This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Comparison of Serum C Type Natriuretic Peptide Levels Between Polycystic Ovary Syndrome Patients and Healthy Women (NCT04006171), a non-randomized na study. The primary outcome is Serum CNP Levels of PCOS and Healthy Participants.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04006171 |
| Phase | NA |
| Condition | Polycystic Ovary Syndrome, c Type Natriuretic Peptide, Menstrual Irregularity |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 90 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Near East University, Turkey |
| Results posted | Yes |
2. Clinical Question
Population
Women with polycystic ovary syndrome and healthy women of reproductive age are the groups described. The registry lists 36 patients with PCOS and 30 patients with regular normal menstrual cycles. It also reports overall enrollment of 90; how that enrollment relates to the two arm descriptions is not reported in the registry record.
Intervention
The listed intervention is C type natriuretic peptide, classified as a diagnostic test. The study compares serum levels; it does not describe a therapeutic intervention.
Comparator
Serum CNP levels in women with PCOS are compared with levels in healthy women. Allocation is non-randomized, so the groups are not assigned to conditions by chance.
Primary question
The primary question is whether serum CNP levels differ between women with PCOS and healthy women. The measurement is specified for the second or third day of menstruation, with levels expressed in pg/ml and summarized using the median and inter-quartile range. The numerical comparison is not reported in the registry record.
This is a group-comparison question, not a question about whether CNP treatment changes an outcome. The registry background describes a proposed relationship between CNP, ovarian processes, and PCOS, and notes that serum CNP may differ between healthy women and women with PCOS. The study aims to examine that difference using serum measurements. A comparison can describe whether the observed groups differ, but a non-randomized design cannot by itself show that PCOS caused any observed difference. Other characteristics that vary between groups could also be relevant. The record does not report which characteristics were controlled for in the analysis or whether adjusted comparisons were performed.
3. Trial Design
The registry describes a completed, non-randomized, parallel-group study. It lists no masking. The study is associated with Near East University, Turkey, and has an overall enrollment of 90. The registry describes one group as 36 patients with PCOS and another as 30 patients with regular normal menstrual cycles. The record does not explain how these arm descriptions relate to the overall enrollment figure.
The planned comparison is observational: participants are classified by whether they have PCOS or are healthy, and serum CNP levels are compared between those groups. Since allocation was non-randomized, the groups should not be treated as though they were formed through random assignment. The registry itself flags that the arms are not a like-for-like control comparison. Differences in measured levels could reflect the condition of interest, but they could also reflect other differences between participants. Whether the analysis addressed such factors is not reported in the registry record.
The listed primary outcome is serum CNP level, measured on the second or third day of menstruation. Its unit is pg/ml, and the planned summary is the median with inter-quartile range. The registry also lists comparisons of reproductive and hormone-related measures, including FSH and LH, estradiol, thyroid stimulating hormone, prolactin, androstenedione, DHEAS, and total and free testosterone. The record does not provide numerical results for these comparisons.
The registry marks the study as completed. The protocol details, recruitment process, eligibility criteria, and reasons for the difference between overall enrollment and the arm descriptions are not reported in the registry record. The study's statistical analysis plan and any planned adjustments are also not reported.
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.
Before assignment: For the last 6 months, patients with drug use that may affect menstruation like oral contraceptives, patients with cardiac or renal disease and therefore drug use, patients with hypertension hystory, history of ovarian surgery, current pregnancy, hyperprolactinemia, thyroid disease, congenital adrenal hyperplasia.
