The Effect of the MedSentry System on Medication Adherence: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Effect of the MedSentry System on Medication Adherence (NCT01814696), a randomized na study. The primary outcome is Medical Outcomes Study (MOS) "Adhere".

2. Clinical Question

The study also set out to evaluate usability, satisfaction and clinical outcomes. Its stated hypotheses linked improved adherence with fewer hospitalizations and emergency department visits, and with better health-related quality of life. Those hypotheses describe questions the pilot was intended to explore; they are not evidence that the expected relationships occurred. Secondary outcomes listed in the registry include participants with one or more emergency department visits or hospitalizations, counts of visits, length of hospital stay, and the Minnesota Living With Heart Failure Questionnaire total summary score. The registry record does not report those outcomes in a form that supports a comprehensive assessment of the stated hypotheses.

3. Trial Design

This was a randomized, parallel-group pilot study with no masking recorded. The registry lists an enrollment of 26 and a terminated status. The study start is recorded as 2013-03 and primary completion as 2014-05. The reason for termination is not reported in the registry record, so the status alone does not explain why the study ended or whether termination was related to outcomes, recruitment, logistics, or another issue.

The comparison was between usual medical care and usual medical care with the MedSentry System and electronic pillbox. Random allocation is recorded, but the sequence-generation method, allocation concealment, and procedures for assigning participants are not reported in the registry record. No masking was recorded. The registry does not specify whether outcome collection or analysis was conducted by people unaware of group assignment.

The study is identified as a pilot and has no applicable phase listed. The primary outcome was assessed at 3 months, with its description referring to participants who completed enrollment and closeout questions. The registry does not report the number in each analysis group for that outcome or how incomplete survey data were handled. Although the overall enrollment is recorded, enrollment alone does not show how many participants contributed to each outcome.

Several secondary outcomes address emergency department use, hospitalizations, hospital length of stay and quality of life. The record lists seven outcome measures and 16 analyses, but does not provide enough information to reconstruct the complete analysis plan, the order in which outcomes were tested, or which results were intended to be definitive. It also does not report a sample-size justification for the trial’s own design. The later planning assumptions are illustrations and should not be read as the original design rationale.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who completed questions on enrollment and closeout survey.

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 Medical Outcomes Study (MOS) "Adhere", measured over 3 months.

The primary measure was the Medical Outcomes Study (MOS) “Adhere” medication-adherence item. It asks participants how often they took their medications as prescribed during the past 4 weeks. Responses are classified as nonadherent when participants report “none,” “a little,” or “some of the time,” and as adherent when they report “most” or “all of the time.” The measure is therefore a dichotomized self-report, rather than a direct count of doses taken or an electronic record of medication use.

The endpoint is intended to capture participants’ reported adherence over a recent period. A concise self-report can be useful when adherence is a behavioral outcome and a study needs to collect information directly from participants. Its interpretation remains tied to what the question asks: how often participants say they took medication as prescribed. It does not by itself establish why a participant missed medication, verify medication-taking behavior independently, or show whether any reported difference affected clinical outcomes.

The registry gives a 3-month timeframe and identifies the primary population as participants who completed questions on enrollment and closeout. The record does not report a single reduced comparison for this outcome. It therefore does not provide a group effect estimate, its precision, or a basis for deciding how the observed responses differed between groups. The endpoint definition explains what was measured, but does not substitute for the missing comparative result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General: A randomized parallel-group design compares outcomes among groups assigned to different study conditions. Randomization is intended to make the groups comparable on average at the point of assignment, including with respect to factors that may not have been measured. It does not guarantee balance in a small pilot, and it does not remove the need to describe who was enrolled, who completed follow-up, and how outcomes were analyzed. This record identifies random allocation and a parallel model, but does not report the allocation procedure or a detailed analysis plan.

What does the adherence outcome represent?

The primary endpoint is a dichotomized self-report. Participants were asked how often they took medications as prescribed during the past 4 weeks; response categories were grouped into adherent and nonadherent classifications. Dichotomizing responses creates a straightforward category for comparison, but it also collapses distinctions among the original response options. The resulting outcome does not preserve the full range of reported frequency and is not a direct measurement of medication ingestion.

The endpoint description identifies participants with enrollment and closeout survey responses as the population for the measure. An analysis limited to people with both sets of responses can differ from an analysis that includes all randomized participants. The record does not report the number with completed paired responses or state how missing responses were treated. Without that information, the extent to which the analyzed participants represent everyone randomized cannot be assessed.

Why do effect estimates need uncertainty measures?

General: An effect estimate describes the observed contrast between groups for a chosen outcome. A confidence interval expresses the uncertainty around that estimate under the assumptions of the statistical method. A narrow interval indicates greater precision than a wide interval, while an interval spanning a range of possible effects can leave substantial uncertainty about the magnitude or direction of the contrast. A p-value addresses compatibility of the data with a specified null model; it does not measure the size or clinical importance of an effect.

