Low-level Laser and Lifestyle Modifications: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Low-level Laser and Lifestyle Modifications (NCT05083442), a randomized na study. The primary outcome is Change in Fat Mass From Baseline to 6 Weeks.

2. Clinical Question

This is a comparison of two combinations of treatment, not a comparison of laser therapy with no lifestyle modification. Because both groups received lifestyle modifications, the trial’s contrast addresses the incremental contribution of laser assignment in that setting. The endpoint focuses on change during the 6-week treatment period; it does not describe longer-term weight or fat-mass outcomes.

The registry identifies the study as a feasibility study. The registry record does not report a separate primary question about feasibility measures, nor does it identify other posted results as secondary outcomes. The central posted efficacy question is therefore the between-group comparison in fat-mass change, interpreted with attention to its uncertainty and the small analysis populations.

3. Trial Design

The study is titled “Low-level Laser and Lifestyle Modifications” and is described as a feasibility study of low-level laser as an adjunct to Mayo lifestyle-modification education and wellness coaching. Mayo Clinic is listed as the sponsor. The condition entries are overweight and obesity and weight loss. The registry lists the study as randomized, single-masked, and parallel. The meaning of the masking designation and the party or parties who were masked are not reported in the registry record.

The two groups received lifestyle modifications. Group 1 received low-level laser treatments, while Group 2 received sham laser treatments. This shared background component is important when interpreting the comparison: it is the contrast between the assigned laser and sham components within the lifestyle-modification program, rather than a contrast between lifestyle modification and no lifestyle modification.

The primary completion date is 2024-04-30, and the study status is completed. The registry lists enrollment as 60. Enrollment is not necessarily the same as the number contributing data to a particular endpoint. For the primary endpoint, the analysis population is described as subjects with non-missing values for that outcome; the posted group summaries give n=25 for the laser group and n=24 for the sham group.

The registry lists the phase as NA. It does not report the trial’s original sample-size justification, target power, or other original design assumptions. The primary outcome is change in fat mass from baseline to 6 weeks. Details about the lifestyle curriculum, coaching schedule, laser protocol, sham procedure, adherence, and handling of treatment discontinuation are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis population includes subjects with non-missing values for given outcome (change in fat mass at 6 weeks)

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Change in Fat Mass From Baseline to 6 Weeks, measured over 6 weeks.

The primary endpoint is change in fat mass from baseline to 6 weeks, measured in Kg and summarized as a mean with standard deviation. Change scores express how much the measured fat mass shifted over the treatment period, rather than describing only the final measurement. The posted group means are -1.3 Kg for the low-level laser group and -2.0 Kg for the sham group. Negative changes indicate reductions from baseline under the stated change-score convention.

Comparing change between randomized groups is intended to distinguish their average outcomes over the same period. Here, the mean difference is defined in the posted comparison as the laser-group mean minus the sham-group mean, giving 0.7 Kg in the unadjusted recalculation. That positive contrast accompanies a more negative mean change in the sham group. It is a group-average contrast, not a description of every participant’s experience.

Fat mass is used as a continuous measure of body composition relevant to the study’s focus on reducing central adiposity and fat mass. However, the primary endpoint is fat mass change; it is not itself a direct measure of central adiposity. The registry record does not report the measurement instrument, measurement procedures, or any additional endpoint definition beyond the change at 6 weeks. The analysis population excludes subjects without a non-missing value for this outcome, according to the registry description.

7. Results Posted in the Registry

• Group 1 - LLLT: mean -1.30 versus -2.00 on control; difference 0.70 (95% CI -0.43 to 1.83), standardized effect d = 0.35; z-test p = 0.223.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is continuous: each participant’s outcome is a change in fat mass, and the group result is expressed as a mean with standard deviation. The mean describes the average change in a group. The standard deviation describes the spread of individual changes around that group mean; it is not the uncertainty around the mean itself. The posted standard deviations are 1.5 Kg for the laser group and 2.4 Kg for the sham group.

