Administration of parenteral iron and mortality among hemodialysis patients.

The objective of this study was to evaluate whether the apparent relationship demonstrated in prior studies between iron dosing and mortality in hemodialysis (HD) patients was confounded by incomplete representation of iron dosing and morbidity over time. A cohort study was conducted among 32,566 patients who received at least 1 yr of HD at the Fresenius Medical Corporation dialysis centers during 1996 to 1997. The outcome measure was all-cause mortality through mid-1998. A total of 19 demographic, comorbidity, and laboratory characteristics were available. By proportional hazards analysis, no adverse effect on 2-year survival was found for baseline iron dose over 6 mo of < or = 1000 mg, but statistically significant elevated mortality was demonstrated for iron doses >1000 mg to 1800 mg (adjusted hazards ratio [HR] = 1.09; 95% confidence interval [CI], 1.01 to 1.17) and >1800 mg (adjusted HR = 1.18; 95% CI, 1.09 to 1.27). However, fitting multivariable models that appropriately account for time-varying measures of iron administration as well as other fixed and time-varying measures of morbidity, the authors found no statistically significant association between any level of iron administration and mortality. This study suggests that previously observed associations between iron administration and higher mortality may have been confounded, and it provides cautious support for the safety of the judicious administration of cumulative iron doses >1000 mg over 6 mo if needed to maintain target hemoglobin levels among patients treated with maintenance HD.

The Chronic Renal Insufficiency Cohort (CRIC) Study: Design and Methods.

Insights into end-stage renal disease have emerged from many investigations but less is known about the epidemiology of chronic renal insufficiency (CRI) and its relationship to cardiovascular disease (CVD). The Chronic Renal Insufficiency Cohort (CRIC) Study was established to examine risk factors for progression of CRI and CVD among CRI patients and develop models to identify high-risk subgroups, informing future treatment trials, and increasing application of preventive therapies. CRIC will enroll approximately 3000 individuals at seven sites and follow participants for up to 5 yr. CRIC will include a racially and ethnically diverse group of adults aged 21 to 74 yr with a broad spectrum of renal disease severity, half of whom have diagnosed diabetes mellitus. CRIC will exclude subjects with polycystic kidney disease and those on active immunosuppression for glomerulonephritis. Subjects will undergo extensive clinical evaluation at baseline and at annual clinic visits and via telephone at 6 mo intervals. Data on quality of life, dietary assessment, physical activity, health behaviors, depression, cognitive function, health care resource utilization, as well as blood and urine specimens will be collected annually. (125)I-iothalamate clearances and CVD evaluations including a 12-lead surface electrocardiogram, an echocardiogram, and coronary electron beam or spiral CT will be performed serially. Analyses planned in CRIC will provide important information on potential risk factors for progressive CRI and CVD. Insights from CRIC should lead to the formulation of hypotheses regarding therapy that will serve as the basis for targeted interventional trials focused on reducing the burden of CRI and CVD.