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 Visualization of Asymptomatic Atherosclerotic Disease for Optimum Cardiovascular Prevention (NCT01849575), a randomized na study. The primary outcome is FRS.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01849575 |
| Phase | NA |
| Condition | Cardiovascular Diseases |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 3532 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Umeå University |
| Results posted | Yes |
2. Clinical Question
Population
The study is described as a population-based pragmatic trial within the Västerbotten Intervention Programme and ordinary care. It concerns people with cardiovascular disease risk and asymptomatic atherosclerotic disease; detailed eligibility criteria, age limits, and recruitment criteria are not reported in the registry record.
Intervention
Participants and physicians in the intervention group received written and graphical communication about silent atherosclerosis measured by carotid ultrasound. The description refers to carotid intima-media thickness, vascular age, and plaque formation. The registry description ends before fully specifying how plaque information was visualized.
Comparator
The control group and its physician did not receive the carotid ultrasound results about silent atherosclerosis. They were informed about measured conventional cardiovascular risk factors. Other details about how usual care was delivered are not reported in the registry record.
Primary question
The main question is whether communicating ultrasound evidence of asymptomatic atherosclerosis is associated with a difference between randomized groups in Framingham Risk Score after one year. The broader stated purpose is to assess physicians’ adherence to prevention guidelines and patients’ risk perception, understanding, and motivation. The posted primary outcome is the risk score, not a direct measure of cardiovascular events or behavior.
3. Trial Design
VIPVIZA is a randomized, parallel-group, single-masked, population-based pragmatic trial conducted within the Västerbotten Intervention Programme and ordinary care. Its registry title is “Visualization of Asymptomatic Atherosclerotic Disease for Optimum Cardiovascular Prevention.” Umeå University is listed as sponsor. The phase is listed as not applicable.
The registry lists enrollment of 3532. The intervention was behavioral: written and graphical information about silent atherosclerosis measured by carotid ultrasound was shared with the participant and physician. The control group did not receive the ultrasound results and was informed about conventional cardiovascular risk factors. The registry does not identify who was masked, so “single-masked” should not be interpreted as specifying which trial role was unaware of assignment.
The primary outcome is Framingham Risk Score at one year. Secondary outcomes include SCORE, hospitalizations for stroke, myocardial infarctions and revascularizations, mortality, and carotid atherosclerosis. The study description also refers to repeated carotid ultrasound examinations after three and six years, and to acute events and mortality after 10 years. Those aims describe the broader study; they do not mean that all such outcomes are available in the posted results.
The registry lists a start date of 2013-04-07, primary completion on 2017-11-10, and status “active, not recruiting.” A final study completion date is not reported in the registry record. The method of sequence generation, allocation concealment, randomization ratio, site-level procedures, and detailed eligibility criteria are 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
| Stage | Intervention | Control |
|---|---|---|
| STARTED | 1749 | 1783 |
| COMPLETED | 1599 | 1576 |
| NOT COMPLETED | 150 | 207 |
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.
| Characteristic | Unit | Intervention | Control | Total |
|---|---|---|---|---|
| Participants analysed | 1749 | 1783 | 3532 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1749 | 1783 | 3532 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 940 | 930 | 1870 |
| Sex: Female, Male: Male | Participants | 809 | 853 | 1662 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: Sweden | participants | 1749 | 1783 | 3532 |
| Framingham Risk Score | % risk of CVD within 10 years | 12.9 (SD 9.6) | 12.8 (SD 9.1) | 12.9 (SD 9.3) |
6. Primary Endpoint
The registry lists the primary outcome as FRS, measured over one year.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 99.5% Confidence Interval |
| Unit | % risk of a CVD event within 10 years |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the Framingham Risk Score (FRS), reported as percentage risk of a cardiovascular disease event within 10 years and assessed at one year. It is a composite, gender-specific algorithm based on blood pressure, total cholesterol, LDL-cholesterol, systolic blood pressure, treatment for high blood pressure, diabetes, smoking, and age. Its stated range is from 0 to 100, and a higher score means a worse outcome in the sense of a higher estimated cardiovascular risk.
FRS is a risk estimate, not a count of events observed during the one-year assessment. It is used to represent the combined information in several conventional risk factors as one measure. That makes it relevant to a trial whose stated purpose includes prevention and risk communication, while also limiting what can be concluded: a change in an estimated risk score is not itself evidence of a change in cardiovascular events, mortality, or participants’ understanding.
