Iron deficiency is highly prevalent among candidates for metabolic surgery and may affect perioperative outcomes

Predicting Recurrent Deficiency and Suboptimal Monitoring of Thiamin Deficiency in Patients with Metabolic and Bariatric Surgery

INTRODUCTION

Vitamin B1 (thiamine) deficiency (TD) after metabolic and bariatric surgery (MBS) is often insidious and, if unrecognized, can lead to irreversible damage or death. As TD symptoms are vague and overlap with other disorders, we aim to identify predictors of recurrent TD and failure to collect B1 labs.

METHODS

We analyzed a large sample of data from patients with MBS (n = 878) to identify potential predictors of TD risk. We modeled recurrent TD and failure to collect B1 labs using classical statistical and machine learning (ML) techniques.

RESULTS

We identified clusters of labs associated with increased risk of recurrent TD: micronutrient deficiencies, abnormal blood indices, malnutrition, and fluctuating electrolyte levels (aIRR range: 1.62-4.68). Additionally, demographic variables associated with lower socioeconomic status were predictive of recurrent TD. ML models predicting characteristics associated with failure to collect B1 labs achieved 75-81% accuracy, indicating that clinicians may fail to match symptoms with the underlying condition.

CONCLUSIONS

Our analysis suggests that both clinical and social factors can increase the risk of life-threatening TD episodes in some MBS patients. Identifying these indicators can help with diagnosis and treatment.

Transferrin Saturation, Serum Ferritin, and C-Reactive Protein vs. Serum Ferritin for an optimal Iron Deficiency Diagnosis in Candidates for Bariatric Surgery

INTRODUCTION

Iron has different physiological processes and is regulated by hepcidin that is also an acute phase reactant, which increases with inflammation. Obesity produces a pro-inflammatory state, affecting directly the normal regulation of iron, causing ferritin (FER) deficiency. FER is used as the only indicator of the status of iron in patients with obesity, so the majority of them would be underdiagnosed, leading to a high prevalence of iron deficiency (ID) and anemia. The aim of this study is to evaluate the diagnostic tests: transferrin saturation (TS), FER, and C-reactive protein (CRP) vs. FER with the objective of analyzing the most accurate variable for the diagnosis of ID.

MATERIALS AND METHODS

We present a cross-sectional, analytical, and retrospective study, evaluating the diagnostic tests in 96 patients, to whom two methods were applied for the diagnosis of ID: method 1 (FER < 30 ng/mL) and method 2 divided into 2A (FER < 30 ng/mL), 2B (FER 30-100 ng/mL + CRP ≥ 5 mg/L), 2C (FER 100-300 ng/mL + CRP ≥ 5 mg/L + TS < 20%), and 2D (TS < 20%).

RESULTS

The prevalence of ID obtained using method 1 was 30.2% while 69.8% presented ID using total method 2, confirming an underdiagnosis of 39.6%.

CONCLUSION

The inflammatory state in patients with obesity must be considered in the diagnosis of ID. The use of TS, FER, and CRP has greater validity than the use of serum FER for the diagnosis of ID in patients with obesity.

Tackling the dual burden of malnutrition in pregnancy - pregnancy after weight loss surgery

The dual burden of malnutrition is characterised by the coexistence of undernutrition alongside overweight/obesity and diet-related noncommunicable diseases. It is a paradox which disproportionately affects women and is applicable to those who become pregnant after weight loss surgery. Obesity before and during pregnancy is associated with increased risk of adverse perinatal outcomes in both mother and child. Overall lifestyle interventions targeting weight loss in the preconception period have not proven effective, with people, and women in particular, increasingly seeking weight loss surgery. In women with severe obesity, surgery may normalise hormonal abnormalities and improve fertility. In those who become pregnant after surgery, evidence suggests a better overall obstetric outcome compared to those with severe obesity managed conservatively; however, there is heightened risk of maternal nutritional deficiencies and infants born small for gestational age. Specifically, pregnancy soon after surgery, in the catabolic phase when rapid weight loss is occurring, has the potential for poor outcomes. Lifelong micronutrient supplementation is required, and there is considerable risk of malnutrition if nutritional aftercare guidelines are not adhered to. It is therefore recommended that pregnancy is delayed until a stable weight is achieved and is supported by individualised advice from a multidisciplinary team. Further research is required to better understand how weight loss surgery affects the chances of having a healthy pregnancy and to ultimately improve nutritional management and patient care. In this review, we aim to summarise the evidence and guidance around nutrition during pregnancy after weight loss surgery.

