Low transferrin saturation (TSAT) independently predicts early all-cause mortality in Japanese patients on maintenance hemodialysis (HD), a new study suggests.

Kosaku Nitta, MD, PhD, of Tokyo Women’s Medical University, and colleagues divided 398 patients on HD (median age 67 years; 64.8% male) by their baseline TSAT levels: less than 20%; 20% to 40% (reference); or more than 40%. During a mean 52.2 months, 130 patients died from cardiovascular (CV) causes (15.8%) or infection (11.8%).

Significantly more patients with low TSAT of less than 20% than normal TSAT died from all causes: 9.55 vs 6.44 events per 100 patient-years, according to results published in Blood Purification. Although many patients died from CV issues, the researchers found no significant increase in CV mortality. Hemoglobin per se also did not fully explain the early mortality. The 3 groups did not differ in their receipt of erythropoiesis-stimulating agents or iron supplements.

Infection leading to iron deficiency possibly plays a role, according to the investigators. “These findings suggest that adverse clinical outcomes in patients with low TSAT can be partly attributed to iron deficiency. Future studies should examine the cause of coexisting inflammatory conditions in iron deficiency anemia when TSAT is <20%,” Dr Nitta and her collaborators stated.

The findings might not be generalizable to non-Japanese patients, the team acknowledged. They also relied on a single baseline TSAT measurement and did not analyze ferritin, which are study limitations.

“Further studies are needed to elucidate whether serial monitoring, rather than a single measurement of TSAT, would help in identifying patients with ESRD at high risk of mortality from any cause and whether iron supplements would be beneficial to improve clinical outcomes in patients with low TSAT,” the investigators noted.

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Reference

Sato M, Hanafusa N, Tsuchiya K, et al. Impact of transferrin saturation on all-cause mortality in patients on maintenance hemodialysis. Blood Purif. 2019. doi:10.1159/000499758