Evaluation of Short-term Nutritional Regimens Following Bariatric Surgery

The two types of bariatric procedures most often performed in Europe are adjustable gastric banding (AGB) and gastric bypass (GBP). The use of bariatric surgery has demonstrated long-term effectiveness on weight loss and comorbidities, including three recent studies, which used restrictive and malabsorption procedures, with findings of decreased mortality several years following the bariatric procedures. Gastric bypass, an irreversible restrictive and mildly malabsorptive procedure, is more efficient than AGB, a purely restrictive and reversible procedure, on weight loss and comorbidities. However, GBP potentially induces more nutritional deficits, compared to adjustable gastric binding. Adverse effects of bariatric surgery are not uncommon, but less is known about nutritional complications of bariatric surgery. In the present study, the authors prospectively compared the prevalence of nutritional deficiencies after AGB and GBP procedures.

A one-year prospective study of nutritional parameters was undertaken between 2004 and 2006 with 70 consecutive severe obese patients, of which 21 had undergone AGB and 49 had undergone GBP. Patients who had returned between nine and 15 months after the laparoscopic bariatric surgery were systematically reevaluated one year after surgery. Dietary advice was systematically given to patients before surgery, during hospitalization, and during followup, and included the administration of multivitamin supplements when necessary.

At one year following the procedures, digestive symptoms were more polymorphic in the GBP patients. At one year after surgery, all patients, except for two of the GBP group were taking multivitamin supplements versus none in the AGB group. The most frequent deficiencies before and after bariatric procedures were iron (assessed by transferrin saturation), vitamin B1, and C deficiencies. There were lower concentrations of B12 one year after surgery in the GBP group as compared to presurgery. Anemia was present at one year following the procedures in two AGB patients and five GBP patients. Three of the anemic patients had vitamin B12 deficiency, five patients had iron deficiency, and no patients had folate deficiency.

The authors concluded that the results demonstrated that severe nutritional deficiencies could be prevented on a short-term basis. Although systematic prescription of multivitamins may be unnecessary after AGB, oral vitamins B1 and C or iron should be prescribed when necessary. There was a high prevalence of iron, thiamine, and vitamin C deficiencies before surgery that affected nearly 50% of the obese population. Bariatric surgery did not worsen these deficiencies, except for a slight decrease of vitamin B1 after AGB.

Coupaye M, Puchaux K, Bogard C, Msika S, Jouet P, Clerici C, Larger E, Ledoux S. Nutritional consequences of adjustable gastric banding and gastric bypass: a 1-year prospective study. Obes Surg. 2009 Jan;19(1):56-65.

NAAC Expert Commentary:
Bariatric or weight loss surgery has become one of the most frequently performed surgical procedures in recent years. Contributors to the growth of bariatric surgery include the large number of morbidly obese patients, the success of the procedure where other methods of weight loss have failed, and the development of laparoscopic techniques. The standard today remains a Roux-en-Y bypass (GBP) that involves stapling of the stomach to create a small gastric pouch followed by bypass of the remaining stomach and duodenum by anastomosis of a segment of small bowel. A more recent approach involves banding the stomach to create the pouch and avoidance of any surgical bypass (ABP). The band is adjustable and removable, making this procedure reversible, whereas GBP is permanent.

Adverse effects of either procedure are common and range from death – a rare occurrence – to wound infection, hernia, and nutritional abnormalities. The latter includes deficiencies in iron, calcium, vitamins, as well as protein malabsorption, which leads to anemia, osteopenia, and neurological complications. Anemia is the most prevalent of all these adverse effects.

Coupaye and colleagues recently reported the results of their one-year prospective study of 110 consecutive patients who underwent either GBP or ABP. All patients had been instructed to take daily oral multivitamin supplements. Their primary goal was to differentiate one procedure from the other in terms of incidence of nutritional consequences. They evaluated all patients one year after surgery with a host of parameters including clinical findings and standard laboratory values. These included assessment of creatinine, vitamin, mineral, and iron levels. All patients lost weight with better results in the GBP group. The most frequent deficiencies were iron, vitamin B1, and vitamin C. Seven of the 70 patients (10%) who were studied were anemic. Five patients had iron deficiency; three had vitamin B12 deficiency. The incidence of anemia was not increased from the preoperative period.

