Low hemoglobin levels can lead to kidney failure

Keep an eye on the heart in kidney patients

AMSTERDAM. Blood transfusions could potentially pose a risk to kidney patients regardless of the acute benefit in anemia. Apparently, the red cell concentrates lead to more hospital admissions for heart failure in this group of patients.

This is indicated by a new analysis from the USA, which was presented on Sunday morning in Amsterdam at the 51st annual meeting of the European nephrologist society ERA-EDTA.

It mainly affects patients with high-grade chronic kidney disease (CKD stages 4 and 5). Most of the patients with a significantly reduced glomerular filtration rate (GFR below 40 ml / min) develop anemia over time. The main decisive factor here is the erythropoietin deficiency caused by renal insufficiency.

As is well known, the growth factor is mainly produced in the kidneys. As a result of renal insufficiency, the hemoglobin level (Hb) in the serum falls.

From below 11.5 g / dl in women and 13.5 g / dl in men, nephrologists speak of renal anemia requiring treatment. She is usually treated with recombinant EPO and iron supplements.

In acute anemic phases, the symptoms can be treated with red cell concentrates. And, at least in the USA, more and more nephrologists are turning to it. From 2002 to 2008, the number of transfusions in patients with end-stage kidney disease (ESRD) more than doubled (NDT 2013; 28 (6): 1504).

But that can have unpleasant consequences. Because in the current analysis by private lecturer Brian Bradbury, who researches for the pharmaceutical manufacturer Amgen, the transfusion of Ery concentrates was not without risk.

For the analysis, Bradbury and his colleagues selected almost 8,000 patients with stage 4 or 5 chronic kidney disease from a US database of health reports from insurance companies.

After adjustment, the risk is four times higher

None of the patients required dialysis. Almost 70 percent were over 50 years old. A total of 1,381 patients were reportedly hospitalized (or admitted to the emergency room) for heart failure. According to Bradbury, that gives an incidence rate of 16.3 cases per 100 person-years. It was clearly higher in older patients, diabetics and those who had other cardiovascular diseases.

Using the diagnosis date, Bradbury and his team each looked back a week in the medical history. They also looked at several other weeks of patients in which no hospitalization for heart failure was documented. The patients were thus their own controls.

The researchers also compared the days on which the patients received a blood transfusion: If there was an admission for heart failure on the following three days, this was recorded as a case. The periods without an event were included in the controls.

The obligatory one-week "follow-up" was possible in retrospect for 1110 of the patients who had been admitted to the hospital for heart failure. They had previously had a blood transfusion in 0.7 percent of the cases. Compared with the only 0.1 percent in the control periods, the researchers come to a heart failure risk rate of 13.4.

Even after adjusting the data for the patients with acute kidney failure, previous hospitalization, anemia or gastrointestinal bleeding, the risk was still significantly increased at a rate of 3.8.

Bradbury recommends that his colleagues keep this risk in mind when making decisions about a blood transfusion in the future. This is especially true for patients with a cardiorenal syndrome, who have both cardiovascular and renal diseases that can mutually benefit. (no)