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| Journal of the New Zealand Medical Association,
25-May-2012, Vol 125 No 1355
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Nurse titration clinics to achieve rapid control of
blood pressure
Dominic Taylor, Veronica van der Merwe, Walter van der Merwe
Good long-term outcomes in hypertension depend on achieving
target blood pressures, and, it is increasingly evident, doing so in a short
period of time.1,9 In the
VALUE2 and
ASCOT3 trials, blood pressures attained at 3
months predicted long-term outcome. In addition, other trials, like
ALLHAT4 have shown that blood pressure
differences in treatment groups achieved in the first few months of a five year
trial tended to persist throughout the trial, despite repeated encouragement of
investigators to achieve blood pressure control.
The old adage “start low and go slow” with blood
pressure medication mitigates against an aggressive approach to blood pressure
management and encourages “clinician inertia” and results in
patients being seen on multiple occasions with blood pressure not at target but
not having their medications adjusted.5
Part of the problem is reluctance of clinicians to add
medications and titrate doses upwards is a (usually misplaced) concern about
inducing unacceptable hypotension,1 and also a
reluctance to follow the JNC-7 guideline9 which
suggests starting (previously untreated) patients with stage two hypertension
(systolic ≥ 160 mmHg ± diastolic ≥ 100 mmHg) on combination
therapy de novo.
Another impediment to timely blood pressure medication
titration may be the need for check laboratory tests after the addition or
increase in dose of RAS-blockers (angiotensin converting inhibitors/
ACE-inhibitors and angiotensin receptor blockers/ARBs) and diuretics, with the
small amount of additional effort and follow-up that that entails. There may
also be patient-related factors, for example the cost and inconvenience of
attending for multiple medication adjustments with their doctor.
The Waitemata Hypertension Clinic has been operating since
March 2009. At one ½ day clinic per week it sees mostly GP referrals of
patients with difficult or resistant hypertension, and over 300 new referrals
have been seen to date. A minority of referred patients have secondary causes of
hypertension requiring specialised investigation, but in the majority, the main
function of the clinic is optimisation of blood pressure with the use and
titration of complex multi-drug regimens. Multiple visits are often required to
achieve target blood pressure, and because of pressure on clinic space these
repeat visits are either far apart, or take place at the expense of valuable new
patient slots.
A potential solution to this is the use of nurse or
pharmacist titration clinics with which there is experience in the United States
and elsewhere.6,7 The experience in some large
organisations which use nurse titration clinics (e.g. Kaiser Permanente HMO in
the USA) is that compliance rates are high and blood pressure control rates are
excellent (80%).
In New Zealand, Clinical Nurse Specialists (CNS) are trained
to provide care within a specialist area of practice, within Registered Nurse
scope. This may include delegated medical responsibilities, diagnostics, and
implementation of treatment protocols.8
Nurse-led clinics have proven beneficial in other specialties in New
Zealand and have been associated with improved patient
outcomes.9–11
Nurse specialist salaries in New Zealand are approximately
half of registrar salaries and one third of medical specialist salaries—if
similar outcomes can be achieved in equivalent numbers of nurse-led vs doctor
clinic visits, they would clearly be cost-effective. The Waitemata Renal Service
appointed a Hypertension Clinical Nurse Specialist (CNS) in July 2010 and one of
her roles was to establish blood pressure medication titration clinics. We
audited the first 50 GP-referred patients attending these clinics, and compared
their outcomes to 50 patients seen and followed up exclusively at the physician
clinic.
We aimed to show that the new clinic model was at least
equivalent to the previous clinic model in terms of timely achievement of blood
pressure targets, and more efficient in terms of physician time. We also wished
to compare number of clinic visits required to achieve target blood pressure
with the two models and assess patients’ satisfaction with the new
model.
Methods
50 consecutive patients referred from general
practitioners with difficult or resistant hypertension were seen for their first
clinic visit by a senior registrar. At this visit, a full history and physical
examination were undertaken. The examination included careful resting blood
pressure measurement with a manual oscillometric sphygmomanometer, according to
the JNC-7 guideline.9
Special investigations were ordered as appropriate and
referrals made to smoking cessation and nutritional services if needed. In
addition an initial adjustment was made to their antihypertensive medication.
Other drugs, specifically aspirin and statins were added as appropriate. Cases
were discussed with the consultant as required.
Patients’ next and subsequent visits were
exclusively at the Hypertension CNS Clinic. They were seen at 2-4 weekly
intervals until the blood pressure was at target (or as close to that as deemed
achievable) on a regimen with which the patient felt comfortable.
At the initial nurse titration clinic, patients’
blood pressure was checked again according to JNC-7
guidelines,12 using a Microlife
automated office blood pressure monitor (Microlife AG, Widnau,
Switzerland). Weight, height and abdominal circumference were measured.
Obstructive sleep apnoea questionnaires were performed as appropriate.
Education was provided on hypertension, cardiovascular
risk, lifestyle matters, and drug-related issues particularly potential side
effects. Antihypertensive medication adjustment was made according to
pre-arranged algorithms. Follow up laboratory tests were performed according to
protocol (for example addition of, or increase in the dose of ACE-inhibitor,
ARB, or diuretic required urea, creatinine and electrolytes to be rechecked
2–3 weeks after the change). A further appointment was made for two
weeks’ time if BP was not at target.
