Discussion
This is the first study to investigate the impact of PIMs and PPOs at
discharge from geriatric rehabilitation on unplanned readmissions and
mortality among geriatric rehabilitation inpatients in Australia. While
the prevalence of PIM and PPO use at different time points during the
transition into geriatric rehabilitation care was high, the proportion
of patients taking any PIMs/PPOs significantly reduced from acute
admission to geriatric rehabilitation discharge. The use of at least 1
PIMs, PPOs or PIPs at geriatric rehabilitation discharge were not
associated with an increased risk of unplanned readmission and
mortality, be it in the short or long-term. Specific groups of PIMs
(CNS/psychotropics and fall risk increasing medications) were
significantly associated with the 30-day hospital readmission and
cardiovascular PPOs with the 12-month mortality. Furthermore, an
increased number of discharge medications was significantly associated
with 30-day and 90-day hospital readmissions. The use and number of PPOs
that also included vaccine omissions were negatively associated with
gains in IADL scores at 90-days following discharge from geriatric
rehabilitation.
Temporal changes in the prevalence of PIMs and PPOs from acute admission
to geriatric rehabilitation discharge were investigated in this study.
It showed a significant reduction in PIMs and PPOs as patients moved
from acute admission to discharge. While these findings were consistent
with other studies,31,32 there were also studies that
did not show a significant difference10,33 or have
shown a rather increased PIM prevalence during the transition from
admission to discharge.13 The current study has shown
that the longer that patients stayed in geriatric rehabilitation ward,
the fewer patients were likely to be exposed to PIMs. Therefore, it was
not surprising to see a decline in the prevalence of PIM use from acute
admission to discharge in this study.
In the present study, neither PIMs, PPOs nor PIPs were shown to have an
association with readmission and mortality, but a higher number of
discharge medications was a major predictor for unplanned hospital
readmission at 30-days following discharge from geriatric
rehabilitation. This finding is not consistent with previous reports
conducted in acute care,7,34 in relation to hospital
readmission and mortality. A recent meta-analysis highlighted the burden
of medication-related harm due to potentially inappropriate
prescribing.7 For example, patients using at least 1
PIM use in the inpatient setting (compared with non-users) were
associated with a 91% increased odds of medication-related hospital
admission (AOR 1.91, 95% CI 1.21-3.01), and 60% increased odds of
dependency in at least 1 ADL (AOR 1.60; 95% CI 1.28–2.01). Informed by
this review, a prospective telephone follow-up study with clinical audit
of electronic medical record in general medical wards was also
subsequently conducted to assess the links between inappropriate
medication and clinical and functional outcomes (e.g., unplanned
hospital readmission, dependency in activities of daily
living).34 It was found that exposure to at least 1
PIM use was associated with an increased occurrence of unplanned
hospital readmission (AOR 5.09; 95% CI 2.38─10.85), and there was also
an increased in the likelihood of patients experiencing dependency in at
least 1 ADL after hospital discharge (AOR 2.31; 95% CI
1.08─4.20).34 The reason for this difference may be
that related to the healthcare setting itself, in that patients admitted
to geriatric rehabilitation wards stayed longer (median 19.8 days vs 5
days)34 and were likely exposed to fewer PIMs than
patients discharged from general medical wards. In addition, the
previous study34 was conducted during the intense lock
down due to COVID-19 and this may have impacted healthcare provision
because of understaffing. The morbidity and mortality pattern were also
different – for example, 90-days readmission was 36% in a previous
study34 but 21.7% in the current study, it may be due
to COVID-related restrictions with limited eligibility for hospital
care. The lack of association between hyper polypharmacy (defined as
prescription of 10 or more medications) and clinical outcomes in a
previous study34 may be because only regular
medications were counted unlike the current study. Medications
prescribed pro re nata , including benzodiazepines for sleep aid
may have been missed in the calculation, which was the main limitation
for the previous study.34 It should be noted that the
prescription of psychotropic and fall risk increasing PIMs were
associated with 30-day readmission in the present study.
The present results are consistent with previous
studies,35,36 showing that as the number of
medications increase, so does the prevalence of 30-day and 90-day
hospital readmissions. Basnet et al.35 found that the
number of discharge medications was significantly associated with
increased hospital readmission within 30-days, with the risk of
rehospitalization increasing by 4% for every added medication (OR 1.04;
95% CI 1.03─1.05). Another study36 of 647 patients
discharged from geriatric medicine acute care wards showed that taking
eight or more medications was significantly associated with 90-day
hospital readmission.