DISCUSSION
Polypharmacy is common in patients with cardiovascular disease13, increasing risk of DDIs8 that
worsen treatment outcomes 18. DDI screening tools
embedded within EMR can assist with DDI identification and management,
however, DDIs are still highly prevalent 14. The
objective of the current study was to evaluate the prevalence of DDIs in
the CVICU at MM and to compare it to the prevalence in an ICU in KTH,
Pakistan. Our study confirmed a high prevalence of DDIs in MM (58%),
but a significantly lower prevalence than KTH (95%, p< 0.01).
Estimates of DDI prevalence worldwide varies from 38% to 71%,
depending on the study setting, population and tools employed to
evaluate DDIs 8, 19, 20. At MM 1.57 DDIs per patient
were present, which is lower than the DDIs per patient at KTH (3.09) or
reported from an ICU in Serbia (~6). The lower
prevalence of DDI at MM likely reflects the effectiveness of DDI
screening by the EMR, as there is no computerized DDI screening system
at KTH or Serbia 21.
Polypharmacy and longer ICU stay increased risk of DDIs in MM (both,p < 0.01), while in KTH only polypharmacy increased DDI
risk (p < 0.01). Polypharmacy and length of stay have
been previously reported to increase DDI risk in various studies
conducted in the US and worldwide 22-25. Gender and
age have also been reported to be associated with DDIs22-25 but were not associated with DDIs in MM or KTH
(p > 0.05). Prior reports of association may have
been due to analyzing cohorts from mixed treatment units with mixed
disease states, which could introduce issues with confounding.
Of the total clinically relevant DDI observed in MM CVICU patients, only
21% (14/66) were undetected by the MM EMR. In comparison, 100% of
clinically relevant DDIs are undetected at KTH due to the lack of any
DDI screening system. Recent studies highlighted the effectiveness of
EMR based DDI detection tools and pharmacists in reducing medication
errors and DDIs 26-28. Thus implementation of an EMR
based DDI screening tool and pharmacist screening could help prevent
DDIs at KTH. At MM, a subset of clinically relevant DDIs were not
detected by the EMR. Of the 8 DDI pairs that were not detected, 2 pairs
resulted in 57% of observed DDIs. The DDI of tacrolimus and omeprazole
is important in transplant patients as omeprazole may increase
tacrolimus concentrations leading to increased risk of hepatotoxicity
and nephrotoxicity 29, 30. EMR DDI detection systems
could be further improved by enhancing information display and
contextualization, and providing DDI management recommendations that are
tailored to the individual provider and unit 31.
Strengths of the study include a large sample size, inclusion of all
concurrently administered drugs and use of multiple tools to analyze
clinical relevance of DDIs. However, several limitations should be
considered. This study was conducted in a single unit of a single
tertiary care hospital, limiting the generalizability of these findings.
Additionally, the retrospective study design precludes meaningful
analyses of the number of DDIs that were detected and appropriately
managed.