Case 25-2004: A Woman with Severe Obesity, Diabetes, and Hypertension
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《新英格兰医药杂志》
To the Editor: Pratt and colleagues (Aug. 12 issue)1 provide an excellent discussion of the multidisciplinary treatment of a severely obese woman. One point that deserves further discussion is the evidence base, or lack thereof, behind the use of bariatric surgery. To date, no randomized, controlled trials or prospective cohort studies have reported a reduction in the incidence of myocardial infarction, stroke, or death with surgical treatment. The Swedish Obese Subjects study has reported a lower incidence of diabetes (odds ratio, 0.16; 95 percent confidence interval, 0.07 to 0.36) in surgically treated patients than in matched controls but not a lower incidence of hypertension or a reduction in medication costs.2,3
The complication rates reported by large, specialized centers in highly selective patient populations may underestimate the morbidity and mortality associated with bariatric procedures. The lack of suitable alternative therapies for severely obese persons should not be used as an excuse to forgo the collection of methodologically rigorous data. With the dramatic rise in the number of surgeries performed in the United States in the past decade,4 it is vital the effect of bariatric surgery on cardiovascular-related morbidity and mortality be evaluated.
Raj Padwal, M.D.
University of Alberta
Edmonton, AB T6G 2B7, Canada
rpadwal@ualberta.ca
References
Case Records of the Massachusetts General Hospital (Case 25-2004). N Engl J Med 2004;351:696-705.
Sjostrom CD, Peltonen M, Wedel H, Sjostrom L. Differentiated long-term effects of intentional weight loss on diabetes and hypertension. Hypertension 2000;36:20-25.
Narbro K, Agren G, Jonsson E, Naslund I, Sjostrom L, Peltonen M. Pharmaceutical costs in obese individuals: comparison with a randomly selected population sample and long-term changes after conventional and surgical treatment: the SOS intervention study. Arch Intern Med 2002;162:2061-2069.
Steinbrook R. Surgery for severe obesity. N Engl J Med 2004;350:1075-1079.
To the Editor: The patient described by Pratt and colleagues was found before undergoing bariatric surgery to have vitamin B12 deficiency, which — in the opinion of one of the discussants — occurs in a small number of patients with obesity who have followed many dieting programs. Drug-induced vitamin B12 deficiency should also be considered. The woman's diabetes was treated with metformin; this medication has been reported to reduce intestinal absorption of vitamin B12 and may lower serum vitamin B12 concentrations in up to 10 percent of patients, although it rarely causes megaloblastic anemia.1
Gracjan P. Podgorski, M.D.
Greenacres Hospital
Port Elizabeth 6057, South Africa
podgorsk@iafrica.com
References
Tomkin GH. Malabsorption of vitamin B12 in diabetic patients treated with phenformin: a comparison with metformin. Br Med J 1973;3:673-675.
The authors reply: Dr. Padwal highlights the importance of obtaining more information about the long-term benefits and risks of weight-loss surgery. Numerous studies have shown an improvement in coexisting conditions of obese patients after gastric bypass surgery. Buchwald and colleagues recently reported a meta-analysis, based on 136 primary studies, that showed an improvement in or complete resolution of type 2 diabetes mellitus, obstructive sleep apnea, hyperlipidemia, and hypertension in a substantial majority of patients after gastrointestinal weight-loss surgery.1 In addition, three large case–control cohort studies have shown substantial improvement in short- and long-term mortality after this surgery.2,3,4 The failure of surgery to generate sustained improvement in hypertension in the Swedish Obesity Subjects study is intriguing. This observation, however, is at odds with the results of several other published studies.1 Despite the preponderance of data supporting the benefit of weight-loss surgery, we agree with Dr. Padwal that further studies are needed. These studies should be designed to characterize the risks and benefits of different procedures, determine their effects on long-term outcomes and mortality, assess short- and long-term cost-effectiveness, and identify predictors of the outcome, to allow for better risk stratification of patients with obesity.
Dr. Podgorski makes an important point about the risk of vitamin B12 deficiency in patients with type 2 diabetes mellitus that is treated with metformin and describes a scenario that may well have contributed to our patient's low levels of vitamin B12 at the time of the initial evaluation. We and others have observed, however, that a small number of patients with severe obesity present with mild vitamin B12 deficiency, most of whom have not received metformin therapy. We have ascribed deficiencies of vitamin B12 and other nutrients in this population to the effect of nutrient-poor or unbalanced diets during years of attempted weight loss. For example, one recent study highlighted the prevalence of vitamin D deficiency in people with obesity.5 In the case we discussed, with oral supplementation, the patient's serum vitamin B12 level had increased to a normal value (461 pg per milliliter) by the time of her weight-loss surgery. Despite continued treatment with metformin, her vitamin B12 level has remained in the normal range with modest vitamin supplementation since surgery.
Janey S. Pratt, M.D.
Lee M. Kaplan, M.D., Ph.D.
Massachusetts General Hospital
Boston, MA 02114
References
Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA 2004;292:1724-1737.
Sjostrom CD, Lissner L, Wedel H, Sjostrom L. Reduction in incidence of diabetes, hypertension and lipid disturbances after intentional weight loss by bariatric surgery: the SOS Intervention Study. Obes Res 1999;7:477-484.
MacDonald KG Jr, Long SD, Swanson MS, et al. The gastric bypass operation reduces the progression and mortality of non-insulin-dependent diabetes mellitus. J Gastrointest Surg 1997;1:213-220.
Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg 2004;240:416-423.
Parikh SJ, Edelman M, Uwaifo GI, et al. The relationship between obesity and serum 1,25-dihydroxy vitamin D concentrations in healthy adults. J Clin Endocrinol Metab 2004;89:1196-1199.
The complication rates reported by large, specialized centers in highly selective patient populations may underestimate the morbidity and mortality associated with bariatric procedures. The lack of suitable alternative therapies for severely obese persons should not be used as an excuse to forgo the collection of methodologically rigorous data. With the dramatic rise in the number of surgeries performed in the United States in the past decade,4 it is vital the effect of bariatric surgery on cardiovascular-related morbidity and mortality be evaluated.
Raj Padwal, M.D.
University of Alberta
Edmonton, AB T6G 2B7, Canada
rpadwal@ualberta.ca
References
Case Records of the Massachusetts General Hospital (Case 25-2004). N Engl J Med 2004;351:696-705.
Sjostrom CD, Peltonen M, Wedel H, Sjostrom L. Differentiated long-term effects of intentional weight loss on diabetes and hypertension. Hypertension 2000;36:20-25.
Narbro K, Agren G, Jonsson E, Naslund I, Sjostrom L, Peltonen M. Pharmaceutical costs in obese individuals: comparison with a randomly selected population sample and long-term changes after conventional and surgical treatment: the SOS intervention study. Arch Intern Med 2002;162:2061-2069.
Steinbrook R. Surgery for severe obesity. N Engl J Med 2004;350:1075-1079.
To the Editor: The patient described by Pratt and colleagues was found before undergoing bariatric surgery to have vitamin B12 deficiency, which — in the opinion of one of the discussants — occurs in a small number of patients with obesity who have followed many dieting programs. Drug-induced vitamin B12 deficiency should also be considered. The woman's diabetes was treated with metformin; this medication has been reported to reduce intestinal absorption of vitamin B12 and may lower serum vitamin B12 concentrations in up to 10 percent of patients, although it rarely causes megaloblastic anemia.1
Gracjan P. Podgorski, M.D.
Greenacres Hospital
Port Elizabeth 6057, South Africa
podgorsk@iafrica.com
References
Tomkin GH. Malabsorption of vitamin B12 in diabetic patients treated with phenformin: a comparison with metformin. Br Med J 1973;3:673-675.
The authors reply: Dr. Padwal highlights the importance of obtaining more information about the long-term benefits and risks of weight-loss surgery. Numerous studies have shown an improvement in coexisting conditions of obese patients after gastric bypass surgery. Buchwald and colleagues recently reported a meta-analysis, based on 136 primary studies, that showed an improvement in or complete resolution of type 2 diabetes mellitus, obstructive sleep apnea, hyperlipidemia, and hypertension in a substantial majority of patients after gastrointestinal weight-loss surgery.1 In addition, three large case–control cohort studies have shown substantial improvement in short- and long-term mortality after this surgery.2,3,4 The failure of surgery to generate sustained improvement in hypertension in the Swedish Obesity Subjects study is intriguing. This observation, however, is at odds with the results of several other published studies.1 Despite the preponderance of data supporting the benefit of weight-loss surgery, we agree with Dr. Padwal that further studies are needed. These studies should be designed to characterize the risks and benefits of different procedures, determine their effects on long-term outcomes and mortality, assess short- and long-term cost-effectiveness, and identify predictors of the outcome, to allow for better risk stratification of patients with obesity.
Dr. Podgorski makes an important point about the risk of vitamin B12 deficiency in patients with type 2 diabetes mellitus that is treated with metformin and describes a scenario that may well have contributed to our patient's low levels of vitamin B12 at the time of the initial evaluation. We and others have observed, however, that a small number of patients with severe obesity present with mild vitamin B12 deficiency, most of whom have not received metformin therapy. We have ascribed deficiencies of vitamin B12 and other nutrients in this population to the effect of nutrient-poor or unbalanced diets during years of attempted weight loss. For example, one recent study highlighted the prevalence of vitamin D deficiency in people with obesity.5 In the case we discussed, with oral supplementation, the patient's serum vitamin B12 level had increased to a normal value (461 pg per milliliter) by the time of her weight-loss surgery. Despite continued treatment with metformin, her vitamin B12 level has remained in the normal range with modest vitamin supplementation since surgery.
Janey S. Pratt, M.D.
Lee M. Kaplan, M.D., Ph.D.
Massachusetts General Hospital
Boston, MA 02114
References
Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA 2004;292:1724-1737.
Sjostrom CD, Lissner L, Wedel H, Sjostrom L. Reduction in incidence of diabetes, hypertension and lipid disturbances after intentional weight loss by bariatric surgery: the SOS Intervention Study. Obes Res 1999;7:477-484.
MacDonald KG Jr, Long SD, Swanson MS, et al. The gastric bypass operation reduces the progression and mortality of non-insulin-dependent diabetes mellitus. J Gastrointest Surg 1997;1:213-220.
Christou NV, Sampalis JS, Liberman M, et al. Surgery decreases long-term mortality, morbidity, and health care use in morbidly obese patients. Ann Surg 2004;240:416-423.
Parikh SJ, Edelman M, Uwaifo GI, et al. The relationship between obesity and serum 1,25-dihydroxy vitamin D concentrations in healthy adults. J Clin Endocrinol Metab 2004;89:1196-1199.