Can we Reduce Hospital Attendance Without Compromising Care by the Use of Telephone Consultation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Can we Reduce Hospital Attendance Without Compromising Care by the Use of Telephone Consultation (NCT00129701), a na na study. The primary outcome is Patient Satisfaction.

2. Clinical Question

The practical question behind the study was whether telephone consultation could reduce the need for hospital attendance without compromising care. The registry description notes that clinic attendance can involve travel, waiting, expense, and disruption to patients’ lives and occupations. It also describes earlier work suggesting that telephone consultations may be acceptable to patients and can support respiratory care. Those observations motivate the question; they are not results from this study.

The study involved patients attending respiratory clinics for a range of respiratory conditions. Its primary satisfaction population was restricted to participants who attended both a telephone consultation and a face-to-face consultation. The record does not report how many participants met that condition, whether satisfaction was assessed separately after each type of consultation, or whether the primary question was a direct comparison between the two experiences.

Accordingly, the registry supports a description of the study’s aim and structure, but it does not establish whether satisfaction was high, whether telephone consultations reduced attendance, or whether care was preserved. Those outcomes require reported data and an analysis that addresses the study’s single-group design.

3. Trial Design

This was a completed, single-group study sponsored by Imperial College London. The registry lists an enrollment of 104 and describes participants as receiving a telephone consultation and then having a face-to-face appointment at the next appointment. The listed study dates are 2003-11 for the start and 2005-10 for primary completion. The phase and allocation are recorded as NA, and masking is recorded as none.

The study was intended to evaluate feasibility, acceptability, time savings, and safety of telephone consultation in 3 respiratory clinics in the Department of Respiratory Medicine at Charing Cross Hospital. The conditions listed are asthma, COPD, sleep apnea syndromes, interstitial lung diseases, and bronchiectasis. The record’s primary outcome is patient satisfaction, measured after consultation within 1 months.

This design does not provide a randomized, parallel control group. The registry explicitly cautions that the arms are not a like-for-like control comparison. Since participants were described as having a telephone consultation followed by a face-to-face appointment, experiences may be related within a participant, but the record does not specify whether the analysis treated the observations as paired or made a direct comparison. The order described in the record also means that the two consultation experiences cannot be assumed to differ only in consultation mode.

The enrollment figure describes the registered study enrollment; it does not establish how many participants contributed data to the primary endpoint. The primary population is stated as participants who attended both types of consultations, but the number in that population and any participant flow are not reported in the registry record. The sample-size justification, recruitment details, eligibility criteria, and reasons for any missing outcome data are also 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: Participants who attended both types of consultations

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.

Population: Baseline characteristics were not collected

6. Primary Endpoint

The registry lists the primary outcome as Patient Satisfaction, measured over After consultation within 1 months.

The primary endpoint is patient satisfaction, measured with the MISS-21 satisfaction scale. The record describes 21 items, each scored on a 7-point Likert scale from 1, very strongly disagree, to 7, very strongly agree. The stated total-score range is 21 to 147. Higher scores are described as very strong satisfaction and the minimum score as very strong dissatisfaction.

Satisfaction is relevant to this study because the proposed service change would alter how patients consult respiratory services. A structured patient-reported scale can capture aspects of the consultation experience that are not represented by attendance counts or clinic time alone. It may therefore help describe acceptability from the patient’s perspective. It does not, by itself, measure clinical outcomes, safety, time saved, or whether hospital attendance was reduced.

The stated primary population is participants who attended both types of consultations. The timeframe is recorded as after consultation within 1 months. The registry record does not clarify which consultation the primary satisfaction score refers to, whether scores were collected after both consultations, or whether a within-participant difference was the intended estimand.

The outcome is specified as a mean with standard deviation, but the registry record does not report the observed mean, standard deviation, or number of participants contributing to that endpoint. Therefore, the scale’s interpretation can be described, but the level and precision of satisfaction in this study cannot be determined from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes the outcome as a continuous measure summarized by a mean and standard deviation. A mean represents the average score in the analyzed population. A standard deviation describes how spread out individual scores are around that average. These summaries answer different questions: the mean describes the group’s location on the scale, while the standard deviation describes variability among participants. Neither is reported for the primary endpoint in the registry record.

What does a scale score represent?

The MISS-21 is described as containing 21 Likert-scale items, with responses ranging from 1, very strongly disagree, to 7, very strongly agree. The record states that the total score ranges from 21 to 147, with higher scores representing stronger satisfaction. A mean score would summarize the average total score, but its meaning depends on the instrument and the population being assessed. The record does not provide item-level results, score distributions, or an observed total-score mean.

General statistical explanation: summarizing a scale with a mean can be useful when the total score is treated as a quantitative measure. The mean alone can conceal differences in the distribution. For example, groups can have similar means but different spreads or concentrations of scores. The standard deviation offers information about spread, but it does not show the full shape of the distribution. A histogram or other distribution summary can help, but the registry record does not report such details for this endpoint.

Why does the study design matter?

