Northwestern University and Access Community Health Network Medication Education Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Northwestern University and Access Community Health Network Medication Education Study (NCT01578577), a randomized na study. The primary outcome is Systolic Blood Pressure.

2. Clinical Question

The study asks whether two primary care-based medication therapy management strategies that use an electronic health record are associated with different outcomes from standard care among hypertensive patients at safety net clinics. One strategy is the Electronic Health Record-based Health Literacy Medication Therapy Management Intervention, or EHMI; the other combines EHMI with a nurse educator. Standard care is the control group and receives no intervention.

The primary measure is systolic blood pressure in mm Hg. The posted comparisons are unadjusted mean differences between each intervention group and standard care. The study also lists secondary outcomes concerning the strategy’s effectiveness over several follow-up time points and possible differences by patients’ literacy skills. These registry results describe the posted group summaries and comparisons; they do not, by themselves, provide a complete account of the trial’s analysis plan or all outcomes named in the study objective.

3. Trial Design

The registry identifies this as a randomized, parallel-group study with no masking. It lists Northwestern University as the sponsor and reports enrollment of 920. The condition is hypertension. The study status is completed, with a start date of 2012-04 and a primary completion date of 2016-06. The phase is listed as NA.

The groups are Standard Care, EHMI, and Nurse Educator + EHMI. Standard Care is described as receiving no intervention. EHMI is described as an electronic health record-based medication therapy management intervention using the Epic EHR platform; the posted arm description ends before its full account of the components is complete. The arm description for Nurse Educator + EHMI is blank. The registry record therefore does not report enough detail to reconstruct the full intervention content, how the nurse educator participated, or the care delivered to the control group beyond the statement that no intervention was given.

The study objective describes strategies intended to promote patient understanding, medication reconciliation, medication adherence, and disease control. These are aims, not all reported results. The primary endpoint is systolic blood pressure measured approximately one year after the baseline interview. The posted primary outcome summaries include 254 participants in Standard Care, 262 in EHMI, and 278 in Nurse Educator + EHMI. The registry also reports secondary outcome summaries at baseline and follow-up time points, but does not provide a complete account of who contributed measurements at each time point.

Details of sequence generation, concealment of assignment, stratification, eligibility criteria, sites beyond the safety net clinic description, follow-up procedures, and the original sample-size justification are not reported in the registry record. Although the record identifies the study as randomized, it does not provide the detail needed to assess those design features independently.

4. Participant Flow and Accounting

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

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Systolic Blood Pressure, measured over one year.

The primary endpoint is systolic blood pressure, reported as a mean in mm Hg with a standard deviation. It was measured approximately one year after the baseline interview. Systolic blood pressure is the upper pressure value recorded during a heartbeat cycle; as a continuous measure, it retains information across the range of observed values rather than reducing the result to a yes-or-no category.

For a comparison of groups, the mean describes the central value of the measurements, while the standard deviation describes how spread out individual measurements are around that mean. The standard deviation is not the same as the uncertainty in the estimated group mean. That uncertainty depends both on variability among participants and on how many observations contribute to the estimate.

Blood pressure is relevant to the study’s stated aim of evaluating disease control among hypertensive patients. The registry names medication understanding, reconciliation, adherence, and disease control as objectives of the strategies, but the primary endpoint is the systolic blood pressure measurement rather than a direct measure of each of those processes. The endpoint therefore addresses one clinical outcome at a specified follow-up point; it does not alone establish whether medication-management processes changed or explain why any group values differed.

The registry record does not report a target threshold or a minimally important difference for systolic blood pressure. It also does not report whether the primary analysis adjusted for baseline blood pressure or other participant characteristics. Interpretation is consequently based on the posted group means and unadjusted comparisons, not on an adjusted estimate or a stated clinical decision threshold.

7. Results Posted in the Registry

• EHMI: mean 141.70 versus 134.50 on control; difference 7.20 (95% CI 3.53 to 10.87), standardized effect d = 0.34; z-test p = <0.001.
• Nurse Educator + EHMI: mean 134.60 versus 134.50 on control; difference 0.10 (95% CI -3.33 to 3.53), standardized effect d = 0.00; z-test p = 0.954.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Effectiveness of the Electronic Health Record-based Health Literacy Medication Therapy Management Strategy (EHMI), With and Without a Nurse Educator, Compared to Standard Care.

