Pharmacists and Pharmacy Technicians to Improve Admission Medication History Accuracy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pharmacists and Pharmacy Technicians to Improve Admission Medication History Accuracy (NCT02026453), a randomized na study. The primary outcome is Mean Severity-weighted Admission Medication History (AMH) Error Score.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial comparing usual care with two additional approaches to admission medication history collection. The registry lists the allocation as randomized and masking as none. In the usual-care arm, physicians and nurses obtained the history. In one intervention arm, a pharmacist obtained it; in the other, a pharmacy technician did. Usual care could continue in either intervention arm, so those arms represent adding a designated pharmacist or technician history-taking role rather than necessarily replacing routine practice.

The registry reports enrollment of 306. For the primary outcome, the reported group sizes were 95 for usual care, 94 for the pharmacist arm, and 89 for the pharmacy technician arm. These are the group sizes attached to the posted outcome estimates; the record does not explain how they relate to the enrollment figure or describe any exclusions from the outcome analysis.

The study was marked completed. Its recorded start was 2014-01, and primary completion was recorded as 2014-02. The sponsor was Cedars-Sinai Medical Center. The phase entry is NA. The registry summary describes the study as addressing admission medication histories and related medication errors, but a protocol-level account of allocation procedures, sequence generation, or concealment is not reported in the registry record.

The primary outcome was a continuous score, reported as a mean with a 95% confidence interval. The record also lists mean severity-weighted admission medication order error score as a secondary outcome. It does not provide a formal analysis plan, specify which comparisons were primary to the statistical analysis, or report analysis results for the secondary outcome.

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 Mean Severity-weighted Admission Medication History (AMH) Error Score, measured over Attempted to obtain the day after admission.

The primary endpoint was the mean severity-weighted admission medication history error score. An admission medication history records medications a patient was taking before admission. To identify errors, the study compared the intervention and control group histories with reference-standard histories. At least 2 investigators independently identified and rated admission medication history errors and resultant admission medication order errors.

The score weights error counts by rated severity. A significant error contributes 1 point, a serious error contributes 4 points, and a life-threatening error contributes 9 points. Consequently, a larger score can reflect more errors, errors with greater severity, or both. A score of 0 indicates zero errors; the stated range extends from 0 to infinity.

A severity-weighted measure is used to distinguish errors that may differ in their clinical importance, rather than treating every identified error as equivalent. The mean describes the average score in an arm, while the 95% confidence interval conveys uncertainty around that estimated mean. The timeframe was an attempt to obtain the history the day after admission. The registry does not report further details about the reference-standard process or how unresolved differences between investigators were handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean describe?

The primary outcome is a continuous score, and the registry reports a mean for each arm. A mean summarizes the scores by their average. It is useful for describing the overall level of the severity-weighted error score in a group, but it does not show how scores are distributed among individuals. In particular, the same mean can arise from different patterns of individual scores. The registry record does not report the distribution, a standard deviation, or other summaries of variability among individuals.

The score is not an ordinary unweighted count. Its assigned points are 1 for significant errors, 4 for serious errors, and 9 for life-threatening errors. Thus, a mean score can reflect both the occurrence and severity of errors. An interpretation as the average number of errors would be incorrect: the score weights errors, and a single error can contribute more than one point.

What does a 95% confidence interval convey?

General statistical context: a confidence interval describes uncertainty in an estimate under a statistical procedure and its assumptions. A 95% confidence interval is constructed so that, over repeated use of that procedure in comparable settings, the intervals would cover the target quantity at the stated rate if the assumptions held. It does not mean that 95% of individual scores fall within the interval, nor does it guarantee that the particular interval contains the true value.

The record gives an interval for each arm mean: 19.7 to 26.2 for usual care, 2.7 to 5.5 for the pharmacist arm, and 2.6 to 5.6 for the pharmacy technician arm. Those intervals concern arm means, not contrasts between arms. A direct comparison requires an estimate of the contrast and its uncertainty, generally calculated using the individual-level data or an appropriate model. The registry record does not report those contrast estimates or tests.

Why does the score's distribution matter?