This is recorded as a single-group study, and the description says participants had a telephone consultation followed by a face-to-face appointment at the next appointment. The registry warns that the arms are not a like-for-like control comparison. General statistical explanation: a randomized comparison is designed to make treatment groups comparable, on average, with respect to factors that could affect an outcome. That protection is not available simply because two consultation types appear in a study record. In a sequential, single-group setting, time, order, changes in a participant’s condition, and other differences between encounters may be entangled with consultation type.

Because the primary population includes participants who attended both consultation types, some observations may be linked within participants if both experiences were measured. General statistical explanation: paired methods account for the fact that measurements from the same person are often more similar to one another than measurements from different people. An analysis that treats linked measurements as independent can misstate uncertainty. However, the registry record does not state that both consultations generated primary scores, identify a paired contrast, or describe the statistical method used. It would be inappropriate to assume that a paired analysis was performed.

What would uncertainty measures add?

General statistical explanation: a confidence interval describes a range of values compatible with the observed data under a specified statistical model and procedure. It communicates precision as well as the estimated value. A narrow interval indicates greater precision than a wide interval, but does not by itself establish that an effect is important or free from bias. A p-value, when used, describes how compatible the observed data are with a stated null model; it does not measure the probability that the null hypothesis is true, nor does it measure clinical importance.

No confidence interval, p-value, or other inferential statistic for satisfaction is reported in the registry record. No model, test, covariate adjustment, or assumption checking is described. The absence of those details means that the registry record does not allow readers to evaluate the statistical procedure or reconstruct its uncertainty.

How should the enrollment and analysis population be read?

The registry lists enrollment as 104. The primary outcome population is participants who attended both types of consultations. These are different descriptions: enrollment is not evidence that every enrolled participant attended both visits or contributed a complete satisfaction score. The number analyzed, the amount of missing outcome data, and the handling of incomplete questionnaires are not reported in the registry record.

General statistical explanation: analysis of only participants with complete data can be biased if completeness is related to satisfaction or other participant characteristics. Missing-data methods can sometimes use available information, but their validity depends on assumptions and on transparent reporting. The registry record does not identify any missing-data method, so no particular approach should be attributed to the study.

The record lists 3 outcome measures and 1 analysis. It does not identify the full set of outcome results, specify whether the analysis was primary or secondary, or describe a statistical plan. A sample-size illustration is described using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect stated as a fraction of the observed effect. The record identifies that calculation as a planning illustration rather than the trial’s own design. Its two-arm assumptions do not describe the registered single-group design and should not be read as evidence of observed power or as the study’s original sample-size justification. The actual sample-size justification is not reported in the registry record.

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("Telephone Consultation", "Face-to-face Consultation")
n   <- c(45, 45)
m   <- c(114.3, 116.8)
sp  <- c(14, 15)
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  Telephone Consultation  45  114.300  14.000  110.094  118.506
CARM  Face-to-face Consultation  45  116.800  15.000  112.294  121.306

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 3 outcome measures and 1 analysis, but does not identify all outcome measures, explain how outcomes were prioritized, or describe a multiplicity strategy. It therefore does not establish whether multiple outcome tests were conducted, whether any adjustment was planned, or how the primary outcome was distinguished from other outcomes in the analysis. The designation of patient satisfaction as the primary outcome is reported, but the statistical plan behind that designation is not reported in the registry record.

General statistical explanation: when researchers test several outcomes or make several comparisons, the chance of obtaining a seemingly notable result by chance can increase. A prespecified analysis plan and appropriate interpretation help readers understand how much emphasis to place on individual findings. Without detail about the analyses performed, the registry record does not permit an assessment of multiplicity or selective outcome reporting.

Missing-data information is also absent. The primary outcome population is participants who attended both consultation types, but the record does not report how many participants were eligible for that population, completed the scale, or were included in the analysis. It does not describe questionnaire completion, missing items, exclusions, or imputation. The enrollment figure alone cannot establish the endpoint denominator.

General statistical explanation: missing outcomes can reduce precision and can also affect validity if participants with missing data differ systematically from those with observed data. The direction and size of any resulting bias depend on the reasons for missingness and the analysis approach. Since neither is documented in the registry record, the extent of missing-data risk cannot be assessed.

The analysis population is described only as participants who attended both types of consultations. The registry record does not say whether an intention-to-treat, per-protocol, or other analysis population was used, and those labels should not be inferred from the description.

12. 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 0% reporting threshold.

The adverse-event record lists 104 patients attending at risk for serious events and 0 serious events; it also lists 104 at risk for other events and 0 other events. Deaths are recorded as 0, and no serious-event terms are listed. These are registry counts, not a complete description of how safety was monitored.

Zero recorded events does not mean that the underlying risk is zero. General statistical explanation: when no events are observed, the data still allow uncertainty about the event rate, particularly when the observation period, event definitions, and completeness of follow-up are not known. No confidence interval or other uncertainty estimate for these counts is reported in the registry record.

The record does not report how serious or other events were defined, how they were collected, the duration of safety follow-up, or whether events were assessed for relation to the consultation. It also does not provide detail about adverse outcomes beyond the listed categories. Therefore, the figures should be read narrowly as the counts entered in the registry, rather than as proof that telephone consultation was free of risk or that all possible harms were excluded.