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • EHMI: 43.2% (48/111) versus 46.9% (61/130) on control; risk difference -3.7 percentage points (95% CI -16.3 to 8.9), risk ratio 0.92 (0.70–1.22); unadjusted two-proportion z-test p = 0.567.
  • Nurse Educator + EHMI: 59.8% (64/107) versus 46.9% (61/130) on control; risk difference 12.9 percentage points (95% CI 0.2 to 25.5), risk ratio 1.27 (1.00–1.62); unadjusted two-proportion z-test p = 0.048.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between EHMI and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically higher for Nurse Educator + EHMI than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Effects of These Strategies by Patients' Literacy Skills

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • EHMI Likely Limited Health Literacy: mean 141.70 versus 135.50 on control; difference 6.20 (95% CI 1.35 to 11.05), standardized effect d = 0.30; z-test p = 0.012.
  • Nurse Educator + EHMI Likely Limted Health Literacy: mean 133.80 versus 135.50 on control; difference -1.70 (95% CI -6.64 to 3.24), standardized effect d = -0.09; z-test p = 0.500.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for EHMI Likely Limited Health Literacy than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Nurse Educator + EHMI Likely Limted Health Literacy and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes broaden the focus beyond the primary one-year systolic blood pressure comparison. One concerns a participant-count outcome across baseline and follow-up time points; the other presents systolic blood pressure summaries across health-literacy categories. Together, they touch on the study’s stated interests in strategy effectiveness and whether patterns vary with literacy, but the registry’s posted summaries do not provide complete analyses for every question named in the study objective.

The secondary findings do not form a single uniform pattern across the interventions and outcomes. Some posted comparisons are more suggestive of a difference than others, while several estimates are uncertain. The participant-count outcome includes a comparison with a p-value near 0.05, but that isolated result does not resolve the primary blood pressure question. The literacy-stratified results are also not a substitute for a formal test of whether treatment effects differ by literacy category. Such a test is not reported.

These secondary outcomes relate to the primary result by offering additional, but distinct, information. A participant count is not the same endpoint as mean systolic blood pressure, and a subgroup-specific mean does not by itself establish a different intervention effect in that subgroup. They may help describe possible patterns for further evaluation, but they cannot identify the mechanism behind the primary group differences or establish a comprehensive effect on medication understanding, reconciliation, adherence, and disease control.

Unadjusted secondary results carry less weight because multiple outcomes and comparisons create more opportunities for an apparently notable result to arise by chance. The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or a full set of prespecified analyses. It also does not report adjusted analyses for the secondary outcomes. The posted secondary findings should therefore be treated as exploratory context rather than independent confirmation of a treatment effect. This caution applies even when an individual estimate appears more decisive than others.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Effectiveness of the Electronic Health Record-based Health Literacy Medication Therapy Management Strategy (EHMI), With and Without a Nurse Educator, Compared to Standard Care.
• Effects of These Strategies by Patients' Literacy Skills

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous, so the registry reports a mean and standard deviation for each group. A mean difference expresses how far apart the two group means are, using the same units as the endpoint. In these comparisons, the reference group is Standard Care. A positive difference means the intervention group’s mean is higher than the Standard Care mean; a negative difference means it is lower. This direction describes the arithmetic contrast and does not itself say whether a difference is beneficial or harmful.

What do the standard deviations describe?

A standard deviation describes the spread of participant measurements within a group. It is not a measure of how certain the estimated mean is. The standard error is a measure of the estimate’s sampling uncertainty and becomes smaller when measurements are less variable or when more observations contribute. The registry posts standard errors alongside the group summaries. Standard errors and standard deviations answer related but distinct questions: one concerns uncertainty in an estimated mean, while the other concerns variability among individual measurements.

For the primary comparisons, the posted interval gives a range of values compatible with the observed data under the calculation’s assumptions. An interval that crosses zero leaves both positive and negative mean differences compatible with the data; an interval that lies to one side of zero indicates a more definite direction for the unadjusted contrast. The interval does not give the probability that a particular treatment effect is true, and it does not account for unreported sources of bias or model uncertainty.

How should the p-values be read?

