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Research Papers
- Prospective study of a laparoscopically placed, adjustable gastric band in the treatment of morbid obesity.
O'Brien P, Brown W, Smith A, McMurrick P, Stephens M,
British Journal of Surgery, 1999 86:113-118
This is the initial report of our experience. It covers perioperative and late complications and changes in weight loss and health in the first 300 patients treated.
- Gastroesophageal reflux in obesity: The effect of Lap Band placement.
Dixon J, O’Brien P,
Obesity Surgery, 1999; 9: 527-531.
A study of the prevalence of gastroesophageal reflux in an obese population and of the effects of Lap-Band placement on the disease. The Lap-Band provides effective and early control of this disease.
- Marked improvement in Asthma after Lap Band Surgery for Morbid Obesity.
Dixon J, Chapman L, O'Brien P,
Obesity Surgery, 1999; 9: 385-389.
Asthma is not generally seen as a comorbidity of obesity. We found the prevalence in our patients to be twice the matched community norm and the placement of the Lap-Band was associated with marked improvement in the severity of the disease.
- Revisional surgery for morbid obesity – Conversion to the Lap Band.
O’Brien PE, Brown WA, Dixon JB,
Obesity Surgery 2000; 10: 557-563. Previously, failed gastric stapling procedures were known generally to do poorly when repair of the defect – stenosis, dilatation, dehiscence – was attempted. We have converted a group of these patients to Lap-Band and we found that their subsequent progress was equal to that of our primary Lap-Band patients.
- Elevated homocysteine levels with weight loss after gastric restrictive surgery: higher folate and vitamin B12 levels required to maintain homocysteine level.
Dixon JB, Dixon ME, O’Brien PE,
Int. J. of Obesity. 2001; 25: 219-227.
Homocysteine should be maintained in the normal range to minimize cardiovascular risk. Weight loss tends to push up the homocysteine levels. Folate and Vit B12 reduce the level. These vitamins should be prescribed even if serum levels are normal. We can detect in our patients who is taking their vitamin supplement by looking at their homocysteine levels.
- Elevated Homocysteine with weight loss (Editorial)
Dixon JB, Obesity Surgery.
2001; 11: 537-538
Homocysteine is an important amino acid being an independent marker for risk of cardiac disease along with obesity, smoking and elevated cholesterol. It tends to rise with weight loss. This editorial emphasizes the importance of monitoring homocysteine and of ensuring your patient takes adequate replacement of folic acid and Vit B12 which will minimize the rise.
- A disparity between conventional lipid and insulin resistance markers at BMI levels greater than 34 kg/m2.
Dixon JB, O’Brien PE,
Int. J. Obesity. 2001; 25: 793-797.
Dyslipidemia is one of the independent markers of cardiovascular risk, along with obesity, hypertension, imparied glucose tolerance and elevated homocysteine. How different are the lipid profiles of the severely obese in comparison with the community norms? This study compares the profiles for an Australian population.
- Preoperative predictors of weight loss at 1 year after Lap Band surgery.
Dixon JB, Dixon ME, O’Brien PE,
Obesity Surgery. 2001; 11(2): 200 - 207. Who will do well and who will not do so well? These are important questions. We looked for the answers in our extensive database and identified one group who will do better than the rest, and several groups who do not do so well. However, none did so badly that they should not have the procedure.
- Non-alcoholic fatty liver disease: Predictors of non-alcoholic steatohepatitis and liver fibrosis in the severely obese.
Dixon JB, Bhathal PS, O’Brien PE,
Gastroenterology. 2001; 121: 91-100. NASH is a major concern to the hepatologist. It appears to be increasing in prevalence, it can lead to cirrhosis and the impact of weight loss needs to be established. When should the obese patient with abnormal LFTs have a liver biopsy? We have studied 100 patients with liver biopsy and a broad clinical and biochemical screening and have established predictors that indicate if NASH is likely to be present.
- Pregnancy after Lap Band surgery: Management of the band to achieve healthy weight outcomes.
Dixon JB, Dixon ME, O’Brien PE,
Obesity Surgery. 2001; 11(1): 59-66.
Homocysteine is an important amino acid being an independent marker for risk of cardiac disease along with obesity, smoking and elevated cholesterol. It tends to rise with weight loss. This editorial emphasizes the importance of monitoring homocysteine and of ensuring your patient takes adequate replacement of folic acid and Vit B12 which will minimize the rise.
