Pairwise meta-analysis

Percent body weight change

Overweight or obesity without diabetes (adults)

weeks 40 to 104 (target week 68)While on treatmentDoses of a drug pooledMean difference

Randomized trials

Treatments

2,572

Participants

Trial arms

In plain language

Across 2 trials with 2,572 participants, 1 of 1 treatment had a clearly better result than placebo on percent body weight change. The most favorable estimate was for Semaglutide injection: mean difference -12.71 percentage points (95% credible interval -16.87 to -7.39).

Lower values favor the treatment. "Clearly" means the 95% credible interval excludes no difference. These are averages across trials; they do not say how any one person will respond. Not medical advice.

Network of trials

Each circle is a treatment; each line joins treatments that were randomized against each other in at least one trial.

Node area shows participants; line width shows trials comparing two treatments directly. Blue: GLP-1 receptor agonist containing treatments; grey: comparators. Hover over or tab to a node or line for details.

Effects compared with Placebo

Mean difference in percentage points. Lower values favor the treatment.

Versus Placebo. Blue: Bayesian random effects posterior median with 95% credible interval (thick) and 95% prediction interval (dashed). Amber diamond: frequentist estimate with 95% confidence interval. Hover over or tab to a row for its values.

Effects of each treatment versus Placebo
Treatment	Bayesian MD (95% CrI)	95% prediction interval	Frequentist MD (95% CI)	Verdict
Semaglutide injection SEMA_SC	-12.71 (-16.87 to -7.39)	-20.48 to -4.12	-12.73 (-14.98 to -10.48)	Better

Ranking

How likely each treatment is to be among the best. Rankings ignore the size of differences and their certainty, so read them with the effects above.

Heterogeneity, fit and convergence

Bayesian random effects (primary)

Heterogeneity (tau): 2.242 (95% CrI 0.443 to 6.799)
Residual deviance: 4.2 for 4 data points
DIC: 8.3 (pD 4.1)
Largest R-hat: 1.001
Smallest ESS: bulk 2,358, tail 1,977
Divergent transitions: 0
Convergence: All criteria met
Priors: PR01 N(0, 35^2); PR03 N(0, 17.5^2); PR07 half normal(0, 3.5^2) on tau

Frequentist check (netmeta)

Method: inverse variance, REML, MD
Tau: 1.525
I squared: 88%
Q (total): 8.27 on 1 df, P = 0.004

Inconsistency

Do trials comparing two treatments directly agree with the indirect evidence through other treatments?

No comparison here has both direct and indirect evidence, so inconsistency cannot be checked by node splitting.

Small study effects

A comparison adjusted funnel plot: each point is one trial comparison, centered on its own network estimate. Asymmetry can signal that small trials with unfavorable results are missing.

Fewer than ten trial comparisons, too few to judge funnel plot asymmetry.

Baseline characteristics of the trials

The baseline value of each effect modifier or prognostic factor that applies here, per trial: mean or percent over arms, weighted by the number randomized. A note under a value names a stand in (a median for a mean, 100 minus the male share, Asian subgroup rows, an all Asian site list); "not reported" means no source of the trial prints it.

Baseline effect modifiers and prognostic factors per trial
Trial	Baseline BMI or body weight (kg/m2) effect modifier, prognostic factor; 2 of 2	Type 2 diabetes share in weight trials (percent of participants) effect modifier; 2 of 2	Sex (percent female) effect modifier, prognostic factor; 2 of 2	Asian ancestry or region (percent Asian) effect modifier, prognostic factor; 2 of 2	Treatment duration (weeks) effect modifier; 2 of 2	Lifestyle co-intervention intensity (none standard intensive) effect modifier, prognostic factor; 2 of 2
STEP 1 S000144	37.87	0 population codes	74.07	13.33	68	standard
STEP 3 S000988	38	0 population codes	81.01	1.8	68	intensive

Comparability of the trials

Checked across designs (the set of treatments each trial compares) for eligibility, outcome definition and assessment, and the baseline factors above. Flags point to possible intransitivity; notes describe variation that is not tied to design.

No comparability concerns were found.

Comparability items per trial
Trial	time weeks	analysis set	definition	instrument	adjudicated	proportion method	intercurrent events (discontinuation)	intercurrent events (rescue)	blinding	funding	start year	Eligibility
STEP 1	68	full_analysis	not stated	not stated	not stated	not stated	not stated	not stated	double_blind	industry	2018	adults; BMI 30 or more, or 27 or more with a weight related condition; no diabetes; HbA1c below 6.5 percent
STEP 3	68	full_analysis	not stated	not stated	not stated	not stated	not stated	not stated	double_blind	industry	2018	BMI 30 or more, or 27 with comorbidity; no type 2 diabetes

Trial data

What each trial contributes. Arm rows give the arm value with its standard error, or events over participants; contrast rows give the mean difference on the analysis scale against the trial's first row. Flags mark converted, combined or approximated inputs.

Trial data entering this analysis
Trial	Arm	Treatment	Week	Data	Value	SE	Events / N	Source
STEP 1	A1	SEMA_SC	68	arm, percent_change	-16.900	0.260	1,306	registry:outcomes
STEP 1	A2	PLACEBO	68	arm, percent_change	-3.100	0.250	655	registry:outcomes
STEP 3	A1	SEMA_SC	68	arm, percent_change	-17.600	0.476	407	registry:outcomes
STEP 3	A2	PLACEBO	68	arm, percent_change	-6.100	0.532	204	registry:outcomes

Rerun this analysis yourself

Remove treatments or trials and refit the frequentist and Bayesian models in your browser, with the same methods as the published analysis.

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