Decision to treat mild hypertension after assessment by ambulatory monitoring and World Health Organisation recommendations

Daily usage and efficiency of remote home monitoring in hypertensive patients over a one-year period

We evaluated daily self-monitored blood pressure (BP) data collected over one year using remote home monitoring. Fifty treated, moderately hypertensive subjects (26 males, mean age 50 years; 17 females, mean age 54 years; seven exclusions) were recruited for the study in which semi-automatic arm-cuff BP measurement devices were used. The daily self-monitoring regimen had two phases of usage: one of initial enthusiasm (the first one to two months) followed by a phase of lower usage (89% versus 64%, P<0.01). Monitoring was missed more often (P < 0.01) during weekends (7.3 instances per patient) compared with workdays (5.0). Lack of motivation was not considered to be a major barrier. Approximately half of the study population was willing to continue the trial at the end of the one-year study. The occurrence of extreme BP values dropped significantly after the initial study month (P = 0.02). In conclusion, routine remote BP monitoring is capable of collecting consistent and accurate data, with sufficient sensitivity to reveal trends.

Relationship between ambulatory blood pressure and follow-up clinic blood pressure in elderly patients with systolic hypertension

BACKGROUND

Patients with elevated clinic blood pressure and normal ambulatory blood pressure have a better prognosis than patients with sustained ambulatory hypertension, and may not have to be treated with antihypertensive drugs. On the contrary, current guidelines emphasize repeated clinic blood pressure measurements for the initiation of antihypertensive therapy.

OBJECTIVE

To examine the relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up in untreated hypertensive patients, and the relationships of these pressures with the subsequent incidence of cardiovascular events.

METHODS

Patients who were > or = 60 years old, with systolic clinic blood pressure of 160-219 mmHg and diastolic pressure < 95 mmHg, participated in the Systolic Hypertension in Europe trial. The relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up was examined in 295 patients enrolled in the Ambulatory Blood Pressure Monitoring substudy and randomized to the placebo arm, and who were still on double-blind treatment and not taking other antihypertensive drugs after 6 months follow-up.

RESULTS

Age averaged 70 +/- 6 years, 41% were men, and baseline daytime ambulatory blood pressure was 152 +/- 16/84 +/- 10 mmHg; clinic blood pressure decreased from 173 +/- 10/86 +/- 6 mmHg at baseline to 163 +/- 20/85 +/- 9 mmHg at month 6. Systolic daytime ambulatory blood pressure at baseline and systolic clinic blood pressure at month 6 were considered normal if < 140 mmHg. Of the 74 patients with normal systolic daytime ambulatory blood pressure at baseline, only seven (9.5%) had a normal systolic clinic blood pressure during follow-up. Conversely, of the 24 patients with normal follow-up clinic blood pressure, only seven (29%) had a normal systolic daytime ambulatory blood pressure at baseline. The incidence of cardiovascular events beyond the 6-month visit was significantly related to baseline ambulatory blood pressure but not to follow-up clinic pressure.

CONCLUSIONS

Baseline daytime ambulatory blood pressure and follow-up clinic blood pressure do not identify the same patients for antihypertensive treatment. Baseline ambulatory pressure is a better predictor of cardiovascular events than follow-up clinic pressure.

Maximizing the benefit of treatment in mild hypertension:three simple steps to improve diagnostic accuracy

BACKGROUND

Most patients only have three measurements of blood pressure before being labelled as hypertensive. This may lead to inaccurate classification, unnecessary treatment and dilution in treatment benefit for the population.

AIM

To examine the accuracy of current methods of diagnosing mild hypertension, and to explore ways to improving targeting of antihypertensive treatment without entailing lengthy observation.

DESIGN

Re-analysis of published data.

METHODS

We tested current diagnostic methods using the data for 3965 individuals who were followed for a year in the placebo arm of the MRC Mild Hypertension Trial. We calculated the proportion selected for treatment by current methods and the diagnostic accuracy, using average blood pressure beyond 6 months as representing 'true' long-term blood pressure. We examined the benefit of averaging blood pressures, of prolonging observation modestly and of estimating within-person blood pressure variability.