- Improved quality of life after Lap Band placement – Influence of time, weight loss and comorbidities.
Dixon JB, Dixon ME, O’Brien PE,
Obesity Research. 2001; 9(11): 713-721
Quality of life is one of the key outcomes which should show improvement to justify a treatment for obesity. We have used the SF-36 to document major improvement associated with weight loss after Lap-Band placement. The dramatic improvement is sustained for the four years of the study.
- Sleep disturbance and obesity: changes following surgically induced weight loss.
Dixon JB, Schachter LM, O’Brien PE,
Archives of Internal Medicine. 2001; 161: 102-106.
At least one of the major disturbances with sleep, particularly habitual snoring, sleep apnea, datime somnolence and poor sleep quality, are almost universal in the morbidly obese. Weight loss in 317 post Lap-Band patients had a profound effect on all these problems with a reduction of observed sleep apnea fro 33% to 2%.
- Alcohol Consumption in the Severely Obese: Relationship with the Metabolic Syndrome
Dixon JB, Dixon ME, O’Brien PE,
Obesity Research 2002; 10:245-252
Moderate alcohol consumption is associated with a range of health benefits including reduced cardiovscular mortality. The “French Paradox” describes a reduction in heart attacks in wine drinking areas in spite of diets high in saturated fats. This study looks at the relationship between alcohol intake and type 2 diabetes, insulin resistance and known cardiovascular risk factors in the severely obese.
- Light to Moderate Alcohol Consumption: Obesity and the Metabolic Syndrome
Dixon J, Dixon A, O’Brien P,
American Journal of Bariatric Medicine, 2002; 17:11-14
A review paper summarising the benefits across a broad area of health for light to moderate alcohol intake.
- Body image: Appearance orientation and evaluation in the severely obese and post-obese.
Dixon JB, Dixon ME, O’Brien PE,
Obesity Surgery 2002; 12:65-71
The obese appear to have just as much focus on the importance of appearance as the general population but their evaluation of their own appearance is severe. They are their own worst critics. After weight loss, they show a marked improvement in their evaluation of their own appearance, with positive correlations with the extent of weight loss and with the improvements in quality of life.
- Health outcomes of severely obese type 2 diabetic subjects one year after laparoscopic adjustable gastric banding.
Dixon JB, O’Brien PE,
Diabetes Care. 2002. 25:2 356-363
Type 2 diabetes is an epidemic parallelling the rise in obesity and is arguably the most important single health problem that arises from obesity. Weight loss after Lap-Band placement has a profound effect on this disease. Given the safety and simplicity of Lap-Band placement, this approach to weight loss has the potential to offer major benefit to this common and lethal disease.
- Reduced plasma homocysteine in red wine consumers: A potential contributor to reduced cardiovascular risk status.
Dixon JB, Dixon ME, O’Brien PE,
Eur. J. Clin. Nutri. 2002; 56:608-614
Good news! Modest alcohol intake (< 100 g / week), in particular red wine, is associated with the most optimal levels of homocysteine and therefore reduced cardiovascular risk when compared with non drinkers. Please note that only Australian red wine was tested in this study!
- The Laparoscopic Adjustable Gastric Band (Lap-Band®): A Prospective Study of Medium-Term Effects on Weight, Health and Quality of Life
Paul E. O’Brien, John B. Dixon, Wendy Brown, Linda M. Schachter, Leon Chapman, Anthony J. Burn, Maureen E. Dixon, Carlos Scheinkestel, Christine Halket, Lisa J. Sutherland, Anna Korin, Peter Baquie.
Obesity Surgery, 2002; 12:652-660
This paper provides a global view of our experience with the Lap-Band. It is a prospective study of 700 consecutive Lap-Band patients followed for up to 6 years. The outcome measures include perioperative and late complications, extent and pattern of weight loss, the changes in a range of common comorbidities and the effects on quality of life.
- Lipid profile in the severely obese: Changes with weight loss following Lap Band surgery.
Dixon JB, Dixon ME, O’Brien PE,
Obesity Research 2002; 10:903-910
515 patients were followed with conventional lipid profiles for up to 4 years after Lap-Band placement. Triglcerides, HDL-cholesterol and the ratio of total cholesterol to HDL-C improved markedly and remained so for the 4 yr follow-up. The extent of improvement coulde be predicted from the fall in blood glucose, the improvement in insulin sensitivity and the extent of weight loss.
