Systematic review highlights micronutrient deficiencies after bariatric surgery

A systematic review of case reports on late micronutrient deficiencies after bariatric surgery highlights the wide range of deficiencies that can occur; the range of ways in which these can present; and that once one deficiency is identified, more are often found. The review, carried out by researchers from Norwich Medical School, University of East Anglia, Norfolk, and Sheffield Teaching Hospitals, Northern General Hospital, Sheffield, UK, found that there were missed opportunities for earlier intervention, including appropriate nutritional counselling and support to adhere to nutritional supplements.

“This is the first systematic review of case reports and case series describing micronutrient deficiencies occurring at least two years following bariatric surgery,” the authors noted. “Although case reports are considered lower down the evidence hierarchy, their synthesis provides details on the sequelae for real patients of micronutrient deficiencies and highlights issues around follow-up, contributing factors, correct recognition of deficiencies by clinicians, and variability in treatment.”

Their review sought to provide a greater understanding of the circumstances in which micronutrient deficiencies two or more years after bariatric surgery may occur, their consequences for individual patients, and factors contributing to these deficiencies to help direct future intervention efforts.

This rapid systematic review consisted of case reports and case series of patients who developed micronutrient deficiencies two years or more post-bariatric surgery. Bariatric surgery included gastric bypass, gastric band, biliopancreatic diversion (BPD) and duodenal switch, sleeve gastrectomy and any other recognised form of bariatric surgery. The bariatric surgery must have been performed ≥ 2 years ago. Studies were included from any country. The review identified 83 cases meeting the inclusion criteria, reported in 74 articles.

Forty-one cases (reported in 37 articles) were from the USA, 9 from Italy (8 articles), 6 from Belgium, 5 from Spain (4 articles), 4 from the UK, 3 from France (2 articles), 3 from Greece (2 articles), 2 from each of Australia (1 article), Germany and Israel and one from each of Austria, Brazil, Canada, Denmark, Taiwan and Netherlands. Studies were published between 2002 and 2023. Five included articles were case series and the remainder were case reports.

Outcomes

Thirty-one cases (reported in 29 articles) had a Roux-en-Y gastric bypass, 18 cases had BPD, eight cases reported on “gastric bypass” surgery with no further details of the specific procedure provided, six cases had a laparoscopic gastric band, six cases (reported in five articles) had BPD with duodenal switch, two cases were described as “duodenal switch” with no further details, six cases (in five articles) had jejunoileal bypass, two cases (in one article) reported on sleeve gastrectomy [98], and one case reported on each of the following procedures: one anastomosis gastric bypass; vertical banded gastroplasty, gastroileal bypass, and sleeve gastrectomy and duodenal switch.

The researcher identified:

• Patients in 65 cases had a ‘main’ deficiency, which related to the presenting complaint and was the primary focus of the report, along with other reported incidental or long-standing deficiencies. The remaining cases (n = 18) reported multiple deficiencies.

• Fifteen cases (in 11 articles) reported primarily on vitamin A deficiency, 11 cases (in eight articles) presented with primarily ophthalmological symptoms, of these, eight cases (in seven articles) presented with night blindness, one with visual deterioration, one with a corneal ulcer and one with eye pain and sensitivity.

• Fifteen cases (in 15 articles) reported on copper deficiency, eight cases reported concurrent vitamin deficiencies including zinc, iron, vitamin A, vitamin E, vitamin D, vitamin B6, vitamin B1 and vitamin B12.

• Twelve cases (in 10 articles) reported primarily on vitamin D deficiency, nine of these cases also had associated hypocalcaemia, five cases reported other nutritional deficiencies, including vitamin A, vitamin B12, zinc, vitamin E, magnesium and iron.

• Six cases (in six articles) reported primarily on zinc deficiency, three cases also mentioned other deficiencies including copper, vitamin D, vitamin A, vitamin E and vitamin B6.

• Three case reports (in two articles) focused on vitamin B12 deficiency, two on folate deficiency and one on vitamin B12 and folate deficiency together. Co-occurring vitamin deficiencies included vitamin D, vitamin A, iron and zinc.

• Five cases (in five articles) focused on thiamine deficiency.

• No studies focused on selenium alone as the main deficiency. Seven cases (in six articles) discussed selenium deficiency, one as a focus of the article alongside zinc deficiency, the others as one of a number of deficiencies, but not the main deficiency discussed.

• In two cases the main deficiency discussed was vitamin K.

• In two cases the main deficiency was vitamin E.

• One case focused on vitamin B3 (niacin) deficiency.

Eighteen cases (in 15 articles) did not discuss a “main deficiency” but multiple deficiencies.

Factors reported as contributing to the development of late nutritional deficiencies after bariatric surgery were extracted where reported. Fifty-one cases (in 48 articles) included contributing factors. These were divided into patient factors and healthcare factors.

Patient Factors

Twenty-one cases (20 articles) reported patient non-adherence to vitamin supplementation. Three cases highlighted financial difficulties as a contributing factor to inadequate vitamin supplementation. Perceived lack of efficacy of supplementation was reported in one case. A further 16 cases (16 articles) reported insufficient vitamin supplementation as a contributing factor but did not report further details on the cause of insufficient supplementation (e.g., prescribing, adherence).

Healthcare Factors

In 14 cases (12 articles) the diagnosis of vitamin deficiency was delayed. In 11 of these 14 cases (9 articles) this was due to initial misdiagnosis and in 4 of these 14 cases (2 articles) an initial misdiagnosis led to inappropriate treatment. In one case, delayed test results were a contributing factor. Loss of the patient to follow-up after bariatric surgery was reported in nine cases and inadequate follow-up in three cases. Two cases mentioned the role of primary care. One case explicitly stated that a contributing factor was loss to follow up with the General Practitioner and another highlighted misdiagnosis in Primary Care. Lack of health professional knowledge about adequate supplement doses was mentioned in three cases (one article). Insufficient patient education was identified in two cases. One case reported lack of input from a nutritionist post-operatively as a contributing factor.

“Health professionals must be aware of the risk of harm from late nutritional deficiencies and consider these in patients whose surgery may have been many years ago and so may not, on presentation, be the most obvious cause of their symptoms,” the authors concluded. “Given that some of the deficiencies identified in the included case studies preceded or caused permanent disability or death, preventing late nutritional deficiency post-bariatric surgery, and early identification and management of deficiencies that do occur, is key.”

The findings were reported in the paper, ‘Nutritional Deficiencies Following Bariatric Surgery: A Rapid Systematic Review of Case Reports of Vitamin and Micronutrient Deficiencies Presenting More Than Two Years Post-Surgery’, published in Clinical Obesity. To access this paper, please click here