Sendi Pedram, Palmer Andrew J, Hauri Philipp, Craig Bruce A, Horber Fritz F
Medical Informatics and Technology Assessment Research Group, Baar, Switzerland.
Obes Res. 2002 Apr;10(4):291-5. doi: 10.1038/oby.2002.40.
Morbid obesity is associated with premature death. Adjustable gastric banding may lead to substantial weight loss in patients with morbid obesity. Little is known about the impact of weight loss on survival after adjustable gastric banding. We therefore developed a mathematical model to estimate life expectancy in patients with a body mass index (BMI) > or =40 kg/m(2) undergoing bariatric surgery.
We developed a nonhomogeneous Markov chain consisting of five states: the absorbing state ("dead") and the four recurrent states BMI > or =40 kg/m(2), BMI 36 to 39 kg/m(2), BMI 32 to 35 kg/m(2), and BMI 25 to 31 kg/m(2). Scenarios of weight loss and age- and sex-dependent risk of death, as well as BMI-dependent excess mortality were extracted from life tables and published literature. All patients entered the model through the state of BMI > or =40 kg/m(2).
In men aged either 18 or 65 years at the time of surgery, who moved from the state BMI > or =40 kg/m(2) to the next lower state of BMI 36 to 39 kg/m(2), life expectancy increased by 3 and 0.7 years, respectively. In women aged either 18 or 65 years at the time of surgery, who moved from the state BMI > or =40 kg/m(2) to the next lower state BMI 36 to 39 kg/m(2), life expectancy increased by 4.5 and 2.6 years, respectively. Weight loss to lower BMI strata resulted in further gains of life expectancy in both men and women.
Within the limitations of the modeling study, adjustable gastric banding in patients with morbid obesity may substantially increase life expectancy.
病态肥胖与过早死亡相关。可调节胃束带术可能会使病态肥胖患者大幅减重。关于减重对可调节胃束带术后生存率的影响，人们了解甚少。因此，我们建立了一个数学模型来估计体重指数（BMI）≥40kg/m²的患者接受减肥手术后的预期寿命。
我们建立了一个非齐次马尔可夫链，包括五个状态：吸收状态（“死亡”）以及四个循环状态，即BMI≥40kg/m²、BMI 36至39kg/m²、BMI 32至35kg/m²和BMI 25至31kg/m²。从生命表和已发表的文献中提取了减重情况、年龄和性别相关的死亡风险以及BMI相关的额外死亡率。所有患者均通过BMI≥40kg/m²的状态进入该模型。
手术时年龄为18岁或65岁的男性，从BMI≥40kg/m²状态转变为下一个较低的BMI 36至39kg/m²状态时，预期寿命分别增加了3年和0.7年。手术时年龄为18岁或65岁的女性，从BMI≥40kg/m²状态转变为下一个较低的BMI 36至39kg/m²状态时，预期寿命分别增加了4.5年和2.6年。减重至较低的BMI分层会使男性和女性的预期寿命进一步增加。
在该建模研究的局限性范围内，病态肥胖患者接受可调节胃束带术可能会大幅提高预期寿命。