- Neck circumference - a good predictor of raised insulin and free androgen index in obese pre-menopausal women: Changes with weight loss.
Dixon JB, O’Brien PE,
Clinical Endocrinology 2002; 57:769-78.
Neck circumference is so easy to measure and so valuable that it must be a part of each initial clinical evaluation of an obese patient. We have already shown how it is the best predictor of sleep apnea. In this study we now show that it correlates well with the components of the polycystic ovary syndrome – androgen excess, insulin resistance in premenopausal women.
- Sweet eating is not a predictor of outcome after Lap-Band placement. Can we finally bury the myth?
Hudson SM, Dixon JB, O’Brien PE,
Obesity Surgery 2002; 12:789-94.
The sweet eaters certainly get bad press. Based on a single small study, they have been maligned for years, banished to the land of malabsorption because they were not considered good enough for the restrictive option. We reexamine this thesis and conclude that they have been punished enough.
- Sweet Eating is not a Predictor of Outcome after Lap-Band® Placement? A Reply to a Letter to the Editor
O’Brien PE, Dixon JB, Hudson S.
Obesity Surgery 2003; 13:468-71.
We explore the problems of small sub-group analyses in association with randomized controlled trials; how a small incidental finding can lead us down the wrong path and how a receptive audience will believe just what they want to hear. A plea for careful evidence based research.
- Obesity – the extent of the problem
O’Brien PE, Dixon JB,
The American Journal of Surgery 2002; 184:S4-8.
Obesity is now our worst pathogen. This is a review paper covering the prevalence of obesity, its impact on survival and its effects on health.
- Selecting the optimal patient for Lap-Band placement
Dixon JB, O’Brien PE,
The American Journal of Surgery 2002; 184:S17-20.
With the Lap-Band, we now have a safe, effective and acceptable approach to managing weight loss. How do we select those who will benefit the most? How do we identify those who are expected not to be helped? This paper reviews the data which enable us to predict who will do well and who will not.
- Patient management after LAP-BAND placement Favretti F, Paul E.
Favretti F, Paul E. O’Brien, John B. Dixon,
The American Journal of Surgery. 2002; 184:S38-41.
Good follow-up is an important element in the management of any chronic disease – obesity is no exception. This paper details the important elements in management of sever obesity after Lap-Band® surgery. Band adjustment is a key to success and two methods of adjustment are described.
- The outcomes after Lap-Band placement: 1. Weight loss, early and late complications – the International experience
O’Brien PE and Dixon JB,
The American Journal of Surgery 2002; 184:S42-5.
As part of a symposium on the Lap-Band in the management of obesity, this paper reviews the outcomes which have been reported from centers outside the USA. The review covers mortality, early postoperative morbidity, late morbidity and weight loss.
- Outcomes after Lap-Band placement: 3. Changes in comorbidities and improvements in quality of life.
Dixon JB and O’Brien PE,
The American Journal of Surgery 2002;184:S51-4.
Continuing the Lap-Band symposium, this paper is focussed particularly on the changes in health and quality of life that have been reported internationally after Lap-Band placement.
- A Rational Approach to Cholelithiasis in Bariatric
O’Brien PE and Dixon JB,
Archives of Surgery 2003; 138:908-12.
Gallstones are more common in the obese population and may be formed during rapid weight loss. We demonstrate that the gentle weight loss following Lap-Band® surgery does not increase the risk of symptomatic cholelithiasis. We recommend noninterventionist approach to the gallbladder in those presenting for surgery. Results contrast with those of RYGB.
- Cardiovascular benefit of light to moderate alcohol consumption Dixon AFR,
Dixon JB and Paul E O’Brien.
The Australian Family Physician 2003; 32:649-52.
Our research into comorbidity in severely obese patients has revealed substantial benefits of light to moderate alcohol consumption. This review for the general practitioner presents, more broadly, the now considerable evidence base for benefit and provides recommendations.
- Improvements in insulin sensitivity and beta cell function (HOMA) with weight loss in the severely obese.
Dixon JB, Dixon AF, O’Brien PE,
Diabetic Medicine 2003; 20:127-34.
