Continuos Subcutaneous Insulin Infusion in Italy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Continuos Subcutaneous Insulin Infusion in Italy (NCT02620917), a registered phase not stated study. The primary outcome is Number of Patients With Glycated Hemoglobin on Target.

2. Clinical Question

Statistically, the question is descriptive: among the patients recorded in this survey, how many were reported to have HbA1c within the specified age-based target? Because the study is observational and cross-sectional, the registry description does not define a treatment contrast capable of isolating the effect of CSII. The record also does not provide the outcome count separately by age group, or report the number eligible for each threshold. Those details would be needed to interpret the reported count in relation to the population assessed.

3. Trial Design

The registry describes this study as observational, multicenter, and cross-sectional. Its stated purpose is to collect clinical and metabolic information about patients treated with CSII in Italy. It is listed as completed, with a recorded enrollment of 6623. The sponsor is the University of Padova. The recorded study start is 2015-11-01 and the primary completion date is 2017-12-01.

This design differs from a randomized controlled trial. The registry does not describe random allocation to CSII or to a comparator, and the allocation field is not stated. The record identifies a CSII Treatment group for adverse-event reporting, but that does not constitute a control group. As the registry notes, any arms are not a like-for-like control comparison. Consequently, group differences should not be read as randomized treatment effects.

The primary outcome is the number of participants with glycated hemoglobin on target, with age-specific HbA1c thresholds and a timeframe of 1 year. The record also names a secondary outcome concerning patients with HbA1c on target using advanced pump functions, continuous glucose monitoring, and carbohydrate counting. Four outcome measures are recorded, but details for the other measures are not reported in the registry record.

The registry lists no analyses. It does not report the method used to recruit participants, the dates of data collection for each participant, the duration of CSII use, or how clinical and metabolic measurements were obtained. The protocol’s statistical analysis plan and sample-size justification are not reported in the registry record. These omissions limit assessment of how the enrolled group was formed, how the outcome was measured, and whether the analysis matched a prespecified plan. The design supports describing the recorded group; the registry description does not establish a causal comparison.

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 Number of Patients With Glycated Hemoglobin on Target, measured over 1 year.

The primary endpoint is the number of participants who achieved the HbA1c target. The registry specifies a target of < 7,5% in patients < 18 years old and <7% in adult patients, with a timeframe of 1 year. HbA1c is a measure of longer-term glycemic exposure, so a threshold-based endpoint expresses whether a participant’s value falls on the target side of a defined cutoff. The registry’s endpoint is a count of participants meeting that definition, rather than a reported average HbA1c value or a change from baseline.

In general, a target-based measure can make a clinical outcome easier to interpret as the share or count meeting a prespecified criterion. It also simplifies a continuous measurement into categories. That simplification can obscure how far a value lies from the cutoff, and results can depend on the exact threshold and its application. Here, age-specific thresholds are specified, but the registry does not report the outcome count by age category or provide the number assessed in each category.

The count achieving target is not reported in the registry record. Nor are the underlying HbA1c distribution, missing measurement handling, or the operational details for applying thresholds reported. Without those data, the outcome definition is clear at a broad level, but its observed magnitude and precision cannot be evaluated from the registry entry.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as observational and cross-sectional, and the primary endpoint is a number of participants meeting a threshold. These features determine what statistical methods would be relevant in general, but the registry does not report which methods were actually used. The analysis method, uncertainty calculations, adjustment strategy, and statistical analysis plan are not reported in the registry record.

What does a count endpoint represent?

A count endpoint records how many participants meet a defined condition. Here, the condition is achieving the age-specific HbA1c target during the stated timeframe of 1 year. A count is most informative when its denominator is also clear: readers need to know how many participants were assessed and eligible for the outcome definition. The registry gives an enrollment of 6623, but it does not state the number with an HbA1c result available for this endpoint or provide age-specific denominators. The outcome count itself is not reported in the registry record.

For a binary outcome, analysts commonly describe both the number meeting the criterion and the number assessed, sometimes with a proportion and an interval expressing uncertainty. A confidence interval gives a range of estimates compatible with the data under the chosen statistical model. It helps distinguish an imprecise estimate from a more precisely estimated one; it does not resolve bias in how participants were selected or measured. No interval or corresponding outcome estimate is reported in the registry record.

Why does the study design matter?

In a randomized trial, random allocation can support comparison by balancing, on average, factors that might influence outcomes. This registry describes no random allocation and no like-for-like control group. In an observational study, treatment status is not assigned by the study according to the described design. Comparisons between groups, if made, can reflect differences in participant characteristics or care as well as treatment. Statistical adjustment can address measured differences under assumptions, but it cannot guarantee removal of unmeasured confounding. The registry does not report an adjusted analysis or the covariates that might have been considered.

