Prevalence of Vitamin D Insufficiency and Deficiency in Morbidly Obese Patients: A Comparison with Non-Obese Controls

Background Vitamin D deficiency is common in patients after bariatric surgery. However, obesity itself has also been associated with decreased vitamin D. The prevalence of vitamin D deficiency in obese persons has not previously been compared to non-obese controls when controlling for factors that could affect vitamin D status. Methods We evaluated 25 hydroxy vitamin D, iPTH, calcium, albumin, and creatinine in 41 patients undergoing Roux-en-Y gastric bypass. We then compared them to healthy non-obese controls matched for age, sex, race/ethnicity, and season of vitamin D measurement. Results Ninety percent of the pre-bariatric surgery patients had 25-OH-D levels <75 nmol/l, and 61% had 25-OH-D levels <50 nmol/l versus 32 and 12% in controls, respectively. Additionally, 49% of the pre-bariatric surgery patients had secondary hyperparathyroidism versus 2% of controls. These differences persisted after controlling for sunlight exposure and dietary intake of calcium and vitamin D. Mean calcium, corrected for albumin, and creatinine were not significantly different between the groups, but mean albumin levels were significantly lower among surgery patients. Conclusion Vitamin D deficiency is common in obese patients at the time of bariatric surgery and is also accompanied by secondary hyperparathyroidism approximately half the time. These findings suggest that vitamin D deficiency after bariatric surgery is multifactorial and in part caused by preoperative vitamin D deficiency rather than postoperative malabsorption alone. In this study, increased vitamin D deficiency in obese persons cannot be explained by a difference in calcium/vitamin D intake or sunlight exposure.     

Intra-abdominal Pressure in the Morbidly Obese

Background: Recent data suggests that increased intra-abdominal pressure (IAP) is one factor associated with the morbidity of morbidly obese patients, who have a BMI >35 kg/m². IAP has been proposed to be an abdominal compartment syndrome (ACS). This study investigated the characteristics of IAP in morbidly obese patients. Methods: 45 morbidly obese patients (mean BMI 55±2 kg/m²) had IAP measured using urinary bladder pressure. Results: The mean IAP for the morbidly obese group was 12±0.8 cmH₂O, increased when compared to controls (IAP=0±2 cmH₂O). The IAP correlated to the sagittal abdominal diameter, an index of the degree of central obesity (r=+0.83, P<0.02); however, it did not correlate to basal insulin, body weight, or BMI. The end-expiratory IAP did not change when measured after the laparotomy incision was made, but IAP measured in the last 15 patients increased during the first 2 postoperative days. The IAP for patients with pressure-related morbidity (gastroesophageal reflux disease, hernia, stress incontinence, diabetes, hypertension, and venous insufficiency) was 12±1 cmH₂O, while those without these morbidities had an IAP of 9±0.8 cmH₂O. Conclusion: We conclude that IAP is increased in morbid obesity. This increased IAP is a function of central obesity and is associated with increased morbidity. The degree of IAP elevation correlates with increased co-morbidities. We also conclude that elevation in IAP in morbid obesity is not a true ACS but represents a direct mass effect of the visceral obesity.     

Calcium Metabolism in the Morbidly Obese

Background: Morbidly obese patients are known to have abnormal calcium metabolism compared with the non-obese, but the clinical significance of this is unknown. Since surgical treatment of obesity may itself cause hyperparathyroidism, it is important to understand the preoperative physiology of these patients. Methods: 213 consecutive patients (M 37 : F 176, ages 21-68) presenting for surgical treatment of morbid obesity between October 2000 and June 2002 were prospectively evaluated. Preoperative levels of serum calcium corrected for albumin, alkaline phosphatase, parathyroid hormone (PTH), 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were measured. We recorded the prevalence of abnormalities in study parameters and correlated them with PTH levels. Results: Hyperparathyroidism (PTH >65 pg/ml) was present in 25.0% of subjects. By contrast, abnormalities of serum calcium were rare. The prevalence of hypocalcemia was 3.5%, and of hypercalcemia was 0.5%. Only 4.3% of patients had increased levels of alkaline phosphatase. 21.1% of patients had abnormally low levels of 25-hydroxyvitamin D (median 15 ng/ml), and 23.1% had increased levels of 1,25-dihydroxyvitamin D (median 49 pg/ml). PTH was positively correlated with BMI (r=.30, P=<.001) and 25-dihydroxyvitamin D (r=.27, P=.01), and was negatively correlated with alkaline phosphatase (r=.21, P=.02). There was no correlation between PTH and calcium, 1,25-dihydoxyvitamin D, age, or sex. Conclusions: Parathyroid hormone levels are increased in the morbidly obese and are positively correlated with BMI. Recognition of preoperative hyperparathyroidism is important because of the risk of attributing postoperative hyperparathyroidism to the effects of surgery. Further studies are needed to elucidate the cause of elevated PTH in these patients.     

