Anemia complicating type 2 diabetes: Prevalence, risk factors and prognosis

To determine the prevalence, risk factors and prognosis of anemia in representative community-based patients with type 2 diabetes.

Data from the Fremantle Diabetes Study Phase II (FDS2; n=1551, mean age 65.7years, 51.9% males) and Busselton Diabetes Study (BDS; n=186, mean age 70.2years, 50.0% males) cohorts, and from 186 matched BDS participants without diabetes, were analyzed. The prevalence of anemia (hemoglobin ≤130g/L males, ≤120g/L females) was determined in each sample. In FDS2, associates of anemia were assessed using multiple logistic regression and Cox proportional hazards modeling identified predictors of death during 4.3±1.2years post-recruitment.

The prevalence of anemia at baseline was 11.5% in FDS2 participants, 17.8% in BDS type 2 patients and 5.4% in BDS participants without diabetes. In FDS2, 163 of 178 patients with anemia (91.6%) had at least one other risk factor (serum vitamin B₁₂<140pmol/L, serum ferritin <30μg/L and/or transferrin saturation<20%, serum testosterone <10nmol/L (males), glitazone therapy, estimated glomerular filtration rate (eGFR) <60mL/min 1.73m², malignancy, hemoglobinopathy). More anemic than non-anemic FDS2 patients died (28.7% versus 8.0%; P<0.001). After adjustment for other independent predictors (age as time-scale, male sex, Aboriginality, marital status, smoking, eGFR), anemia was associated with a 57% increase in mortality (P=0.015).

Type 2 diabetes at least doubles the risk of anemia but other mostly modifiable risk factors are usually present. Anemia is associated with an increased risk of death after adjustment for other predictors.