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Qual Life Res. 2016 May;25(5):1237-44. doi: 10.1007/s11136-015-1153-x. Epub 2015 Oct 7.

Health-related quality of life in two randomized controlled trials of phentermine/topiramate for obesity: What mediates improvement?

Author information

1
Department of Community and Family Medicine, Duke University School of Medicine, Durham, NC, USA. rkolotkin@qualityoflifeconsulting.com.
2
Quality of Life Consulting, 732 Ninth Street #563, Durham, NC, 27705, USA. rkolotkin@qualityoflifeconsulting.com.
3
Department of Health Studies, Sogn og Fjordane University College, Førde, Norway. rkolotkin@qualityoflifeconsulting.com.
4
Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway. rkolotkin@qualityoflifeconsulting.com.
5
Pennington Biomedical Research Centre, Baton Rouge, LA, USA.
6
VIVUS, Inc., Mountain View, CA, USA.
7
Neuropsychiatric Research Institute, Fargo, ND, USA.
8
Department of Psychiatry and Behavioral Science, University of North Dakota School of Medicine and Health Sciences, Fargo, ND, USA.

Abstract

PURPOSE:

Phentermine/topiramate combination therapy resulted in significant weight loss and improvements in cardiometabolic risk factors in patients with obesity/overweight in two published 56-week randomized, placebo-controlled trials (EQUIP and CONQUER). The purpose of the current study was to examine whether phentermine/topiramate is also associated with greater improvements in health-related quality of life (HRQOL) and whether HRQOL improvements are solely attributable to weight reduction.

METHODS:

Patients in EQUIP (n = 751) had a body mass index (BMI) ≥ 35 with no obesity-related comorbidity. Patients in CONQUER (n = 1623) had a BMI ≥ 27 and ≤ 45 and at least two obesity-related comorbid conditions. HRQOL was assessed with Impact of Weight on Quality of Life-Lite (IWQOL-Lite) and Medical Outcomes Study Short Form (SF-36) (CONQUER only).

RESULTS:

Significant improvements in both obesity-specific and physical HRQOL were observed at 56 weeks in both trials (p < .0001). In EQUIP, BMI reduction fully mediated improvements in IWQOL-Lite total score (p < .0001). In CONQUER, both BMI reduction (all p values < .0001) and change in depressive symptoms (all p values < .025) were significant mediators of improved IWQOL-Lite total score and SF-36 Physical Component Summary score. Gender, psychiatric history, and baseline triglycerides moderated these relationships.

CONCLUSIONS:

Both trials demonstrated that treatment with phentermine/topiramate improved HRQOL compared with placebo. Although reduction in BMI accounted for the majority of improvements in obesity-specific and physical HRQOL, decrease in depressive symptoms was also a significant mediator. Results highlight the predominance of weight reduction as a key factor in improving HRQOL in obesity.

KEYWORDS:

Health-related quality of life; Impact of Weight on Quality of Life-Lite (IWQOL-Lite); Mediation analysis; Phentermine/topiramate; Short-Form-36 (SF-36); Weight loss

PMID:
26446094
DOI:
10.1007/s11136-015-1153-x
[Indexed for MEDLINE]

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