What does the mean difference represent?

The posted unadjusted comparison subtracts the sham-group mean from the laser-group mean. The group means are -1.3 Kg and -2.0 Kg, respectively, and the resulting mean difference is 0.7 Kg. This is a contrast in average change between groups. It does not mean that each participant in one group changed by that amount relative to a participant in the other group, and it does not describe the distribution of individual outcomes.

As general statistical context, the standard error describes how much an estimate would be expected to vary across repeated samples under a statistical model. A confidence interval combines an estimate with its standard error to show a range of values compatible with the data and model. A p-value measures how unusual the observed data, or data more extreme, would be under a specified null hypothesis and model. Neither a p-value nor an interval alone establishes clinical importance.

What is the sponsor’s ANCOVA analysis?

The sponsor reports an ANCOVA analysis with a net mean difference of 0.8 Kg, a 95% confidence interval from -0.4 to 1.9, and p=0.19. ANCOVA is a general method for comparing group means while accounting for one or more covariates. The specific covariates, model specification, and analysis details are not reported in the registry record. The reported net estimate is therefore described as the sponsor’s analysis, without inferring which adjustments were made.

The recalculated comparison is an unadjusted calculation from the posted group summaries. It reports a mean difference of 0.7 Kg and p=0.223. It does not substitute for the sponsor’s analysis because it does not incorporate any model adjustments that may have been made in the ANCOVA. Since the sponsor’s analysis is reported and the discrepancy field is false, the sponsor’s own analysis takes precedence when describing the trial’s reported result.

Why can adjusted and unadjusted results differ?

As general statistical context, adjustment can change an estimate and its uncertainty when the model accounts for participant characteristics related to the outcome. The exact consequences depend on the variables and model used. Even when point estimates are similar, the analyses can differ because they use different assumptions or information. Here, the two estimates are close, but the registry record does not provide enough model detail to explain their difference further.

The p-values, 0.19 for the sponsor’s analysis and 0.223 for the unadjusted recalculation, are not probabilities that either treatment is effective or ineffective. A p-value is conditional on the null hypothesis and analysis assumptions. The confidence interval from the sponsor’s analysis includes zero, which is the value corresponding to no mean difference under its contrast definition. This indicates that the posted result is not precise enough to rule out no difference using that interval.

What does the analysis population mean?

The registry describes the primary outcome population as subjects with non-missing values for change in fat mass at 6 weeks. This is an outcome-specific analysis population, rather than a statement that every randomized participant contributed data. The reason for missing values, the number of missing measurements, and the method for addressing missingness are not reported in the registry record. As general statistical context, analyses restricted to observed outcomes can be affected if outcome availability is related to group assignment or outcome values.

The posted primary group summaries use n=25 for the laser group and n=24 for the sham group. Those counts describe the endpoint summaries, not necessarily every analysis in the study. The safety figures use their own at-risk counts. Different outcomes can have different analysis populations, so one set of counts should not be assumed to apply to every result.

What can the methods establish?

Random allocation is intended, as a general design principle, to make groups comparable on average before treatment, subject to the allocation process and chance variation. The registry identifies the allocation as randomized but does not report the randomization sequence, concealment procedures, or masking details. The primary outcome is an average change over 6 weeks, and the reported estimates describe that endpoint in the analyzed participants. The registry record does not report enough detail to assess all aspects of conduct, model assumptions, or robustness. Statistical interpretation should therefore stay close to the posted estimand and acknowledge the uncertainty and missing methodological details.

10. Confidence Intervals and Precision

Precision concerns how narrowly the data estimate the between-group difference. The sponsor’s reported estimate is 0.8 Kg, and its 95% confidence interval runs from -0.4 to 1.9. Because this interval includes zero and extends to both negative and positive values, the data are compatible with no mean difference and with differences in either direction under the reported analysis. The interval also shows that the estimate is not narrowly determined.