The registry reports one-year group estimates with 99.5% confidence intervals. It does not report a primary between-group effect estimate, its confidence interval, or a p value for the primary endpoint. The score’s listed description specifies higher values as worse, but the registry record does not provide a posted primary analysis that quantifies the randomized-group contrast.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
At one year, the intervention group’s mean FRS was 12.2, with a 99.5% confidence interval from 11.6 to 12.9. The control group’s mean was 13.3, with a 99.5% confidence interval from 12.6 to 14.0. The reported group sizes were 1599 and 1576, respectively. These are separate group summaries. The registry does not report a primary between-group estimate, confidence interval, or p value, so the group summaries alone do not supply a formal estimate of the randomized treatment contrast.
The score is an estimate of 10-year cardiovascular risk based on risk factors; it is not a count of cardiovascular events. The posted values therefore describe the risk-score outcome at one year, not the number of events prevented or caused. The registry’s definition says that higher FRS represents higher estimated risk. No claim about clinical benefit or harm follows solely from the numerical ordering of the two group means.
For carotid atherosclerosis at three years after baseline, the intervention group mean was 0.68 mm (standard deviation 0.151; n=1575), and the control group mean was 0.685 mm (standard deviation 0.165; n=1579). The recalculated, unadjusted mean difference was -0.005 mm, with a 95% confidence interval from -0.016 to 0.006 and p=0.375. This calculation uses the posted group summary statistics and is not the same as the registry’s separately reported ANCOVA analysis.
The registry reports an ANCOVA analysis for carotid atherosclerosis with p=0.001, but does not give its adjusted estimate or confidence interval. The adjusted analysis and the unadjusted recalculation are different analyses; the registry does not state which covariates were included in the ANCOVA. The p value alone does not convey the adjusted effect’s direction or size. The unadjusted recalculation should therefore be read as a separate descriptive analysis, not as a replacement for the reported ANCOVA result.
Overall, the primary endpoint has arm-specific estimates but no posted primary contrast, while the secondary carotid outcome has both an adjusted p value and a recalculated unadjusted contrast. Their different forms of reporting restrict direct comparison. The outcome values and analyses should be interpreted as the specific results recorded, without treating secondary findings as confirmation of the primary question.
9. Statistical Methods Explained
What does a confidence interval describe?
General explanation: a confidence interval expresses uncertainty around an estimate under the assumptions of the method used to construct it. A narrower interval indicates greater precision for that particular estimate; a wider interval indicates more uncertainty. A confidence interval is not a range containing every individual participant’s value, and it does not by itself answer whether groups differ. For the primary endpoint, the registry reports 99.5% confidence intervals around each group mean, not around a between-group difference. The carotid outcome’s recalculated interval is around an unadjusted mean difference.
The primary group estimates are 12.2 (99.5% confidence interval 11.6 to 12.9) for the intervention group and 13.3 (12.6 to 14.0) for control. The registry does not report an interval for the primary randomized-group contrast. A comparison of two separate confidence intervals is not a substitute for the confidence interval of the contrast, because the uncertainty of the difference must be evaluated directly.
How should the carotid outcome analyses be distinguished?
The posted carotid outcome summarizes means and standard deviations at three years after baseline. A recalculated unadjusted comparison uses those group summaries to estimate the mean difference between intervention and control. The recalculated result is -0.005 mm, with a 95% confidence interval from -0.016 to 0.006 and p=0.375. It is explicitly an unadjusted calculation from the posted summary statistics, not a participant-level model fit.
The registry also reports an ANCOVA analysis with p=0.001. ANCOVA is a general statistical approach that compares outcome means while adjusting for specified covariates. General explanation: adjustment can account for measured characteristics included in the model, and the resulting estimate and uncertainty can differ from a simple unadjusted comparison. The registry does not name the covariates, provide the adjusted estimate, or give its confidence interval. Thus the adjusted result cannot be described in terms of its magnitude from the reported p value alone. The two results answer related but not identical statistical questions.
A p value describes how compatible the data are with a specified null hypothesis under the analysis assumptions; it is not the probability that the null hypothesis is true and does not measure effect size. Here, p=0.375 belongs to the unadjusted recalculation, whereas p=0.001 belongs to the reported ANCOVA. They should not be merged or presented as competing values from one identical analysis. The record does not report a discrepancy flag for these results.
What do the planning illustrations mean?
The sample-size illustrations are based on the observed carotid effect and are not reported as the trial’s original design justification. They use a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. The scenarios consider detecting 100%, 75%, or 50% of the observed effect. General explanation: such calculations ask how many participants per arm a hypothetical future study might need under stated assumptions. They are planning illustrations, not observed power, and should not be read as evidence that the present study was designed or powered according to those values.
Power calculations depend on the assumed effect, variability, statistical test, and design conditions. A smaller effect to detect generally requires a larger sample under otherwise comparable assumptions. That general relationship does not establish that any particular future sample size is appropriate. The record does not report the original sample-size justification, the assumptions used to plan enrollment of 3532, or whether the trial’s design targeted a particular effect or power for the primary endpoint.
What is not specified about the analyses?