RESULTS

Prolonging observation to 3 months selects a smaller (by about 12%) proportion of the sample for treatment, a proportion similar to that defined as 'truly' hypertensive. The diagnostic accuracy of current methods is poor, with up to 69% discrepancy in classification. This discrepancy was improved by up to 18% in absolute terms by prolonging observation to 3 months and using average blood pressures. Identifying those individuals with low within-person variability allows marked improvement in the prediction of 'true' hypertension.

DISCUSSION

Although some inaccuracy in the diagnosis of hypertension is inevitable, observation for 3 months, averaging blood pressures and estimating within-person blood pressure variability can markedly improve upon current practice.

Diagnosis of hypertension using home or ambulatory blood pressure monitoring: comparison with the conventional strategy based on repeated clinic blood pressure measurements

OBJECTIVE

To investigate whether measurement of blood pressure at home (HBP) and by ambulatory monitoring (ABP) are reliable alternatives to the traditional strategy for the diagnosis of hypertension based on blood pressure measurement on repeated clinic visits (CBP).

DESIGN

Comparison of the diagnosis of hypertension based on HBP (on six workdays) or ABP monitoring (two occasions) with that based on CBP (five visits within 3 months).

SETTING

Outpatient hypertension clinic.

PARTICIPANTS

We enrolled 133 individuals with a diastolic CBP of 90-115 mmHg on the initial visit.

MAIN OUTCOME MEASURES

CBP, HBP and ABP values, and the diagnosis of hypertension.

RESULTS

Hypertension was diagnosed in 70, 63 and 56% of individuals using the CBP, ABP and HBP methods respectively (P = 0.04). Agreement in the diagnosis of hypertension between all three methods was found in 59% of individuals. Disagreement between CBP and ABP was found in 27%, between CBP and HBP in 29% and between ABP and HBP in 26% of individuals. The sensitivity, specificity and positive and negative predictive values of ABP to diagnose hypertension correctly were 76, 67, 85 and 53% respectively; for HBP the respective values were 69, 77, 88 and 51%. The same parameters for HBP compared with ABP in the detection of white-coat hypertension were 61, 79, 48 and 86% respectively.

CONCLUSIONS

Indiscriminate use of HBP or ABP monitoring in the evaluation of all individuals with high blood pressure will probably result in confusion and therefore should be discouraged. However, in the detection of white-coat hypertension, HBP appears to be useful as a screening test, which, if positive, requires confirmation with ABP monitoring.

Pressure for change: unresolved issues in blood pressure measurement

The use of mercury is likely to be prohibited within a few years and clinicians have not yet seriously considered what sphygmomanometers they will use, nor is authoritative advice available on alternative instruments. Doubts also surround the thorny question of cuff size. Most blood pressures are taken in assessing cardiovascular health, and serial consulting room measurements may not be the best way of doing this. What is the role of continuous ambulatory monitoring in routine care? What is the place of home monitoring by patients, now that accurate and easy-to-use electronic sphygmomanometers are available?

'Home hypertension': exploring the inverse white coat response

BACKGROUND

The classical 'white coat response' to blood pressure measurement has been studied thoroughly. However, little is known about patients showing a reverse pattern, i.e. who have lower blood pressure readings at the clinic than outside healthcare facilities.

AIM

To estimate the proportion of patients whose blood pressure levels as determined by self-measurements at home are higher than those taken at the clinic and to explore possible associations with demographic, clinical, and psychological variables.

METHOD

Patients consecutively attending (n = 214) an academic family medicine department in Toronto, Canada, were eligible. Subjects aged below 16 years and those on psychotropic or blood pressure-lowering agents were excluded. The clinic-home blood pressure difference (CHBPD) was calculated for each participating subject by subtracting home blood pressure from clinic blood pressure. Those who had negative values were compared with the rest of the sample.

