Prevalence of Anaemia and Related Micronutrient Deficiencies After Bariatric Surgery

Anaemia and micronutrient deficiencies are common complications following bariatric surgery. This study aimed to determine the prevalence of anaemia after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), and to identify anaemia associated risk factors.

A cross-sectional study was conducted among 100 adults who underwent RYGB or SG between 2016 and 2022 at Hospital Raja Permaisuri Bainun, Ipoh. Demographics, biochemical parameters, and multivitamin (MVT) adherence data were analysed according to the type of surgery.

Among the participants, 44 underwent RYGB and 56 underwent SG, with a mean follow-up of 3 years. Most were female and over half were still menstruating. The overall prevalence of anaemia increased from 14% pre-surgery to 47% post-surgery. Anaemia increased from 9.1% to 47.7% in the RYGB group and from 17.9% to 46.4% in the SG group, with no significant difference in severity of anaemia (P=0.897). Postoperatively iron, folate and vitamin B12 deficiencies were observed in 44%, 14%, and 9% of patients, respectively. Folate deficiency was higher after SG (23.2% vs. 2.3%, P=0.003), while vitamin B12 deficiency occurred only after RYGB (20.5% vs. 0%, P<0.001). Iron deficiency was slightly higher in the RYGB group but not statistically significant (P=0.547). Menstruating females had higher risk of iron deficiency (P=0.001). Only 46% showed good adherence to MVT intake.

Anaemia affected nearly half of post-bariatric surgery patients, with menstruating women at highest risk. Lifelong monitoring and prophylactic iron supplementation are essential to prevent anaemia and related micronutrient deficiencies.