Overall Study
| Stage | Women With Polycystic Ovary Syndrome | Healthy Women of Reproductive Age |
|---|---|---|
| STARTED | 48 | 42 |
| COMPLETED | 36 | 30 |
| NOT COMPLETED | 12 | 12 |
Reasons for not completing this period:
| Reason | Women With Polycystic Ovary Syndrome | Healthy Women of Reproductive Age |
|---|---|---|
| Withdrawal by Subject | 8 | 7 |
| missing serum samples | 2 | 2 |
| insufficient sample volume | 2 | 3 |
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: 36 PCOS patient according to Rotterdam criterias and 30 healthy control women
| Characteristic | Unit | Women With Polycystic Ovary Syndrome | Healthy Women of Reproductive Age | Total |
|---|---|---|---|---|
| Participants analysed | 36 | 30 | 66 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 36 | 30 | 66 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 22 (21 to 24.8) | 24 (21.8 to 25) | 23 (21 to 25) |
| Sex: Female, Male: Female | Participants | 36 | 30 | 66 |
| Sex: Female, Male: Male | Participants | 0 | 0 | 0 |
| Race/Ethnicity, Customized: Cypriot | Participants | 36 | 30 | 66 |
| Region of Enrollment: Cyprus | participants | 36 | 30 | 66 |
| Body Mass Index | kg/m^2 | 23.20 (SD 4.26) | 21.17 (SD 1.88) | 22.28 (SD 3.52) |
6. Primary Endpoint
The registry lists the primary outcome as Serum CNP Levels of PCOS and Healthy Participants, measured over Second or Third Day of Menstruation.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | pg/ml |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is serum C type natriuretic peptide (CNP) level in women with PCOS compared with healthy women. The registry specifies measurement on the second or third day of menstruation, reports the unit as pg/ml, and identifies the median and inter-quartile range as the summary statistics.
The median describes the midpoint of the observed values when ordered, while the inter-quartile range describes the spread of the middle portion of those values. These summaries can be useful when a distribution is asymmetric or includes values that make a mean and standard deviation less representative. This is general statistical context; the registry does not report the distribution of CNP measurements or explain why it selected these summaries.
The endpoint addresses whether the measured serum levels differ between the two groups. It does not, by itself, identify the mechanism behind any difference or establish that PCOS caused it. Numerical group summaries, an estimated between-group contrast, and uncertainty around that contrast are not reported in the registry record. Consequently, the magnitude and precision of the primary comparison cannot be assessed from the record details.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies serum CNP level as the primary outcome, but numerical results for that comparison are not reported in the registry record. There is therefore no basis in the record details for describing the direction or size of a difference between the PCOS and healthy groups, or for judging its statistical precision. A p-value, confidence interval, and any conclusion about statistical significance are not reported in the registry record.
The outcome is intended to be summarized by medians and inter-quartile ranges. These summaries would describe the observed level and spread in each group. A comparison between groups would be needed to address the primary question, and an interval estimate would help show how much uncertainty surrounds that comparison. General statistical context: a confidence interval expresses a range of values compatible with the data and the method used to calculate it. It does not guarantee that the true value lies within the interval, and its interpretation depends on the study design and analysis.
Even if numerical differences were reported, the non-randomized design would require cautious interpretation. Participants were not randomly allocated to PCOS or healthy status. Group differences may therefore reflect factors associated with group membership as well as any relationship with CNP. The registry does not report whether potential confounders were measured, adjusted for, or otherwise considered. The record also states that the arms are not a like-for-like control comparison.
The listed overall enrollment is 90, while the arm descriptions state 36 patients with PCOS and 30 healthy women. The registry record does not explain how the arm descriptions relate to overall enrollment. It also does not report the number of participants with available primary outcome measurements or the analysis population used for the CNP comparison. These omissions make it difficult to assess how complete the outcome data were and which participants contributed to any analysis.
The registry lists several secondary hormone comparisons, but their numerical findings and the approach to interpreting multiple comparisons are not reported in the registry record. Without outcome estimates and analysis details, the record cannot support a conclusion about whether serum CNP differs between the groups, how precisely any difference was estimated, or whether it is independent of other characteristics. The study's stated objective remains a comparison of serum levels, not a test of treatment efficacy.
9. Statistical Methods Explained
The registry identifies a comparison of serum CNP levels between women with PCOS and healthy women. It specifies medians and inter-quartile ranges for the primary outcome, but does not report the inferential method used to compare groups. The analysis plan, including any model, adjustment variables, or method for estimating uncertainty, is not reported in the registry record.
What do medians and inter-quartile ranges describe?
General statistical context: the median is the central observation after measurements are ordered. The inter-quartile range describes the span from the lower to the upper quartile, capturing the middle part of the observations. These summaries are often useful when data are skewed or when extreme observations could strongly affect a mean. They describe the data; on their own, they do not quantify the uncertainty in a between-group difference or establish whether groups differ beyond what might arise from sampling variation.
