Pilot Trial of Phototherapy for Acute Depression in Hospitalized Cystic Fibrosis Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pilot Trial of Phototherapy for Acute Depression in Hospitalized Cystic Fibrosis Patients (NCT01822197), a na na study. The primary outcome is Length of Hospitalization.

2. Clinical Question

This is a pilot study of phototherapy among hospitalized patients with CF and depression. The registry describes depressive symptom scores and quality-of-life scores at admission (Day 0) and after treatment (Day 7) as secondary outcomes. These assessments could describe change over time in participants who receive phototherapy, but without a separate control group they cannot establish how those changes compare with what would have occurred without the intervention.

The primary question concerns hospital length of stay, but the record does not report an estimated mean, standard deviation, confidence interval, or statistical test for that outcome. It therefore describes what the investigators planned to examine, rather than providing a numerical answer about the outcome. Participant characteristics, eligibility details, and the operational definitions of the secondary measures are not reported in the registry record.

3. Trial Design

The registry lists this as a completed, single-group study with an enrollment of 30. Its phase and allocation are recorded as NA, and masking is listed as none. The record does not describe random assignment or a separate comparator group. The study sponsor is Nationwide Children's Hospital. The recorded start is 2013-03 and primary completion is 2015-05.

One intervention is listed: phototherapy, classified as a device intervention. The treatment description specifies bright light phototherapy for 30 minutes daily in the morning over one week, with the schedule written as Days 0-7. The record does not provide further operational details about the device, light exposure, adherence, or how deviations from the schedule were handled.

Length of hospitalization is the primary outcome, expressed in days. The timeframe says participants would be followed for the length of the hospital stay, described as an average of 14 days. Depressive symptom scores and quality-of-life scores at admission and Day 7 are listed as secondary outcomes. The registry lists three outcome measures, but no analysis entries.

In general, a single-group design can describe outcomes among participants who receive an intervention, and repeated measurements can describe change within participants. It does not, by itself, separate an intervention-related change from changes that might occur over time for other reasons. Since no randomized or concurrent control comparison is reported, the study design does not support a direct treatment-versus-control estimate. The registry record does not report a protocol, a sample-size justification for the trial, or details of any analysis plan.

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

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 Length of Hospitalization, measured over participants will be followed for the length of hospital stay, an average of 14 days.

The primary endpoint is length of hospitalization, measured in days. The registry specifies that it will be summarized as a mean with a standard deviation. The stated follow-up is the length of the hospital stay, described in the record as an average of 14 days.

Length of stay is a measure of time spent in the hospital. In general, it can provide a way to describe hospital use during an admission, which is relevant to the study’s stated interest in illness recovery. It is also an outcome that can be summarized across participants as a continuous measure. A mean describes the average observed duration, while a standard deviation describes how spread out individual durations are around that mean. Neither summary alone establishes why participants stayed for different lengths of time.

The endpoint’s definition does not specify how transfer, discharge, or other changes in hospitalization status would be handled. Those details are not reported in the registry record. Nor does the record provide the observed mean or standard deviation, an effect estimate, a confidence interval, or a test of a hypothesis for this outcome. Consequently, the registry describes what was intended to be measured but does not provide a numerical primary-outcome result to interpret.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a continuous primary outcome: length of hospitalization in days, with the mean as the summary measure and standard deviation as the measure of dispersion. No outcome analysis is listed. The following are general explanations of the statistical concepts relevant to the stated outcome; the registry record does not report that these methods were used in this trial.

What does a mean and standard deviation describe?

In general, a mean is the arithmetic average of the observations included in an analysis. For hospital length of stay, it would describe the average duration among the participants whose data were analyzed. The standard deviation describes variation among those observations around the mean. A larger standard deviation indicates more spread in the observed durations; it does not describe uncertainty in the estimated mean. The registry specifies mean and standard deviation as the endpoint summary, but it does not report their observed values.

Why does the study design matter?

A single-group study observes participants receiving an intervention without a concurrent control arm. In general, a summary of outcomes in one group can describe what happened among the participants measured. It cannot, on its own, distinguish intervention effects from other explanations for a change or an outcome level. A within-participant comparison between admission and Day 7, if analyzed, would describe change between those measurements. It would not be equivalent to a randomized comparison with a group that did not receive phototherapy. The record does not report a comparison group or an analysis of the secondary outcomes.

The registry lists allocation as NA and masking as none. It does not report the reasons for these entries, a randomization procedure, or masking of outcome assessment. No further design detail should be inferred from the registry entries alone.

What would an estimate and confidence interval add?

