Effectiveness of SMS Text Reminders to Improve Blood Pressure Among Patients With Hypertension: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effectiveness of SMS Text Reminders to Improve Blood Pressure Among Patients With Hypertension (NCT01255436), a randomized na study. The primary outcome is Mean Absolute Change in Systolic Blood Pressure After 12 Weeks.

2. Clinical Question

3. Trial Design

The record describes a randomized, controlled, parallel-group trial in which the patient was the unit of randomization. It lists single masking, but does not specify who was masked; that detail is not reported in the registry record. The trial was marked completed and recorded enrollment of 700 participants. The record gives a start of 2011-01 and primary completion in 2012-03.

One group received text messages on top of the usual care received from physicians; the comparison group received usual physician care without the messages. The intervention was planned to send messages twice a week for 12 weeks. The stated target population was ambulatory adults with essential hypertension who were taking maintenance blood pressure-lowering medications and had access to a mobile phone and the ability to use text messages, either themselves or with help from someone in their household.

The primary outcome analysis population is described as participants who completed follow-up and had evaluable data. The reported systolic-change summaries include 151 participants in the SMS group and 135 in the no-SMS group. The registry record does not explain the relationship between those analyzed groups and the enrolled total, or provide a participant-flow account, reasons for missing outcome data, or details about how missing measurements were handled. The original allocation ratio, sequence-generation procedure, concealment method, and the specific party or parties masked are not reported in the registry record.

The sponsor is listed as the University of the Philippines. The registry record gives no further protocol details about site-level conduct or implementation of the text-message program.

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: Only participants who completed follow up and had evaluable data were analyzed.

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 Mean Absolute Change in Systolic Blood Pressure After 12 Weeks, measured over baseline and 12 weeks.

The primary endpoint is mean absolute change in systolic blood pressure from baseline to 12 weeks, measured in mmHg. In this context, “change” refers to each participant’s follow-up systolic measurement relative to their baseline measurement, with the group mean describing the average change among the analyzed participants. A negative mean indicates that the follow-up values were lower than baseline on average; it does not by itself describe every participant’s trajectory.

Change from baseline is used to compare how the measured outcome shifted over the follow-up period in each randomized group. Considering the group means together with their dispersion and the between-group confidence interval helps distinguish the observed pattern from the uncertainty around it. A group’s average change alone is not the randomized comparison: the relevant question is whether the changes differ between groups, and how precisely that contrast is estimated.

The registry record specifies that only participants who completed follow-up and had evaluable data were analyzed for this endpoint. It does not report a detailed missing-data method or an analysis of all randomized participants. The primary endpoint is systolic pressure; although diastolic pressure is described among the trial’s primary outcomes in the summary, a separate diastolic result is not included in the posted results described in the registry record.

7. Results Posted in the Registry

• No SMS Text Reminders: mean -9.50 versus -13.70 on control; difference 4.20 (95% CI -1.10 to 9.50), standardized effect d = 0.19; z-test p = 0.120.

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.

Medication Adherence Rate

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • No SMS Text Reminders: 47.4% (64/135) versus 59.6% (90/151) on control; risk difference -12.2 percentage points (95% CI -23.7 to -0.7), risk ratio 0.80 (0.64–0.99); unadjusted two-proportion z-test p = 0.039.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for No SMS Text Reminders than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Percentage of Patients With Controlled Blood Pressure at the End of 12 Weeks

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • No SMS Text Reminders: 54.1% (73/135) versus 68.2% (103/151) on control; risk difference -14.1 percentage points (95% CI -25.4 to -2.9), risk ratio 0.79 (0.66–0.96); unadjusted two-proportion z-test p = 0.014.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for No SMS Text Reminders than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Across the two posted secondary outcomes, the SMS group has higher reported percentages than the group without reminders. The sponsor’s reported Fisher exact analyses also give results favoring the SMS group for medication adherence and controlled blood pressure at 12 weeks. The recalculated unadjusted comparisons have the same general direction. This pattern is directionally consistent with the primary group means, but the primary recalculated interval includes zero and does not establish a clear between-group difference in systolic change.

