Exercise, liraglutide, or both to keep weight off: S-LiTE

Why this study matters

Losing weight is often easier than keeping it off. Many people regain weight after a diet ends. S-LiTE asked a practical question: once someone has lost weight, what helps them maintain it, a structured exercise program, a daily weight-management medicine, or both? Because it tested each option head to head in the same group of people, it is one of the few trials that can speak to combined care rather than medicine alone.

Who was in the study

The trial enrolled adults with obesity who did not have diabetes and had a body mass index (BMI) of 32 to 43. BMI compares weight with height. Everyone first followed an 8-week low-calorie diet. After the diet, 195 participants had lost a mean of 13.1 kg and were randomized. The maintenance phase lasted one year. The summary we reviewed does not state the age range or where the trial was run.

What the researchers did

This was a randomized, head-to-head, placebo-controlled trial with four groups. Randomized means chance decided the group. Placebo is an injection with no active medicine. The four strategies were:

• exercise: a moderate-to-vigorous exercise program plus placebo injection;
• liraglutide: liraglutide 3.0 mg per day plus usual activity;
• combination: the exercise program plus liraglutide;
• placebo: placebo injection plus usual activity.

The primary outcome was the change in body weight from randomization to the end of the one-year treatment period. Change in body-fat percentage was the main secondary outcome. The analysis used the intention-to-treat population, meaning everyone was counted in the group they were assigned to, whether or not they finished.

What they found

At one year, all three active strategies kept more weight off than placebo (R32-C107). A confidence interval (CI) is the range in which the true difference most likely sits.

The combination did better than exercise alone. But when the combination was compared with liraglutide alone, the difference of -2.7 kg had a confidence interval that crossed zero, so that difference could be due to chance (R32-C107).

Body fat told a clearer story. The combination lowered body-fat percentage by 3.9 percentage points, about twice the reduction with exercise alone (-1.7 percentage points, 95% CI -3.2 to -0.2) or liraglutide alone (-1.9 percentage points, 95% CI -3.3 to -0.5). Only the combination group improved HbA1c (a blood test of average blood sugar), insulin sensitivity, and cardiorespiratory fitness.

The summary we reviewed does not report the mean weight change within each group, only the differences between groups.

Side effects and people who stopped

The abstract reports that increased heart rate and gallstones (cholelithiasis) were seen more often in the liraglutide-alone group than in the combination group. It does not give numbers.

The published summary we reviewed does not report how many people stopped treatment in each group, or how many stopped because of side effects.

What this study does not tell you

• Everyone in the trial had already lost weight on a strict diet. People who did not respond to the diet were not randomized, so the results apply to diet responders.
• The trial did not show that combining exercise with liraglutide keeps off more weight than liraglutide alone. The difference was not statistically significant.
• With 195 people across four groups, each group was small, which is why the confidence intervals are wide.
• The trial lasted one year on treatment. A separate follow-up study looked at what happened in the year after treatment stopped, and it is explained on its own page.
• The summary we reviewed does not describe exactly how missing data were handled.
• People with diabetes were excluded.

What it means in Canada

This trial suggests that structured exercise and a weight-management medicine each helped people keep weight off, and that combining them improved body fat and fitness more than either alone. It does not tell any individual what to do. To learn about the medicine, see liraglutide in Canada. For what provincial plans pay for, see public drug coverage by province. To see how programs that combine medicine with lifestyle support differ, see compare services.

Related reading

Other studies in this library that bear on the same question.

Source