In general, an effect estimate quantifies the contrast or change defined by an analysis. A confidence interval communicates uncertainty around that estimate: narrower intervals indicate greater precision, while wider intervals indicate less precision. Interpretation depends on the chosen estimand, analysis population, and method. Because the registry does not report an outcome estimate or confidence interval, the magnitude and precision of a primary-outcome effect cannot be evaluated. The registry also does not report a statistical test or p-value.

What do the planning illustrations mean?

The planning illustrations are described as calculations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe hypothetical planning for a comparison, not the actual single-group design recorded for this trial. The assumed effect is a stated fraction of the observed effect. Such planning quantities are not observed power and do not show the probability that this completed study detected an effect. The record does not report that these assumptions were used to determine the trial’s enrollment, nor does it report a trial-specific sample-size justification.

For general interpretation, participants per arm for 80% power is a planning quantity: it refers to an assumed future design and target power under stated modeling assumptions. It is not the number analyzed in this study. Any planning estimate depends on the effect chosen, variability assumptions, significance level, allocation, and analysis model. The record’s planning description also notes that time-to-event calculations use a total event count, whereas other calculations use participants per arm. Length of hospitalization is recorded as a continuous outcome, but no additional endpoint-specific planning method is reported.

What could affect analysis of hospital stay?

In general, continuous outcomes are often analyzed using methods that compare means, but the appropriate method depends on the study design and the distribution of the data. Hospital stay durations can be unevenly distributed, and unusual values can influence a mean and standard deviation. Over-dispersion is a general concern when observed variability is greater than a model assumes; if a model fails to account for this, its uncertainty estimates may be unreliable. The registry does not report the distribution of length of stay, diagnostic checks, transformations, robust methods, or a model. It is therefore not possible to say whether these issues arose or how they were handled in this trial.

Outcome-specific definitions, handling of incomplete observations, and analysis populations are also necessary to understand a result. Those details are not reported in the registry record. Statistical concepts explain how results could be interpreted if estimates and methods were available; they do not substitute for the missing trial analyses.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Phototherapy")
n   <- c(30)
m   <- c(11)
sp  <- c(3.6)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Phototherapy  30  11.000  3.600  9.656  12.344

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and secondary assessments of depressive symptoms and quality of life at admission and Day 7. It lists three outcome measures, but does not report analysis entries. The registry record does not describe a hierarchy among the outcomes beyond identifying length of hospitalization as primary, nor does it report a multiplicity adjustment or a strategy for interpreting multiple tests.

In general, when several outcomes or time points are tested, the chance of at least one apparently unusual result can increase if each test is interpreted independently. Analysis plans may address this by specifying a primary hypothesis, adjusting for multiple comparisons, or treating secondary analyses as exploratory. No such procedure is reported for this study. Since the endpoint estimates and tests are not posted, multiplicity cannot be evaluated from results.

The record does not report how missing outcome measurements were handled, the amount of missing data, or reasons for missingness. It also does not identify an analysis population, such as all enrolled participants or a subset with complete measurements. Enrollment of 30 does not establish how many participants contributed data to each outcome. The registry does not report an intention-to-treat analysis, a per-protocol analysis, imputation, or a sensitivity analysis. These details are not reported in the registry record; their absence should not be interpreted as proof that no analysis or data-handling decisions occurred outside the registry.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry’s safety entries list 30 participants at risk for serious adverse events and zero participants affected. It also lists 30 at risk for the other adverse-event category and zero affected. These are the counts recorded for the phototherapy group. The record does not list serious adverse-event terms.

These entries describe reported counts, not a comparison of safety between treatment groups: no separate control group is reported. Zero affected participants in the listed categories does not establish that no adverse experiences occurred under any definition or during any period. The registry does not report the adverse-event collection window, event definitions, severity criteria, attribution procedures, or completeness of ascertainment. Deaths are not reported in the registry record; the death entry is not a reported zero.

In general, safety counts are interpreted in the context of the number monitored, definitions, follow-up, and how events were collected. With a small single-group study and limited registry entries, the listed counts provide only a narrow description of the recorded events. They do not support a precise estimate of comparative risk.

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

The registry record establishes that a completed pilot study enrolled 30 participants in a single-group phototherapy study and designated length of hospitalization as its primary outcome. It also records an intervention schedule and secondary assessments of depressive symptoms and quality of life. These design details identify the questions the study was intended to address.

The record does not report numerical outcome results or analyses. There is no posted primary-outcome mean, standard deviation, effect estimate, confidence interval, or p-value. Depressive symptom and quality-of-life results are likewise not reported. The hypothesis that phototherapy might improve symptoms or decrease length of stay is not evidence that either outcome changed. Equally, missing results do not show that there was no change or that an intervention had no effect.

