Dr. Arterburn discusses reassuring news from his PCORnet study of the most widely used anti-obesity drug in the United States.

By 大卫·阿特本，医学博士，公共卫生硕士, a senior investigator at 2022世界杯下注网站健康世界杯下注网站所 and an internal medicine physician at 华盛顿永久医疗集团

As time goes by, we’re recognizing more and more how chronic and tenacious obesity can be. 全面的, intensive interventions to achieve lifelong changes in lifestyle — including diet and exercise — are the cornerstone of treatment, 长期随访. 但这类项目对多达三分之一的患者无效. 6个月后体重反弹是很常见的, the point when such programs can yield weight loss of 5 percent to 10 percent.

Weight-loss medications are one way to help more people to have larger, 而且可能更持久, 对生活方式干预的反应, 正如安慰剂对照试验所显示的. 但这些药物往往不会被广泛使用, 主要是因为没有保险, 导致患者的自付费用很高, 但也因为担心副作用.

Phentermine is the most commonly used anti-obesity medication in the United States. 1959年，它被批准用于减肥, 肥胖的慢性本质也不为人所知. The Food and Drug Administration (FDA) limited treatment to 12 weeks or less. 相比之下, FDA批准了一种新的品牌组合药物, 芬特明/ Topiramate-CR (Qsymia), in 2012, 这是一年或更长时间的长期使用.

Many doctors prescribe phentermine, on its own, to patients for more than 12 weeks. And anecdotal reports from many of my colleagues suggested that it was helpful for many patients long-term. 但缺乏对其长期安全性和有效性的世界杯下注网站. 芬特明是一种廉价的非专利药物, 但是人们开始担心上瘾和, 因为它的作用, 心血管副作用. The medication is a stimulant, so it’s possible that it could raise blood pressure. We clearly needed more research to understand the benefits and risk of longer-term phentermine use.

填补知识空白

在我们的新 study, “Safety and Effectiveness of Longer-Term Phentermine Use: Clinical Outcomes from an Electronic Health Record Cohort,发表于 Obesity, my colleagues and I found evidence of better weight loss with longer-term use of phentermine — up to 2 years’ follow-up. And we didn’t find any link between longer-term use and risk of cardiovascular disease or death up to 3 years from starting phentermine.

要做到这一点 study, we used electronic health records from the Patient Outcomes Research to Advance Learning (PORTAL) cohort, part of the National Patient-Centered Clinical Research Network (PCORnet) initiative funded by the Patient-Centered Outcomes Research Institute (PCORI). This cohort included information from 8 health systems in the United States, 包括2022世界杯下注网站(南加州), Colorado, 西北, 华盛顿, Hawaii, 丹佛健康和健康伙伴(明尼苏达州). 这项世界杯下注网站是由我的长期合作伙伴领导的, 克里斯蒂娜·刘易斯, MD, MPH, SM, 在温斯顿-塞勒姆的维克森林医学院, NC.

We studied nearly 14,000 phentermine users, 8 in 10 of whom were women. 他们的平均身体质量指数是38，对于一个5英尺6英寸的人来说是235磅. But they included people with a BMI as low as 27, which is 168 pounds for a 5’ 6” person. (肥胖始于体重指数为30.) Three in 10 of them were prescribed phentermine for more than 3 months. 6个月时, a year, 服用芬特明2年后, weight loss was clinically significantly greater among people who used the medication longer-term (more than a year) or medium-term (more than112 days but less than a year) than in people who used it for only 3 months. The 144 people who used phentermine continuously for more than a year had kept off more than 7 percent of their baseline weight at 2 years.

It’s important to monitor patients for their response to phentermine treatment. About a third of people prescribed phentermine lost less than 3 percent of their weight within the first 3 months of starting the drug. 这些“无反应者”不应继续使用芬特明治疗, 因为他们不太可能从中获得临床益处. 相比之下, people who had an early response to the medication — losing at least 3 percent of their weight by 3 months — tended to have greater overall long-term success at weight loss with the aid of the medication.

就安全而言, 我们预计会看到血压升高, but instead found that systolic blood pressure was reduced at 24 months in long-term users of phentermine relative to short-term users. It’s possible that this decrease in blood pressure was due to sustained weight loss in the longer-term users of phentermine. 41 (0.百分之三),972 phentermine users experienced a major adverse event (36 cardiovascular events; 5 deaths), 但这些人都不是长期使用者.

对肥胖治疗的影响

世界杯下注网站受到观察性的限制, 不是随机对照试验, and by having a relatively small sample of long-term users — and it didn’t address the issue of possible addiction. 但由于芬特明的广泛可用性和低成本, our findings could have a significant impact on obesity treatment in people at low risk for heart disease.

Similar to what we have seen in studies of the combination medication Qsymia, it appears that some patients can safely maintain long-term weight loss with phentermine alone. Still, 直到FDA的政策有所改变, off-label longer-term prescribing of phentermine should be done cautiously with full consideration of the legal and medical licensure implications, 每个州都不一样.

更重要的是, 鉴于与其他减肥药相比，芬特明的成本较低, this study should motivate a future randomized trial to establish more definitively phentermine’s long-term efficacy and safety.