Non-adherence in patients on chronic hemodialysis: an international comparison study

Abstract

Adherence to diet and fluid restrictions by adults on hemodialysis treatment is challenging. This study compared non-adherence (NA) to diet and fluid restrictions between adult US and German hemodialysis patients, and assessed potential predictors for NA. A cross-sectional multicenter comparative study of 456 adult hemodialysis patients was conducted in 12 outpatient-based hemodialysis centers in the United States and Germany. NA was based on self-report using the Dialysis Diet and Fluid Non-adherence Questionnaire (DDFQ). Laboratory marker, interdialytic weight gain (IDWG) and dialysis adequacy (Kt/V) information were obtained from medical records. Mean time on dialysis was 50 months (range 3-336); mean age was 62 years (range 19-91), with the majority of patients (89.7%) being white. Self-reported frequency of NA to diet was 80.4% and to fluid 75.3% in the total sample. The degree of NA to diet and fluid differed significantly, with the US patients (68.1% vs. 61.1%) reporting less NA when compared with German (81.6% vs. 79.0%) patients (p<0.0001). Phosphorus, albumin, IDWG and Kt/V levels were higher in the US compared with the German subsample (all p<0.0001; IDWG p<0.003). Generalized regression models revealed that education (p<0.01) and smoking (p<0.01) predicted NA to diet, whereas single marital status (p<0.008) and male sex (p<0.04) were independent predictors for NA to fluid. NA persists as one of the most challenging tasks in health care of patients with chronic conditions, including hemodialysis patients. Our findings suggest that patient, condition-related, socioeconomic and health care system-related factors may contribute to NA to diet and fluid restrictions.