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Hypocalcemia After Bariatric Surgery: Prevalence and Associated Risk Factors



The reported prevalence of hypocalcemia after bariatric surgery ranges from 1% after Roux-en-Y gastric bypass (RYGB) to 25% after bilio-pancreatic diversion-duodenal switch (BPD-DS).


We aimed to define the prevalence of post-operative hypocalcemia and identify clinical predisposing factors.


The study was conducted in an Academic Medical Center, USA.


Retrospective analysis of all patients undergoing bariatric surgery from May 2008 to December 2014 at Mayo Clinic Rochester, Minnesota was performed. Patients with revision surgeries were excluded. Hypocalcemia was defined as the lowest recorded serum calcium occurring at least 2 weeks post-operatively.


Nine hundred ninety-nine patients fulfilled the criteria above. After correction for serum albumin concentration, 36 patients had serum calcium ≤8.9 mg/dl. Mean serum calcium was 8.1 ± 0.6 mg/dl. The prevalence was 1.9% in the RYGB group, 9.3% in the sleeve gastrectomy (SG) group, and 10% in the BPD-DS group.

In all three surgical types, patients with hypocalcemia had significantly lower serum albumin and serum 25 (OH) vitamin D concentrations when compared to their normocalcemic counterparts (P < 0.01). The presence of renal insufficiency and vitamin D deficiency was associated with the highest risk of developing hypocalcemia after surgery [OR 16.8 (6.45–47.7) and 7.1(2.9–17.3), respectively]. Pre-operative renal insufficiency increased the odds of developing hypocalcemia by 20-fold.


In our series, hypocalcemia was identified in 3.6% of patients undergoing all bariatric surgery. Patients who are predisposed to developing post-operative hypocalcemia, such as those with pre-operative renal impairment, or post-operative vitamin D deficiency and renal insufficiency, may benefit from increased surveillance and prevention strategies.

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Correspondence to Meera Shah.

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Disclosure Statement

M.S. and M.S.M had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. A.S. participated in data analysis and manuscript preparation. A.S., K.A.K, R.A.W, and T.A.K participated in critical review of the manuscript. The authors report no conflicts of interest.

This article does not contain any studies with human participants or animals performed by any of the authors. For this type of study formal consent is not required.

This project was supported by Grant Number UL1TR000135 from the National Center for Advancing Translational Science (NCATS). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

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Shah, M., Sharma, A., Wermers, R.A. et al. Hypocalcemia After Bariatric Surgery: Prevalence and Associated Risk Factors. OBES SURG 27, 2905–2911 (2017).

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  • Hypocalcemia
  • Roux-en-Y gastric bypass
  • Sleeve gastrectomy
  • Bilio-pancreatic diversion
  • Duodenal switch
  • Renal impairment
  • Vitamin D deficiency