Secondary outcomes can add context by showing whether the observed pattern extends beyond the primary continuous measure. They do not replace the primary endpoint, and they may differ in definition, scale, and susceptibility to measurement or reporting issues. The registry record does not explain how adherence was assessed or provide the operational definition used for controlled blood pressure, so those details cannot be evaluated from the posted record.

The reported secondary p-values are unadjusted, and the registry record does not report a multiplicity plan. When several outcomes are tested, the chance of at least one apparently notable result can increase even if no underlying effect exists for any outcome. For this reason, secondary findings are generally more appropriately treated as supportive or exploratory unless the protocol’s hierarchy and multiplicity control are known. The record does not establish whether these outcomes were prespecified in a formal testing sequence.

The secondary results should therefore be read as a consistent descriptive pattern rather than as independent confirmation of the primary comparison. Their interpretation also depends on the same concerns about evaluable follow-up, missing data, and analysis population that apply to the primary endpoint.

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

• Medication Adherence Rate
• Percentage of Patients With Controlled Blood Pressure at the End of 12 Weeks

9. Statistical Interpretation

10. Statistical Methods Explained

The record describes a randomized parallel-group comparison, with the patient as the randomization unit. Randomization is intended to make the groups comparable on average, including with respect to factors that are measured and factors that are not. It does not guarantee identical groups in a particular trial. The registry record does not provide the randomization sequence method or concealment details, so those aspects cannot be assessed from the record.

What does a mean change measure?

Systolic blood pressure is a continuous measurement. For each analyzed participant, change is the follow-up value relative to baseline; the reported arm-level mean summarizes those individual changes. A negative mean represents an average decrease from baseline, while the standard deviation describes how widely individual changes vary around the arm mean. A standard deviation is not the same as a confidence interval: it describes observed variability among participants, whereas a confidence interval expresses uncertainty about an estimated quantity.

The posted primary summaries give means and standard deviations for the two analyzed groups. A mean difference compares the group summaries on the same scale. Its sign depends on the order in which the groups are subtracted. The recalculated estimate is expressed as no SMS reminders minus SMS reminders, while the sponsor’s posted analysis labels its parameter as a mean difference in final values and reports a negative estimate. Because the registry record does not fully describe the sponsor’s analysis, the direction and estimand should be read alongside that wording rather than assuming the calculations use the same contrast.

What do the confidence interval and p-value convey?

A confidence interval gives a range of values compatible with the observed data under the specified statistical procedure. Its width reflects uncertainty: a wider interval permits a broader set of underlying contrasts than a narrower interval. The interval is not a range containing a stated proportion of individual participants’ outcomes, and it does not assign a probability to the true effect after the data have been observed.

A p-value measures how unusual the data, or more extreme data, would be under a specified null hypothesis and analysis model. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of a difference. The recalculated primary p-value is unadjusted; the sponsor reports a one-sided test. Those results are not interchangeable because they do not use the same stated test direction or necessarily the same outcome parameter.

Why distinguish the sponsor analysis from recalculation?

The recalculated comparison is an unadjusted calculation from the posted group-level means, standard deviations, and sample sizes. It is not a reconstruction of any individual-participant analysis. The sponsor’s reported analysis is a separate registry result, described as a one-sided t-test of mean difference in final values. Different outcome definitions, test direction, baseline handling, or analysis populations can affect estimates and uncertainty. The record does not give enough detail to determine which of those distinctions account for the difference in presentation.

For a continuous outcome, a t-test compares group means while accounting for sampling variability. The sponsor specifies a one-sided test, which evaluates a directional alternative; the recalculation uses an unadjusted two-sided comparison for the confidence interval and p-value. General statistical practice treats the choice of direction as something that should be established in the analysis plan, not selected after seeing the results. The trial’s original statistical plan is not reported in the registry record.

How should the binary outcomes be understood?

Medication adherence and controlled blood pressure are presented as percentages of participants at 12 weeks. Their group percentages summarize the proportion meeting the recorded outcome definition in each analyzed group. A risk difference expresses the difference in those proportions, while a risk ratio compares one group’s proportion with the other’s. Both are relative to the group order specified by the analysis. For binary outcomes, the number meeting the outcome and the analyzed group size are useful context for interpreting percentages.