The authors correctly pointed out that assessment of transferrin saturation rather than ferritin concentration is the most accurate way to determine iron deficiency. Ferritin is an acute-phase reactant protein that fluctuates in response to several factors including inflammation and insulin response. Transferrin saturation value, typically 20-50% in non-anemic patients, reports the percentage of iron bound to the transport protein, transferrin. Because transferrin has a relatively short half-life compared, for instance, to albumin, it is often used in overall nutritional assessments of protein turnover. Like ferritin, transferrin is influenced by insulin kinetics and inflammation, which leads to decreased levels.

What can we learn from the study by Coupaye et al? The incidence of pre-operative and postoperative anemia was the same, probably because of the authors’ postoperative multivitamin treatment regimen. The primary cause of anemia was iron deficiency, which has been reported by several other authors. Of most importance, we observe that anemia remains a chronic problem.

Several other reports of anemia after bariatric surgery have reached similar conclusions, with several key points emerging: (1) Anemia is common with reported incidence ranging from 17-67%; (2) Anemia is chronic, worsens over time, and is recurrent after treatment; (3) Most post-bypass anemia is caused by iron deficiency, but other deficiencies including vitamin B12 and micronutrients can occur. The latter are particularly difficult to appreciate because of the long interval from bypass to depletion of reserves. Physicians should look for other causes by rounding up the usual suspects such as menstrual and gastrointestinal bleeding. (4) Anemia appears to be more prevalent after GBP than ABP, but ABP is still in its infancy. (5) Multi-vitamin and vitamin C oral treatment helps prevent the development of iron deficiency anemia. However, some people are resistant to oral treatment and will require parenteral iron. The bottom line is that bariatric surgery patients need life-long follow-up for diagnosis and treatment of anemia.

Anemia Associated with Osteoporosis in Older Populations

There is a potential association in the elderly between hypoxemia, bone mineral density, osteoporosis, and hemoglobin (Hb) levels. In fact, several studies have reported a concurrence of osteoporosis and anemia in certain conditions, including sickle cell anemia, chronic inflammatory conditions, and renal failure. However, little is known about the association between Hb levels and osteoporosis in general older populations.

The study by Laudisio et al assessed the association of Hb levels with ultrasound-derived T score, Z score, and stiffness index in all 358 subjects age 75 or older living in Tuscania, Italy January 2004. The authors also identified Hb cutoff levels that could potentially be used to identify participants with osteoporosis. Of the 387 participants living in the small Italian town, 23 subjects were excluded for missing data and 6 participants were excluded for treatment with biphosphonates. Questionnaires were used to assess socioeconomic status, lifestyle habits, physical activity, nutritional parameters, and other variables. Anemia was defined according to the World Health Organization criteria: Hb level <12 g/dL in women and Hb level <13 g/dL in men.

Anemia was detected in 43/358 (12%) of participants and osteoporosis was found in 153/358 (43%) of participants. In the final regression models, Hb levels were still associated with the ultrasound-derived T score (β=0.13; 95% CI=0.01–0.25; p=0.030), Z score (β=0.11; 95% CI=0.01–0.22; p=0.045) and stiffness index (β=1.87; 95% CI=0.51–3.21; p=0.007) after simultaneously adjusting for all potential confounders. The authors concluded that the results of the study demonstrated that Hb levels are independently associated with all ultrasonographic bone mineral parameters in unselected, community-dwelling older populations. Results also showed that osteoporosis could be best predicted in this population in individuals with Hb levels <13 g/dL (women) and <14 g/dL (men).

Laudisio A, Marzetti E, Pagano F, Bernabei R, Zuccalà G. Haemoglobin levels are associated with bone mineral density in the elderly: a population-based study. Clin Rheumatol. 2009 Feb;28(2):145-51.

