Background: Health administrative data are frequently used for health services and population health research. Comparative research using these data has been facilitated by the use of a standard system for coding diagnoses, the International Classification of Diseases (ICD). Research using the data must deal with data quality and validity limitations which arise because the data are not created for research purposes. This paper presents a list of high-priority methodological areas for researchers using health administrative data.

SummaryAdequate pre-dialysis care reduces mortality among end-stage renal disease (ESRD) patients. We tested the hypothesis that individuals with ESRD due to sickle cell disease (SCD-ESRD) receiving pre-ESRD care have lower mortality compared to individuals without pre-ESRD care. We examined the association between mortality and pre-ESRD care in incident SCD-ESRD patients who started haemodialysis between 1 June, 2005 and 31 May, 2009 using data provided by the Centers for Medicare and Medicaid Services (CMS). SCD-ESRD was reported for 410 (0Á1%) of 442 017 patients. One year after starting dialysis, 108 (26Á3%) patients with incident ESRD attributed to SCD died; the hazard ratio (HR) for mortality among patients with SCD-ESRD compared to those without SCD as the primary cause of renal failure was 2Á80 (95% confidence interval [CI] 2Á31-3Á38). Patients with SCD-ESRD receiving pre-dialysis nephrology care had a lower death rate than those with SCD-ESRD who did not receive predialysis nephrology care (HR = 0Á67, 95% CI 0Á45-0Á99). The one-year mortality rate following an ESRD diagnosis was almost three times higher in individuals with SCD when compared to those without SCD but with ESRD and could be attenuated by pre-dialysis nephrology care.