Prevalence of Anemia 10 Years After Roux-en-Y Gastric Bypass in a Single Veterans Affairs Medical Center | Bariatric Surgery | JAMA Surgery | JAMA Network
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Figure 1.  Rates of Anemia Over Time After Roux-en-Y Gastric Bypass
Rates of Anemia Over Time After Roux-en-Y Gastric Bypass

The study population includes 74 veterans.

Figure 2.  Anemia Rates by Follow-up Cohort
Anemia Rates by Follow-up Cohort

Preoperative and 10-year postoperative rates are compared. No Follow-up indicates the cohort that did not have follow-up with a bariatric specialist (n = 58); Follow-up, the cohort that had follow-up (n = 16). P values were calculated using the 2-tailed t test, comparing preoperative vs 10-year rates.

aP < .001.

bP = .07.

Research Letter
January 2018

Prevalence of Anemia 10 Years After Roux-en-Y Gastric Bypass in a Single Veterans Affairs Medical Center

Author Affiliations
  • 1Surgical Service, Palo Alto Veterans Affairs Health Care System, Palo Alto, California
  • 2Surgical Service, Department of Surgery, Stanford School of Medicine, Stanford University, Stanford, California
JAMA Surg. 2018;153(1):86-87. doi:10.1001/jamasurg.2017.3158

Obesity is common among US veterans,1,2 and Roux-en-Y gastric bypass (RYGB) is the criterion standard operation for weight loss. Potential adverse outcomes, such as mineral and/or vitamin deficiency, are well documented,3,4 but few studies have described long-term outcomes in the veteran population.5 This study evaluates the prevalence of anemia 10 years after RYGB and assesses whether postoperative bariatric follow-up influences rates of anemia.


After approval by the institutional review board of Stanford University, we performed a retrospective review of a prospective, 10-year database of RYGB at a single Veterans Affairs Medical Center; the institutional review board granted an exemption for informed consent. We evaluated outcome data and quality of outpatient follow-up. Patients who did not have follow-up with a bariatric specialist more than 5 years postoperatively were compared with patients who had at least 1 visit with a bariatric specialist after 5 years by using a 2-tailed t test and logistic regression. P < .05 indicates statistical significance. The institutional definition of anemia is a hemoglobin concentration of less than 13.5 g/dL for men and less than 12.0 g/dL for women (to convert to grams per liter, multiply by 10.0).


From 2002 through 2006, 102 patients underwent RYGB. We excluded patients lost to or unavailable for follow-up in the National Veterans Affairs system (n = 12), those who underwent revision surgery (n = 1), and those who died during the follow-up period (n = 15). Of the remaining 74 patients (58 men [78%] and 16 women [22%]; mean [SD] age, 51 [11] years), preoperative body mass index (calculated as weight in kilograms divided by height in meters squared) was 46.2. At 10 years, the mean body mass index was 33.7, with 60% excess body mass index loss. The mean rate of preoperative anemia was 20% (15 patients); and the rate increased after RYGB to 28% at 1 year (21 patients), 31% at 5 years (23 patients), and 47% at 10 years (35 patients) (Figure 1).

At 10 years after RYGB, the anemia rate in the cohort without bariatric specialist follow-up (n = 58) increased to 33 patients (57%), from 13 (22%) before surgery (P < .001). The rate of anemia in the cohort with bariatric specialist follow-up (n = 16) did not increase significantly after 10 years (3 [19%] vs 2 [13%]; P = .07) (Figure 2). Compared with patients with bariatric specialist follow-up, patients without bariatric specialist follow-up had significantly higher odds of anemia at 10 years (odds ratio, 6.1; 95% CI, 1.4-27.6; P = .02) after adjusting for preoperative anemia.


Long-term complications of RYGB, such as anemia, may go unrecognized by nonbariatric specialists. Causes include iron, vitamin B12, and folate deficiency; less common causes include copper, vitamin A, and selenium deficiency and bleeding marginal ulcers. We found high anemia rates 10 years after RYGB; these rates may reflect a mixed vitamin and mineral deficiency, because patients had normocytic anemia. Our study suggests that follow-up with bariatric specialists more than 5 years after surgery, rather than with specialists with no bariatric expertise, can decrease long-term anemia risk. This finding may demonstrate the bariatric specialist’s specific understanding of the long-term risk for nutritional deficiency after RYGB and the importance of vitamin and mineral supplementation. All patients receiving iron supplements who still had anemia at 10 years were in the group without bariatric specialist follow-up (n = 11), a finding suggesting an inappropriate choice of treatment or inadequate follow-up. No similar effect of follow-up was observed for other long-term outcomes, such as excess weight loss and medication requirements.

This study emphasizes the importance of long-term specialty-specific follow-up for bariatric surgery. The major limitation of this study was the size of the cohort with bariatric specialist follow-up, which may be too small to identify a significant difference in the 10-year anemia rates compared with preoperative rates. Nonetheless, the significant difference observed in the cohort without bariatric specialist follow-up suggests an opportunity for an intervention to improve follow-up and decrease anemia rates and other long-term complications. Long-term follow-up should be an integral part of bariatric programs, and additional studies are needed to identify potential barriers to successful follow-up. In the VA population, such barriers include distance from a bariatric center and lower socioeconomic status. We implemented a hub-and-spoke model for bariatric care, including health care specialist education, in which the bariatric team communicates regularly with the patient’s primary care clinician before and after surgery.6 This model may prove to be an effective tool to overcome such barriers and improve outcomes.


Anemia rates are high 10 years after RYGB. Long-term follow-up with a bariatric specialist is imperative in mitigating the risk for anemia.

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Article Information

Corresponding Author: Dan Eisenberg, MD, MS, Surgical Service, Department of Surgery, Stanford School of Medicine, Stanford University, 3801 Miranda Ave, Mail Code GS 112, Palo Alto, CA 94304 (

Accepted for Publication: June 12, 2017.

Published Online: September 20, 2017. doi:10.1001/jamasurg.2017.3158

Author Contributions: Dr Eisenberg had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Chen, Eisenberg.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Chen, Eisenberg.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Chen.

Study supervision: Kubat, Eisenberg.

Conflict of Interest Disclosures: None reported.

Additional Contributions: Amber Trickey, PhD, MS, Stanford Surgery Policy Improvement Research and Education Center, reviewed the manuscript. She was not compensated for this work.

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