Exercise Capacity and Dyspnea in Obese Patients With Metabolic Syndrome: Effects of Weight Loss

Study Overview
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Brief Summary
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Dyspnea is a common complaint in obese patients. The mechanisms behind this dyspnea and the effects of weight loss on dyspnea are not completely understood. The objectives of this study were to examine the relationships between exercise parameters and dyspnea in obesity and assess the effects of weight loss. The investigators compared pulmonary function, exercise performance and dyspnea in 34 patients with abdominal obesity and metabolic syndrome (MS) against 34 age and sex-matched controls. The study also assessed within-group changes in physiology and symptoms in a subset of patients following participation in a weight management program. Because obesity is a heterogeneous condition, with variable genetic associations, co-morbidities and distributions of adipose tissue, the study focused on patients with abdominal obesity who met diagnostic criteria for metabolic syndrome.

Detailed Description
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The study has two parts: first, the investigators compared dyspnea, pulmonary function and exercise measurements between obese patients and control subjects with normal weight; then, the investigators assessed the effects of medical weight loss in the obese group on these parameters. Baseline dyspnea was assessed using the baseline dyspnea index.The effect of weight loss on dyspnea was assessed using the transitional dyspnea index. The main physiologic measurement of interest was the inspiratory capacity (L, measured at rest and during exercise).

Official Title
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Exercise Capacity and Dyspnea in Obese Patients With Metabolic Syndrome: Effects of Weight Loss

Conditions
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Obesity, Metabolic Syndrome

Intervention / Treatment
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* Other: Weight Management Program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals accepted into the behavioural weight management program at the Ottawa Hospital Bariatric Centre Age between 20 and 60 years BMI greater than 30 Abdominal girth (for females) greater than 88 cm Abdominal girth (for males) greater than 102 cm Plus any two of the other criteria for Metabolic Syndrome: i.e. Blood Pressure greater or equal to 130/85; Fasting Glucose greater or equal to 6.1 mmol/L Controls-normal weight (NW) and sedentary Exclusion Criteria: Smoker Any medical conditions which would affect exercise performance Use of medications that could affect exercise performance (i.e. Beta-blockers) Inability to pedal on a cycle ergometer and provide reproducible inspiratory capacity (IC) measurements

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Health Services Research
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Weight Management Program<br>Obese subjects participate in a year long medically supervised weight management program. | Other: Weight Management Program<br>* Obese subjects partake in a medically supervised weight management program. This lifestyle modification program involves weekly three hour sessions for six months and monthly sessions for six months. The first twelve weeks comprise an initial weight loss phase when patients are placed on a 900 Kcal/day meal replacement. This is followed by a four week transition to a 1200-1800 Kcal diet followed by a ten week maintenance phase of 10 weekly sessions.The majority of weight loss occurs during the first 26 weeks followed by a 26 week period of stabilization of weight loss. Hence subjects are evaluated after the first 26 weeks.<br>|
| No Intervention: Normal Weight Controls<br>Normal weight age and sex-matched controls. Unlike the obese subjects, the controls did not participate in the Weight Management Program. Pulmonary function, exercise performance and dyspnea results for normal weight controls were compared against the results for obese subjects. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dyspnea (measured by Transitional Dyspnea Index) | Dyspnea was assessed using a questionnaire based on the Transitional Dyspnea Index | Within 6 months following completion of 6 months (weight loss period) in the weight management program | 
| Resting Inspiratory Capacity (L) | Inspiratory capacity (difference between total lung capacity and functional residual capacity), measured at rest | Within 6 months following completion of 6 months (weight loss period) in the weight management program | 
| Inspiratory Capacity during Exercise (L) | Inspiratory capacity measured at identical time points during incremental exercise tests, performed before and after weight loss | Within 6 months following completion of 6 month (weight loss period) in the weight management program | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Metabolic Syndrome, Dyspnea, Pulmonary Function, Exercise Capacity