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Effects of community based nurses specialising in Parkinson's disease on health outcome and costs: randomised controlled trial

BMJ 2002; 324 doi: (Published 04 May 2002) Cite this as: BMJ 2002;324:1072

Rapid Response:

Parkinson’s Disease Nurse Specialists

EDITOR - We are grateful to Jarman and colleagues for demonstrating
the beneficial effects of Parkinson's Disease (PD) Nurse Specialists on
patient well being. We feel that this having been achieved at no
additional cost is very encouraging.1 However, we believe that their study
significantly underestimates the potential effectiveness of the nurses,
many of whom have been employed in the UK in the last decade, for a number
of reasons.

As the authors of the study admit, the nurses were evaluated over the
first two years of their practice when they were still on their learning
curve. It is the common experience of PD Nurse Specialists that it takes
around two years to reach their full level of effectiveness, even after
attendance at a nationally recognised training course (e.g. ENB A43). So
in the trial they may not have been working to their full capacity. This
will have seriously underestimated their benefits on quality of life and
even mortality. In a condition with survival in the region of 15 years,
this two year study is notably short. Empirically it would seem likely
that the benefits of such nurses will be more marked in later disease once
postural instability, falls, and other complications begin, often leading
to fractures and fatalities. This suggests that a much longer prospective
study should have been performed. In particular, one would consider that
the value of patient and carer education would take a considerable period
to be seen.

There have been claims that selegiline is neuroprotective for some
years, although this has not been conclusively proved. The withdrawal of
many patients from selegiline in the UK was prompted by the Parkinson's
Disease Research Group’s trial apparently showing increased mortality in
selegiline treated patients.2 A later analysis corrected for baseline
covariates failed to confirm this3 and a meta-analysis showed no effect of
selegiline on mortality.4 If selegiline is neuroprotective, the withdrawal
of more patients in the nurse-treated group from selegiline may have led
to an artefactual increase in mortality in the nurse group thereby masking
any potential beneficial effect they may have had on mortality. We believe
the authors do have data to support this suggestion in an unpublished
subgroup analysis.

In clinical practice, most PD Nurse Specialists work closely with
consultant neurologists and geriatricians who provide advice on diagnostic
and treatment issues. However, this study was performed in a primary care
setting so it is unlikely that such access was available to at least some
of the nurses in the trial. This could have seriously impaired their
effectiveness in this trial setting. The authors raise the issue of the
diagnostic error rate in general practice which was shown in a recent
study to be as high as 47%.5 This should not have affected the trial as
randomisation should have ensured that equal numbers of misdiagnosed cases
occurred in each arm. However, this was not documented in the report and
imbalance at baseline could have confounded the overall results.

The authors acknowledge the possibility of contamination of the
control group since nurses may have been working with other patients in
the same practice. Whilst the nurses themselves may have excluded contact
with controls, the individual general practitioners will have learned from
their possibly improved experience with nurse-treated patients and applied
this to control patients.

Superficial inspection suggests that this is a trial of 1028 patients
randomised to PD Nurse Specialists and 808 to standard medical care.
However, a case can be made for this being a cluster randomised trial of
just nine nurses versus control. In this case the trial may have been
seriously underpowered to detect the small but clinically relevant effects
that the nurses may have had on quality of life and mortality.

Further long-term studies of larger numbers of fully trained PD Nurse
Specialists would be required if more precise estimates of their effects
on quality of life, health economics and mortality are required. Meanwhile
we have clinical and anecdotal evidence of the positive contribution that
these specialist nurses can make and the valuable results of this study
confirm that they are cost neutral; a ‘win-win’ scenario for patients,
clinicians and government.

C E Clarke
reader in clinical neurology

City Hospital and the University of Birmingham

D G MacMahon
consultant physician

Royal Cornwall Hospitals NHS Trust

L J Findley
professor of neurology

Romford Hospital, Essex

L Osborne

Parkinson's Disease Nurse Specialists Association

S Thomas
nursing policy adviser

Royal College of Nursing, London

L Kelly
chief executive,

Parkinson's Disease Society, London

1. Jarman B, Hurwitz B, Cook A, Bajekal M, Lee A. Effects of
community based nurses specialising in Parkinson's disease on health
outcome and costs: randomised controlled trial. British Medical Journal

2. Lees AJ, Parkinson's Disease Research Group of the United Kingdom.
Comparison of the therapeutic effects and mortality data of levodopa and
levodopa combined with selegiline in patients with early, mild Parkinson's
disease. British Medical Journal 1995;311:1602-1607.

3. Ben-Shlomo Y, Churchyard A, Head J, Hurwitz B, Overstall P, Ockelford
J, et al. Investigation by Parkinson's Disease Research Group of United
Kingdom into excess mortality seen with combined levodopa and selegiline
treatment in patients with early, mild Parkinson's disease: further
results of randomised trial and confidential inquiry. BMJ

4. Counsell C. Effect of adding selegiline to levodopa in early, mild
Parkinson's disease. British Medical Journal 1998;317:1586.

5. Meara J, Bhowmick B, Hobson P. Accuracy of diagnosis in patients with
presumed Parkinson's disease. Age and Ageing 1999;28:99-102.

Competing interests: No competing interests

30 May 2002
C E Clarke
Reader in Clinical Neurology
D G MacMahon, L J Findley, L Osborne, S Thomas, L Kelly
City Hospital, Dudley Road, Birmingham, B18 7QH