Treatment of Urolithiasis in the Morbidly Obese

Background: Morbidly obese patients with urolithiasis present a therapeutic and diagnostic challenge to the Urologist. Management is reported and potential difficulties discussed. Methods: Morbidly obese patients (body mass index ≥ 40kg/m2) with stone disease were identified by retrospective review. Stone load was calculated and treatment modalities noted. Results: 18 renal units (kidneys) were treated in 17 patients. Of these, 2 required no treatment, 2 had open procedures, and 15 were treated with flexible ureteroscopy. Mean stone burden in patients treated with flexible ureteroscopy was 18 mm, but 8 patients had stone loads >15 mm and in these patients mean stone burden was 23 mm. All were successfully treated or rendered asymptomatic. There were no major complications. Conclusion: Obesity is increasingly prevalent and associated with a high incidence of co-morbidity and complications. Imaging can be difficult and treatment options are limited. Flexible ureteroscopy has proven to be the most successful treatment option, and can avoid the need for more invasive procedures. Furthermore, stone loads greater than normally acceptable can be successfully undertaken in these patients, and should be attempted due to problems associated with other techniques.     

Estimating Blood Volume in Obese and Morbidly Obese Patients

Preoperative assessment of blood volume (BV) is important for patients undergoing surgery. The mean value for indexed blood volume (_InBV) in normal weight adults is 70 mL/kg. Since _InBV decreases in a non-linear manner with increasing weight, this value cannot be used for obese and morbidly obese patients. We present an equation that allows estimation of _InBV over the entire range of body weights.     

Altered Olfactory Acuity in the Morbidly Obese

Background: Obese individuals have been reported to have a heightened desire for and ability to identify sweets when compared with leaner persons. Smell, like taste, may also be altered in obese persons compared with leaner subjects. This study was designed to determine if the sense of smell is different between morbidly obese and moderately obese individuals. Methods: 101 adult volunteers undergoing preoperative evaluation completed the 12-item Cross-Cultural Smell Identification Test (CC-SIT) before surgical intervention. Age, BMI, and smoking history were also obtained. Results: 101 subjects completed the preoperative CC-SIT (87 female, 14 male). Mean age of the subjects was 40 ± 12 years. Mean BMI was 42.5 ± 12.5 kg/m². 46 subjects (46%) had a BMI >45. 21 were smokers (21%). 9 subjects (9%), all female non-smokers, had a CC-SIT score representing olfactory dysfunction. Subjects with BMI >45 were more likely to have olfactory dysfunction than subjects with BMI <45 (16% vs 4%, P <0.05). Conclusion: Morbidly obese individuals are more likely than moderately obese individuals to demonstrate CC-SIT scores consistent with olfactory dysfunction. The reason for this is unclear but is probably related to metabolic changes occurring in morbidly obese individuals.     