The obese, particularly the centrally obese, have high risk of type 2 diabetes because they are insulin resistant and the pancreatic beta cells fail to generate sufficient insulin to compensate.Weight loss reduces the insulin resistance. Does it help the beta cells? We studied this in 254 patients before and at one year after Lap-Band placement. The results indicate, not only that we should treat the obesity of types 2 diabetes, but that we should treat it early.
- Laproscopic Adjustable Gastric Banding in the Treatment of Morbid Obesity
O’Brien PE and Dixon JB,
Archives of Surgery 2003;138:376-382
A report of the overall world experience to date with Lap-Band placement, including details of the experience from our own series.
- Lap-Band®: Outcomes and Results
O’Brien PE and Dixon JB
, Journal of Laparoendoscopic & Advanced Surgical Techniques 2003; 13:265-270
This is a review paper as a part of a symposium on Bariatric Surgery and includes discussion of the weight loss and health outcomes of Lap-Band placement.
- Predicting sleep apnea and excessive day sleepiness in the severely obese: Indicators for polysomnography
Dixon JB, Schachter LM and O’Brien PE,
Chest 2003; 123:1134-41.
Who should you test for obstructive sleep apnea? It is expensiveand time-consuming. Can we narrow down the group at risk? What are the best predictors? How specific? How sensitive? This is the challenge taken on in this paper, in which 100 severely obese who show clinical grounds for OSA, are analysed.
- Laparoscopic Adjustable Gastric Banding for Severe Obesity: An Important Role for the Bariatric Physician
Dixon JB and O’Brien PE,
American Journal of Bariatric Medicine 2002; 18:15-20
There are so many severely obese people that we cannot expect surgeons to be able to care for all of them. The effectiveness of surgery is so clearly head and shoulders above current medical therapy that there is a great need to broaden the workload. The Bariatric physician is ideally placed to play a key role in selection, evaluation and ongoing care of surgically treated patients.
- The effects of obesity on asthma
Dixon JB,
In: Progress in obesity Research: 9 Editors Medeiros-Neto G, Halpern A, Bouchard C. 2003 Published by John Libbley Eurotext;
This invited review explores the emerging relationship between obesity and asthma. We have demonstrated that asthma improves dramatically with weight loss. This is an area of important future clinical research.
- Depression in association with severe obesity: Changes with weight loss.
Dixon JB, Dixon ME, O’Brien PE,
Archives of Internal Medicine 2003; 163:2058-65.
What comes first – the depression which makes you eat too much or the obesity which makes you depressed? The Beck Depression Inventory is a validated marker for clinical depression. In 487 obese patients, the initial BDI was in the mild/moderate depresion range. The worst of these were the younger female with poor body image. Lap-Band placement and subsequent weight loss lead to marked improvement in BDI which has remained for 4 yr of follow-up. It would appear that the obesity is often the primary problem.
- Laparoscopic adjustable gastric banding in the treatment of obesity: A systematic literature review
Andrew E. Chapman, George Kiroff, Philip Game, Bruce Foster, Paul O’Brien, John Ham, and Guy J. Maddern.
Surgery, Volume 135, Number 3, 326-351
An important and comprehensive systematic review of all obesity surgery outcomes from the LAGB in comparison with RYGB and VBG, looking at safety and efficacy.
- Patient motivation for Bariatric surgery: Characteristics and impact on outcomes
Marije Libeton, John B Dixon, Cheryl Laurie and Paul E O’Brien
Obesity Surgery, 2004; 14: 392-3398
A study of why people seek Bariatric surgery and the relationship between the main reason and the outcomes.
- Obesity is a surgical disease: overview of obesity and bariatric surgery
Paul E. O'Brien , John B. Dixon and Wendy Brown ANZ J.
Surg. 2004; 74: 200–204
This is an overview of the current status of Bariatric surgery in Australia with emphasis on its rapid growth as an important treatment for obesity and its co-morbidities.
- Non-alcoholic Fatty Liver Disease: Improvement in liver histology with weight loss.
Dixon JB, Bhathal P, O’Brien PE,
Hepatology, 2004; 39:1647-1654
Liver biopsy before and after weight loss demonstrates marked improvement in the features of NASH in association with weight loss.
- Laparoscopic Adjustable Gastric Banding - ASBS Consensus Conference 2004
John B Dixon,
Jaime Ponce Surgery for Obesity and Related Diseases, 2005; 1: 310-316
A review paper of the outcomes of laparoscopic adjustable gastric banding, provided to enable the ASBS to consider new guidelines in Bariatric surgery.
