Associations between cardiorespiratory fitness and weight loss in patients with severe obesity undergoing an intensive lifestyle intervention program: retrospective cohort study

Abstract

Background: To assess the association between cardiorespiratory fitness (CRF) and weight changes in treatment seeking patients with severe obesity who underwent a 1-year intensive lifestyle intervention (ILI) program.

Methods: Retrospective cohort study conducted at a tertiary care outpatient rehabilitation center from November 1, 2013 through January 1, 2017. CRF was measured as maximal oxygen consumption during a maximal oxygen uptake (VO_2max) test on a treadmill or bicycle at baseline and after 3 months.

Results: A total of 180 patients had a baseline mean (SD) BMI 41.1 (4.8) kg/m² and CRF of 79.4 (14.9) mL·kg^-0.75·min^{- 1}. Patients with a baseline CRF above median achieved a greater 3-month and 1-year weight loss compared with patients with CRF below median; mean (95% CI) 2.5 kg (1.3, 3.8) and 4.0 kg (0.8, 7.2), respectively. In addition, patients with 3-month changes of CRF above median had 4.0 kg (0.9, 7.1) greater weight loss at 1-year follow-up than those below median.

Conclusions: Among patients with severe obesity who underwent a 1-year ILI program, higher baseline CRF was associated with significantly larger weight loss after 3 months and 1 year. In addition, those with higher initial 3-month CRF changes had greater weight loss at 1 year.

Trial registration: Retrospectively registered in Regional Committees for Medical and Health Research Ethics (REC) south east September 22, 2016 (2016/1414) and clinicaltials.gov August 13, 2018 (identifier: NCT03593798 ).

Keywords: Lifestyle intervention; Severe obesity; VO2max; Weight change.

Fig. 1

Flow chart

Fig. 2

Proportions of patients in the two groups who at 3-month follow-up achieved at least 5, 10% or 15% weight loss. Data are presented as percentage of participants with standard error of the mean (SEM), either above or below baseline CRF median, who achieved at least 5, 10% or 15% weight loss at 3-month follow-up. Baseline CRF above median, N = 87. Baseline CRF below median, N = 87. In the above median CRF group, the number of patients who achieved at least 5, 10% or 15% was 66 (76%, SEM 5%), 24 (28%, SEM 5%), 2 (2%, SEM 2%), respectively. In the below median CRF group, the number of patients who achieved at least 5, 10% or 15% was 57 (66%, SEM 5%), 6 (7%, SEM 3%), 0 (0%, SEM 0%), respectively

Fig. 3

Proportions of patients in the two groups who at 1-year follow-up achieved at least 5, 10% or 15% weight loss. Data are presented as percentage of participants with standard error of the mean (SEM), either above or below baseline CRF median, who achieved at least 5, 10% or 15% weight loss at 1-year follow-up. Baseline CRF above median, N = 80. Baseline CRF below median, N = 80. In the above median CRF group, the number of patients who achieved at least 5, 10% or 15% was 53 (66%, SEM 5%), 30 (38%, SEM 5%), 18 (23%, SEM 5%), respectively. In the below median CRF group, the number of patients who achieved at least 5, 10% or 15% was 38 (48%, SEM 6%), 25 (31%, SEM 5%), 12 (15%, SEM 4%), respectively

Fig. 4

Proportions of patients in the two groups, who achieved median 3-month percentage increases in CRF, who at 1-year follow-up achieved at least 5, 10% or 15% weight loss. Data are presented as percentage of participants with standard error of the mean (SEM), either above or below median 3-month percentage increases in CRF, who achieved at least 5, 10% or 15% weight loss at 1-year follow-up. 3-month percentage increases in CRF above median, N = 72. 3-month percentage increases in CRF below median, N = 71. In the above median CRF group, the number of patients who achieved at least 5, 10% or 15% was 48 (67%, SEM 6%), 34 (47%, SEM 6%), 18 (25, 5%), respectively. In the below median CRF group, the number of patients who achieved at least 5, 10% or 15% was 37 (52%, SEM 6%), 19 (27%, SEM 5%), 10 (14%, SEM 4%), respectively