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 Low Risk 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.

Routine measurement is often flawed Same population with routine and research measurement

Blood Pressure varies through the day and between seasons Hypertension. 2006;47:

Multiple measurements better estimate mean blood pressure

This variability means that measurement error can drown out the truth

Even on a single occasion BP drops  Approx 1500 patients  24 practices  6 readings at 1min intervals  12 mmHg systolic drop  Stable after 5 th reading

Family Practice 1997; 14: BP takes some time to settle with repeated measurement over weeks/months

Many factors affect BP measurement BMJ 2001;322;

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 ABPM  Other 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: /bmj.d3621

Many people currently potentially misdiagnosed... Worse if only studies around diagnostic threshold used: sensitivity of 86% and specificity 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 1 st 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 5.3 mmHg 2.5 mmHg

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 efficacyBehaviour 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 –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 – 1 st 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

Results Invited (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 175 Target 150 mmHg systolic; Mean reduction SBP around 12mmHg Journal 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