Cases were discussed at a weekly meeting between the
CNS and the registrar and/or consultant, or ad hoc if needed (e.g: for
deviations from the algorithms). Prescriptions were provided by the medical
team. Written communication was made with the primary care physician at each
visit, and once at target blood pressure a written doctor summary was provided
outlining recommendations for ongoing treatment.
Data on patient demographics, comorbidities, medication
changes, secondary causes of hypertension and blood pressures were recorded
prospectively. Similar data from the 50 GP-referred patients seen in the
physician hypertension clinic immediately prior to introduction of the new
clinic were collected retrospectively, and compared to the study data.
Figure 1. Structure of new clinic
model
 Figure 2: Content of nurse clinic
visits
 Results50 patients were studied from each group. Their demographic
details are shown in Table 1.
Table 1. Demographic details
Their comorbidities are shown in Table 2.
Table 2: Comorbidities
Of the current smokers, the mean number of pack-years was 22
for the physician group, 18 for the nurse group. The number of patients with the
metabolic syndrome, defined by IDF criteria13,
was higher in the nurse clinic group.
There was no significant difference in the number of clinic
visits required to reach target blood pressure (Table 3; p=0.16). The mean
number of antihypertensive drugs at discharge was the same for both groups.
Table 3. Visit number and drugs
prescribed
Mean blood pressure reductions are shown in Table 4.
Table 4: Blood pressure (BP) reduction by
clinic
“Paired-samples” t-tests were performed to
compare systolic and diastolic blood pressures at presentation and at discharge.
There were significant reductions in both measurements for both clinics (table
4; p<0.01), and the reduction in systolic BP was significantly larger in the
nurse clinic group (p=0.02).
Figure 3. BP measurements at presentation to,
and at discharge from each clinic.
 The box-and-whisker plots in Figure 5 illustrate the range
of blood pressures measured at presentation to, and discharge from, each clinic.
The box represents the interquartile range (IQR), the line dividing the box the
median value. The whiskers indicate values 1.5 IQR lower than the first quartile
and 1.5 IQR higher than the third quartile, and dots any outlying
values.
The classes of drugs added in each group are shown in Figure
4. The drugs added in each clinic were similar. The number of patients
discharged on the maximum dose of a thiazide diuretic or DHB calcium channel
blocker was higher in the nurse clinic than the physician clinic (Figure
5).
Figure 4. Percentage of patients taking each
class of drug at presentation, and at discharge or last follow-up
Physician-only clinic
 Nurse titration clinic
 Figure 5: Number of patients taking the maximum
dose in each class of drug at discharge from each clinic
 All patients were investigated for secondary causes of
hypertension. In the nurse titration clinic group, three cases of possible
obstructive sleep apnoea were identified all of whom are awaiting sleep studies.
Two patients were investigated for possible primary hyperaldosteronism but both
had normal aldosterone suppressibility on saline suppression testing. One
patient had renovascular disease.
DiscussionWe trialled a new model of hypertension clinic using an
initial physician visit, followed by nurse titration and education clinics, with
the aim of reducing the load on the physician hypertension clinic, and achieving
target blood pressures quickly and efficiently.
The groups compared were of a similar demographic, with
similar comorbidities. The physician group had a longer duration of
hypertension.
We found no significant difference in the total number of
clinic visits needed to achieve target blood pressure between the two groups.
Blood pressures at discharge were similar between the
groups, with significantly lower systolic BP reduction in the nurse clinic
group. The mean number of drugs used per patient was the same.
Patients were asked to complete a questionnaire following
their last visit. Feedback was uniformly positive. The majority emphasised the
benefits of the extra time spent on education, which seems to have been a factor
encouraging compliance both with medication and with lifestyle modifications.
Patients also stated that the relaxed, unhurried atmosphere of the nurse clinic
encouraged free discussion and questions, in contrast to doctor clinics where
time pressure is often evident.
This model has the advantage of an initial physician
assessment, and ongoing background supervision. However, because physician
clinic visits are reduced by more than 2 for each patient, more new patients are
able to be put through the clinic in a timely fashion (two twenty minute
follow-up visits saved makes one 40-minute new patient clinic slot).
Additionally, cost-effectiveness of nurse-led clinics is
evidenced by equivalent outcomes to doctor-only clinics in similar numbers of
visits, given the considerably lower hourly cost of nurse specialists compared
with doctors. Other advantages include accurate, unhurried electronic blood
pressure measurement in the nurse clinic, and liberal time for education which
is important for long-term medication
compliance.14
In conclusion, hypertension nurse-specialist clinics may be
a useful and cost-effective tool for management of GP-referred patients with
difficult or resistant hypertension. We plan to widen the scope of the
hypertension titration clinics to Nephrology patients seen in our department. We
plan to encourage the development of similar projects in primary care to allow
easier patient access. We continue to prospectively audit the process.
Competing interests: None
declared.
Author information: Dominic M Taylor, Renal
Registrar, North Shore Hospital and Auckland City Hospital; Veronica van der
Merwe, Clinical Nurse Specialist – Hypertension, Renal Service, North
Shore Hospital, Auckland; Walter van der Merwe, Medical Specialist, Nephrology
and Hypertension, North Shore Hospital, Auckland
Correspondence: Walter van der Merwe,
Waitemata DHB Renal Services, 122 Shakespeare Road, Takapuna, Auckland 0620, New
Zealand. Email Walter.VanDerMerwe@waitematadhb.govt.nz
References:
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