The posted primary p-values are unadjusted. A p-value measures how unusual data at least as incompatible with a specified null value would be if that null value and the statistical model were correct. It is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of a difference. The registry does not report a multiplicity adjustment. Since the study has multiple arms and secondary outcomes, interpreting each unadjusted p-value as if it were the only planned test can overstate the strength of evidence.

The record identifies the study as randomized, which makes group comparisons relevant to evaluating intervention strategies. However, the registry does not report enough detail to determine how the posted comparisons handled the randomized design, baseline measures, repeated observations, missing outcomes, or possible clustering by clinic. No adjusted analysis is posted for the displayed outcomes. Accordingly, the comparisons should be read as unadjusted summaries rather than as estimates known to account for all design or analysis features.

What do the secondary outcome summaries represent?

One secondary outcome is reported in units of participants, with counts and denominators across baseline and follow-up time points. The registry’s summary does not provide a fuller definition of the event or participant status being counted in the displayed outcome. The resulting risk-difference comparisons are unadjusted contrasts between the reported group proportions. A risk difference is the difference between two proportions, expressed on the probability scale; its interval represents uncertainty about that contrast. The registry also provides relative measures for these comparisons, but the outcome’s precise operational definition and analysis details are not reported.

The other posted secondary outcome reports mean systolic blood pressure by literacy category and intervention group. Some subgroup comparisons are posted, but a full set of subgroup contrast estimates is not reported. A result within one subgroup does not establish that the treatment effect differs between subgroups. That question is generally addressed by testing an interaction, which compares effects across categories; such an analysis is not reported in the registry record.

What does the planning illustration calculate?

The sample-size illustration uses the observed effect as its reference and shows planning scenarios for detecting the full observed effect, 75% of the observed effect, or 50% of the observed effect. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The values are participants per arm for these continuous and binary outcomes. They are not the original trial’s design calculation: the registry does not report the original sample-size assumptions or justification. The illustration is a planning exercise based on the observed estimates, not evidence about the probability that the completed study detected an effect.

These statistical explanations are general. The registry record does not identify the software, exact interval method, model specification, analysis population, missing-data method, or whether any prespecified analysis plan governed the posted results. Without those details, it is not possible to assess whether the displayed summary calculations correspond to the trial’s intended primary analysis.

11. Confidence Intervals and Precision

Precision is conveyed most directly by the interval around a comparison estimate. For EHMI versus Standard Care, the mean difference is 7.2 mm Hg and the interval extends from 3.532 to 10.87. The interval lies above zero, so the posted unadjusted estimate points to a higher mean in EHMI than in Standard Care, with the range still allowing a range of difference sizes. The p-value is p < 0.001.

For Nurse Educator + EHMI versus Standard Care, the estimate is 0.1 mm Hg and the interval extends from -3.33 to 3.53. Because this range includes zero and values on both sides, the data are compatible with a small difference in either direction as well as with little separation in group means. This is not evidence that the groups are identical; it is a limitation on how precisely their difference is estimated.

The intervals should be interpreted together with the group standard deviations and the number of observations contributing to each estimate, not in isolation. The registry posts group-specific counts and standard deviations, but does not report a confidence level or the interval method in the record. The interval calculations are presented as posted and should not be assigned an unreported confidence level.

Statistical precision is not the same as clinical importance. The registry does not report a threshold for a meaningful systolic blood pressure difference, and the interval cannot supply that judgment. Nor does an interval address possible bias from missing observations, deviations from assigned care, or unreported analysis choices. The uncertainty described is uncertainty in the posted unadjusted comparison under its calculation, not a complete measure of uncertainty about the study’s conclusions.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total events. They are planning illustrations based on the observed effect, not the trial’s original design calculation. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set in turn to 100% of the observed effect, 75% of the observed effect, or 50% of the observed effect.

The 80% power column gives the estimated participants per arm under those assumptions for a design intended to have an 80% chance of detecting the specified effect if that effect were the true effect and the assumptions held. The 90% power column uses a higher target probability of detecting that effect, and therefore generally requires a larger planned sample. These are conventional design probabilities, not guarantees about what a particular study will find.

Smaller effects are harder to distinguish from random variation, so planning to detect a smaller fraction of the observed effect requires more participants per arm. This pattern is visible across the effect scenarios. The very large values in some rows arise because the observed contrast used as the basis for those planning calculations is small; the illustration should not be taken as a recommendation for a future study without a separate design rationale.