The registry reports Fisher exact analyses for both secondary outcomes, expressed as risk ratios. The recalculated risk differences and their intervals are additional unadjusted summaries, not replacements for the sponsor’s posted analyses. Exact-test methods are often used for categorical data when the outcome counts are limited; the registry does not provide further rationale for its method choice.

Why can over-dispersion matter?

General: when observed variability is greater than a model assumes, standard errors can be too small and confidence intervals too narrow if that excess variability is ignored. The primary outcome has standard deviations of 19.1 and 25.7, but the registry record does not report an over-dispersion diagnostic or a model-based adjustment. The recalculation uses the posted summary data and should not be mistaken for an adjusted model.

More broadly, interpretation depends on the analysis population, outcome definition, missing-data handling, and multiplicity plan. The record identifies completers with evaluable data for the primary analysis but does not describe a full intention-to-treat analysis or the handling of missing measurements. These omissions limit the ability to reproduce the sponsor’s analysis or assess all assumptions behind its results.

11. Confidence Intervals and Precision

The primary recalculated mean difference has a 95% confidence interval from -1.099 to 9.499 mmHg, using the no-SMS-minus-SMS contrast. The interval includes zero and spans values on either side of it. This means the estimate is not highly precise enough to exclude a null average contrast using this interval; it also leaves room for differences in either direction. The interval should be interpreted with the contrast definition in mind.

The sponsor’s 95% confidence interval for its reported final-value mean difference is -9.4 to 1.0. It too includes zero. The registry record describes that result as a one-sided t-test, while the interval is labeled 95%; the basis for relating the one-sided test to the interval is not detailed. The recalculated interval and sponsor interval arise from differently described analyses and should not be combined or treated as duplicate estimates.

Precision is influenced by outcome variability and the amount of evaluable information. The primary group standard deviations are 19.1 and 25.7, and the analyzed group sizes are 151 and 135. Those summaries show that participant-level changes varied substantially around the group means. The registry record does not report a prespecified precision target or the original sample-size justification, so it is not possible to judge the estimate against a documented design target.

A confidence interval does not indicate that every value inside it is equally plausible, and it does not resolve questions about bias from missing outcome data or the choice of analysis population. The primary analysis excluded participants without completed follow-up and evaluable data, according to the record, but the number and reasons for missing outcomes are not reported there. Statistical precision and protection against bias are separate considerations.

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 sample-size figures are planning illustrations based on the observed effects, not the trial’s original design assumptions. For the continuous primary outcome and the binary secondary outcomes, the displayed quantities are participants per arm. The assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The planning scenarios use the observed effect, 75% of the observed effect, and 50% of the observed effect.

The 80% power column gives the estimated participants per arm for a hypothetical study designed to have an 80% chance of detecting the stated effect under those assumptions, if that effect is the true one and the planning model applies. The 90% power column gives the corresponding per-arm planning figure for a 90% chance. These are design calculations, not a description of what happened in the completed trial. They are not observed power.

For the primary endpoint, planning for 100% of the observed effect gives 449 participants per arm for 80% power and 601 participants per arm for 90% power. Planning for 75% of the observed effect gives 798 and 1,069 participants per arm, respectively; planning for 50% gives 1,796 and 2,404 participants per arm. The secondary-outcome planning figures are listed separately for their respective observed effects. Such values are illustrations of how assumptions change planning needs, not evidence that those effects are reproducible.

The curve should be read as a visual display of how the planning requirement changes with the effect being targeted, under the stated assumptions. Smaller effects require more participants to distinguish them from random variation with the same planned power. The trial’s own original sample-size assumptions and justification are not reported in the registry record.

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 = 4.200; pooled standard deviation σ = 22.457.
2. n = 2 × (1.96 + 0.842)² × 22.457² / 4.200² = 448.8, rounded up to 449 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 <- 4.2                      # observed difference in means
sigma <- 22.4570921072941                     # 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(1255436)
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 = 449 (80% power), 601 (90% power)
 75% of observed effect: n per arm = 798 (80% power), 1,069 (90% power)
 50% of observed effect: n per arm = 1,796 (80% power), 2,404 (90% power)
power.t.test: 449.8 
Simulated power at n = 449 per arm: 0.796 (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. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a one-sided t-test of mean difference in final values. It gives a difference of -4.2, a 95% confidence interval from -9.4 to 1.0, and p = 0.06. The sponsor’s result is the trial’s posted analysis and should be distinguished from the recalculated unadjusted comparison of the posted change-score summaries.