NAAC Expert Commentary
The authors wish to study whether Hb levels are associated with bone density, becasue it has been recognized that anemia correlates with osteoporosis. This study by Laudisio et al is cross-sectional, in which non-selected elderly individuals in an Italian village were examined in their homes. One problem with this study is that it uses ultrasound, rather than using dual-energy x-ray absorptiometry (DEXA) for measuring bone density. The ultrasound device was used because of its portability, since elderly patients were examined in their homes. As DEXA is the standard measure, it is more difficult to evaluate the data presented by this study.

Nonetheless, the authors found that Hb levels were independently associated with bone density using a multiple regression analysis. This should heighten our awareness that anemia may be a significant contributor to osteoporosis. Further study of this intriguing possibility may help reveal whether treating anemia is effective for reducing the effects of osteoporosis and preventing fracture.

Anemia Incidence and Prevalence of Cancer Patients in Critical Care

The prevalence of anemia in cancer patients has been well documented. Rates range from 30-39%. However, the prevalence and incidence of anemia in cancer patients in need of critical care is not known. Furthermore, among patients with cancer, anemia has been associated with decreased response to chemotherapy, diminished quality of life, and increased financial burden of the disease. Determining the relative impact of clinical and demographic factors would be important because certain subgroups of patients are at higher risk of developing anemia during the course of the disease.

In this study by Cardenas-Turanzas et al, demographic information collected at the time of ICU admission was used during a retrospective chart review of adult patients admitted to the ICU at the University of Texas M.D. Anderson Cancer Center. Demographic information included age, sex, race, and marital status. Clinical information included recently treated cancer type, previous cancer treatments, length of stay before the ICU admission, and other variables. The risk of mortality was computed by calculating a revised sequential organ failure assessment (SOFA) score. Patients received a score of 0-20, with higher numbers indicating greater risk of mortality. Hemoglobin levels were measured at ICU admission and classified according to severity as mild, moderate, or severe.

Clinical and demographic data was collected for 4705 patients enrolled in the study. The prevalence of anemia at ICU admission was 68%. Of the patients with anemia, 38% had mild anemia, 24% had moderate anemia, and 6% had severe anemia. There were significantly higher proportions of anemia in the medical patients and in surgical patients compared to standard prevalence rates, for all age categories except for those older than 80 years. Overall, moderate to severe anemia was more prevalent in medical patients than in surgical patients. Anemia developed in 46.6% (701/1502) of the patients who were initially without anemia at ICU admission. Among the patients developing anemia, 65.6% (460/701) were eventually diagnosed with mild anemia, 29.0% (203/701) with moderate anemia, and 5.4% (38/701) with severe anemia. All factors that significantly predicted incident anemia during ICU stay were similar to those associated with prevalent anemia at ICU admission. Independent clinical determinants included severity of illness score, admission to the MICU, prior chemotherapy, diagnosis of a hematologic cancer, and length of stay before ICU admission. Independent demographic determinants included female sex, nonwhite ethnicity, and age.

Cardenas-Turanzas M, Cesta MA, Wakefield C, Wallace SK, Puana R, Price KJ, Nates JL. Factors associated with anemia in patients with cancer admitted to an intensive care unit. J Crit Care. 2009 Jul 2.

NAAC Expert Commentary
In their study, Cardenas-Turnanzas and colleagues describe both the incidence and prevalence of anemia in this selected population of patients with cancer admitted to the ICU.The prevalence of anemia reflects the current published data that reports astonishingly high rates of this condition. Development of anemia in this population is also comparable to previous incidence reports.

Drawbacks of this study include its retrospective nature, lack of control, and the fact that different cancers were included. Although acute leukemia and lymphoma patients had a high incidence of anemia with lower hemoglobin levels, their chances of recovery with remission may be better than some other cancers. Identification of anemia in these patients may or may not affect patient outcomes.

The value of studying anemia in this population would come from correlating the length of presence of the cancer, hemoglobin levels, and survival. This correlation was not done. However, had it been studied, this correlation would lead other investigators to perform studies on intervention and outcome. This analysis would also help address the controversy of whether hemoglobin is a reflection of the severity of the underling disease, as opposed to being an independent marker of survival.