C Kugler et al. Non-adherence in patients on chronic hemodialysis: an international comparison study. Jorunal of Nephrology, October 15, 2010.

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.

WHAT THE STUDY MAY MEAN TO YOU AS A HEALTH CARE PROVIDER: 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.

WHAT THE STUDY MAY MEAN TO YOU AS A HEALTH CARE CONSUMER: The factors noted as leading to the change between German and Americans is interesting.
It is likely due to the variables summarized above or to an interaction among these factors.