The recalculation expresses the primary contrast as no SMS reminders minus SMS reminders and estimates 4.2 mmHg, with a 95% confidence interval from -1.099 to 9.499 and p = 0.12. The sign differs because the comparison is written in the opposite group order; in addition, the sponsor labels its parameter as a difference in final values, whereas the primary endpoint is described as change from baseline. The registry record does not report enough analysis detail to determine whether the estimates otherwise target the same quantity.

The discrepancy flag is false. The sponsor’s analysis therefore does not need to take precedence over the recalculation on the basis of a flagged discrepancy. Still, the sponsor’s posted test and the recalculation answer differently specified statistical questions, so both should be described accurately rather than presented as one result. The original analysis plan, including the rationale for a one-sided test and whether baseline values were incorporated, is not reported in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists systolic blood pressure change as the reported primary endpoint and describes both systolic and diastolic change in the trial summary. It also posts medication adherence and controlled blood pressure as secondary outcomes. The record does not report a multiplicity adjustment, a hierarchy for testing outcomes, or whether confirmatory claims were limited to a particular endpoint. Without that information, the p-values across outcomes should not be read as if each were the sole planned test.

Multiplicity matters because repeated testing across outcomes or analyses can increase the chance of at least one small p-value arising through random variation. General statistical approaches include prespecifying a primary test, controlling an overall error rate, or treating secondary findings as exploratory. Which approach, if any, was used in this trial is not reported in the registry record.

The primary analysis population is stated to include only participants who completed follow-up and had evaluable data. The results list 151 analyzed participants in the SMS group and 135 in the no-SMS group for the primary endpoint. The record does not provide a flow of randomized participants by group, the number excluded from each analysis, or reasons for non-completion and missing outcome data. It also does not say whether missing values were imputed, whether sensitivity analyses were performed, or whether analyses followed the randomized assignment regardless of adherence.

These omissions matter because an analysis restricted to completers can be affected if completion or evaluability is related to outcome or group assignment. Randomization supports comparison at assignment, but a restricted analysis may not retain all of its protections. The registry record does not report enough detail to assess the direction or extent of any such bias, or to reproduce the sponsor’s analysis population.

16. 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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: all-cause mortality (0.9%), myocardial infarction (0.3%), stroke (0.3%).

The posted serious adverse event figures list 333 participants at risk in the SMS group, with 4 affected, and 329 at risk in the group without SMS reminders, with 3 affected. Other adverse events are listed as 0 in each group. No distinct death count is entered in the record. These figures are descriptive counts and do not, by themselves, establish whether the groups differ in safety.

The record also lists all-cause mortality at 0.9%, myocardial infarction at 0.3%, and stroke at 0.3% among the top serious-event terms. It does not provide enough detail in these entries to assign each term to a particular arm, clarify overlap between terms and serious-event counts, or describe event timing and relatedness. The at-risk totals for adverse events also differ from the analyzed sample sizes for the blood pressure outcome, and the registry record does not explain the safety population or follow-up completeness.

Small event counts can yield uncertain comparisons, and no safety-effect estimate or confidence interval is posted in the record. These data should be read as registry-reported event counts and terms, not as a definitive comparison of harms.

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

The results describe a randomized comparison of SMS text reminders added to usual care against usual care alone in an outpatient population with hypertension. Among participants who completed follow-up and had evaluable data, mean systolic pressure decreased from baseline in both groups. The recalculated contrast is uncertain, with a confidence interval that includes zero. The sponsor’s posted final-value analysis also has an interval that includes zero and is described as a one-sided test.

The secondary results show higher posted percentages for adherence and blood pressure control in the SMS group, with sponsor-reported comparisons favoring that group. These outcomes provide a potentially relevant pattern, but their statistical interpretation is limited by the absence of a reported multiplicity plan and by missing details about outcome definitions and analysis methods. They should not be treated as conclusive evidence independent of the primary result.