Psychological Profile of the Morbidly Obese

Background: In the surgical treatment of morbid obesity, surgery on its own represents only one element. In fact, bariatric surgery is a forced behavior modification; in addition to surgery, psychological factors play an important role in its results. Because of the importance of the psychological factors and the possibility to intervene in them, there is a need for a better understanding of morbidly obese patients, especially those who are candidates for bariatric surgery. Thus, this article reviews their psychological profile. Methods: A systematic literature search identified relevant variables reflecting personality and psychopathology, eating behavior, social problems, and quality of life. Results: Morbidly obese patients are described as depressed, anxious,having poor impulse control, low self-esteem, and impaired quality of life. Dieting, rigid control, and disinhibition characterize their eating behavior. This seems to be especially true for morbidly obese patients seeking surgical treatment for their obesity. Conclusion: The existing literature about the characteristics of the morbidly obese is far from conclusive; this may in part be due to the use of poor methods of assessment.     

Postural Changes in Morbidly Obese Patients

Background: Postural deviations in morbidly obese individuals may contribute to low self-esteem and to long-term adverse effects on bones and joints. In a case-control study, the axial skeleton was investigated, to disclose the main abnormalities found in obese compared to non-obese groups. Methods: 2 groups were compared. Group 1, severely obese patients (n= 32), age 41.5 ± 8.2 years, BMI 49.4 ± 6.6 kg/m², 93.8% females, and group 2 non-obese (n= 30), age 43.5 ± 5.8 years, BMI 24.6 ± 5.1 kg/m², 96.7% females, had their posture analyzed through clinical examination and radiological imaging. Variables measured were anterior, lateral and posterior angular deviation from the vertical body axis at the head, shoulders, pelvis, Thales triangle, spine, knees, ankles and feet. Data are shown as a percentage of abnormal angles in the 2 groups. Results: On anterior analysis of the 2 groups, disturbances affected head (37.5% vs 13.3%), Thales angle (78.1% vs 53.3%), knees (84.4% vs 33.3%), legs (59.4% vs 30.0%) and support base (59.4% vs 26.7%) (P<0.05). On posterior view, the spine was the deranged segment (87.5% vs 36.7%) (P<0.05), and on lateral assessment, 100% of the results were abnormal. Conclusions: 1) Individuals with morbid obesity present important postural alterations. 2) Seriously altered posture was the rule for the obese population in this study, especially in the spine, knees and feet. 3) Most patients had compatible clinical complaints, but they rarely associated the bone and joint pain with the obesity and axial skeleton deviations. 4) Planned physical activity should be part of the treatment of severe obesity, in order to correct deviations, prevent new ones, and improve quality of life.     

Robot-Assisted Sleeve Gastrectomy in Morbidly Obese Versus Super Obese Patients

Background and Objectives:

This study evaluates our technique for robot-assisted sleeve gastrectomy for morbidly obese and super obese patients and our outcomes.

Methods:

A retrospective analysis of patients who underwent robot-assisted sleeve gastrectomy at a single center was performed. The procedure was performed with the da Vinci Si HD Surgical System (Intuitive Surgical, Sunnyvale, California). The staple line was imbricated with No. 2-0 polydioxanone in all cases. The super obese (body mass index ≥50 kg/m²) subset of patients was compared with the morbidly obese group in terms of demographic characteristics, comorbidities, operative times, perioperative complications, and excess body weight loss.

Results:

A total of 35 patients (15 female and 20 male patients) with a mean body mass index of 48.17 ± 11.7 kg/m² underwent robot-assisted sleeve gastrectomy. Of these patients, 11 were super obese and 24 were morbidly obese. The mean operative time was 116.3 ± 24.7 minutes, and the mean docking time was 8.9 ± 5.4 minutes. Mean blood loss was 19.36 ± 4.62 mL, and there were no complications, conversions, or perioperative deaths. When compared with the morbidly obese patients, the super obese patients showed no significant difference in operative time, blood loss, and length of hospital stay. There was a steep decline in operating room times after 10 cases of robot-assisted sleeve gastrectomy.

Conclusion:

This study shows the feasibility and safety of robot-assisted sleeve gastrectomy. Robotic assistance might help overcome the operative difficulties encountered in super obese patients. It shows a rapid reduction in operative times with the growing experience of the entire operative team. Robot-assisted sleeve gastrectomy can be a good procedure by which to introduce robotics in a bariatric surgery center before going on to perform Roux-en-Y gastric bypass and revision procedures.