General statistical context: a continuous outcome need not follow a symmetric, bell-shaped distribution. Error scores are nonnegative and can be concentrated at low values while a smaller number of high scores raise the mean. When data are skewed or contain unusually large values, an analysis that assumes a particular distribution can give misleading uncertainty if that assumption is not suitable. Over-dispersion is a related concern: observed variation can be greater than a model expects, which may make standard errors and confidence intervals too small if the model does not account for it.

The score's stated range begins at 0 and has no finite upper limit. This makes it important to know how scores were distributed and what methods were used to estimate means and intervals. The registry record does not report the distribution, the method used to calculate the confidence intervals, model diagnostics, or any adjustment for over-dispersion. No conclusion about whether a specific modeling assumption was appropriate can be made from the arm means alone.

How should the randomized design be reflected?

Random allocation is intended to make assigned groups comparable on average at the time of allocation, helping support an interpretable comparison. In analysis, the relevant question is the difference in outcome between assigned groups, with uncertainty appropriate to the design and outcome. Reporting the separate arm means is informative but does not by itself provide that comparison. The registry lists no analyses, so it does not identify whether the reported estimates came from an intention-to-treat population, another analysis population, or a particular model.

There are three arms, which permit more than one pairwise comparison. A statistical analysis plan would ordinarily clarify which comparisons were intended and how multiple comparisons were handled. That plan and any multiplicity procedure are not reported in the registry record. It is also not reported whether any adjustment for baseline characteristics was planned or used.

What do planning illustrations mean?

General statistical context: sample-size planning asks how many participants per arm would be needed to detect a defined effect under stated assumptions. The planning illustrations associated with this record are described as using the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are planning assumptions, not a report of the trial's original design rationale. The registry record does not report its own sample-size justification or statistical plan.

Such illustrations are conditional on the assumed effect and analysis framework. They do not indicate the probability that the completed trial found a real effect, and they are not observed power. The record's explanatory description identifies the planning exercise as an illustration based on the observed effect, rather than evidence about the design choices made before the trial. No planning value should be interpreted as a trial result.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and a secondary outcome: mean severity-weighted admission medication history error score and mean severity-weighted admission medication order error score, respectively. It reports two outcome measures and one posted secondary outcome. No analysis results are listed, and the record does not describe how multiple outcomes or multiple pairwise comparisons were handled. A prespecified multiplicity strategy, if any, is not reported in the registry record.

Missing-data information is also not reported in the registry record. The outcome group sizes are 95 for usual care, 94 for the pharmacist arm, and 89 for the pharmacy technician arm, while overall enrollment is 306. The record does not explain the differences among these counts, state how many outcome values were missing, or describe whether any values were excluded or imputed. The reported outcome sizes should not be treated as a complete account of participant flow.

The analysis population is not reported in the registry record. It is therefore unclear whether estimates included all randomized participants, participants with an available primary outcome, or another defined set. The record does not state whether participants were analyzed according to assigned group, whether deviations from assigned intervention were addressed, or whether any sensitivity analyses were performed.

General statistical context: missing outcomes can affect both the estimated group means and the validity of a comparison, particularly if the reasons for missingness differ among groups or relate to the outcome. An analysis plan typically explains how missing values and analysis populations are handled. Without such details, the posted estimates can be described as reported, but their relationship to all randomized participants cannot be established.

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

The results give arm-specific estimates for a weighted error score. The usual-care mean was 23.0, and the pharmacist and pharmacy technician means were each 4.1. The accompanying 95% confidence intervals describe uncertainty in each arm mean. Taken as descriptive statistics, these values show lower reported mean scores in the two intervention arms than in usual care.

That description is not the same as a completed statistical comparison. The registry record reports no analysis results, between-arm effect estimates, or p-values. It therefore does not establish the size or precision of a difference between assigned groups, nor whether any observed difference could be explained by sampling variation. It would be inappropriate to turn the separate means into a newly calculated contrast or to infer a formal result from the confidence intervals alone.

The endpoint combines the frequency and severity of identified errors. The means do not tell how many individual patients had errors, how many errors of each severity were found, or whether a lower score reflects fewer errors, less severe errors, or both. Nor do these primary outcome results establish an effect on medication order errors, adverse drug events, or other downstream outcomes.

