Discussion
There is a paucity of research on drug-drug interactions and
prescriptions appropriateness among ESRD patients who have been
prescribed QTcP-inducing drugs in Jordan. We adopted holistic and valid
operational techniques to detect DDIs and evaluate the prescriptions
appropriateness. Our findings can be confidently generalised, since the
sample in our study was representative, with low margin of error, and
randomly selected from all regions in Jordan. However, our study had
limitations; this research was conducted in outpatient setting, and thus
our data cannot reflect the prescribing behaviour in the inpatient
settings. Due to insufficient resources and the limited nature of our
data, patients with acquired r congenital QTc prolongation were not
clinically identified. Nevertheless, we were tied by the study aims and
the nature of the data, and our study can provide comprehensive
assessment of prescribing behaviour in the outpatient clinics of Jordan.
In Jordan, Ahmad Al-Azayzih et al., (18), investigated the patterns of
QTcP-inducing drugs usage among geriatric patients in North Jordan. DDIs
and prescriptions appropriateness were not assessed, and ESRD patients
were not screened. Furthermore, their findings cannot be generlised as
they targeted patients in geographic area in Jordan. Many previous
studies were conducted in the USA (37,38), Colombia (39), Germany (40),
and India (41) assessed the patterns of QTcP-inducing drugs
prescriptions. Despite that patients with ESRD are at high risk of
developing fatal QTcP, none of the recent studies screened for DDIs or
prescriptions appropriateness among this patient group particularly.
Among the included patients in our study, 954 QTcP-inducing drugs were
prescribed; most of them were furosemide (36.2%) and lanzoprazole
(28.9%). This was consistent with Ahmad Al-Azayzih et al., (18), where
lanzoprazole (20.7%) and furosemide (15.8%) accounted for the most
common prescribed QTcP-inducing drugs. Most of dispensed QTcP-inducing
drugs in our study were categorised as conditional risk of QTcP. A
recent study reported higher rate of mortality among patients who have
been prescribed QTcP-inducing drugs with known or possible risk of QTcP
than those who were on drugs with conditional risk or not on
QTcP-inducing drugs at all (42). This finding focused on patients in
psychiatry clinics, and thus cannot be generlised to other patient
groups.
Our results suggested high rate of DDIs (64.8%) between QTcP inducing
drugs and other medications; more than one-third of these DDIs were
major and moderate. In addition, polypharmacy and co-morbidity were
significantly related to this proportion. This result may attributed to
low pharmaceutical care interventions, physicians poor adherence to the
guidelines, and absence of clinical decision support system in the
operated computerized physician order entry system (CPOE) . Our findings
are in line with other studies in Jordan that indicated high rate of
DDIs and poor adherence to the guidelines by physicians (21,22,27). The
difference between the recent studies in Jordan and our study is that
the patient group in our research is highly vulnerable to severe deadly
complications, and thus urgent precautionary measures are necessary. In
Saudi Arabia, pharmacists had a major role in intervening on DDIs in
outpatient psychiatry clinics (43). Other studies explained how
pharmacists are responsible for identifying DDIs and notifying
physicians and patients about the potential consequences (44,45). For
safer medication use especially among high risk groups of patients, we
believe comprehensive plan to deliver continual professional development
courses to pharmacists and physicians as well in outpatient clinics is
indispensable.
Our results indicated that more than one-quarter (26.4%) of the
dispensed QTcP-inducing drugs were prescribed based on inappropriate
decision, and this was significantly associated with urology clinics. A
recent study conducted in Germany, found that inappropriate prescribing
can lead to negative adverse drug events including QTcP, hyperkalaemia
and haemorrhage in patients with kidney diseases (46). Lower rate of
inappropriate prescribing was found in the USA (47). Due to
inconsistencies in the operational definitions of prescribing
appropriateness, results of different studies are barely comparable.
To sum up, patients with ESRD are underrepresented in most of the
previous research and as there is no cleared approach for polypharmacy
management, clinical assessment of potentially risk factors regarding
inappropriate prescribing behaviour, and DDIs monitoring, health
officials should efficiently utilised our data to implement concise
patient education programme aiming to improve self-monitor of side
effects for early detection of potential harm. Furthermore, pharmacists
should be encouraged and trained to intervene on DDIs and erroneous
medication orders. Further multicentric study to assess the quality of
prescribing in hospital settings is required.