Introduction
Obesity is a major health issue that causes more annual deaths in the U.S. than breast and colon cancer do (Patterson, Urbach, & Swanstrom, 2003, p. 379). Obesity affects the primary systems of an organism, such as cardiovascular, urogenital, reproductive, and so on. There are various methods to treat morbid obesity, including surgical interventions, pharmacological therapy, and lifestyle and diet changes. The study by Patterson et al. (2003) aims to compare the effectiveness of diet and exercise therapy with laparoscopic Roux-en-Y gastric bypass surgery in treating morbidly obese patients with a BMI over 40.
Background of the Study
As noted by Patterson et al. (2003), there were not enough quantitative clinical trials to compare the efficiency of conventional lifestyle change therapy, including diet and exercise, with bariatric surgical intervention results. Determining a more efficient weight-loss method would help many patients with a significant degree of obesity to increase their life expectancy and to live a healthier life. The authors of the study outline the importance of the research problem on the first two pages. First, they explain the prevalence of the condition and the threats associated with it. For instance, Patterson et al. (2003) write: “More than 25% of American adults are obese, and the percentage is rising. In the United States (US), an estimated 300,000 deaths per year are attributable to obesity” (p. 379). The authors also mention health complications that arise out of obesity, such as type II diabetes, cardiac disease, hypertension, urinary stress incontinence, infertility, and degenerative joint disease (Patterson et al., 2003, p. 379).
Patterson et al. (2003) state that, even though a proper therapy helps the patients to lose weight, it is still unclear as to which method is more effective in the long term due to the lack of sufficient clinical trials: “randomized controlled trials of medical versus surgical therapy for morbid obesity are rare; in fact, we are only aware of one” (p. 380). The goal of the study was thus to perform a comparative quantitative analysis of the two methods of treatment – diet and exercise therapy versus laparoscopic Roux-en-Y gastric bypass surgery by evaluating not just the actual weight loss in the short-term, but also relative life expectancy figures following the intervention. The authors aimed to answer several research questions, for instance, “Which method achieves better short-term results?”, “Which method provides durable results” and, finally, “Which method allows to improve the patients’ health and life expectancy overall?”. All of the research questions posed by the authors were consistent with the aim and scope of the study.
Method
The authors utilized a Markov decision analysis model to provide a mathematical framework for modeling the results and evaluating survival and weight loss rates in the patients. The baseline scenario assumed the patient of interest to be a 45-year old woman with a BMI of 40 (Patterson et al., 2003, p. 380). This assumption was based on the typical patient’s portrait, derived from previous practice (Patterson et al., 2003, p. 380). The determinant of a successful weight loss was a 60% decrease in excess body weight. To prove the applicability of the chosen treatment strategy, the authors built a decision tree using a special software package for medical decision analysis. Markov model was applied to simulate the decision outcomes. The authors explained that this model “allows a hypothetical cohort of patients to ‘cycle’ within different health states in the tree, and allows crossover between different health states where appropriate” (Patterson et al., 2003, p. 380). Sensitivity analysis was applied to all estimated probabilities, such as operative mortality, the relative risk of death from obesity, and the probability of weight regain after surgery.
Results
Using previously conducted randomized controlled trials, the researchers found that low-calorie diets reduce body weight by an average of 8% over a year, while the combination of diet and exercise results in an additional weight loss of 4.2 lb (Patterson et al., 2003, p. 380). The overall probability of weight loss following a diet and exercise program was 20%, whereas the probability of weight loss following a gastric bypass surgery was 80%. Life expectancy after the laparoscopic Roux-en-Y gastric bypass was 69.7 years and 67.3 years for the diet and exercise program (Patterson et al., 2003, p. 382). The authors concluded that the 2.4-year increase in life expectancy is substantial, especially when compared to the results of surgical intervention for other conditions: “For example, a Boston group compared staging laparotomy with no laparotomy for patients with early-stage Hodgkin’s disease, and found that surgery resulted in a gain in life expectancy of 9 months, or 7 quality-adjusted months” (Patterson et al., 2003, p. 383). The authors come to the conclusion that laparoscopic Roux-en-Y gastric bypass had a greater efficiency for treating severely obese patients than exercise and diet therapy. The authors’ conclusion is consistent with the results of the study.
Limitations
Patterson et al. (2003) outline several limitations to their method of study and analysis. For example, the use of estimates and assumptions, even when supported by a Markov decision analysis model and medical decision analysis, could be different from the results obtained in practical studies. Another limitation was the assumption of the successful weight loss being a decrease in BMI from 40 to 30 (Patterson et al., 2003, 383). Finally, the results for the life expectancy rate used in conclusion were not quality-adjusted: “There are no existing utility estimates for morbid obesity or for patients after laparoscopic gastric bypass or those undergoing diet and exercise therapy” (Patterson et al., 2003, p, 383).
Ethical Considerations
For this study, there were some ethical considerations that the authors failed to address. For instance, a lot of secondary research was considered, which means that the authors used patient data from previous research without informing the patients and obtaining their consent. Secondly, there is no mention that the present study was approved by the Institutional Review Board, which means that the risk-benefit analysis for this research has not been conducted. Furthermore, there are ethical issues associated with revealing life expectancy information as it might affect the people who fall under the patient categories examined in this research. Nevertheless, the authors did not disclose the patients’ names or other personal information that is considered confidential, so some ethical guidelines were still followed.
Conclusion
Overall, this is a thorough, well-founded study that addresses a major health issue that affects many developed countries. The authors were conscious and consistent in addressing the main research questions throughout the study and utilized an adequate method for yielding the results on the matter. However, there were still many limitations to the study that could have affected the results and conclusions presented by the authors, whereas many ethical issues regarding this type of research remained unaddressed by the researchers. With further research on the topic, this study could be used in nursing practice to improve the quality of treatment and care for patients with obesity.
References
Patterson, E. J., Urbach, D. R., & Swanstrom, L. L. (2003). A comparison of diet and exercise therapy versus laparoscopic Roux-en-Y gastric bypass surgery for morbid obesity: A decision analysis model. Journal of the American College of Surgeons, 196(3), 379-384. Web.