The Comprehensive Dialysis Study (CDS) is a special data collection study in which physical activity, health-related quality of life, and work/disability data were requested from patients identified as initiating maintenance dialysis during 2005 to 2007. The CDS study aimed to understand factors contributing to physical, functional, and nutritional health status among patients starting dialysis. The study was coordinated in part by the United States Renal Data System (USRDS), which maintains an extensive database that facilitates biomedical and economic research on end-stage renal disease (ESRD) in the U.S. population. In a subset of participants, dietary intake and nutritional status were also evaluated. The study represents one of few cohorts in which laboratory proxies of nutrition and inflammatory status were measured simultaneously. The study successfully gathered information and samples from participants and generated baseline characteristics for patients undergoing maintenance dialysis. Information reported by CDS participants was linked with patient-specific modality history, mortality, hospitalization, and cost information in USRDS files.

The primary objective of the CDS study was to better understand interrelations among patients’ general health, nutritional status, physical function and health-related quality of life.

Outcome measures included a patient questionnaire completed by all study participants to collect baseline information. Patients from a pre-identified subset of dialysis units were also asked to provide data for a nutrition sub-study by completing the Block 2000-Brief Food Questionnaire (FQ), and serum samples were requested from dialysis units for these patients. Patients in the sub-study were also asked to complete both the patient and food questionnaire at 12 months after baseline data collection.

Participants were enrolled who met the following inclusion criteria:

• On dialysis for no more than 6 months
• Able to speak English or Spanish
• Able to provide voluntary written informed consent

The CDS contains detailed information on health-related quality of life, self-reported physical activity, and macronutrient intake and represents one of few cohorts in which laboratory proxies of nutrition and inflammatory status were measured simultaneously. Information reported by CDS participants was linked with patient-specific modality history, mortality, hospitalization, and cost information in USRDS files. The CDS therefore provides a unique resource from which to inform the design of interventions addressing several related conditions that affect longevity and health status in ESRD.