Because the endpoint is summarized with medians, a reader would need to know how the investigators compared those distributions and what estimand the analysis targeted. Different methods can address different questions, such as a difference in central tendency or a broader difference in distributions. The registry does not state which question the inferential analysis addressed. Nor does it report group-level outcome values or a comparison estimate.
How should uncertainty be assessed?
General statistical context: an estimate is more informative when accompanied by an interval that conveys its uncertainty. A confidence interval can show the range of effect values reasonably compatible with the observed data under the statistical model and assumptions. Its width is influenced by factors such as variability, the amount of usable information, and the analysis method. A p-value, if reported, addresses compatibility of data with a specified null model; it does not measure the size or practical importance of an effect. No confidence interval, p-value, or other uncertainty measure for the primary comparison is reported in the registry record.
The registry record includes assumptions for planning illustrations: a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. Such illustrations are planning calculations, not observed power, and they do not replace the trial's analysis or show that a result is precise. The registry does not report the numerical planning outputs or a sample-size justification used to design the study.
Why does over-dispersion matter?
General statistical context: over-dispersion occurs when the observed variability is greater than a model assumes. If an analysis treats data as less variable than they are, standard errors may be too small and intervals too narrow; if it accounts for extra variability, uncertainty may be represented more appropriately. This issue is especially relevant to models for counts or rates. The primary endpoint is a serum measurement summarized by median and inter-quartile range, and the registry does not report a model or variance assumption. Whether over-dispersion is relevant to any analysis in this study is not reported in the registry record.
What does the non-randomized design imply?
General statistical context: randomization can balance measured and unmeasured characteristics on average, while a non-randomized comparison does not have that design feature. Differences between groups may be confounded by other factors. Statistical adjustment can address measured factors when appropriate data and a suitable model are available, but it cannot automatically resolve unmeasured confounding. The record does not report whether adjustment was undertaken or which variables were considered. Its explicit note that the arms are not a like-for-like control comparison reinforces the need to treat any group contrast as an association rather than a causal effect.
The registry also does not report an interim analysis plan, missing-data method, analysis population, or prespecified multiplicity procedure. Those details matter for understanding how estimates were selected and how uncertainty should be interpreted. In their absence, the outcome summaries and analysis choices cannot be independently assessed from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary comparison of serum CNP and several secondary comparisons involving hormone measures. When multiple outcomes or hypotheses are examined, the chance of obtaining at least one apparently notable result can increase. General statistical context: multiplicity procedures may control this risk or define a hierarchy of confirmatory and exploratory analyses. The registry does not report whether any such procedure was planned or used, or how the primary and secondary outcomes were prioritized for inference.
Missing-data information is also limited. The registry provides overall enrollment and arm descriptions, but does not state how many participants had an available primary CNP measurement, whether any measurements were excluded, or why data might be missing. The missing-data mechanism, handling method, and any sensitivity analyses are not reported in the registry record. Without these details, the extent to which the reported analysis—if any—represents all enrolled participants cannot be assessed.
The analysis populations are not described. The record does not say whether analyses included all enrolled participants, only those with outcome measurements, or a different defined group. It also does not describe eligibility criteria or analysis exclusions. The relationship between overall enrollment of 90 and the arm descriptions of 36 and 30 is not explained in the registry record.
The registry does not report interim analyses, stopping rules, or a statistical analysis plan. These omissions do not establish that such procedures were absent; they mean that the relevant information is not reported in the registry record. Accordingly, the reported information is insufficient to evaluate multiplicity control, completeness of outcome data, or the exact population underlying any group comparison.
11. What the Result Does, and Does Not, Mean
The registry record describes a study intended to compare serum CNP levels in women with PCOS and healthy women. It specifies the timing of measurement, the unit, and the use of median and inter-quartile range summaries. However, numerical primary outcome results are not reported in the registry record. The direction, magnitude, and precision of any group difference therefore cannot be stated.
The study's non-randomized design also limits what a group comparison could establish. An observed association would not show that PCOS caused a difference in CNP, because other characteristics may differ between the groups. Whether the investigators measured or adjusted for potential confounders is not reported in the registry record. The registry itself cautions that the arms are not a like-for-like control comparison.