The unadjusted recalculation gives a mean difference of 0.7 Kg. Its interval likewise has one endpoint below zero and the other above zero. It therefore tells a similar broad story about uncertainty, though it is not the same interval or analysis as the sponsor’s ANCOVA result. The sponsor’s result should be used as the reported analysis; the recalculation is a simple unadjusted comparison based on the posted summaries.

As general statistical context, a confidence interval is not a range that guarantees the true value lies within it. It describes the uncertainty of an estimate under the analysis model and repeated-sampling interpretation. A wide interval can include effects that differ meaningfully in direction or magnitude, while a point estimate alone does not convey that uncertainty. The registry record does not report a threshold for clinical importance, so the interval cannot be classified against such a threshold.

The group standard deviations also indicate that individual changes varied around their respective means, with greater reported spread in the sham group. Those standard deviations do not replace the confidence interval for the between-group contrast. Taken together, the estimated contrast and interval support a cautious reading: the posted data do not determine the direction or size of a between-group difference precisely.

11. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size table and curve are planning illustrations based on the observed effect, not the trial’s original design assumptions. The figures are participants per arm, not total events. The calculation assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It considers detecting the stated fraction of the observed effect.

The 80% power column gives the planned number of participants per arm under those assumptions for a design intended to have an 80% chance of detecting the selected effect, if that effect is the true one and the model assumptions hold. The 90% power column uses the corresponding higher target chance of detection. These are design targets, not guarantees for a future study.

At 100% of the observed effect, the illustration gives 128 participants per arm for 80% power and 171 participants per arm for 90% power. At 75% of the observed effect, it gives 226 participants per arm for 80% power and 303 participants per arm for 90% power. At 50% of the observed effect, it gives 509 participants per arm for 80% power and 681 participants per arm for 90% power. The pattern reflects a general design principle: smaller effects are harder to distinguish from random variation and require more participants under the same assumptions.

These calculated requirements are not observed power, and they do not describe the power of this completed trial. They are planning illustrations derived from the observed estimate, which itself is uncertain. The trial’s own original sample-size assumptions are not reported in the registry record.

12. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 0.700; pooled standard deviation σ = 1.992.
2. n = 2 × (1.96 + 0.842)² × 1.992² / 0.700² = 127.1, rounded up to 128 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 0.7                      # observed difference in means
sigma <- 1.99189848498062                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(5083442)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 128 (80% power), 171 (90% power)
 75% of observed effect: n per arm = 226 (80% power), 303 (90% power)
 50% of observed effect: n per arm = 509 (80% power), 681 (90% power)
power.t.test: 128.1 
Simulated power at n = 128 per arm: 0.799 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

13. Analyses Reported by the Sponsor

The sponsor reports a net mean difference of 0.8 Kg from an ANCOVA analysis, with a 95% confidence interval from -0.4 to 1.9 and p=0.19. This is the trial’s reported comparative analysis for the primary outcome. Because the registry record identifies a sponsor analysis and the discrepancy field is false, that analysis takes precedence over the simple unadjusted recalculation when describing the reported result.

The unadjusted recalculation from the group summaries gives a mean difference of 0.7 Kg and p=0.223. Its result is close in direction and size to the sponsor’s estimate, but it is not a reproduction of the ANCOVA. The registry record does not identify the covariates or full model specification for the sponsor’s analysis, so the reason for the small difference between estimates cannot be determined from the posted information.

Both analyses yield an interval that includes zero, and both p-values are above common thresholds often used for statistical testing. These results indicate uncertainty, not proof of equivalence or proof that there is no effect. The sponsor’s adjusted estimate should be distinguished from the unadjusted recalculation rather than blended with it.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures and 2 analyses, while the posted record identifies 0 secondary outcomes. The primary result discussed is change in fat mass from baseline to 6 weeks. The registry record does not report a multiplicity-adjustment procedure or explain how the reported analyses relate to any planned testing hierarchy. It is therefore not possible to determine from the record whether the sponsor’s p-value was adjusted for multiple comparisons or how the primary outcome was prioritized among analyses.

