Adherence to treatment and hospitalization risk in hemodialysis patients

Background: The aim of this study was to evaluate whether adherence to treatment is associated with hospitalization risk in hemodialysis patients. Methods: We completed a cohort analysis of risk factors during 1 census month (November) and 1 year of follow-up during 5 consecutive years (2002-2006) in all end-stage renal disease patients hemodialyzed in the Kaunas region. During the census month, we collected data on noncompliance defined as (i) skipping of a hemodialysis (HD) session, (ii) shortening of 1 or more HD sessions, (iii) presence of hyperkalemia, (iv) presence of hyperphosphatemia, or (v) interdialytic weight gain (IDWG). In addition, data on age, sex, disability status, comorbidities, anemia control, malnutrition and inflammation, calcium-phosphorus metabolism and hospitalization rate were collected. Relative risk of hospitalization was estimated using Cox regression evaluating time to first hospitalization. Results: We analyzed 559 patients for a total of 1,163 patient-years during the 5 years of the study. On multi-variate analysis, adjusting for ischemic heart disease, diabetes mellitus, higher number of comorbid conditions, higher systolic blood pressure before dialysis, worse disability status, lower hemoglobin, albumin and urea before dialysis, the relative risk for hospitalization increased by 1.1 for every additional percentage point of IDWG and by 1.19 with each 1 mmol/L rise of serum phosphorus level. Skipping or shortening of hemodialysis sessions and serum potassium level were not associated with hospitalization. Conclusions: Higher IDWG and higher serum levels of phosphorus independently increased the relative risk of hospitalizations in hemodialysis patients. With skipped and shortened dialysis sessions, higher serum potassium level was not associated with hospitalization risk.