Primary Immunodeficiency in Kuwait: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Primary Immunodeficiency in Kuwait (NCT03618147), a registered phase not stated study. The primary outcome is Number of Participants With Different Epidemiological Features.

2. Clinical Question

The registry’s stated objectives extend beyond counting cases. They include describing clinical presentation patterns, natural history and particularities of PIDD in the population, as well as assessing health impact and supporting strategies to improve care and quality of life. These are objectives, not findings: the posted record does not state whether the anticipated patterns were observed.

The study hypothesis proposes that PIDD is relatively common in Kuwait compared with populations from different geographic areas, and that the distribution differs, with more severe forms being more frequent. Those claims require suitable population denominators and comparable information from other settings. The registry record does not report those comparative data or a statistical analysis of the hypothesis.

3. Trial Design

This is a registry study titled “Primary Immunodeficiency in Kuwait,” with the official title “Kuwait National Primary Immunodeficiency Registry (KNPIDR).” The sponsor is the Kuwait Society for Allergy and Clinical Immunology. The registry lists the study as completed, with a start date of 2018-07-16 and a primary completion date of 2019-05-01. Enrollment is listed as 314.

The described population is patients with PIDD who presented at different clinics or hospitals in Kuwait. The summary says patients with secondary immunodeficiencies, including drug-induced, virus-induced and immunodeficiency associated with metabolic disorders, are excluded. It also states that patients registered in KNPIDR since 2004 were to be included alongside new patients recruited during the study period. The primary outcome timeframe is 15 years. The record does not explain how this timeframe relates to each participant’s observation period or specify the exact period covered by the registry data.

No treatment assignment or randomized intervention is described. Allocation is not stated, and the record does not describe a like-for-like control comparison. The stated aims are descriptive and epidemiological: determining prevalence and frequency, describing clinical presentation and natural history, and assessing health impact and features specific to the population in Kuwait.

The record does not report a protocol-level account of recruitment procedures, data sources, follow-up methods, case definitions, or the handling of repeat records. It also does not report a sample-size justification. Enrollment of 314 is a registry entry, not evidence by itself that the data represent all people with PIDD in Kuwait. Whether the enrolled patients represent the relevant population depends on case ascertainment and coverage, details 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

Analysis population for the primary outcome, as defined in the registry: PID patients

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: All PID patients

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Different Epidemiological Features, measured over 15 years.

The primary outcome is titled “Number of Participants With Different Epidemiological Features.” Its unit is patients, its parameter is a number, its population is PID patients, and its timeframe is 15 years. In practical terms, this describes counts of patients classified according to epidemiological features. The registry record does not specify which feature categories were analyzed, how each feature was defined, or the count for any category.

Counts are useful in a registry because they show how many recorded patients fall into defined groups. They can help describe the clinical and demographic profile of the registered population and provide a basis for further epidemiological investigation. A count alone, however, does not establish how common a disorder is in the general population. Prevalence requires a defined population denominator and a specified period, alongside consistent case identification. The record’s stated objective includes determining prevalence and frequency, but it does not report the denominator or prevalence estimates.

The outcome’s 15-year timeframe also needs context for interpretation. It does not, on its own, establish that every patient was observed for the same duration or that the count represents new cases arising within that period. The registry record does not report the timing rules used for inclusion or the distinction between newly identified and previously registered patients. Consequently, the primary outcome describes an intended count-based summary, while the posted record does not provide enough detail to interpret it as an incidence rate, population prevalence estimate or time-to-event measure.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry outcome is count-based: it is defined as the number of participants with different epidemiological features. A count records how many eligible patients satisfy a stated definition. To interpret such counts, readers need to know the feature definitions, the rules for assigning patients to categories, and whether the categories can overlap. Those details are not reported in the registry record. The record also does not provide the feature-specific counts, so no numerical comparison between categories can be described.

What does a count tell the reader?

In general, a count describes the number of observations captured in a dataset. It is not automatically a rate or a measure of population frequency. A rate requires a denominator that represents the population at risk, and often a defined observation period. A prevalence estimate likewise needs a defined population and a clear rule about which cases are included. The study objectives mention prevalence and frequency, but the posted record does not report denominator information or prevalence estimates. Enrollment of 314 is not, by itself, a population denominator.

The distinction between a registry count and a population estimate matters because registry coverage may be incomplete. Patients may be identified through participating clinics and hospitals, while other patients may not be recorded. The record identifies patients presenting at clinics or hospitals in Kuwait, but does not describe the coverage of those settings, referral pathways, case-finding procedures or completeness of registration. Without such information, readers cannot determine how closely the registry population corresponds to all patients with PIDD in Kuwait.

Why do case definitions matter?

