Savings from Preventing Comorbid Conditions in Obese Patients

New Orleans—Patients who took the extended release combination of phentermine and topiramate and modified their lifestyle to manage obesity developed fewer comorbidities than they would have without treatment, according to an economic model. The authors noted that therapeutic intervention could lead to cost savings because of decreased incidences of hypertension, type 2 diabetes, and dyslipidemia.

Results were presented during a poster session at the ISPOR annual international meeting. The poster was titled The Potential Cost Savings Associated with Preventing the Development of Hypertension, Diabetes, and Dyslipidemia in an Obese Population.

The FDA approved phentermine/topiramate in July 2012 to be used with a reduced calorie diet and exercise to treat obese or overweight adults who have at least 1 condition related to their weight such as hypertension, type 2 diabetes, or dyslipidemia. The agency defined obese as people with a body mass index (BMI) of ≥30 kg/m² and overweight as a BMI of ≥27 kg/m².

According to the poster’s authors, 35.9% of adults ≥20 years of age have a BMI of ≥30 kg/m² (grade 1 obesity), 15.5% have a BMI of ≥35 kg/m² (grade 2 obesity), and 6.3% have a BMI of ≥40 kg/m² (grade 3 obesity). They also noted that the prevalence of hypertension is 45% in patients with grade 1 obesity and 54% in patients with grade 2 or 3 obesity; diabetes is 18% in patients with grade 1 obesity and 26% in patients with grade 2 or 3 obesity; and dyslipidemia is 51% in patients with grade 1 obesity and 48% in patients with grade 2 or 3 obesity.

In developing their model, the authors assumed the annual cost of treating the comorbidities was $1489 for hypertension, $7802 for diabetes, and $2334 for dyslipidemia. They based the rates of progression on results of a phase 3 trial that evaluated phentermine/topiramate in patients with ≥2 comorbidities. They defined progression as patients who did not take any medications for a comorbidity at baseline, but took at least 1 medication during the 56-week study.

Compared with patients who only had lifestyle modifications, the annual cost savings for patients with grade 1 obesity who progressed to hypertension were $37.23 if they took
7.5-mg phentermine/46-mg topiramate and $58.07 if they took 15-mg phentermine/
92-mg topiramate. The annual savings for patients with grade 2 obesity were $40.20 in the lower dose group and $25.32 in the higher dose group; the savings for patients with grade 3 obesity were $8.93 in the lower dose group and $22.34 in the higher dose group.

In addition, the annual cost savings for patients with grade 1 obesity who progressed to diabetes were $85.82 if they took 7.5-mg phentermine/46-mg topiramate and $85.83 if they took
15-mg phentermine/92-mg topiramate. The annual savings for patients with grade 2 obesity were $109.23 in the lower dose group and $85.82 in the higher dose group, while the savings for patients with grade 3 obesity were $23.41 in the higher dose group. Patients with grade 3 obesity had higher diabetes-related annual costs if they took the lower dose of the combination drug than if they only had the lifestyle modification.

Finally, the annual cost savings for patients with grade 1 obesity who progressed to dyslipidemia were $56.02 if they took 7.5-mg phentermine/46-mg topiramate and $21.01 if they took
15-mg phentermine/92-mg topiramate. The annual savings for patients with grade 2 obesity were $28.01 in the lower dose group and $21.01 in the higher dose group. Patients with grade 3 obesity had higher dyslipidemia-related annual costs if they took the lower dose or higher dose of the combination drug than if they only had the lifestyle modification.

This study was supported by funding from VIVUS Inc.