The findings do not establish that the reminders caused every observed difference, nor do they demonstrate that the groups were identical when the primary comparison was uncertain. An estimate with an interval including zero can still be compatible with meaningful differences in either direction; the interval expresses uncertainty rather than proof of no effect. The record does not report enough detail about missing data, analysis populations, or the original statistical plan to resolve these uncertainties.

The trial concerns a particular group of ambulatory adults with essential hypertension, maintenance medication use, and household access to text messaging. The registry results do not directly answer questions about people outside those eligibility conditions, other message programs, other follow-up periods, or outcomes not reported. No medical decision should be inferred from these registry statistics alone.

18. Why This Trial Matters Statistically

This trial raises a useful statistical question about how an intervention intended to influence medication-taking behavior should be evaluated. The record includes both a continuous physiological outcome, mean systolic change, and behavioral or threshold-based secondary outcomes. Comparing these measures makes clear that a coherent pattern across endpoints can be informative, while still requiring careful separation of primary evidence from secondary findings.

It also illustrates why the analysis definition matters. The primary endpoint is described as change from baseline, while the sponsor’s posted test is labeled as a comparison of final values. The recalculation uses the posted group-level change summaries. When analyses use different outcome parameters or group order, signs and estimates can be difficult to compare unless the contrast is explicitly stated. Transparency about the estimand, baseline handling, and test direction would make the result easier to interpret.

The registry record reports group-level uncertainty as well as means, which allows readers to consider precision rather than focusing only on point estimates. The confidence intervals leave substantial uncertainty around the primary contrast. The sample-size illustrations also show, under their stated planning assumptions, how the number of participants required rises when planning for smaller effects.

Finally, the record points to important reporting needs: participant flow, missing-data handling, analysis-population definitions, multiplicity methods, and the original sample-size rationale. These details are central to judging how robust a trial result is, particularly when the primary and secondary outcomes are analyzed in different ways.

19. 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.

Several trial-specific limitations follow from the registry record. The primary result is based on participants who completed follow-up and had evaluable data, rather than a clearly described analysis of all randomized participants. The record does not explain how many randomized participants lacked evaluable outcomes, why data were missing, or whether missingness differed between groups. This restricts assessment of potential selection bias.

The sponsor’s primary analysis is described as a one-sided t-test of final values, while the listed primary endpoint is change from baseline. The registry record does not explain the analysis rationale, baseline adjustment, or how the one-sided test was prespecified. This makes it difficult to fully reconcile the sponsor’s result with the unadjusted recalculation from the change summaries.

The record does not report the original sample-size justification, planned statistical analysis, multiplicity strategy, or interim analyses. It also does not identify who was masked despite listing single masking. Details about sequence generation and allocation concealment are not reported in the registry record.

The eligible population was restricted to ambulatory adults with essential hypertension who were taking maintenance medication and had access to text messaging, personally or through someone in their household. The findings may not address people outside these eligibility conditions. The posted summary also does not give the actual message content, adherence-measurement method, or a detailed definition of controlled blood pressure. Those omissions limit assessment of how the intervention and secondary outcomes were operationalized.

Safety reporting is limited to the posted event counts and terms, without event-level timing, relatedness, or comparative uncertainty estimates. The registry record does not explain the difference between the safety population and the primary outcome analysis population.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Effectiveness of SMS Text Reminders to Improve Blood Pressure Among Patients With Hypertension — NCT01255436.
• Registry record last updated 2017-02-23; status last verified 2017-01.
• Results first posted 2012-10-02.
• 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.

23. Record Summary

The registry record describes a completed randomized, single-masked, parallel-group trial sponsored by the University of the Philippines. It enrolled 700 participants and compared SMS text reminders added to usual care with usual care alone. The intended message schedule was twice weekly for 12 weeks.

The primary posted outcome is mean absolute systolic blood pressure change from baseline to 12 weeks among participants completing follow-up with evaluable data. The registry reports group means and a sponsor analysis; an unadjusted recalculation gives a separate estimate with a confidence interval that includes zero. Two secondary outcomes, medication adherence and controlled blood pressure, show a pattern favoring the SMS group in the posted results, but no multiplicity plan is reported.

Important details about the original statistical plan, missing-data handling, participant flow, and analysis populations are not reported in the registry record.