Clinical significance of iron deficiency among candidates for metabolic surgery

BACKGROUND

Iron deficiency (ID), a known complication after metabolic surgery, is common among preoperative patients in the presence of inflammation. Evidence is now accumulating that preoperative ID may adversely affect perioperative outcomes.

OBJECTIVES

To investigate the relationship between preoperative iron status and the risk of postoperative severe anemia. In addition, this study investigates the relationship between preoperative iron status and length of surgical stay SETTING: A large regional tertiary health system.

METHODS

Among patients who underwent metabolic surgery between 2004 and 2020, 5171 patients had a full iron nutritional assessment prior to surgery. Study patients were divided into multiple smaller groups (10 female groups and 7 male groups) on the basis of levels of serum ferritin and Transferrin Saturation (T Sat) < or ≥20%. Study patients were followed after surgery and the time to the development of severe anemia (hemoglobin < 8 gm/dL) was recorded. Hospital length of stay (LOS) was analyzed in relation to preoperative iron status.

RESULTS

Lower ferritin levels were associated with older age in males (P = .0001) and younger age in females (P < .0001). For males, after adjustment for age, body mass index (BMI), and year of surgery, surgical LOS was prolonged in those with T Sat <20% (P = .0041). For females the time until the development of severe anemia was associated with baseline iron status (P < .0001).

CONCLUSIONS

Male preoperative patients for metabolic surgery with T Sat <20% are at risk for increased surgical LOS. Females with low ferritin levels consistent with ID are at increased risk for the development of postoperative severe anemia.

What We Are Missing: Using Machine Learning Models to Predict Vitamin C Deficiency in Patients with Metabolic and Bariatric Surgery

PURPOSE

Vitamin C (VC) is implicated in many physiological pathways. Vitamin C deficiency (VCD) can compromise the health of patients with metabolic and bariatric surgery (patients). As symptoms of VCD are elusive and data on VCD in patients is scarce, we aim to characterize patients with measured VC levels, investigate the association of VCD with other lab abnormalities, and create predictive models of VCD using machine learning (ML).

METHODS

A retrospective chart review of patients seen from 2017 to 2021 at a tertiary care center in Northeastern USA was conducted. A 1:4 case mix of patients with VC measured to a random sample of patients without VC measured was created for comparative purposes. ML models (BayesNet and random forest) were used to create predictive models and estimate the prevalence of VCD patients.

RESULTS

Of 5946 patients reviewed, 187 (3.1%) had VC measures, and 73 (39%) of these patients had VC<23 μmol/L(VCD. When comparing patients with VCD to patients without VCD, the ML algorithms identified a higher risk of VCD in patients deficient in vitamin B1, D, calcium, potassium, iron, and blood indices. ML models reached 70% accuracy. Applied to the testing sample, a "true" VCD prevalence of ~20% was predicted, among whom ~33% had scurvy levels (VC<11 μmol/L).

CONCLUSION

Our models suggest a much higher level of patients have VCD than is reflected in the literature. This indicates a high proportion of patients remain potentially undiagnosed for VCD and are thus at risk for postoperative morbidity and mortality.

Long-Term Outcomes of Iron Deficiency Before and After Bariatric Surgery: a Systematic Review and Meta-analysis

PURPOSE

This study reviews the prevalence of iron deficiency (ID) in bariatric surgery candidates and the long-term outcomes of the prevalence of ID after bariatric surgery.

MATERIALS AND METHODS

A systematic literature search and meta-analysis were performed in PubMed for articles published by August 31, 2022, including these search terms: bariatric surgery, metabolic surgery, weight loss surgery, obesity surgery, sleeve gastrectomy, gastric banding, gastric bypass, duodenal switch, duodenojejunal bypass, iron, iron deficiency, sideropenia, and hypoferritinemia. Fifty-seven studies examining a total of 26,328 patients with morbidly obese were included in this meta-analysis finally.

RESULTS

The results showed a prevalence of 17% of ID in bariatric surgery candidates and a prevalence of 14%, 17%, 26%, 34%, 23%, 38%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after bariatric surgery, respectively. Additionally, the results showed a prevalence of 15%, 19%, 35%, 38%, 29%, 30%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after Roux-en-Y gastric bypass, respectively; a prevalence of 12%, 12%, 15%, 31%, and 17% of ID at 1-, 2-, 3-, 4-, and 5-year follow-up after sleeve gastrectomy, respectively; and a prevalence of 19% of ID at 1-year follow-up after anastomosis gastric bypass.

CONCLUSION

As a result, preoperative evaluation and correction of ID may lead to better outcomes for bariatric surgery candidates. ID is also common in patients after bariatric procedures, especially RYGB. Long-term, even lifelong, medical and nutritional monitoring and tailored interventions are critical.