The primary outcome is reported as a number with a 99.5% confidence interval, but the primary analysis method and a direct between-group test are not reported in the registry record. The statistical model, covariate adjustments, handling of repeated measurements, and estimand are not reported. The analysis population, treatment of participants with missing outcomes, and any imputation procedures are also not reported in the registry record.
General explanation: missing observations can affect precision and, depending on why data are missing and how they are handled, can also affect the interpretation of an estimate. An analysis restricted to participants with recorded outcomes may differ from one that uses all randomized participants under an explicit missing-data model. Without information about missingness and the analysis population, the posted denominators should be treated as outcome-specific reported group sizes rather than assumed to represent a particular analysis principle.
Likewise, randomization supports a between-group comparison when the analysis preserves the randomized assignment and relevant assumptions hold, but the registry record alone does not establish which analysis population or model was used for every result. The reported methods are sufficient to identify the ANCOVA label for the secondary carotid analysis, but not to reproduce or fully assess that model.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists eight outcome measures and five posted secondary outcomes. It reports one analysis in the record-level count, while the secondary carotid outcome itself has a reported ANCOVA result and a separate unadjusted recalculation based on summary statistics. These counts do not establish a complete testing hierarchy. The registry does not report whether secondary outcomes were prespecified in a ranked order, whether any multiplicity correction was used, or whether the secondary analyses were confirmatory or exploratory.
General explanation: testing several outcomes can increase the chance of false-positive findings if each is interpreted using an unadjusted threshold. A multiplicity strategy can control that risk, but different strategies answer different questions and may change how evidence is interpreted. Since the strategy is not reported in the registry record, the ANCOVA p value should be interpreted as the result of that stated analysis, without assuming either that it was adjusted for other tests or that it was intended as a definitive finding.
Missing-data methods are also not reported. The record does not state how many randomized participants lacked each outcome, why data were missing, whether any imputation was performed, or whether the analysis used an intention-to-treat, per-protocol, or other population. The posted group sizes vary by outcome, but those denominators alone do not reveal the reasons for differences or the handling of missing observations.
The registry does not report the primary analysis model, the treatment of participants who deviated from assigned intervention, or sensitivity analyses for missing data. It also does not provide a detailed statistical analysis plan. These omissions limit assessment of whether the posted analyses follow a prespecified approach and whether assumptions about missingness or multiplicity affect interpretation. They do not invalidate the reported values, but they mean that statistical uncertainty and robustness cannot be fully evaluated from the registry record alone.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Intervention | 0 | 1749 | 0.0% |
| Control | 0 | 1783 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Intervention | 5 of 1749 |
| Control | 2 of 1783 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Intervention | 50 of 1749 |
| Control | 0 of 1783 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Intervention | Control |
|---|---|---|---|
| Anxiety | Psychiatric disorders | 50 of 1749 | 0 of 1783 |
The registry reports zero serious adverse events among 1749 participants at risk in the intervention group and zero among 1783 at risk in control. It lists 50 other adverse events in the intervention group and zero in control. Deaths are listed as 5 in the intervention group and 2 in control. These are counts as recorded, not estimates of comparative risk.
The record does not provide descriptions of the 50 other adverse events, their severity, timing, relatedness to the intervention, or whether they occurred in unique participants. It also does not identify the causes of the deaths in these safety entries or explain how deaths relate to the adverse-event counts. The registry lists no serious adverse-event terms in its top serious terms.
General explanation: adverse-event counts are descriptive and need context such as event definitions, follow-up duration, ascertainment procedures, and participant-level overlap. A zero count in the registry does not establish that an event is impossible or that safety has been comprehensively characterized. Because the group sizes and event counts are not accompanied by a comparative analysis or detailed event descriptions, they should not be interpreted as evidence of causation or as a complete account of safety.
12. What the Result Does, and Does Not, Mean
The results describe a randomized study that compared communication about ultrasound-detected silent atherosclerosis with control communication limited to conventional cardiovascular risk-factor results. At one year, the registry reports separate FRS means and confidence intervals for the two groups. FRS estimates 10-year cardiovascular risk from a collection of risk factors; it does not record whether a participant experienced a cardiovascular event during follow-up.
The primary results therefore do not establish the size or precision of a between-group difference in FRS, because a primary contrast and its interval or test are not reported. The values can be read as group-specific estimates, but they should not be converted into a claim of treatment effect. The broader aims involving physician guideline adherence, patient understanding, motivation, behavior, biomarkers, events, and mortality are not all represented by the one-year primary score.
The carotid outcome adds a different kind of evidence. Its unadjusted recalculation estimates a mean difference in a measured ultrasound quantity, while the registry also gives a p value for an ANCOVA analysis without the adjusted estimate. That record supports describing the analyses as reported, but not stating the size of the adjusted association or treating the two analyses as interchangeable. Secondary outcomes also require caution because multiplicity handling and the full analysis plan are not reported.