As general statistical context, multiplicity arises when several outcomes, time points, or comparisons are examined. Repeated testing can increase the chance of obtaining at least one apparently unusual result by chance. Adjustment procedures or prespecified testing strategies can address that issue, but neither an adjustment nor a strategy should be inferred when it is not reported. The listed outcome and analysis counts alone do not establish how many statistical tests were conducted or which were considered confirmatory.

The primary outcome description states that the analysis population includes subjects with non-missing values for change in fat mass at 6 weeks. The posted group summaries give n=25 for the laser group and n=24 for the sham group. The reasons for missing outcome values, the number of participants with missing data, and the handling of missingness are not reported in the registry record. No imputation method or sensitivity analysis is described.

As general statistical context, restricting analysis to available outcomes can be appropriate under some assumptions, but conclusions may be affected if missingness is related to treatment assignment or the outcome. The record does not provide enough information to assess those assumptions. The analysis population also should not be conflated with the safety population, for which separate at-risk counts are posted.

The registry identifies the reported method as ANCOVA but does not report the covariates, model diagnostics, or detailed analysis population for that model. It also does not report an intention-to-treat statement or a per-protocol analysis. These omissions limit assessment of whether the reported model and analyzed participants match a prespecified plan.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse event figures list 30 participants at risk in each group and 0 affected by serious adverse events in either group. Deaths are recorded as 0 in both groups. No serious adverse event terms are listed. These entries describe the posted serious-event counts during the registry’s stated safety reporting; the record does not provide further detail about event definitions or the observation period.

For other adverse events, the record lists 6 affected in the low-level laser group and 0 in the sham group, with 30 at risk in each group. Those figures are separate from the serious adverse event counts. The record does not give descriptions, severity, timing, relatedness assessments, or the number of events per affected participant, so no further characterization is possible from these figures alone.

As general statistical context, an absence of recorded serious events in these groups does not establish that serious events cannot occur. Safety counts are also not directly comparable to the primary efficacy analysis counts: the primary outcome population is defined by non-missing fat-mass values, while the safety listing reports its own at-risk counts. The registry record does not explain the difference in analysis populations or provide additional safety detail.

16. What the Result Does, and Does Not, Mean

The result describes average fat-mass change over 6 weeks among participants with non-missing outcome data. The laser group’s mean change was -1.3 Kg, and the sham group’s mean change was -2.0 Kg. The unadjusted mean difference was 0.7 Kg, while the sponsor’s ANCOVA estimate was 0.8 Kg. These values describe group-level contrasts, not individual responses.

The sponsor’s 95% confidence interval from -0.4 to 1.9 includes zero, and the unadjusted recalculated interval also crosses zero. The posted estimates therefore do not precisely determine whether the average change differed between groups or how large a difference might be. A nonsignificant result is not evidence that the groups are equivalent; equivalence requires an appropriate design and prespecified margin, neither of which is reported in the registry record.

The comparison is specifically low-level laser plus lifestyle modifications versus sham laser plus lifestyle modifications. It cannot establish the effect of lifestyle modifications relative to no lifestyle program. The primary endpoint is fat-mass change, not a separate measurement of central adiposity, and the record does not provide a longer-term outcome for assessing persistence beyond 6 weeks.

The study is identified as a feasibility study, and the registry does not report the original design assumptions or detailed analysis plan. The sample-size illustrations are planning calculations based on the observed effect, not evidence about the trial’s ability to detect effects. The posted results should therefore be read as an uncertain estimate from a feasibility study, rather than as a definitive answer about treatment efficacy or broader health outcomes.

