Associates of Mortality and Hospitalization in Hemodialysis: Potentially Actionable Laboratory Variables and Vascular Access

Background

To determine the most significant potentially actionable clinical variables associated with mortality and hospitalization risk in hemodialysis (HD) patients.

Study Design

Cohort study.

Setting & Participants

Adult maintenance HD patients in the Fresenius Medical Care, North America database as of January 1, 2004, with baseline information from October 1, 2003, to December 31, 2003, comprising approximately 26% of the US HD population.

Predictors

Case-mix (age, sex, race, diabetes, vintage, and body surface area), vascular access, and laboratory (albumin, equilibrated Kt/V, hemoglobin, calcium, phosphorus, creatinine, bicarbonate, biointact parathyroid hormone, transferrin saturation, and white blood cell count) variables.

Outcomes

1-year mortality and hospitalization risk from January 1 to December 31, 2004.

Measurements

Cox proportional hazards models for death and hospitalization.

Results

The cohort (N = 78,420) had a mean age of 61.4 ± 15.0 years, 47% were women, 49% were white, 41% were black race (10% defined as “other”), and 52% had diabetes. The top 5 actionable variables were the same for mortality and hospitalization. Final case-mix plus laboratory–adjusted hazard ratios for these top 5 actionable variables indicate 177% increased risk of death and 67% increased risk of hospitalization per 1-g/dL decrease in albumin level, 39% and 45% greater risk with catheters compared with fistulas, 18% and 9% greater risk per 1-mg/dL greater phosphorus level, 11% and 9% lower risk per 1-g/dL greater hemoglobin level, and 5% and 2% greater risk per 0.1-unit decrease in equilibrated Kt/V, respectively (all P < 0.0001).

Limitations

Observational cross-sectional study with limited comorbidity adjustment (for diabetes).

Conclusion

The same variables are associated with both mortality and hospitalization in HD patients. The top 5 potentially actionable variables are readily identifiable, with albumin level and catheter use the most prominent, and all 5 are appropriate targets for improvement.

Index Words: Dialysis, end-stage renal disease (ESRD), mortality, hospitalization, case-mix, vascular access