In general, a case definition determines which records count as cases and how subtypes or features are classified. Consistent definitions support meaningful comparisons between groups, periods and locations. The summary says secondary immunodeficiencies are excluded, with drug-induced, virus-induced and metabolic-disorder-associated examples. However, diagnostic criteria, confirmation procedures, and definitions for the different PIDD features are not reported in the registry record. Comparisons with other geographic areas would also require compatible definitions and similar ascertainment methods; those details are not reported.

The summary describes inclusion of patients already registered since 2004 together with new patients recruited during the study period. This implies that the assembled registry information spans more than the recruitment dates alone, but the record does not specify the data-freeze date, the rules for identifying newly recruited patients, or whether historical information was collected consistently. The primary outcome lists a timeframe of 15 years, but the record does not explain how that timeframe was applied to individual patients or to each feature. A count over a period should not be interpreted as a count of newly occurring cases unless the data collection and case timing support that interpretation.

How should comparisons be interpreted?

The study hypothesis compares Kuwait with other geographic areas, but the record does not describe a specific external comparator or comparative dataset. In general, geographic comparisons can be affected by differences in population age structure, diagnostic access, referral patterns, case definitions and registry coverage. A difference in recorded counts may reflect these factors as well as differences in disease occurrence. The posted record does not report methods for standardizing or adjusting comparisons, nor does it report comparative estimates.

The record does not describe a randomized allocation or treatment comparison. Its stated aims are descriptive, and the registry entry identifies no analyses. General methods such as regression adjustment or formal hypothesis testing should not be assumed to have been used. The record does not report a statistical analysis plan, model specifications, covariates, or an approach to uncertainty estimation. Accordingly, no adjusted or inferential result can be attributed to the study on the basis of the registry record.

What does the planning illustration mean?

Any sample-size values associated with planning illustrations should be understood as hypothetical planning outputs, not as the registry’s observed power or as evidence that the study was designed around those assumptions. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. The registry record does not describe a randomized two-arm design, and allocation is not stated. The record also does not report an observed comparative effect or a study-specific sample-size justification. Such an illustration therefore does not establish the actual design rationale or demonstrate that a planned analysis was performed.

In general, a significance level is a threshold used in a specified testing procedure, while a normal approximation uses a mathematical distribution to approximate the behavior of an estimator or test statistic. Equal allocation is an assumption about how participants are divided between comparison groups. These concepts are relevant only when the analysis and comparison match the assumptions. They do not turn an epidemiological registry into a controlled trial, and they cannot replace details about the data, estimand or analysis plan. No sample-size results or analysis results are reported in the registry record.

Finally, the outcome is a patient count rather than a reported continuous measure or time-to-event estimate. General count-data methods may account for differences in exposure time or variation beyond a simple count model, but the record does not report that such methods were used. Over-dispersion, in general, means that observed count variation exceeds what a basic count model expects; if present, ignoring it can make uncertainty estimates too narrow. The record does not provide the data needed to assess over-dispersion or identify a count model. No particular statistical method should be inferred from the outcome title alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures but does not describe the additional outcome measure in the information available for interpretation. It reports no analyses. The record does not identify a statistical analysis plan, a hierarchy among outcomes, a prespecified set of tests, or a method for addressing multiplicity. Therefore, it is not possible to determine whether multiple outcomes or feature categories were tested, or how any resulting uncertainty was handled.

In general, multiplicity arises when several outcomes, groups or hypotheses are examined. Repeated testing can increase the chance of finding an apparently notable result by chance. A prespecified outcome hierarchy or an adjustment procedure can help clarify how results should be interpreted. These are general considerations; the registry record does not report that any specific procedure was planned or used.

The record does not report how missing information was handled, whether all enrolled patients contributed to each outcome, or how the analysis population was defined. It also does not describe rules for incomplete records, loss to follow-up, duplicate entries, or unknown feature status. These details matter because the number with a recorded feature may differ from the number with complete information for that feature. No imputation method, sensitivity analysis or missingness assessment is reported in the registry record.

In general, an analysis population should be defined in relation to the study objective and the available data. For a registry description, it is important to distinguish patients with a documented feature from those whose feature status is unknown. Without denominators for each feature and information about missingness, readers cannot assess whether the reported counts would be vulnerable to incomplete documentation. The posted record gives no analysis-population details with which to resolve these questions.

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

The record establishes that a Kuwait registry study of PIDD was completed and lists enrollment of 314. It describes epidemiological objectives and a primary outcome based on counts of patients with different features over 15 years. This information indicates what the study set out to characterize, but the posted record does not report the feature counts or other primary outcome results.