The safety listing records no serious adverse events and no deaths in either group, alongside other adverse events recorded in the laser group. Those counts do not resolve the uncertainty in the primary endpoint and do not provide a full characterization of safety. Interpretation should remain within the endpoints, time frame, and information reported in the registry record.

17. Why This Trial Matters Statistically

This trial illustrates why the design contrast matters. Both groups received lifestyle modifications, while assignment differed between low-level laser and sham laser. Any between-group estimate pertains to the laser component as an adjunct to the shared lifestyle-modification setting. Without a group that did not receive lifestyle modifications, the posted comparison cannot isolate the effect of that program.

It also shows the importance of separating an estimate from its precision. The mean difference is a compact description of the group contrast, but the interval includes zero and extends in both directions. The point estimate alone would not communicate how uncertain the contrast is. The adjusted sponsor analysis and simple unadjusted recalculation are close, yet they remain different analyses, and the registry record does not provide enough model detail to explain their relationship fully.

The study’s feasibility designation gives context to the evidence. The posted endpoint counts are modest, and the sample-size illustrations show how planned requirements rise when a smaller fraction of the observed effect is targeted. Those illustrations rely on the observed estimate, which is itself uncertain, so they are useful for planning discussion rather than as confirmation of the result.

Finally, the record shows why analysis populations and safety counts need to be read outcome by outcome. The primary endpoint uses participants with non-missing measurements, while safety has separately reported at-risk counts. Missing-data handling, multiplicity procedures, and key model details are not reported. Those omissions do not erase the posted results, but they limit the strength and scope of statistical interpretation.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation evident in the posted efficacy results is uncertainty around the between-group estimate. The sponsor’s 95% confidence interval includes zero and allows values in either direction. The analysis population is defined by non-missing change in fat mass at 6 weeks, but the registry record does not report why values were missing or how missingness was handled. This makes it difficult to assess whether the analyzed participants represent all randomized participants for the endpoint.

The study is described as a feasibility study, and the registry lists enrollment as 60. The primary endpoint summaries use n=25 and n=24. The original sample-size justification and design assumptions are not reported in the registry record. The post hoc planning illustrations use the observed effect and should not be read as evidence that the trial had a particular observed power.

The sponsor identifies ANCOVA as the analysis method, but the covariates, model specification, and diagnostics are not reported. Randomized allocation is recorded, but sequence generation, allocation concealment, and masking details are not reported. The registry identifies single masking without describing who was masked.

The intervention descriptions do not report the laser treatment schedule, sham procedures, adherence, or additional details of lifestyle education and wellness coaching. The endpoint is limited to fat-mass change at 6 weeks; longer-term results and a distinct central-adiposity measure are not posted in the registry record used for this analysis. Multiplicity procedures and a detailed missing-data plan are also not reported. These gaps constrain evaluation of the trial’s conduct and the generalizability of its findings.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Low-level Laser and Lifestyle Modifications — NCT05083442.
• Registry record last updated 2025-04-03; status last verified 2025-04.
• Results first posted 2025-04-03.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

NCT05083442 is a completed, randomized, single-masked, parallel feasibility study sponsored by Mayo Clinic. It compares low-level laser therapy plus lifestyle modifications with sham laser plus lifestyle modifications. The registry lists enrollment as 60 and identifies change in fat mass from baseline to 6 weeks as the primary outcome.

The posted mean changes are -1.3 Kg for the laser group and -2.0 Kg for the sham group. The sponsor’s ANCOVA estimate is 0.8 Kg, with a 95% confidence interval from -0.4 to 1.9 and p=0.19. The unadjusted recalculation gives a mean difference of 0.7 Kg and p=0.223. Both results carry uncertainty, and the sponsor’s analysis takes precedence as the reported result.

The safety listing records 0 serious adverse events and 0 deaths in each group, with other adverse events recorded as 6 in the laser group and 0 in the sham group. Important details about missing data, model specification, masking, and the original sample-size plan are not reported in the registry record.