General explanation: statistical significance, clinical importance, and causal interpretation are distinct. A p value does not quantify clinical importance; an effect estimate and its uncertainty are needed to describe magnitude and precision. Randomization is intended to support causal comparisons, but interpretation also depends on the analysis population, follow-up, missing data, outcome measurement, and adherence to the assigned approach. Those details are not fully reported for these results.
Accordingly, the posted findings should be understood as registry-reported outcome summaries and analyses, not as a complete evaluation of every stated trial aim. They do not on their own establish that the intervention does or does not change cardiovascular outcomes, mortality, behavior, or clinical care.
13. Why This Trial Matters Statistically
This trial raises a statistical question about how an informational intervention is evaluated. The intervention concerns visual and written communication of a risk-related imaging result, while the primary endpoint is a composite estimate of cardiovascular risk. That distinction matters: changes in a score, changes in imaging measurements, and changes in clinical events represent different outcomes and should be interpreted on their own terms.
The registry also illustrates why the form of a result matters as much as its numerical value. Separate arm means and confidence intervals do not provide the same information as a randomized-group contrast and its confidence interval. For the primary outcome, the record gives the group summaries but not the contrast. For the secondary carotid outcome, both a summary-statistics recalculation and an adjusted-model p value are recorded, but the adjusted estimate is absent. Readers therefore need to distinguish descriptive summaries, unadjusted calculations, and model-based analyses rather than treating them as one result.
Another statistical issue is the relationship between planned and observed results. The sample-size illustrations are explicitly based on the observed effect and hypothetical assumptions; they are not the trial’s original design justification and are not observed power. Keeping planning calculations separate from the trial’s actual design prevents retrospective calculations from being mistaken for evidence about the original design or the certainty of its findings.
Finally, the trial’s broad scope includes risk scores, ultrasound measures, patient and physician responses, and longer-term clinical outcomes. Reporting complete estimates, uncertainty, analysis populations, missing-data handling, and multiplicity procedures would help readers assess how those different endpoints fit together. The registry record offers useful details about design and selected results, while leaving several elements needed for a full statistical appraisal unreported.
14. 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 provide a primary between-group estimate or test for the one-year FRS endpoint. As a result, the reported arm-specific means and 99.5% confidence intervals do not quantify the uncertainty of the primary contrast. The primary endpoint’s listed population is blank, and eligibility criteria and detailed participant characteristics are not reported in the registry record.
The intervention description is incomplete: it identifies written and graphical information, carotid intima-media thickness, vascular age, and plaque formation, but ends before fully describing the visualization. The record also does not specify who was masked, how the random sequence was generated, how allocation was concealed, or how intervention delivery and adherence were assessed. These omissions restrict assessment of implementation and potential bias.
For the secondary carotid outcome, the adjusted ANCOVA estimate and confidence interval are absent, as are the covariates used in that model. The unadjusted recalculation is based on posted group summaries and cannot reproduce the participant-level analysis. The registry does not report a full statistical analysis plan, multiplicity handling, analysis populations, missing-data procedures, or sensitivity analyses. It does not give enough information to assess the completeness of follow-up for each outcome.
The listed secondary outcomes include clinical events and mortality, but the available record does not provide numerical results for every listed outcome. The safety entries include counts but no event descriptions or detailed ascertainment information. Finally, although the registry reports active-not-recruiting status and a primary completion date, a final study completion date is not reported in the registry record. These limitations concern the information available for interpretation and should not be mistaken for evidence that unreported procedures or results did not exist.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Visualization of Asymptomatic Atherosclerotic Disease for Optimum Cardiovascular Prevention — NCT01849575.
- Registry record last updated 2026-06-29; status last verified 2026-05.
- Results first posted 2020-05-07.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
VIPVIZA is a randomized, parallel-group, single-masked pragmatic trial sponsored by Umeå University. It compares communication of carotid ultrasound information about asymptomatic atherosclerosis with control communication about conventional cardiovascular risk factors. The registry lists enrollment of 3532, a start date of 2013-04-07, primary completion on 2017-11-10, and status active, not recruiting.
The primary endpoint is FRS at one year. The record reports group means and 99.5% confidence intervals but no primary between-group analysis. Secondary carotid atherosclerosis results include group summaries, an unadjusted recalculation, and an ANCOVA p value without an adjusted estimate. The registry also lists longer-term clinical and mortality outcomes, but not all corresponding numerical results are reported.
Important details—including the full analysis plan, missing-data methods, multiplicity procedures, analysis populations, and final study completion date—are not reported in the registry record. The available results therefore support a focused reading of the recorded estimates and analyses, rather than a complete appraisal of every stated study aim.