- Research update and opportunities III – ASBS Consensus Conference 2004 John B Dixon
Surgery for Obesity and Related Diseases, 2005; 1: 348-352
Obesity surgery is rapidly expanding and has a very bright future. This paper presented to the 2004 ASBS consensus conference outlines a framework for future research directions in Bariatric surgery. A framework that CORE has developed and is actively pursuing.
- Laparoscopic Adjustable Gastric Banding induces prolonged satiety: A randomized blind crossover study.
Andrew F.R Dixon, John B. Dixon, Paul E. O’Brien
Journal of Clinical Endocrinology & Metabolism, 2005; 90(2): 813-819
Satiety is shown in this blinded trial to be a key effect of the Lap Band. This appears to be at least as important as the restrictive effect characterized as fullness noted soon after eating a small amount.
- Surgery as an effective early intervention for diabesity
John B Dixon, Walter J Pories, Paul E O’Brien, Phillip R Schauer, Paul Zimmet
Diabetes Care, 2005; 28(2): 472-474
An editorial reviewing the data on the effectiveness of surgically induced weight loss on diabetes, and questioning the reluctance of physicians to respond appropriately to the data.
- Polysomnography before and after weight loss in obese patients with severe sleep apnea.
JB Dixon, LM Schachter and PE O’Brien
International Journal of Obesity, 2005: 1-7
Weight loss provides major improvement or resolution of OSA and CPAP requirements. It also reduces daytime sleepiness. Lap Band placement should be considered a broadly effective therapy for sleep apnea in the severely obese patient.
- Flaws in methods of evidence-based medicine may adversely affect public health directives
JG Kral, JB Dixon, FF Horber, S Rossner, S Stiles, JS Torgerson, and HJ Sugerman
Surgery, 2005; 137: 279-284
The paper discusses the flaws in applying EBM methods to many areas of surgical practice and recommends alternative approaches to assessing the effects of Bariatric surgery on health.
- Preoxygenation is more effective in the 25° head-up position than in the supine position in severely obese patients
Benjamin J Dixon, John B Dixon, Jennifer R Carden, Anthony J Burn, Linda M Schachter, Julie M Playfair, Cheryl P Laurie, Paul E O’Brien
Anesthesiology, 2005; 102: 1110-1115
This randomised controlled trial shows that patients in the head-up position desaturate more slowly after pre-oxygenation than in the supine position. This provides additional time for intubation in at-risk patients.
- Permeability of the silicone membrane in Laparoscopic Adjustable Gastric Bands has important clinical implications
John B Dixon, Paul E O’Brien
Obesity Surgery, 2005; 15: 624-629
The balloon of all LAGBs is not totally impermeable to saline. Over a period of months there will be a predictable loss of volume from the system and additional fluid is needed to retain the satiety-inducing effects.
- Sustained weight loss in obese subjects has benefits that are independent of attained weight.
John B Dixon, Margaret Anderson, David Cameron-Smith and Paul E O’Brien
Obesity Research, 2004; 12(11): 1895-1902
This study shows improved health benefits of reducing weight to BMI 30 -35 range compared to being at BMI 30 – 35 all along.
- Severe gastroesophageal reflux is associated with reduced carbon monoxide diffusing capacity.
Linda M Schachter, John Dixon, Robert Pierce and Paul O‘Brien
CHEST, 2003;123: 1932-1938
Gas exchange was significantly reduced in 147 severely obese with gastroesophageal reflux.
- Profibrotic polymorphisms predictive of advanced liver fibrosis in the severely obese.
John B Dixon, Prithi S Bhathal, Julie R Jonsson, Andrew F Dixon, Elizabeth E Powell, Paul E O’Brien
Journal of Hepatology, 2003; 39: 967-971
The study identifies two genotypes associated with increased risk of fibrosis in non-alcoholic fatty liver disease.
- Shoulder pain is a common problem following Laparoscopic Adjustable Gastric Banding surgery
John B Dixon, Yigal Reuben, Christine Halket, Paul E O’Brien
Obesity Surgery, 2005; 15: 1-7
Shoulder tip pain is one of the common causes of postoperative discomfort after upper abdominal laparoscopic surgery. The observational study seeks to identify the factors which predict the presence and duration of this troublesome symptom.
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