For this trial, the registry record does not report a reduced primary-outcome comparison, an effect estimate, a confidence interval, or a p-value for that comparison. Therefore, these quantities cannot be interpreted for the primary adherence endpoint. The lack of a reported estimate should not be recast as a null finding or as evidence of equivalence.

How should event counts be read?

General: Binary event outcomes can be described by the number of participants experiencing an event and the number considered at risk or included in the comparison. Those counts provide context, but a comparative conclusion also depends on the analysis method and the uncertainty around the group contrast. For outcomes such as hospitalizations or emergency department visits, it is important to distinguish participants who experienced at least one event from the total number of events. Repeated visits by one participant can contribute to an event count without representing additional participants.

The registry lists both participant-based outcomes and visit-count outcomes among the secondary measures. It does not provide a complete set of comparative estimates or analysis details for those outcomes. The serious adverse event figures are participant counts at risk and affected, with separate event terms also listed. They should not be treated as the primary endpoint or as an estimate of the effect on adherence.

What do planning illustrations mean?

General: A sample-size calculation asks how many participants would be needed under stated assumptions to detect a specified effect with a chosen significance level and power. Such a calculation is a planning exercise, not a statement about what an already completed study demonstrated. A calculation based on an observed effect can be especially sensitive to the uncertainty in that effect; an unstable estimate can lead to unstable planning requirements.

The registry’s planning assumptions specify a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as fractions of the observed effect. They characterize planning illustrations rather than the trial’s own design justification. The record does not report an original sample-size justification. Because the primary outcome has not been reduced to a single comparison in the registry record, the observed primary effect needed to understand such illustrations is not available in the posted record. Planning quantities should not be mistaken for observed power or evidence that the study was capable of detecting a particular effect.

What can be inferred from the listed analyses?

The record lists 16 analyses and several outcomes. Multiple analyses can raise questions about multiplicity: when many outcomes or comparisons are examined, the chance of obtaining at least one apparently unusual result can increase. General methods for addressing this include prespecifying a primary comparison, adjusting inference across selected tests, or treating secondary analyses as exploratory. Which approach was used in this study, whether any adjustment was made, and how analyses were prioritized are not reported in the registry record. Consequently, the number of listed analyses alone does not establish how strongly any individual result should be interpreted.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures and 16 analyses, including the primary adherence measure and secondary measures concerning emergency department visits, hospitalizations, hospital length of stay and quality of life. When a study examines multiple outcomes or comparisons, multiplicity can affect how results are interpreted. General: testing many hypotheses without an appropriate plan can increase the chance that at least one result appears notable by chance. Prespecified priorities or an adjustment strategy can help clarify the intended interpretation.

The registry record does not report whether the analyses were adjusted for multiplicity, whether outcomes were ordered into a testing hierarchy, or whether any secondary results were designated exploratory. It also does not provide a complete statistical analysis plan. The number of analyses listed should therefore be understood as a description of the registry’s analysis entries, not as evidence that a particular correction was or was not applied.

The primary outcome description applies to participants who completed enrollment and closeout questions. The number of participants with both measurements, the amount and pattern of missing outcome data, and the method used to handle missing responses are not reported in the registry record. The record also does not state whether the primary analysis included all randomized participants or only those with complete survey data. These details matter because exclusions for missing outcomes can affect the composition of the analyzed groups.

Allocation is recorded as randomized, but the record does not describe the analysis population in enough detail to determine how assignment was handled after randomization. The handling of withdrawals, crossovers, or nonadherence to assigned procedures is not reported in the registry record. No assumptions about these procedures should be inferred from the pilot designation or the terminated status.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: ed visit (28.6%), hospitalization (28.6%).

The registry reports serious adverse event counts separately for the control and intervention groups. In the control group, 14 participants were listed as at risk and 7 as affected. In the intervention group, 11 were listed as at risk and 3 as affected. These figures describe participants with a serious adverse event in the registry’s reporting, not the primary medication-adherence endpoint.

The top serious-event terms are “ED Visit” and “Hospitalization,” each listed as 28.6%. Those percentages are reported as event terms; the record does not explain whether they refer to participants, events, or another coding denominator. They should not be combined with the group counts or treated as a comparative risk estimate without that clarification. Counts and percentages also do not describe when events occurred or whether they were considered related to the intervention.

The deaths field is not reported in the registry record. The reason for termination, event-level details, attribution, and a formal statistical comparison of serious adverse events are also not reported in the registry record. These safety entries can be described as recorded, but they do not establish that the intervention caused, prevented, or changed the likelihood of serious events.

