These analyses estimate 10-year and lifetime gross per capita savings when Medicare beneficiaries with overweight (and at least one weight-related comorbidity) and obesity lose 10% or 15% of body weight, whether that weight loss is temporary or permanent. Over ten years, gross per capita savings to the Medicare program range from $6,456 to $13,474 depending on BMI category, percent weight loss, and sustainability of weight loss. Aggregate savings to the Medicare program will depend on the number of seniors with overweight and obesity who take the medication, and the cost of drug to Medicare each year. Sustained weight loss is difficult to achieve via lifestyle intervention due to physiologic mediators of appetite that encourage weight re-gain. Until recently, the lack of effective medical therapies has left only bariatric surgery as an option for some patients. However, new obesity medications have the potential to produce and/or sustain these levels of weight loss, and this provides rationale and relevance for our analyses. Two obesity drugs have recently been approved by the FDA, namely phentermine/topiramate ER (Qsymia®) and lorcaserin (Belviq®). The manufacturer of a third drug, bupropion SR/naltrexone SR (Contrave®), has reached an agreement with the FDA to conduct a pre-approval cardiovascular outcomes trial.
In Phase III clinical trials, all three drugs have been studied in patients with obesity (BMI
) and overweight (BMI of 27–29.9) with weight-related co-morbidities, all of whom were provided lifestyle counseling and randomized to drug or placebo. While all three drugs produce significant weight loss relative to placebo, there is some variability in the degree of weight loss achieved. Specifically, 1-year studies demonstrate that lorcaserin treatment was associated with a 5.8% weight loss compared to 2.2–2.8% for placebo [10
], and bupropion SR/naltrexone SR led to 6.1 to 6.4% weight loss as compared with 1.2–1.3% for placebo [12
]. However, phentermine/topiramate ER produced the magnitude of weight loss that is in keeping with the savings upon which our model is predicated (i.e., 9.8% weight loss in patients with two or more comorbidities vs 1.2% for placebo and 10.9% in severe/extreme obesity vs 1.6% for placebo) [14
]. Further, a long-term (2-year) clinical trial found sustained weight loss with continued treatment (SEQUEL), thus the gross per capita savings may be more in line with the permanent weight loss figures [8
]. This trial also found reductions in fasting glucose and fasting insulin, and resulted in a 54% and 76% (depending on the dose) reduction in the annualized incidence rate for the progression to type 2 diabetes among all patients studied [8
Because the fastest growing obesity category in the United States includes those individuals with BMI
50, it is important to consider the potential efficacy of medication in this population. The EQUIP study is the only phase III trial that did not specifically exclude subjects with extreme obesity (i.e., BMI ≥ 45). The average BMI of the study was 42, which represents the prototypical patient who is referred for bariatric surgery. In this population, one-year weight loss at the highest dose of phentermine/topiramate ER was 10.9% (vs 1.6% for placebo) for the Intent-to-Treat (ITT) analysis and 14.4% for Completers (vs 2.1% for placebo) [15
]. Importantly from both a clinical and cost perspective, significant weight loss (8–10%) occurred within 3 months of treatment, suggesting that non-responders may be identified early. Two-thirds of treated subjects who completed one year of therapy (“Completers”) achieved the NIH target of
10% of body weight, and almost half lost
15%, regardless of baseline BMI, suggesting that individuals with extreme obesity can achieve significant weight loss without surgery.
The CONQUER trial evaluated patients with a minimum of two obesity-related co-morbidities [14
]. This is somewhat analogous to the Medicare population, as 93% of Medicare beneficiaries have at least one obesity-related condition [16
]. The highest dose of phentermine/topiramate ER achieved 9.8% and 12.4% weight loss after one year in the ITT and Completer analyses, respectively, (vs 1.2% and 1.6% for placebo), and showed comparable weight loss regardless of age (~10% of subjects were
65 years of age) [14
]. The one-year extension of this study (SEQUEL) demonstrated the durability of the response with sustained weight loss of 10.5% (vs 1.8% for placebo) for the ITT analysis over the two-year period [8
]. In each of these studies, weight loss of this magnitude was associated with improvements in cardiometabolic risk factors, including blood pressure, fasting glucose, fasting insulin and lipid profiles, which is in keeping with the risk reductions in our model upon which the Medicare savings are based.
Table indicates that each senior with obesity who permanently loses 15% of weight saves Medicare, on average, more than $12,000 in gross savings over a 10-year period. It is therefore evident that effectively treating obesity with medication can be cost-effective. Taking the average of the published Wholesale Acquisition Costs (WAC) for both the recommended and top dosage strengths of phentermine/topiramate ER, and assuming a Medicare Part D tier-3 co-pay of $70 per month, net
per capita savings to Medicare are anticipated to be almost $3,000 over 10 years. Similar calculations for beneficiaries with class II obesity (BMI
35) show even greater net
per capita savings of almost $4,000 over 10 years. These net savings assume continual treatment with phentermine/topiramate ER throughout the 10-year period because it is now recognized that obesity is a chronic disease that requires ongoing intervention to sustain weight loss. The chronic nature of obesity treatment is recognized in the approved indication for phentermine/topiramate ER, which is an adjunct to a reduced calorie diet and increased physical activity for chronic
weight management in adults with obesity (BMI
30), or overweight (BMI
27) with at least one weight-related comorbidity. The objective of pharmacotherapy is to counteract the underlying pathology of obesity, which is the dysregulation of physiologic mediators that affect appetite and satiety. Discontinuation of pharmacotherapy after successful weight loss removes this physiologic counterbalance and is likely to lead to weight regain; hence, there is no maximum time with respect to treatment duration, regardless of the resulting BMI. This is analogous to the continuation of anti-diabetic or anti-hypertensive therapy after reaching an HbA1c target or adequately controlling blood pressure. In both situations, therapy would be continued as the underlying pathology is still present.
It is important to note that these savings do not take into consideration the reduction in dose or number of concomitant medications used to treat the complications of obesity, such as anti-hypertensive agents or drugs used to treat type 2 diabetes. Clinical trials demonstrated that patients taking phentermine/topiramate ER achieved reductions in HbA1c and decreased blood pressure, despite reductions in related medications aimed at reaching recommended therapeutic targets.