This is not observed power. Observed power is not a useful substitute for reading the estimated effect and its interval after data have been collected. The trial’s own sample-size justification, target effect, and original planning assumptions are not reported in the registry record. These illustrations should therefore be read only as hypothetical planning scenarios based on the posted summaries.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 7.200; pooled standard deviation σ = 21.280.
2. n = 2 × (1.96 + 0.842)² × 21.280² / 7.200² = 137.1, rounded up to 138 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 7.19999999999999                      # observed difference in means
sigma <- 21.2802081007057                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1578577)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 138 (80% power), 184 (90% power)
 75% of observed effect: n per arm = 244 (80% power), 327 (90% power)
 50% of observed effect: n per arm = 549 (80% power), 735 (90% power)
power.t.test: 138.1 
Simulated power at n = 138 per arm: 0.793 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The study record lists a primary endpoint and multiple secondary outcomes, with comparisons involving more than one intervention group and, for one secondary outcome, health-literacy categories. When many outcomes, subgroups, or contrasts are examined, the chance of seeing at least one apparently notable result can increase. A prespecified multiplicity strategy can address that issue by controlling how evidence is evaluated across a family of tests. No such strategy is reported in the registry record.

The posted p-values are unadjusted. They should not be interpreted as if each comparison were necessarily the sole planned test. The record does not report a formal hierarchy for primary and secondary outcomes, whether subgroup comparisons were planned in advance, or whether an interaction test was specified for the literacy analyses. It also does not provide the complete analysis plan or reported analyses for the outcomes listed.

Missing-data handling is also not reported. The primary endpoint summaries include group-specific participant counts, but the record does not explain why the number contributing to the outcome may differ from the enrollment figure, how missing measurements were addressed, or whether the analysis used an intention-to-treat population. The secondary participant-count summaries have their own denominators, and their relationship to the enrolled population and time-specific follow-up is not described in enough detail to establish the reasons for those denominators.

The registry does not report whether analyses adjusted for baseline values, how participants were handled if they did not receive their assigned intervention, or whether any sensitivity analyses assessed missing outcomes. It also does not specify an analysis population for the posted estimates. These omissions limit assessment of the robustness of the comparisons and whether the analyses preserve the advantages of random assignment. They do not demonstrate that the trial handled these matters inadequately; they mean the registry record does not provide the information needed to evaluate them.

15. 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.

The adverse-event record lists zero serious adverse events and zero other adverse events in each of the three groups. The corresponding numbers listed as at risk are 305 for Standard Care, 302 for EHMI, and 313 for Nurse Educator + EHMI. The registry also lists no serious-event terms.

These figures describe what is recorded in the registry for the stated at-risk groups. They are not the same denominators as the primary systolic blood pressure summaries, and the record does not explain the difference in populations or the method used to collect and classify events. A zero count in the posted record should not be interpreted as proof that no event occurred outside the scope of ascertainment or reporting.

Deaths are not reported in the registry record. Details such as the adverse-event collection period, event definitions, severity grading, relatedness assessment, and whether events were actively solicited are also not reported. The available figures therefore permit a narrow description of recorded counts, not a complete assessment of safety or a comparison of event risk between groups.

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

The posted data describe mean systolic blood pressure at approximately one year after baseline and unadjusted comparisons with Standard Care. They show a higher mean in the EHMI group than in Standard Care, while the Nurse Educator + EHMI and Standard Care means are close. The intervals indicate that the two comparisons have different degrees of precision: the EHMI interval lies above zero, while the interval for Nurse Educator + EHMI includes zero and extends in both directions.

These are observations about group summaries, not a complete account of the trial’s causal evidence. Random assignment is reported, but key details about allocation procedures, the analysis population, missing outcomes, and adjustment are not available in the registry record. The posted analyses are unadjusted. The figures therefore cannot establish whether the observed contrast reflects the intervention alone, nor do they explain why the group means differ.

The results do not establish clinical importance. The record does not report a threshold for a meaningful difference in systolic blood pressure, and statistical evidence about a nonzero mean difference is not the same as evidence that the difference matters to patients. The results also do not establish equivalence where an interval includes zero, because the registry does not report an equivalence margin or an equivalence analysis.