The study’s hypothesis about frequency and disease distribution in Kuwait is not a reported finding. The registry entry does not provide population denominators, comparative data from other regions, severity classifications or analyses that would support a conclusion about whether PIDD is relatively common or whether severe forms are more frequent. The stated objectives should not be read as evidence that those questions were answered.

The enrollment figure does not show how many people in Kuwait have PIDD, nor does it establish that all eligible patients were captured. It describes enrollment in this registry study. In general, population prevalence depends on a defined population and consistent ascertainment; the registry record does not report the information needed to derive or assess such an estimate.

The record’s death count of 81 is not a mortality rate and does not establish a cause of death or a relationship to treatment. The relevant denominator, timing, follow-up and cause information are not reported in the registry record. The study is not described as a randomized treatment comparison, so the record does not support a causal conclusion about treatment benefit or harm.

More broadly, an absence of posted analysis results is not evidence that the study hypothesis is false, nor is it evidence that a particular outcome did or did not occur. It means that the registry information available for interpretation does not report those results. The appropriate conclusion is limited: the record describes a completed registry study and its intended epidemiological questions, while the quantitative findings and their precision are not reported.

12. Why This Trial Matters Statistically

Registry studies can address questions that are difficult to answer through randomized treatment comparisons. For a condition such as PIDD, a registry may organize clinical information across care settings and support descriptions of patient characteristics, presentation patterns and disease course. The Kuwait study states these aims directly, including determining frequency, identifying clinical presentation patterns, describing natural history and assessing health impact.

Statistically, the value of such work depends not only on the number of records but also on case definitions, coverage, data completeness and the relationship between the registry population and the population the researchers want to describe. Enrollment of 314 documents the scale of this study entry, but the record does not report enough information to determine registry coverage or produce population-level estimates. This distinction is central to interpreting epidemiological counts responsibly.

The study also raises a question about geographic comparisons. Differences between settings may reflect disease patterns, but they may also reflect diagnostic practices, access to care, referral systems or differences in how cases are classified. Comparable definitions and denominators are needed before counts from different settings can support a clear comparison. The hypothesis anticipates geographic differences, while the registry record does not report the comparative data or methods required to evaluate them.

The record’s limited results reporting is itself statistically important. Without feature-specific counts, denominators, uncertainty estimates and analysis details, readers cannot assess the magnitude or precision of the intended findings. This does not negate the potential value of the registry; it defines what can be concluded from the posted record. Clear reporting of methods and results is necessary for clinicians, researchers and health planners to judge how far registry descriptions can inform broader epidemiological understanding.

13. 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 registry record does not report the primary outcome counts, prevalence estimates, confidence intervals or statistical tests. It lists enrollment of 314, but does not provide the number of patients contributing data to each feature or the denominators used for frequency estimates. As a result, the magnitude and precision of the epidemiological findings cannot be evaluated from the posted record.

Important design details are also absent. The record does not describe diagnostic criteria, category definitions, recruitment procedures, data sources, registry coverage, follow-up methods or the handling of historical records. Although the summary says patients registered since 2004 and new patients recruited during the study period were to be included, the record does not specify how those records were assembled or how the 15-year outcome timeframe was applied.

The hypothesis invokes comparisons with other geographic areas, but no comparator population, shared case definition, denominator or comparative analysis is reported. This limits interpretation of the claims about relative frequency and severity. The record also does not report methods for handling missing data, duplicate records, incomplete follow-up or uncertainty.

The adverse-event entry lists 81 deaths, but it does not provide timing, cause, follow-up context or a relationship to an intervention. The study is not described as a randomized treatment comparison, and allocation is not stated. Thus, the death count cannot be interpreted as a rate or as a treatment effect. These limitations are specific to what the registry record reports; additional study documentation may contain details not reported in the registry record.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Primary Immunodeficiency in Kuwait — NCT03618147.
• Registry record last updated 2019-09-09; status last verified 2019-09.
• Results first posted 2019-09-04.
• 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.

17. Record Summary

NCT03618147 is a completed registry study titled “Primary Immunodeficiency in Kuwait,” with the official title “Kuwait National Primary Immunodeficiency Registry (KNPIDR).” The sponsor is the Kuwait Society for Allergy and Clinical Immunology. The registry lists a start date of 2018-07-16, a primary completion date of 2019-05-01 and enrollment of 314.

The study concerns patients with PIDD presenting at clinics or hospitals in Kuwait, with secondary immunodeficiencies described as exclusions. Its aims include characterizing frequency, clinical presentation, natural history and health impact. The primary outcome is a count of participants with different epidemiological features over 15 years.

The registry record does not report primary outcome counts, prevalence estimates, comparative results, confidence intervals or analyses. It describes the study objectives and design context, but the quantitative findings and the detail needed to assess their precision are not reported in the registry record.