In this randomized controlled trial, we found that clinically important medication errors were very common, affecting 50.8% of patients during the first 30 days after hospital discharge. Overall, a health literacy-sensitive pharmacist intervention did not significantly reduce clinically important medication errors or ADEs at the study hospitals. Potential ADEs tended to decline, but this effect was not statistically significant. These results highlight the difficulty of improving medication safety during the transition from hospital to home.
In interpreting the results of this negative trial, a key question is the extent to which its findings are generalizable to other settings. Indeed, as hospitals increasingly implement and evaluate programs to improve care transitions, it is critical to understand contextual factors that may affect the results, as examples of both positive (13
) and negative (31
) studies exist. PILL-CVD was performed at 2 academic hospitals that at baseline had resources to support medication reconciliation, including health information technology. This made it more difficult to show an incremental benefit from the PILL-CVD intervention. Indeed, the effect size was smaller than anticipated and smaller than that found in studies conducted in the pre-medication reconciliation era. Even at these 2 relatively similar academic hospitals, we observed a possible difference in treatment effect. Further study is needed to determine whether hospitals with different characteristics, such as less electronic medical record support for medication reconciliation or fewer pharmacist resources, see benefit over usual care from this type of intervention.
Another factor affecting generalizability is that the study participants on average were well educated (median 14 years of education), cognitively intact (88%), and had a relatively low prevalence of inadequate health literacy (10%), compared to a 26% prevalence in the medical literature (32
). The PILL-CVD intervention, which was designed to accommodate the needs of patients with low health literacy or cognitive impairment, may be more effective among those populations. This too requires further investigation, as the present study was not powered to detect a benefit in these subgroups.
The intervention had no effect on the number of ADEs after discharge. Part of this finding may be artifactual; the adjudication process has some inherent subjectivity. In particular, patients who learn about side effects through the intervention may report symptoms in such a way that they are more likely to be adjudicated as ADEs, thus altering the apparent effect of the intervention (25
). Indeed, intervention patients in this study had a greater number of significant (i.e., symptom-only) ADEs. In addition, reduction of preventable or ameliorable ADEs may require different interventions than those evaluated here, such as closer post-discharge monitoring, clinic-based support, or home visits.
Other findings are noteworthy. The observed incidence of preventable or ameliorable ADEs (30.3%) is more than double that reported by Forster and colleagues, despite similar adjudication procedures (4
). Possible explanations include the present study having a slightly longer period of follow-up (30 days vs. a mean of 24 days), more complete electronic health records for review, and more extensive review of outside medical records (5
). Moreover, patients in the present study had specific cardiac conditions, as compared with a general medical population (5
Potential ADEs were also common, affecting 29.7% of patients overall. Here, potential ADEs were defined as medication discrepancies or non-adherence during the first 30 days after discharge, whereas others have focused on medication discrepancies only and used a 72 hour period of follow-up (7
). It is uncertain how elapsed time affects discrepancies. Medication discrepancies that are present immediately after discharge could be resolved as patients visit their outpatient physicians, though the incidence remained high in the present investigation. Different definitions, data collection procedures, and follow-up duration make comparison to other studies difficult.
Certain study limitations were present. First, as noted above, the characteristics of the study hospitals and participants made it more difficult to show incremental benefit and also limit generalizability. Second, the participants had acute cardiovascular conditions; the number of medication-related problems, classes of medications implicated, and efficacy of this type of intervention may differ in other populations. Third, not all patients received the full intervention as intended, although the vast majority did (14
In conclusion, we found clinically important medication errors commonly occur during the 30 days following a cardiac hospitalization, and we report a much higher incidence than previously shown for preventable or ameliorable ADEs, as well as potential ADEs. A health literacy-sensitive pharmacist intervention that included post-discharge telephone follow-up did not improve medication safety overall. Reducing ADEs and potential ADEs in the post-discharge period is becoming more critical as hospitals have increasing financial penalties tied to readmission rates. Further work is needed to develop and test interventions in this setting, including strategies for higher-risk populations, as well as additional modalities, such as post-discharge medication reconciliation (33
) or closer post-discharge surveillance.