Kidney Week

Abstract: TH-PO487

Iron Status and the Risk for Heart Failure Hospitalization in Veterans with CKD

Session Information

• CKD: Epidemiology, Outcomes - Cardiovascular - I
  November 02, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Chronic Kidney Disease (Non-Dialysis)

• 303 CKD: Epidemiology, Outcomes - Cardiovascular

Authors

• Cho, Monique E., Veterans Health Administration, Salt Lake City, Utah, United States

Monique E. Cho,

• Hansen, Jared, Veterans Health Administration, Salt Lake City, Utah, United States

Jared Hansen,

• Peters, Celena B., Veterans Health Administration, Salt Lake City, Utah, United States

Celena B. Peters,

• Sauer, Brian C., Veterans Health Administration, Salt Lake City, Utah, United States

Brian C. Sauer,

Background

The risk for heart failure (HF) hospitalization associated with abnormal iron balance has not been evaluated in a large pre-dialysis CKD population.

Methods

We performed a historical cohort study using the national data from the Veterans Affairs Informatics and Computing Infrastructure. We identified a pre-dialysis CKD cohort (MDRD eGFR <60 mL/min/1.73m²) with at least one set of iron indices between 2006-2015. The clinical characteristics were determined from the ICD-9 codes and laboratory data during the baseline period, defined as the year preceding the first available iron indices (index date). Patients with ESRD, genetic and chronic disorders affecting iron metabolism were excluded. The cohort was divided into 4 iron groups based on the joint quartiles (Q) of transferrin saturation (Tsat) and ferritin: functional iron deficiency (FID), 1^st Tsat Q + 3^rd−4^th ferritin Qs; Low Iron (LI), reflecting absolute iron deficiency, 1^st Tsat+ferritin Qs; High Iron (HI), 4^th Tsat+ferritin Qs; and Reference (R), 2^nd−3^rd Tsat+ferritin Qs. First hospitalization for HF following the index date was determined by ICD-9 codes. Matching weights were used to determine the effect of FID, HI, and LI on HF hospitalization risk, using R as the reference. Diabetes was examined as a potential effect modifier.

Results

Of the 1,159,371 Veterans with CKD, 148,611 met the inclusion criteria. The mean±SD for age and eGFR were 72±11 years and 43±11 mL/min/1.73 m², respectively. The median (IQR) Tsat and ferritin values were 20 (14, 26)% and 119 (64, 196) ng/mL. Of the study cohort, 42% could not be categorized into any of the 4 iron groups. In the remaining 83,439 Veterans, the prevalence for FID, HI, LI, and R were 13%, 17%, 20%, and 50%, respectively. After matching weights were implemented, the clinical covariates were evenly distributed among the iron groups. During the mean±SD follow-up period of 4.0±2.7 years, FID and LI groups exhibited similarly increased risk for HF hospitalization [risk ratio (95% CI): 1.14 (1.08, 1.21) and 1.13 (1.08, 1.19), respectively]. HI was associated with lower risk for HF hospitalization, 0.86 (0.81, 0.92). The association between iron status and HF hospitalization risk was not modified by the diabetes status.

Conclusion

Iron deficiency, both functional and absolute, is associated with an increased risk for HF in CKD, regardless of the diabetes status.

Funding

• Veterans Affairs Support