Update on hypertension - diagnosis, monitoring and guideline treatment targets

Prof. Richard McManus, Birmingham, United Kingdom

Overview Background Routine measurement of blood pressure

(is rubbish) Diagnosis of hypertension - ABPM? Management of hypertension – Home ? Treatment targets – any changes? Conclusions

Stroke Risk increases with age & usual BP

Similarly for Heart Disease

40-49

60-69

Low

Low

Risk

High

High

Bottom line BP vs Risk

10 mmHg

38% stroke risk

18% CHD risk

If you live long enough you get hypertension

The population is ageing

In mid-2008 the median age of the population was 39 years, up from 37 in 1998.

systolic2402302202102001901801701601501401301201101009080

Dotplot of systolic

Each symbol represents up to 12 observations.

Routine measurement is often flawed

Last_practice_systolic20019018017016015014013012011010090

Dotplot of Last_practice_systolic

Each symbol represents up to 4 observations.

Same population with routine and research measurement

Blood Pressure varies through the day and between seasons

Hypertension. 2006;47:155-161

Multiple measurements better estimate mean blood pressure

This variability means that measurement error can drown out the truth

occasion

systolic

654321

146

144

142

140

138

136

134

132

130

Interval Plot of systolic vs occasion95% CI for the Mean

occasions

diastolic

654321

83

82

81

80

79

78

77

Interval Plot of diastolic vs occasions95% CI for the Mean

Even on a single occasion BP drops

Approx 1500 patients

24 practices 6 readings at 1min

intervals 12 mmHg systolic

drop Stable after 5th

reading

Family Practice 1997; 14:130-135

BP takes some time to settle with repeated measurement over weeks/months

Many factors affect BP measurement

BMJ 2001;322;908-911

Diagnosing hypertension

Traditionally based on clinic measurement Most outcome trials use clinic measures But

– Flawed measure (one off from continuum)– Takes weeks / months to make diagnosis

What about ABPM?Half hourly measurements during the day

Better measure usual BP

Hourly at night Main outcome is mean day time ABPMOther info available (dipping etc)

International Thresholds for hypertension diagnosis (clinic and ABPM)

Mean daytime BP

UK (ABPM) = 135/85 mmHg

What’s normal for ABPM (and home)?

Based on Head et al BMJ 2010

adjust by 5/5 mmHg at lower threshold

(stage 1 hypertension, 140/90 mmHg clinic)

– ie < 135/85 mm Hg

10/5 mmHg at higher threshold

(stage 2 hypertension, 160/100 mmHg clinic)

– Ie < 150/95 mmHg

How do clinic and ABPM compare?

Reviewed literature: 2914 studies of which 20

were relevant 7 compared ABPM with clinic monitoring for

diagnosis Full details:

BMJ 2011;342:d3621 doi: 10.1136/bmj.d3621

Many people currently potentially misdiagnosed...

Worse if only studies around diagnostic threshold used:sensitivity of 86% andspecificity of 46%

What about Home Monitoring?

Relative sensitivity and specificity of clinic and home measurement vs ABPM

Better correlation with end organ damage and outcome (ABPM)

1963 patients

Mean FU 5 yrs

Baseline ABPM

CVD events

1700 patients, 10 years FU, 150 CVAs

Screening = 2 clinic measurements one occasion

Home = 25 measurements over 4 weeks

Journal of Hypertension 2004, 22:1099–1104

Better correlation with end organ damage and outcome (Home)

Detection of white coat and masked HT

But what about costs?

Treatment – ↓drug costs

Follow up – ↓clinician costs

But do additional costs of ABPM out weigh

these?

Is ABPM cost effective?

Modelling to evaluate the most cost-effective

method of confirming a diagnosis of

hypertension in a population suspected of

having hypertension

ABPM vs Home vs clinic

Further details Lovibond et al, Lancet 2011

Markov Model

Health service perspective Lifetime horizon Assume all have raised clinic screening People aged 40 and over

Markov Model

Costs from published sources and NHS Test performance from systematic review Risk calculated using Framingham equation

Results

ABPM most cost effective for every age group

Results

ABPM most cost effective for every age group

Robust to wide range of sensitivity analyses

Results – sensitivity analysis

Results

ABPM most cost effective for every age group

Robust to wide range of sensitivity analyses

Sensitive to

– Assumption of equal test performance

– Assumption of no effect of Rx below

140/90 mmHg

ABPM

Don’t forget ABPM need to be validated and have yearly calibration (bhsoc.org.uk website)

Lack of night time dipping is additional risk (hence rationale for night readings)

Currently limited in PC as most practices either need to refer or only have one ABPM machine

Commissioners need to consider whole health economy

Self Monitoring reduces BP

Bray et al. Annals of Medicine 2010

Small reductions in

blood pressure from

self-monitoring:

– SBP by 3.8 mmHg

– DBP by 1.5 mmHg

Self monitoring costs equivalent to usual care

BMJ 2005;331;493

How many measurements?

Conclusion = at least 4 days monitoring and discard 1st

European (& UK) Guideline is 1 week, 2 readings bd,

discard day 1, take mean (limited rationale)

What is the place of home monitoring?

Management after diagnosis, especially if proven significant white coat effect

More outcome and test performance data needed for diagnosis

Adjunct to other co-interventions and self management...

