Eur J Clin Nutr. 2017 Feb;71(2):198-202.

Improved and more effective algorithms to screen for nutrient deficiencies after bariatric surgery

 

Authors:

Inge Bazuin, MSc1; Sjaak Pouwels, MD, PHD2; Saskia Houterman, PhD3; Simon W. Nienhuijs, MD, PhD4; Johannes F. Smulders, MD4; Arjen-Kars Boer, PhD1

 

Affiliations:

1.Department of Clinical Chemistry, Catharina Hospital, Eindhoven, The Netherlands

2.Department of Surgery, Franciscus Gasthuis & Vlietland, Rotterdam/Schiedam, The Netherlands

3.Department of Eduction and Research, Catharina Hospital, Eindhoven, The Netherlands

4.Department of Surgery, Catharina Hospital, Eindhoven, The Netherlands

 

Correspondence to

Sjaak Pouwels, MD, PhD

Department of Surgery, Franciscus Vlietland,

Vlietlandplein 2, 3118 JH, Schiedam, The Netherlands

Tel.: +31 (0)10 893 0000; Fax: +31 (0)10 8933059

E-mail: Sjaakpwls@gmail.com

 

Abstract

Here, we study whether it is possible to optimize the cost effectiveness of the nutrient panel, by developing an algorithm, which detects nutrient deficiencies in patient’s prior and after bariatric surgery, at lower costs.

Retrospectively, we included 2055 patients who had undergone Laparoscopic Roux-Y Gastric Bypass (LRYGB) and Laparoscopic Sleeve Gastrectomy (LSG) surgery between January 2009 and December 2013. For analysis, the most recent pre- and postoperative measurements were selected for each biochemical parameter separately. Firstly step the amount of moderate and severe deficiencies were calculated. Secondly, we investigated whether each variable (vitamins A, B1, B6, B12, D, folate, ferritin, zinc and magnesium) could predict the presence of deficiency. In total, 561 (LRYGB) and 831 (LSG) patients had at least pre- and postoperative values of vitamin A, B1, B6, B12, D, folate, ferritin, zinc or magnesium. The algorithm reduces vitamin D, B12, B6, B1 and ferritin examinations by 15%, 11%, 28%, 28% and 38%, respectively, without missing clinically relevant deficiencies. The corresponding potential cost savings was 14%. Our developed algorithm showed that substantial costs are saved in laboratory test for both LRYGB and LSG procedures. The potential cost reduction of 14% might even be increased to 42% when less frequent moderate deficiencies are not screened anymore, while >99.0 of moderate deficiencies will be detected.

Keywords: efficient screening, nutrient deficiency, vitamin deficiency, cut-off values cost savings

 

 

 

Supplement

Patients undergoing bariatric surgery are subjected to possible adverse physiological, nutritional and metabolic changes (1). In order to detect these changes as early as possible, most bariatric guidelines recommend frequent monitoring with extensive laboratory panel (2-6). However, the recommended laboratory panels differ in these guidelines. Furthermore, the guidelines sometimes disagree with respect to cut-off levels to detect deficiencies and generally do not specify the corresponding biochemical assays. For example the prevalence of folate deficiency, which can be established in plasma and erythrocytes, varies between 6 and 65% (4).

Roughly, the Laparoscopic Roux-Y Gastric Bypass (LRYGB) and Laparoscopic Sleeve Gastrectomy (LSG) are bariatric surgical procedures that are performed very often worldwide. These patients are extensively screened for numerous biochemical parameters including the nutrients/vitamins A, B1, B6, B12, D, folate, ferritin, zinc and magnesium. Based on the Dutch national defined prices, the cost of this vitamin/nutrient panel is 72.60 euro. Since, the patient is monitored prior and up to 7 times after surgery the total costs of the follow-up period equals 580.80 euro. Since not all patients develop deficiencies and those who do, usually do not develop all deficiencies simultaneously, not all laboratory tests have clinical consequences.

 

Algorithm development

Patients who had undergone LRYGB or LSG surgery (n = 2055) between January 2009 and December 2013 with at least one preoperative and one postoperative laboratory examination were included in this retrospective study. For analysis, the most recent pre- and postoperative measurements were selected for each biochemical parameter separately. In total 561 LRYGB and 831 LGS patients were included. All of our patients were screened for vitamins A, B1, B6, B12, D, folate, ferritin, zinc and magnesium. We were interested whether the costs of lab testing could be reduced. Therefore, the first step was to calculate the amount of moderate and severe deficiencies of the above mentioned. Secondly, we investigated whether each variable (vitamins A, B1, B6, B12, D, folate, ferritin, zinc and magnesium) could predict the presence of deficiency. This was done by calculating combination of deficiencies. For example in how many times is there a combined vitamin A and vitamin B12 deficiency? Or how many times are folate and vitamin B12 deficiencies present before and after surgery? These combinations were made for vitamins A, B1, B6, B12, D, folate, ferritin, zinc and magnesium.

 

References

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