Low preop haemoglobin ups anaemia risk following gastric bypass

Among individuals undergoing gastric bypass, those with low preoperative haemoglobin levels are at higher risk of developing anaemia after the surgical procedure, according to a study. Furthermore, this risk increase is not mitigated by iron supplementation.

The study included 971 individuals with obesity (body mass index 35 kg/m²). Of these, 382 had Roux-en-Y gastric bypass (RYGB), 201 had sleeve gastrectomy, and 388 received medical treatment. Blood samples were collected and data on supplements were self-reported at baseline and 2 years after treatment for obesity. Anaemia was defined as haemoglobin <120 g/L for women and <130 g/L for men.

The frequency of anaemia rose from 3.0 percent at baseline to 10.5 percent at 2 years post-treatment in patients who received RYGB (p<0.05). Iron-dependent laboratory variables and the frequency of anaemia did not significantly differ between the participants who reported use of iron supplements and those who did not at the 2-year follow-up.

Factors associated with the likelihood of anaemia 2 years after gastric bypass were low preoperative levels of haemoglobin and high postoperative percent excessive body mass index loss.

Micronutrient deficiencies after bariatric surgery may lead to anaemia, according to the investigators. As such, individuals are recommended lifelong micronutrient supplementation to prevent postoperative deficiencies. The findings of the present study suggest that supplementation after bariatric surgery does little to prevent anaemia.