The intervention arms allowed usual care practices to continue. Accordingly, the comparison concerns the assigned approaches as described in the record, not necessarily a replacement of physicians' and nurses' role in obtaining histories. The record also does not report detailed implementation or adherence information.

General statistical context: randomized allocation can strengthen causal interpretation when the trial is conducted and analyzed as planned, but conclusions still depend on complete outcome reporting, an appropriate comparison, and an analysis population aligned with the design. Those details are not reported in the registry record. The findings should therefore be read as posted arm-level outcome estimates rather than as a definitive statement about comparative effects.

12. Why This Trial Matters Statistically

This trial addresses a measurement problem at hospital admission: medication histories can contain errors, and the study's score recognizes that errors may differ in severity. Statistically, it illustrates why an outcome definition matters. A weighted score combines information about error occurrence and severity, which may be useful when treating all recorded errors as equivalent would obscure meaningful distinctions. At the same time, a single mean of a composite score cannot reveal which component accounts for an arm's result.

The three-arm randomized design makes it possible to describe usual care alongside pharmacist and pharmacy technician approaches. The arm estimates show how outcomes were reported for each approach, while the absence of formal comparative analyses demonstrates an important distinction between descriptive summaries and inferential evidence. Arm means and their confidence intervals do not substitute for prespecified contrasts and their uncertainty.

The case also highlights the importance of complete registry reporting. Information about outcome missingness, analysis populations, statistical models, and multiplicity is needed to understand how posted estimates relate to the randomized design. Such details help readers assess precision and the scope of conclusions, beyond simply noting which mean is numerically smaller.

Finally, the outcome's nonnegative, unbounded score and severity weighting raise analytic questions about distribution and model fit. These are general considerations for weighted error scores; the record does not give enough methodological detail to determine how they were handled. The trial is therefore useful as an example of both a clinically motivated outcome and the limits of interpretation when comparison and analysis details are absent.

13. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record provides arm means and confidence intervals for the primary outcome but no formal between-group analysis. Without contrast estimates and their uncertainty, the comparative result cannot be characterized statistically. The posted estimates are also insufficient to assess whether the randomized allocation was maintained in the analyzed groups.

The relationship between overall enrollment of 306 and the outcome group sizes is not explained. Missing outcome counts, reasons for missingness, exclusions, and the analysis population are not reported in the registry record. It is consequently unclear how representative the reported group estimates are of all enrolled or randomized participants.

The score is severity-weighted, but the record does not report score distributions or separate results by error severity. It also does not report a standard deviation or explain the method used to estimate confidence intervals. Because a nonnegative score with no finite upper bound may have a skewed distribution, the missing distributional and analytic details limit assessment of the summary measure and its uncertainty.

The record lists no analyses. It does not describe the statistical model, baseline adjustment, planned pairwise comparisons, multiplicity handling, interim analyses, or sensitivity analyses. These matters are not reported in the registry record and cannot be inferred from the arm estimates. The study's eligibility details, implementation measures, and adherence information are also not described in the available record.

Although a secondary outcome on admission medication order errors is listed, no result for it is reported in the information available for this analysis. The registry's adverse-event group entries contain zeros, but the at-risk counts are also zero; these entries do not establish that adverse events were assessed or absent. The record therefore does not support conclusions about safety outcomes or downstream consequences.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Pharmacists and Pharmacy Technicians to Improve Admission Medication History Accuracy — NCT02026453.
• Registry record last updated 2018-02-22; status last verified 2018-01.
• Results first posted 2017-10-06.
• 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.

17. Record Summary

The completed trial, NCT02026453, was sponsored by Cedars-Sinai Medical Center. The registry records a start of 2014-01 and primary completion in 2014-02, with enrollment of 306. It used randomized allocation, a parallel-group model, and no masking.

The three approaches were usual care by physicians and nurses, pharmacist-obtained admission medication history with usual care potentially continuing, and pharmacy technician-obtained history with usual care potentially continuing. The primary outcome was the severity-weighted mean admission medication history error score, with the history attempted the day after admission.

The registry reports primary outcome means and 95% confidence intervals by arm, but no statistical analyses. It lists a secondary admission medication order error score without a posted result in the information available for this analysis. Missing-data handling, analysis populations, and the comparative statistical plan are not reported in the registry record.