Here - Surrey and Borders Partnership NHS Foundation Trust

Research and Audit
Table 5 shows how the GPs and MHNPs
combined diagnoses (BPD or another
condition) performed against the
psychiatrists final diagnosis, which is used
as the gold standard in this study.
Thirty-three patients were seen by both
the psychiatrist and their GP. Of the 7
patients diagnosed with BPD by the
psychiatrist 5 were correctly identified by
their GP whilst 2 received another
diagnosis. However in 4 patients where
the psychiatrist diagnosed another
condition the GP suggested a diagnosis
of BPD. The corresponding sensitivity and
specificity of the GPs diagnoses were
71.4% and 84.6%. The PPV for the GPs
diagnoses was 55.6% while the NPV was
91.7%. However the LR+ and LR- were
4.75 and 0.34 respectively which are
outside of the limits of a good diagnostic
test. (Please refer to Fields A, 2009 for a
detailed explanation of these terms.)
Twenty patients were seen by a MHNP
before seeing the psychiatrist. The MHNP
correctly picked up BPD in 2 of the 4
cases diagnosed with BPD by the
psychiatrist. However in 6 out of 16 cases
the MHNP diagnosed BPD whilst the
psychiatrist diagnosed another condition.
The sensitivity, specificity, PPV and NPV
for the MHNPs diagnoses were 50%,
62.5%, 25% and 80% respectively.
Again the LR+ and LR- which are 1.35
and 0.8 respectively fall outside of the
limits of an acceptable diagnostic test.
Discussion
There is a growing body of evidence
showing the importance of correctly
identifying and treating sufferers of BPD
to improve their quality of life, preserve
their social and occupational functioning
and to lessen the financial burden of
healthcare costs related to the
mismanagement of this important
condition. Equally, the fact that there is
often a delay of several years before this
condition is correctly identified, highlights
the importance of vigilantly screening for
BPD, especially in the primary care setting.
Our first aim was to establish the
frequency with which our primary care
practitioners screened for BPD. In this
sample of patients presenting with
affective symptoms, only 21.1% of those
referred by their GP showed any evidence
that they had been screened for BPD.
Although this figure rose to 38.9% for
MHNPs, this still represents a rather low
proportion of screening for patients who
are within the at risk category. This is
especially important as tools such as the
MDQ are available, short, and easy to
use, and could easily be administered in
the context of a primary care assessment.
A potential downfall of this study design
is that it relied on evidence from the
referral letter that the clinician had
screened for BPD and therefore it is
possible that where a patient screened
negative, it was not mentioned in the
referral letter. However, a good referral
should mention both positive and salient
negative findings and routine use of the
MDQ could circumnavigate this issue.
Secondly, we aimed to establish whether
screening for BPD increases the likelihood
of correctly identifying the signs and
symptoms of this disorder. In our study
both GPs and MHNPs almost exclusively
(with the exception of one patient in
each case) only proposed a diagnosis of
BPD when there was evidence that they
had screened for hypomania. These
highly significant results show that it was
highly unlikely that clinicians would
propose a diagnosis of BPD when they
had not screened for the condition. These
results emphasize the great importance
of consistent screening.
Our third question looks at the accuracy
with which GPs and MHNPs were able to
rule in or rule out BPD in their patients.
As previously mentioned, a good
screening tool should have both good
sensitivity (low false negatives) and good
specificity (low false positives). We also
looked at PPV and NPV as well as LR+
and LR- as these give additional
information about the quality of a
screening test.
14 Surrey and Borders Online Journal www.sabp.nhs.uk/journal