Given that the APID index uses medical record reports
for measuring appropriateness of PDU, this measure could
also, next to a medical record extraction bias, be biased by
the reporting quality. However, the independent reliability
study found minimal differences between the researcher
and the practising elderly care physician’s administration
of the APID index, which supports the concept of using
medical records for an appropriate PDU for NPS index.
Nevertheless, the results also show that the physician could
have additional information about patients’ PD indications
that could influence the index’ score.
The results of mean weights by expert panel 2 and the
score range per individual item, that is, 0e2, resulted in a
summation of seven weighted items that can range from
0 to 102.8 per rated PD, from appropriate to inappropriate,
respectively. In addition, it was found that all seven items
contribute to the summated index score and that there were
no multicollinearity issues. The reliability of the summated
index score is substantial; however, it should be taken into
account that this is not the same as the ‘‘absolute’’ agreement
between raters [40], which is important to consider
if the index is to be used in clinical practice.