Results
Patient
characteristics
Data for 387 patients with 5191 prescriptions at the time of the CMR,
with a median of 13 prescriptions per patient (IQR 9 – 17, range 1 –
35), were analysed. The median age of all included patients was 70 years
(IQR 58 – 79; range 19 – 102): patients on the Upper GI ward were the
youngest, median 68 years (IQR 57 - 75; range 19 – 89] compared with
75 years (IQR 60-84; range 19-102)) for patients on the Internal
Medicine ward, and 72 years (IQR 65-80; range 43-88)) for patients on
the Otolaryngology and Oncology ward. In total, 172 patients (44.4%)
were female: 83 (45.4%) on the Upper GI ward, 78 (48.4%) on the
Internal Medicine ward, and 11 (25.6%) on the Otolaryngology and
Oncology ward (table 1).
Patients on the Otolaryngology and Oncology ward had the most
prescriptions at the time of the CMR (median of 17 (IQR 12 – 19; range
1-32) compared with median 13 (IQR 9-17; range 1-35) on the Upper GI
ward, and median on the Internal Medicine ward 9 (IQR 6-13; range 1-31)
(table 1).
Patients on the three wards differed (p<0.001) in age; the
number of prescriptions at time of the CMR; the number of patients with
impaired renal function (eGFR< 50 mL/min according to the
CKD-EPI formula); the number of patients with at least one PE; and the
incidence of PEs per prescription. There was a non-significant
difference in sex (p=0.064) and the number of patients with a documented
allergy or intolerance (p=0.68) (table 1).
Prevalence, types and moment of
introduction of prescribing
errors
Overall, 799 PEs were detected affecting 279 patients (72.1%). The
overall incidence of PEs per prescription was 0.15, meaning that in
every ten prescriptions, 1.5 PE were detected. In total, 219 PEs were
detected that affected 114 patients (62.3%) on the Upper GI ward, 362
PEs were detected that affected 123 patients (76.4%) on the Internal
Medicine ward, and 218 PEs that affected 42 patients were detected on
the Otolaryngology and Oncology ward. The lowest incidence of PEs per
prescription was seen on the Upper GI ward (0.075), and the highest on
the Otolaryngology and Oncology ward (0.32) (table 1).
At a patient level, 97.7% of all patients admitted to the
Otolaryngology and Oncology ward and selected for a CMR had at least one
clinically relevant PE compared with 62.3% (OR 0.039, 95% CI
0.0053–0.29) of patients on the Upper GI ward and 76.4% (OR 0.077,
95% CI 0.010–0.58) of patients on the Internal Medicine ward and
(table 1).
Overall, 58.8% of the identified PEs were introduced during
hospitalization and 41.7% of these PEs could be defined as ‘overuse’
(table 2) (22). Most (38.1%) PEs involved drugs that were used without
an evidence-based clinical indication. The IPS team advised that these
drugs should be deprescribed and drew up a plan for this in consensus
with ward doctors (table 2). The drug category associated with the most
PEs ‘drugs for acid-related disorders’ (ATC code A02), accounting for
13.6% of all identified PEs (supplementary table 2).
While performing CMRs, the IPS team identified a further 49 potential
ADEs and these were reported to the Junior Adverse Drug Event Manager
team. This resulted in 43 suspected ADRs that were reported to the
Netherlands Pharmacovigilance Centre Lareb. The feedback received from
the Netherlands Pharmacovigilance Centre Lareb was uploaded into the
electronic patient record to enable a patient-specific ADR treatment
plan.
Are doctors able to detect patients at
risk of
PEs?
Forty of the 43 patients (93.0%) on the Otolaryngology and Oncology
ward (cases) who were selected for a CMR by the ward doctor were matched
to 40 patients admitted to either the Internal Medicine and Upper GI
wards and were not selected by the ward doctor(controls). There was no
significant difference in age, number of prescriptions, sex, renal
function, or allergy or intolerance between the matched cases and the
controls (table 3).
The number of patients with at least one PE was significantly higher in
the ward physician-selected patients (97.5%) than in the non-selected
control patients (72.5%; OR=14.8, 95% CI [1.8 - 121.1], p=0.002).
The incidence of PEs per prescription was significantly higher in
patients selected by ward doctors than in non-selected control patients
(0.33 versus 0.11), which means that the PE rate in patients selected by
ward doctors is three times higher than the rate in non-selected control
patients (IRR=3.0, 95% [2.3 - 4.0], p<0.001) (table 3).
Comparison of the 304 unmatched patients of the Upper GI- and Internal
Medicine wards with the 40 matched controls of these wards revealed a
significant difference in the number of prescriptions: 13 prescriptions
(IQR 8 – 16, range 1 – 35) versus 16 prescriptions (IQR 11.3 – 19,
range 2 – 33) (p=0.005). However, further analysis showed that the
matched controls from the Upper GI (N=31) ward did not differ
significantly from the unmatched controls from the same ward (N = 152),
and the same was true for the matched (n = 9) and unmatched controls (n
= 152) from the Internal Medicine ward (supplementary table 1). Thus the
40 controls seem to be representative of the total sample of controls.