The study does not test CNP as a treatment. The registry lists CNP as a diagnostic test and frames the primary outcome as a comparison of serum levels. Thus, its objective is descriptive or comparative, not an evaluation of therapeutic benefit. The record cannot establish that changing CNP levels would change a health outcome.
The available descriptions also do not resolve how overall enrollment relates to the two arm descriptions, how many participants contributed measurements, or how missing observations were handled. These gaps limit assessment of data completeness and generalizability. The results for the listed secondary hormone comparisons, together with the approach to multiple testing, are not reported in the registry record. A careful interpretation is therefore limited to the stated study question and design; no conclusion about the presence or absence of a difference can be drawn from the record details.
12. Why This Trial Matters Statistically
This study matters statistically because it asks whether a serum marker differs between a group defined by PCOS and a healthy comparison group, while using a non-randomized design. That combination makes the distinction between association and causation central. Even a clearly estimated group difference would not, on its own, identify why the difference arose or establish that PCOS caused it.
The choice to summarize CNP using medians and inter-quartile ranges is also relevant. These measures focus on the center and spread of the observed values without requiring the data to be described by a mean and standard deviation. To interpret a group contrast fully, however, the summary statistics need to be accompanied by an appropriate comparison estimate and uncertainty. Those numerical results are not reported in the registry record.
The registry lists multiple hormone outcomes in addition to the primary CNP comparison. Considering several comparisons makes prespecification and multiplicity important to interpretation, yet the registry does not report a multiplicity strategy or analysis plan. It also does not describe missing-data handling or analysis populations. These reporting gaps prevent readers from evaluating how robustly the statistical results address the stated question.
Finally, the enrollment information requires care: the overall enrollment is 90, while the two arm descriptions give 36 and 30 participants. The record does not explain this difference. Taken together, the design and reporting details illustrate why statistical interpretation depends not only on an outcome summary, but also on the comparison method, uncertainty, participant accounting, and handling of multiple outcomes.
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 numerical results for the primary serum CNP comparison. It therefore does not permit assessment of the observed group values, effect estimate, statistical uncertainty, or statistical significance. The stated summary format—median and inter-quartile range—does not replace those results.
The study is non-randomized, and the registry notes that the groups are not a like-for-like control comparison. The record does not report whether potential confounders were measured or whether adjusted analyses were conducted. Consequently, even a reported difference would need to be interpreted as an association rather than a causal effect.
Participant accounting is unclear in the registry record. Overall enrollment is 90, while the arm descriptions state 36 patients with PCOS and 30 healthy women. The record does not explain how these figures relate, identify the analysis population, or report how many participants contributed primary outcome data. Eligibility criteria, missing-data handling, and reasons for exclusions are also not reported.
The registry lists several secondary hormone comparisons but does not report their numerical results or any approach to multiplicity. It also does not report the statistical analysis plan, inferential method, adjustment strategy, or uncertainty estimates. The description of planning assumptions does not provide the numerical planning outputs or a sample-size justification for the study's own design. These limitations restrict both evaluation of the findings and assessment of how completely the analyses address the stated research question.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Comparison of Serum C Type Natriuretic Peptide Levels Between Polycystic Ovary Syndrome Patients and Healthy Women — NCT04006171.
- Registry record last updated 2021-11-05; status last verified 2021-10.
- Results first posted 2021-11-05.
- 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.
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17. Record Summary
The registry describes a completed, non-randomized, parallel-group study comparing serum CNP levels in women with PCOS and healthy women. The primary measurement is specified for the second or third day of menstruation, in pg/ml, and is to be summarized using the median and inter-quartile range. The record lists overall enrollment of 90 and arm descriptions of 36 patients with PCOS and 30 healthy women, without explaining how these figures relate.
Secondary outcomes include comparisons of several hormone measures. Numerical results for the primary and secondary comparisons, the statistical analysis plan, missing-data methods, analysis populations, and multiplicity procedures are not reported in the registry record. Because the comparison is non-randomized and the registry cautions that the arms are not like-for-like controls, any group difference would require cautious interpretation and would not establish causation.