Background

Incident hemodialysis patients have a high mortality risk within the first months after dialysis initiation. Pre-end-stage renal disease (ESRD) factors like anemia management may impact early post-ESRD outcomes. Therefore, we evaluated the impact of pre-ESRD hemoglobin (Hgb) and pre-ESRD Hgb slope on post-ESRD mortality and hospitalization outcomes.

Methods

The study included 31,472 veterans transitioning to ESRD. Using Cox and negative binomial regression models, we evaluated the association of pre-ESRD Hgb and Hgb slope with 12-month post-ESRD all-cause and cardiovascular mortality and hospitalization rates using 4 levels of hierarchical multivariable adjustment, including erythropoietin use and kidney decline in slope models.

Results

The cohort was 2% female, 30% African-American, and on average 68 ± 11 years old. Compared to Hgb 10-< 11 g/dL, both low (< 10 g/dL) and high (≥12 g/dL) levels were associated with higher all-cause mortality after full adjustment (HR 1.25 [95% CI 1.15-1.35] and 1.09 [95% CI 1.02-1.18], respectively). Similarly, Hgb exhibited a U-shaped association with CV mortality, while only lower Hgb was associated with a higher hospitalization rate. Neither an annual pre-ESRD decline in Hgb nor increase was associated with higher post-ESRD mortality risk after adjustment for kidney decline. However, we observed a modest J-shaped association between pre-ESRD Hgb slope and post-ESRD hospitalization rate.

Conclusions

Lower and higher pre-ESRD Hgb levels are associated with a higher risk of early post-ESRD mortality, while there was no association between the pre-ESRD slope and mortality. An increase in pre-ESRD Hgb slope was associated with higher risk of post-ESRD hospitalization. Additional studies aimed at anemia management prior to ESRD transition are warranted.

Background

Hyponatremia is one of the most common electrolyte disturbances in advanced chronic kidney disease (CKD) and end-stage kidney disease (ESKD) patients, and has been shown to be associated with higher mortality risk. However, the relationship between hyponatremia during late-stage CKD and the risk of poor outcomes after ESKD transition is unknown.

Methods

We conducted a retrospective cohort study including 32 257 US veterans transitioning to ESKD from 1 October 2007 to 30 March 2015. We evaluated adjusted associations between the 3-month averaged pre-transition to ESKD serum sodium and all-cause mortality. Secondary outcomes included cardiovascular (CV) mortality, infection-related mortalities and hospitalization rate.

Results

Cohort mean ± standard deviation serum sodium was 139 ± 3 mEq/L, mean age was 67 ± 11 years, 98% were male and 28% were African American. Over a median (interquartile range) follow-up of 702 days (296, 1301) there were 17 162 deaths. Compared with the reference of 135 to <144 mEq/L, the lowest serum sodium group (<130 mEq/L) had a 54% higher all-cause mortality risk [hazard ratio 1.54 (95% confidence interval 1.34-1.76)] in the fully adjusted model. Associations were similar for CV and infection-related mortality, and hospitalization outcomes.

Conclusions

Hyponatremia prior to ESKD transition is associated with higher risk of all-cause, CV and infection-related mortalities, and hospitalization rates after ESKD transition. Future studies evaluating management of pre-ESKD hyponatremia may be indicated to improve patient outcomes for those transitioning to ESKD.