Co-interventions enhance self monitoring effect

Weighted Mean diff.-30 -15 0 15 30

Study % Weight Weighted Mean diff. (95% CI)

-10.10 (-20.61,0.41) Mehos (2000) 5.4

-9.30 (-11.80,-6.80) Green b (2008) 15.3

-4.40 (-10.52,1.72) Zillich (2005) 9.9

-2.00 (-16.33,12.33) Broege(2001) 3.4

-25.60 (-41.78,-9.42) Artinian (2001) 2.8

-8.50 (-14.16,-2.84) Rudd (2004) 10.5

-3.40 (-5.91,-0.89) Green a (2008) 15.2

-0.20 (-3.84,3.44) Parati (2009) 13.6

-5.00 (-10.45,0.45) Mulhauser (1993) 10.8

-0.90 (-4.98,3.18) Freidman (1996) 12.9

-5.29 (-8.26,-2.32) Overall (95% CI)

5.3 mmHg

2.5 mmHg

Weighted Mean diff.-30 -15 0 15 30

Study % Weight Weighted Mean diff. (95% CI)

-0.14 (-2.05,1.77) Baque (2005) 15.3

5.00 (-6.07,16.07) Bailey (1999) 2.5

0.50 (-3.65,4.65) Verberk (2007) 9.8

-18.00 (-27.13,-8.87) Binstock (1988) 3.5

-2.30 (-5.47,0.87) McManus (2005) 12.1

-4.60 (-9.01,-0.19) Marquez-Contreras (2006) 9.2

-2.60 (-7.26,2.06) Midanik (1991) 8.7

-3.30 (-6.77,0.17) Soghikan (1992) 11.3

-0.50 (-3.07,2.07) Vetter (2000) 13.6

-3.10 (-7.93,1.73) Halme (2005) 8.4

-7.50 (-14.28,-0.72) Carnaham (1975) 5.5

-2.52 (-4.43,-0.61) Overall (95% CI)

What’s a co-intervention?

Nurses

Telemonitoring

Patient Education

Self Management

Theoretical basis for self management

Patients Increased patient involvement in management

decisions will result in:

Cues to action Adherence

Increased self efficacy Behaviour change Better use of medication likely to have most effect

Professionals Systematic titration of medication effective Evidence of clinical inertia

TASMINH2 Research Questions

Does self management with telemonitoring and titration of antihypertensive medication by people with poorly controlled treated hypertension result in:1. Better control of blood pressure?2. Changes in reported adverse events or

health behaviours or costs?3. Is it achievable in routine practice and is it

acceptable to patients?

The Trial Eligibility

– Age 35-85– Treated hypertension (no more than 2 BP meds)– Baseline BP >140/90 mmHg– Willing to self monitor and self titrate medication

Patients individually randomised to self-management vs usual care stratified by practice and minimised on sex, baseline SBP, DM status,

Practice GPs determine management

Intervention Self Monitoring – 1st week of every month

Intervention

Blood Pressure Targets: – NICE (140/90 or 140/80

mmHg)– minus 10/5 mmHg

i.e. 130/85 mmHg or 130/75 mmHg

Patients agreed titration schedule with their GP after randomisation

Traffic Light system to adjust medication

Outcomes

Follow up at 6 & 12 months Main outcome Systolic Blood Pressure Secondary outcomes: Diastolic BP / costs /

anxiety / health behaviours/ patient preferences / systems impact

Recruitment target 480 patients (240 x 2) Sufficient to detect 5mmHg difference

between groups

ResultsInvited (n = 7637)

Declined Invitation (n = 5987)

Assessed for eligibility (n = 1650)

Excluded (n = 1123) Not Eligible (n = 1044) Declined to participate (n=79)

Control (n = 264)Received usual care

(n = 264)

Randomised (n = 527)

Analysed (n = 246)Incomplete cases excluded

(n = 18)

Did not attend follow up (n=14)*

Discontinued usual care (n = 0)

Intervention (n = 263)Received intervention

training (n = 241)

Did not attend follow up (n=26)#

Discontinued intervention (n = 53)

Analysed (n = 234)Incomplete cases excluded

(n = 29)

110% recruitment

91% follow up

80% completed intervention

Baseline Results

Results - primary outcome SBP

Results – secondary outcomes DBP

Results - subgroups

Results - medications

212 (80%) self managed for full 12 months

148 (70%) made at least one

medication change

At 12m intervention group prescribed

0.46 (0.34, 0.58) additional antiHT (p=0.001)

Main changes seen in thiazides and

calcium channel blockers

(60% on ACEI/ARB at baseline)

Results – side effects

Similar side effects in intervention vs control

Treatment targets Observational data shows that achieved

blood pressure correlates with CVD outcome Wald meta analysis suggests that treatment

effects similar regardless of baseline– But low baseline BP trials almost exclusively

secondary prevention

Treatment targets

Little convincing benefit from lower than 140/90 mmHg target in uncomplicated HT

Evidence for systolic targets sparse Note reduced targets if out of office measure

What about old people?

Meta analysis – 6701 patients; mean FU 3.5 yrs; mean entry SBP 175Target 150 mmHg systolic; Mean reduction SBP around 12mmHgJournal of Hypertension 2010, 28:1366–1372

Bottom Line Consider enhanced use of out of office

measurement, especially for diagnosis Ambulatory monitoring for diagnosis is cost

effective due to better targeting of treatment Home monitoring useful for ongoing management Patients can do it too! 140/90 mmHg best evidence target unless

secondary prevention or over 80