The study objective includes medication understanding, reconciliation, adherence, and disease control. The posted primary endpoint addresses systolic blood pressure, and the secondary results provide additional, incomplete evidence on other listed outcomes. The record does not show that every objective was measured or resolved by the posted analyses. It also does not establish that the results apply to populations or care settings beyond the hypertensive patients at safety net clinics described in the study summary.

Accordingly, the most defensible reading is limited: the registry posts an unadjusted difference for EHMI versus Standard Care and little separation in the posted means for Nurse Educator + EHMI versus Standard Care, with uncertainty that differs between comparisons. Broader conclusions about intervention effectiveness, mechanisms, safety, or generalizability require fuller trial reporting.

17. Why This Trial Matters Statistically

This study is statistically instructive because it places two related intervention strategies alongside a standard-care control and reports a continuous primary endpoint. The contrasts illustrate why direction, magnitude, and precision should be considered together. A p-value alone cannot convey the size of a difference, and a near-zero estimate with an interval spanning both directions should not be described as proof of no effect.

The record also illustrates the distinction between an observed result and a planning scenario. The sample-size figures use the observed effects to show hypothetical requirements under stated assumptions. They do not reveal the original design rationale and do not measure the probability that the completed trial detected an effect. This distinction is important when reading post-trial calculations that may otherwise be mistaken for evidence about the trial’s adequacy.

Secondary outcomes and subgroup summaries raise another general issue: multiple comparisons can produce findings that appear notable without providing strong confirmatory evidence. Here, the registry does not report a multiplicity plan or a formal analysis of differences by literacy category. That makes careful separation of primary findings, secondary patterns, and subgroup hypotheses especially important.

Finally, registry reporting can support a useful first reading while leaving key statistical questions unresolved. Randomization and the principal endpoint are identified, but analysis populations, missing-data methods, adjusted results, and the original sample-size justification are not reported. The case therefore shows both the value of transparent numerical summaries and the limits of drawing broad conclusions from a registry record alone.

18. 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 leaves important trial-specific details unavailable. The EHMI arm description is incomplete, and the Nurse Educator + EHMI description is blank. The precise intervention components, the nurse educator’s role, the delivery schedule, and the control care are not described in sufficient detail to assess implementation or reproducibility. The study objective names several intended mechanisms and outcomes, but the posted results do not establish how each was measured.

The primary outcome is reported at approximately one year, but the record does not provide baseline systolic blood pressure by randomized group in the primary outcome section, an adjusted estimate, or a complete description of follow-up measurements. It does not explain the difference between enrollment and the numbers contributing to the primary outcome, nor does it report missing-data procedures or reasons for unavailable measurements. The secondary outcome record likewise does not give a full account of the meaning of the participant count or the denominators at each follow-up time.

The registry does not report sequence generation, allocation concealment, eligibility criteria, the analysis population, protocol deviations, an analysis plan, or a multiplicity approach. It also does not report the original sample-size justification. These gaps limit assessment of the trial’s conduct and of whether the posted comparisons match the planned primary analysis. The absence of these details in the registry is not evidence that the procedures were absent; it prevents independent evaluation from this record.

Finally, the subgroup results are incomplete, and no reported interaction analysis establishes whether effects vary with literacy. The adverse-event record contains zero reported events but lacks detail on ascertainment and timing. These limitations mean the posted evidence is best treated as a set of summary comparisons rather than a comprehensive report of effectiveness, subgroup variation, or safety.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Northwestern University and Access Community Health Network Medication Education Study — NCT01578577.
• Registry record last updated 2019-06-28; status last verified 2019-06.
• Results first posted 2019-06-28.
• 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.

22. Record Summary

NCT01578577 is a completed randomized, parallel-group study with no masking, sponsored by Northwestern University. The registry reports enrollment of 920 and a study of hypertensive patients at safety net clinics. The groups were Standard Care, EHMI, and Nurse Educator + EHMI.

The primary endpoint was mean systolic blood pressure in mm Hg approximately one year after baseline. The posted unadjusted comparison showed a positive mean difference for EHMI versus Standard Care, while the Nurse Educator + EHMI comparison was near zero and less precise. Secondary outcomes address participant counts and blood pressure by literacy category, but the registry does not report a complete analysis plan or multiplicity approach.

The record lists zero serious and zero other adverse events in each group; deaths and key details of event ascertainment are not reported. The original sample-size justification, missing-data methods, analysis populations, and complete intervention descriptions are also not reported in the registry record.