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

The registry record shows that a randomized pilot study was designed to compare usual care with usual care plus the MedSentry System and electronic pillbox. It identifies self-reported medication adherence at 3 months as the primary outcome and lists clinical and quality-of-life outcomes as secondary measures. It also records an enrollment of 26 and a terminated status. These details establish the study’s design and intended questions, but they do not establish the size of an intervention effect.

The primary endpoint asks participants to report how often they took medications as prescribed during the past 4 weeks, with responses classified into adherent or nonadherent categories. This is evidence about reported adherence as defined by the measure. It is not, by itself, direct evidence of medication-taking behavior or evidence that adherence affected hospitalization, emergency department use, or quality of life.

The primary comparison is not reported as a single reduced result in the registry record. There is therefore no reported primary effect estimate or measure of its precision to support a conclusion about the direction or magnitude of a difference. This limitation does not mean that the two groups had identical outcomes; it means the record does not provide the comparison needed to evaluate that question. The secondary outcome listings and stated hypotheses likewise do not establish that any expected relationship was observed.

The serious adverse event counts are descriptive entries. They do not show whether events were related to the intervention or provide a formal comparison between groups. The registry’s terminated status does not explain why the study ended, and no reason should be inferred from that status alone. Overall, the record supports a description of the pilot’s design, measures and limited safety entries, but not a claim that the device improved adherence, changed clinical outcomes, or had a particular causal effect.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between a registered research question and a result that can be interpreted quantitatively. The record identifies random allocation, a parallel comparison, an adherence endpoint and a follow-up timeframe. Yet the primary outcome is not presented as a single reduced comparison. Without that contrast and its uncertainty, the central statistical question remains unanswered by the posted result information.

The endpoint also illustrates how measurement choices shape interpretation. The MOS “Adhere” item asks participants to recall medication-taking during the past 4 weeks and classifies responses into two groups. That approach gives a defined outcome, but the outcome remains self-reported and its categorization discards distinctions among response options. Statistical analysis cannot resolve limitations that arise from what the measure captures.

The study’s pilot designation and enrollment of 26 make it particularly important to distinguish exploratory planning from evidence about an effect. Small studies can produce imprecise estimates, but the record does not provide the primary estimate needed to assess precision in this case. Planning illustrations based on an observed effect are not observed power and do not demonstrate that an effect was present or absent.

The secondary outcomes also raise questions about analysis priority and multiplicity. The record lists multiple analyses and outcomes but does not describe the analysis hierarchy or any multiplicity approach. That missing information limits the interpretation of any isolated result. The statistical lesson is not that the device did or did not change outcomes; it is that clear reporting of outcome contrasts, uncertainty, missing data, and analysis decisions is essential for evaluating a randomized pilot.

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 primary outcome is based on a participant’s retrospective report and a dichotomous classification. The registry describes the question and the mapping of responses to adherence categories, but does not report validation details or an independent adherence measure. Therefore, the endpoint reflects the measure’s defined self-report rather than an independently verified record of medication-taking.

The primary analysis population is described as participants who completed questions on enrollment and closeout. The number of participants with those responses is not reported in the registry record. Without completion and missingness information, it is not possible to assess how much outcome information was available or whether missing responses differed across groups.

The overall enrollment is 26, but group-specific primary-outcome denominators and the primary comparative result are not reported. The record also does not provide a confidence interval, p-value, or other estimate of uncertainty for that outcome. Thus, the precision and direction of the primary contrast cannot be evaluated.

No masking was recorded, and the registry does not describe whether survey collection or analysis was masked. The record does not provide the randomization procedure, allocation concealment details, a full analysis plan, or a multiplicity strategy for the listed outcomes and analyses. These omissions limit assessment of potential bias and the interpretive status of secondary findings.

The study is listed as terminated, but the reason is not reported in the registry record. The record also does not explain the disposition of all enrolled participants or provide enough detail to assess the completeness of clinical outcome reporting. These are reporting limitations; the status itself does not establish why the study ended or what its results would have been under a different course.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Effect of the MedSentry System on Medication Adherence — NCT01814696.
• Registry record last updated 2020-09-17; status last verified 2020-08.
• Results first posted 2017-01-05.
• 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.

18. Record Summary

NCT01814696 is a randomized, parallel-group pilot study of the MedSentry System for patients with heart failure. The registry records no masking, enrollment of 26, a terminated status, a start of 2013-03 and primary completion in 2014-05. The intervention group continued usual medical care and used the MedSentry System and an electronic pillbox; the control group continued usual care.

The primary measure was the MOS “Adhere” self-report at 3 months, based on medication-taking during the past 4 weeks. The registry lists secondary measures for emergency department visits, hospitalizations, hospital length of stay and quality of life. It does not report a single reduced primary comparison, its effect estimate, or its precision. The reason for termination, missing-data handling, analysis population details and the full statistical plan are not reported in the registry record.