due to physical health, role limitations due to emotional problems, social functioning, and pain subscale scores were associated with higher mortality in the overall cohort and particularly in Hispanics and blacks. LIMITATIONS: Residual confounding cannot be excluded. CONCLUSIONS: Lower SF-36 Physical Component and subscale scores were associated with higher mortality in hemodialysis patients, including those of minority background. Further studies are needed to determine whether interventions that augment physical health might improve the survival of these diverse populations.