Dynamics of hospitalizations in hemodialysis patients: results from a large US provider

In chronic hemodialysis (HD), patients' hospitalizations result in significant costs and affect the quality of life. We aimed at understanding hospitalization rates before death and to identify patterns in clinical and laboratory parameters that precede the first hospitalization.

We conducted two separate analyses in patients treated in the 51 US Renal Research Institute HD facilities. The first analysis involved hospitalizations before death in all HD patients who died between 1 January 2007 and 31 December 2011. In the second analysis, we studied the evolution of laboratory and treatment parameters before hospitalization in all patients with, at least, one hospital admission between 1 January 2007 and 31 December 2011. Patients were followed from up to 6 months prior to their first hospital admission. For comparison, we selected non-hospitalized patients and observed the evolution of their laboratory and treatment parameters.

We studied 6262 patients in total. The first analysis encompassed 2058 deaths. In these patients, hospitalization increased from 0.32 admissions per patient-month 4 months before death to 1.85 in the month of death. In the second analysis, we studied the first hospitalizations in 4204 patients. Irrespective of the cause of hospitalization, all hospitalizations were preceded by an increase in the neutrophil-to-lymphocyte ratio, a decline in hemoglobin and a reduction in effective treatment time and inter-dialytic weight gain. We noted no comparable trends in non-hospitalized patients.

Hospitalization rates increase sharply before death. Months before the first hospitalization changes in clinical and laboratory parameters ensued. These results suggest that models aiming at predicting hospitalization should include indicators capturing the dynamics of relevant parameters.