The frequency of anemia and main etiologies in patients with recently diagnosed chronic kidney disease without dialysis

Abstract

Introduction: the prevalence of anemia in patients with non-dialysis chronic kidney disease (NDCKD) affects a large percentage of the population and is higher at lower glomerular filtration rates (GFRs). Various factors are involved in its etiology.

Objective: to evaluate the frequency of anemia in patients with NDCKD in a nephroprotection program throughout their different stages and main etiologies, and analyze the overall iron deficiency in this group of patients, regardless of whether they had anemia.

Materials and method: patients referred to the nephrology service due to impaired kidney function or a lower-than-expected GFR for their age, seen between January 2018 and January 2022 in the nephrology department at Hospital de Caldas-Universidad de Caldas, and who met the criteria for chronic kidney disease. They all underwent testing which showed if they had anemia, its most likely origin and their iron deficiency regardless of their GFR.

Results: one thousand three hundred twenty-nine patients were evaluated, with 725 ultimately included. Sixty-seven percent were in Stage 3 CKD, with an average age of approximately 64 years. Regardless of their anemia status, an absolute iron deficiency was found in 10.7 %, a functional deficiency in 5.8 %, folic acid deficiency in 0.6 %, and vitamin B12 deficiency in 13.5 % of the patients. Hemoglobin progressively decreased beginning at Stage 2, reaching an average level of 11.5 to 9.6 in Stages 4 and 5, respectively. Hyperparathyroidism was found in 36.3 % of the patients, with vitamin D levels falling significantly as the GFR decreased. Anemia was found in 18.62 % of the patients, with Stage 4 and 5 patients affected more often (41.25 - 85 %, respectively). In this group, 23.0 % had an absolute iron deficiency and 9.6% a functional deficiency. Only 0.74 % had folic acid deficiency, and 11.9 % had vitamin B12 deficiency. Altogether, 56.30 % of anemic patients had PTH values compatible with hyperparathyroidism, with lower vitamin D levels at lower GFRs.

Conclusions: anemia affects a significant proportion of patients with NDCKD and is more frequent at lower GFRs. Its etiology varies, with notable iron deficiency, vitamin B12 deficiency and secondary hyperparathyroidism.