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

The study addresses a service-delivery question: whether telephone consultation could reduce hospital attendance without compromising care. Its stated aims include feasibility, acceptability, time savings, and safety, and its primary outcome is patient satisfaction. The registry record identifies the setting, intervention, consultation sequence, and satisfaction instrument, but does not report the primary outcome result.

As a result, the record does not show whether patients were satisfied, how satisfaction scores were distributed, or how precise an estimate of satisfaction would be. It also does not report a comparative effect estimate for telephone versus face-to-face consultation. The single-group design and the registry’s warning that the arms are not a like-for-like control comparison further limit causal interpretation. A difference between consultation experiences, if one were reported, would not automatically establish that consultation mode caused the difference.

The record does not report whether hospital attendance was reduced, whether care was maintained, or how much time was saved. Those are central parts of the study’s motivating question, but they cannot be answered from the primary endpoint description or the adverse-event counts alone. The zero event counts are limited to the categories and information entered in the registry and do not demonstrate the absence of all possible harms.

The appropriate interpretation is therefore descriptive: a completed single-group study was registered to assess telephone consultation in respiratory clinics, with satisfaction measured using the MISS-21 among participants who attended both consultation types. The registry record does not provide enough outcome or analysis information to determine the study’s findings or to support conclusions about effectiveness, safety, or impact on attendance.

14. Why This Trial Matters Statistically

This study is statistically notable because its practical question concerns a change in how care is delivered, while its registered design is single-group and sequential. The record describes telephone consultation followed by a face-to-face appointment at the next appointment. It also explicitly warns that the arms are not a like-for-like control comparison. Recognizing that design distinction is essential: the presence of two consultation types does not, by itself, create a controlled comparison.

The study also illustrates the difference between a defined endpoint and a reported result. The MISS-21 is described in detail, including its items, response scale, possible score range, and direction of interpretation. Yet the mean and standard deviation for the primary endpoint are not reported. A clearly described measure can support interpretation only when the observed values and their uncertainty are available.

Another important distinction is between study aims and evidence. Feasibility, acceptability, time savings, and safety are stated aims, but the registry record does not report results for them. Keeping aims separate from findings prevents a proposal’s rationale from being mistaken for demonstrated outcomes.

Finally, enrollment and analysis population are not interchangeable. Although enrollment is listed as 104, the primary population is participants who attended both types of consultations, and the number contributing primary outcome data is not reported. This illustrates why denominator and missing-data reporting matter when interpreting a mean or any comparison. The registry record supplies important design context, but its limited outcome and analysis detail constrains what can be concluded.

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 main trial-specific limitation in interpreting the registry record is the absence of the primary satisfaction result. The endpoint’s mean, standard deviation, and analysis denominator are not reported. Without them, neither the observed satisfaction level nor its precision can be assessed.

The registered single-group design does not provide a randomized control comparison. Participants are described as receiving a telephone consultation and then a face-to-face appointment at the next appointment, and the record cautions that the arms are not a like-for-like control comparison. The record does not clarify whether satisfaction was measured after both encounters or whether the primary outcome was intended as a comparison. This leaves the estimand and the handling of within-participant observations unclear.

The primary population includes participants who attended both types of consultations, but the number meeting that condition is not reported. Participant flow, endpoint completeness, and reasons for missing outcomes are also not reported in the registry record. This prevents assessment of whether the analyzed participants represent everyone enrolled or whether missing data could affect interpretation.

The registry gives no details of the statistical analysis, including the model or test, any adjustment, assumption checks, or uncertainty estimates. Although the record lists 3 outcome measures and 1 analysis, it does not describe multiplicity handling or identify the results for the other outcomes. The sample-size justification and any prespecified analysis plan are not reported in the registry record.

Safety interpretation is limited by the absence of event definitions, collection methods, and follow-up duration. The registry counts should not be treated as evidence that every potential adverse outcome was captured. These limitations concern what can be concluded from the registry record; they do not establish that the underlying study lacked procedures or analyses that were not recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Can we Reduce Hospital Attendance Without Compromising Care by the Use of Telephone Consultation — NCT00129701.
• Registry record last updated 2023-10-16; status last verified 2023-10.
• Results first posted 2020-01-23.
• 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

NCT00129701 is a completed, single-group study sponsored by Imperial College London. It examined telephone consultation in respiratory clinics at Charing Cross Hospital, with participants described as receiving a telephone consultation and then a face-to-face appointment at the next appointment. Enrollment is listed as 104, and the registered conditions include asthma, COPD, sleep apnea syndromes, interstitial lung diseases, and bronchiectasis.

The primary outcome is patient satisfaction measured with the MISS-21 scale among participants who attended both types of consultations. The registry record describes the scale but does not report the satisfaction mean, standard deviation, analysis denominator, or inferential results. It lists zero serious events, zero other events, and zero deaths, without further safety-method details.

The record’s aims include feasibility, acceptability, time savings, and safety. Results for those aims, the statistical analysis plan, missing-data handling, multiplicity strategy, and sample-size justification are not reported in the registry record.