A cross-sectional design generally describes measurements collected in a defined study context rather than establishing a sequence of changes attributable to an exposure. Although the primary outcome has a timeframe of 1 year, the record does not explain the timing or repeated-measure structure behind that timeframe. It does not report baseline HbA1c, follow-up measurement procedures, or whether participants were observed for the same duration. No longitudinal analysis should be inferred from the timeframe alone.

How should the age-specific thresholds be handled?

The endpoint definition uses < 7,5% for patients < 18 years old and <7% for adult patients. In general, an analysis using different thresholds across age categories should specify how age was classified, how participants near a category boundary were handled, and whether results were presented separately or combined. The registry does not report these operational details or age-stratified results. A single aggregate count could conceal differences between the categories, particularly if their sizes or measurement completeness differ.

Thresholding also discards information from the continuous HbA1c measurement. Participants just above and well above a threshold are both classified as not meeting it, while values on opposite sides of a cutoff can be categorized differently despite being close. This is a general property of dichotomizing continuous data, not a claim about the participants in this study. The registry does not report continuous HbA1c summaries that would permit a fuller description.

What do the planning assumptions mean?

The sample-size planning illustration is described as being computed from the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers an effect to detect expressed as a stated fraction of the observed effect. The record does not report the trial’s own sample-size justification or establish that these assumptions were part of its design. Because the study is observational and does not describe a like-for-like pair of arms, equal allocation is a planning assumption rather than a description of the enrolled groups.

In general, a planning calculation estimates the sample size needed under specified assumptions. Its output depends on the effect size, variability or event rate, allocation, significance level, and statistical model. A calculation based on an observed effect is an illustration, not observed power and not evidence that the study was designed to detect that effect. The primary outcome result and effect estimate are not reported in the registry record, so the assumptions should not be read as a protocol-based sample-size rationale.

What can be concluded about the analysis?

The registry lists zero analyses. It does not identify a test, model, confidence-interval method, missing-data method, or analysis population. These details are necessary to assess whether uncertainty was handled appropriately and whether the analytic population matched the stated endpoint. Without them, statistical methods beyond the registry’s general design and planning assumptions cannot be attributed to this study.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Adults on CSII Treatment", "Paediatric Patients on CSII Treatment")
n      <- c(5598, 1025)
events <- c(1288, 445)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Adults on CSII Treatment  5598  1288  23.0  21.9  24.1  21.9  24.1  21.9  24.1
ARM  Paediatric Patients on CSII Treatment  1025  445  43.4  40.4  46.5  40.4  46.5  40.4  46.5

11. Multiplicity, Missing Data and Analysis Populations

The registry records four outcome measures and names the primary endpoint and a secondary outcome concerning HbA1c target attainment in relation to advanced pump functions, continuous glucose monitoring, and carbohydrate counting. The outcome descriptions and results for the remaining measures are not reported in the registry record. No analyses are listed, and no multiplicity strategy is reported.

In general, when a study assesses multiple outcomes or makes multiple comparisons, the chance of at least one apparently notable result can increase. A prespecified analysis plan can define which outcomes are primary, how secondary outcomes are interpreted, and whether any adjustment is used. Adjustment is not always necessary for every descriptive study, but the approach should be clear to readers. The registry does not report whether the outcomes were prespecified in a protocol, whether any multiplicity adjustment was planned, or whether all intended analyses were completed.

Missing-data handling is also not reported. The record does not state how many participants had an HbA1c measurement available, how missing values were treated, or whether missingness differed across age categories. In general, excluding participants with missing measurements can affect interpretation when their missingness is related to their characteristics or outcomes. Other approaches also depend on assumptions that should be described.

The analysis population is not reported in the registry record. The enrollment figure is 6623, but the record does not state whether the primary endpoint was assessed in everyone enrolled or in a subset. The population field for the primary outcome is blank. Without a defined analysis population, denominators, and missing-data procedures, the completeness and representativeness of the endpoint result cannot be assessed.

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 1% reporting threshold.

The adverse-event listing for the CSII Treatment group reports 6223 at risk for serious adverse events and 0 affected. It also reports 6223 at risk for other adverse events and 0 affected, with 0 deaths. These figures describe what the registry record lists; they do not establish that no event occurred outside the reporting definitions or observation procedures used for the record.

The registry does not provide serious adverse-event terms, event-level descriptions, follow-up details, or an explanation of how the at-risk count was determined. It also does not explain why this count differs from the recorded enrollment of 6623. The relationship between the adverse-event population and the population assessed for the primary endpoint is not reported.

In general, a zero count is interpreted in relation to how events were defined, collected, and monitored, and to the completeness of the population under observation. A zero recorded count is not, by itself, proof that the underlying risk is zero. No comparative safety inference is possible from this listing because the registry does not describe a like-for-like control group. The safety figures should therefore be read as registry counts with limited contextual detail, not as a comparative estimate.