In general, an estimate describes the observed magnitude of an outcome or contrast, while uncertainty measures indicate how precisely it has been estimated. A causal interpretation requires a design and analysis capable of addressing alternative explanations. Since the registry reports no separate comparator arm, it does not offer a controlled estimate of what would have happened without phototherapy. Any change over time within a treated group would require cautious interpretation even if those measurements were available.

The listed safety counts indicate zero participants affected in the recorded serious and other adverse-event categories, among 30 listed at risk in each category. The record does not report the definitions or collection details needed to interpret those counts fully, and it does not report deaths. Taken together, the available registry information describes the study structure and selected safety counts, but not the clinical outcome findings. No conclusion about benefit, harm, or absence of an effect can be drawn from unreported outcome analyses.

14. Why This Trial Matters Statistically

This trial is statistically notable because its stated clinical questions include outcomes that are measured differently. Length of hospitalization is a continuous measure summarized by a mean and standard deviation, while depressive symptoms and quality of life are listed as scores measured at admission and Day 7. In general, analysis choices must reflect the outcome scale, timing, and study design. The registry does not report the methods used for these outcomes.

The study is also a single-group pilot. In general, pilot studies can describe feasibility and generate estimates that may inform later research, but an uncontrolled design has limited ability to distinguish an intervention-associated pattern from other changes during care. Here, no separate comparator is reported, so the registry does not support a controlled treatment-effect estimate. The record does not state that the trial was designed to establish efficacy or describe a trial-specific sample-size justification.

The registry includes a planning description based on an observed effect and hypothetical two-arm assumptions. Such calculations are useful only in the context of their assumptions and are not evidence of the power actually achieved by this single-group study. They should not be read as observed results or as a reason to infer that a treatment effect was detected.

Finally, the gap between registered outcomes and posted analyses matters for statistical interpretation. Knowing that an outcome was planned does not tell readers its observed value, how much data were available, or how uncertainty was handled. The record lists three outcome measures and zero analyses, so the stated research question can be understood, but the numerical answer cannot be assessed. This distinction is important when interpreting registry information: design and intent are not substitutes for estimates, uncertainty, and a transparent account of analysis.

15. 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 primary limitation for interpreting this specific trial is that the registry record does not report outcome analyses. It gives no numerical result for length of hospitalization, depressive symptom scores, or quality-of-life scores. Without those results, the direction, size, and precision of observed outcomes cannot be assessed.

The single-group design provides no separate concurrent comparator. Even if admission and Day 7 measurements had been reported, within-participant changes would not by themselves establish that phototherapy caused them. The same limitation applies to interpreting length of stay as a treatment effect: the record does not provide a controlled comparison.

The registry does not report participant characteristics beyond the condition and enrollment, the eligibility criteria, the operational definition of depression, or the details of how the outcome measures were collected. It also does not specify how length of stay was defined when hospitalization status changed. These omissions limit assessment of whom the results would represent and how consistently outcomes were measured.

Analysis populations, missing-data amounts and methods, statistical models, and handling of multiple outcomes are not reported in the registry record. The serious and other adverse-event counts are listed, but event definitions and ascertainment details are absent; deaths are not reported. Finally, the registry does not provide a trial-specific sample-size justification or a detailed protocol. These limitations do not establish that the information or analyses were absent outside the registry, but they restrict what can be concluded from the record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Pilot Trial of Phototherapy for Acute Depression in Hospitalized Cystic Fibrosis Patients — NCT01822197.
• Registry record last updated 2016-12-19; status last verified 2016-10.
• Results first posted 2016-09-07.
• 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.

19. Record Summary

The registry describes a completed pilot study of bright light phototherapy in hospitalized patients with cystic fibrosis and depression. Enrollment was 30. The design is single group, allocation is listed as NA, and masking as none. Treatment is described as 30 minutes each morning over one week, with days listed as Days 0-7.

Length of hospitalization, measured in days and summarized as a mean with standard deviation, is the primary outcome. Depressive symptom scores and quality-of-life scores at admission and Day 7 are listed as secondary outcomes. The record lists three outcome measures and no analysis entries. Numerical outcome results and statistical analyses are not reported in the registry record.

For the phototherapy group, the registry lists zero participants affected in the serious and other adverse-event categories, with 30 at risk in each. Serious adverse-event terms are not listed, and deaths are not reported. Overall, the record describes the intended study and selected safety counts, but does not provide outcome estimates for evaluating the stated clinical questions.