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

The record identifies a completed observational survey of patients with type 1 diabetes treated with CSII in Italy. It specifies a primary endpoint based on whether participants met age-specific HbA1c thresholds during a timeframe of 1 year. It also records adverse-event counts for the CSII Treatment group. These details describe the study’s scope and some of its registered outcome definitions.

The central primary outcome result is not reported in the registry record. There is no reported number achieving target, no outcome denominator, and no estimate of uncertainty. Therefore, the registry entry does not show how often the target was achieved in the assessed population or how precisely that frequency was estimated. It also does not report results by the age categories used in the endpoint definition.

The observational design does not support attributing an outcome to CSII on the basis of a descriptive count. There is no randomized allocation or like-for-like control comparison described. Participants already receiving CSII may differ from people who are not receiving it, and the registry does not report analyses addressing such differences. A target-attainment count, even if available, would describe an observed group and would not by itself establish a treatment effect.

The safety listing reports zero affected for serious and other adverse events and zero deaths, with 6223 at risk for each adverse-event category. Those are registry figures, but the event definitions, ascertainment procedures, and relationship to the enrollment figure are not reported. They should not be expanded into a claim that there was no safety risk.

Overall, the record is informative about the study design, planned clinical question, endpoint definition, and registered safety counts. It does not provide the primary endpoint result, an effect estimate, a confidence interval, or a documented statistical analysis. Conclusions about target attainment, comparative benefit, or comparative safety are not supported by the information recorded.

14. Why This Trial Matters Statistically

This study illustrates why design and reporting details matter alongside an outcome definition. The registry names a clinically interpretable endpoint: the number of participants meeting HbA1c targets that differ by age category. But without the observed count, denominators, and uncertainty, the endpoint cannot be evaluated quantitatively. A clearly worded outcome is not a substitute for a reported result.

It also highlights the distinction between describing outcomes and estimating treatment effects. The study is observational and cross-sectional, with patients already treated with CSII. No like-for-like control group or randomized allocation is described. This means that any reported target-attainment frequency would characterize the surveyed population, not isolate what would have happened under an alternative treatment. That distinction is central to interpreting clinical registry entries.

The record further shows why analysis populations and missing-data procedures are important. Enrollment is recorded as 6623, whereas the adverse-event group lists 6223 at risk. The entry does not explain the difference or specify the population assessed for HbA1c. Without denominators and information about measurement availability, even a reported count could be difficult to interpret.

Finally, the existence of planning assumptions does not establish that the survey was designed as a comparative trial. The listed assumptions include equal allocation between two arms, while the registry describes an observational study without a like-for-like control comparison. Planning illustrations and the actual design must be kept distinct. The record does not report the protocol’s sample-size justification or statistical analysis plan. These limitations make transparent outcome reporting especially important for readers assessing the study’s statistical contribution.

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.

Important design and reporting details are not reported in the registry record. The entry does not describe participant recruitment, eligibility criteria beyond the stated condition and treatment context, or the characteristics of the enrolled population. Without that information, it is difficult to assess how representative the survey group may be of patients with type 1 diabetes treated with CSII in Italy.

The primary endpoint lacks a reported result and denominator. The registry does not state how many participants had HbA1c measurements available, provide results by age group, or describe the measurement and classification procedures. The timeframe is listed as 1 year, but the timing of measurements and whether observation was uniform are not described.

The record does not report an analysis population, missing-data method, statistical test, model, confidence interval, or adjustment strategy. No analyses are listed. The sample-size justification and protocol-based statistical plan are not reported. The adverse-event at-risk count is 6223, while enrollment is recorded as 6623; the registry does not explain the relationship between these figures.

Because the study is observational and no like-for-like control group is described, causal comparisons are not supported by the registry description. The entry also does not report factors that might influence treatment selection or HbA1c outcomes. These limitations concern the information available in the registry record; they do not determine what information may exist in other study materials.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Continuos Subcutaneous Insulin Infusion in Italy — NCT02620917.
• Registry record last updated 2020-04-08; status last verified 2020-03.
• Results first posted 2020-04-08.
• 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

NCT02620917 is a completed observational, multicenter, cross-sectional study of clinical and metabolic information among patients with type 1 diabetes treated with CSII in Italy. The sponsor is the University of Padova. Enrollment is recorded as 6623; the study start is 2015-11-01 and primary completion is 2017-12-01.

The primary endpoint is the number achieving HbA1c < 7,5% in patients < 18 years old and <7% in adults, with a timeframe of 1 year. The primary outcome result and its analysis are not reported in the registry record. The record names a secondary outcome concerning HbA1c target attainment in relation to advanced pump functions, CGM, and CHO counting, and lists four outcome measures overall.

The adverse-event listing reports 6223 at risk and 0 affected for serious adverse events, 6223 at risk and 0 affected for other adverse events, and 0 deaths. The registry lists no analyses and does not report a like-for-like control comparison.