RESULTS

A considerable proportion of patients had lower blood pressure at the clinic than at home (systolic, 34.6%; diastolic, 23.8%). These subjects did not differ from the rest of the sample with regard to age, sex, levels of education attained, immigration status, body mass index, experience of current symptoms, blood pressure levels, or psychological distress. However, in patients with a 'negative CHBPD', i.e. lower blood pressure at the clinic than at home, readings taken by an automatic, self-inflating device when still at the clinic were higher than in the rest of the sample.

CONCLUSION

The results point to measurement bias being at least partly responsible for higher blood pressure readings outside the clinic. Automatic measurement devices used for self/home blood pressure measurement seem to cause an alerting reaction analogous to the well-described 'white coat response'.

Do practice guidelines augment drug utilisation review?

Drug utilisation review (DUR) or drug use evaluation (DUE) studies or programmes are intended to detect and/or correct inappropriate drug use. Appropriateness can be assessed at 3 levels: (i) whether any medication is warranted, or whether either no therapy or nondrug therapy is preferred (level 1); (ii) assuming drug therapy is indicated, which of several alternative drugs is the preferred choice? (level 2); and (iii) appropriateness of the drug regimen, including dosage, duration, type and frequency of monitoring, and drug interactions (level 3). The traditional approach to DUR/DUE has been to begin the appropriateness evaluation after a drug is prescribed. However, changes in healthcare organisation provide the basis for a disease-management or health-maintenance approach to DUR/DUE, and practice guidelines afford a possible source for guiding such studies. We hypothesised that the latter approach to DUR/DUE would be more likely to result in evaluation of level 1 drug-therapy issues than the traditional DUR/DUE approach. We tested this hypothesis by reviewing 56 practice guidelines involving drug therapy and also reviewed research studies published from 1992 to 1996. We found that studies that used the traditional DUR/DUE approach were most likely to examine level 3 drug-therapy issues, never addressed level 1 issues, and typically evaluated adherence to provider- or study team-developed guidelines rather than published guidelines. In contrast, the disease- or health-management approach nearly always examined level 1 issues, seldom addressed level 3 issues, and almost always evaluated adherence to a published practice guideline. Regardless of the DUR/DUE approach, about 40% of studies evaluated level 2 issues. The guidelines themselves were much more likely to include recommendations about level 1 and level 2 issues than about level 3 issues; however, even when a guideline included level 2 or level 3 issues, studies of adherence to the guideline rarely assessed anything beyond level 1 issues. This suggests that guideline recommendations about level 2 and level 3 issues may be too imprecise for use in evaluative studies. The drug-information compendia, on the other hand, provide detailed recommendations about level 3 issues. Revision of drug compendia may be warranted to include recommendations about all levels of drug-therapy issues. The results of intervention studies to improve drug-therapy compliance with guidelines suggest that information provided at the time of prescribing, information presented by local health professionals and information provided with a large amount of provider contact may be more likely to demonstrate significant improvements in drug therapy. We conclude that practice guidelines are a useful resource for augmenting DUR/DUE but that challenges to optimising their use include whether they can be kept current, acceptable and accessible to providers.

Exercise blood pressure predicts mortality from myocardial infarction

Apparently healthy men (n=1999, 40 to 59 years old) were investigated from 1972 through 1975 to determine whether systolic blood pressure during bicycle ergometer exercise predicts morbidity and mortality from myocardial infarction beyond that of casual blood pressure taken after 5 minutes of supine rest. During a follow-up of 31 984 patient-years (average, 16 years), 235 subjects had myocardial infarctions, of which 143 were nonfatal and 92 were fatal. Exercise blood pressure was more strongly related than casual blood pressure to both morbidity and mortality from myocardial infarction. Among 520 men with casual systolic blood pressure = 140 mm Hg, 304 increased their systolic blood pressure to > or = 200 mm Hg during 6 minutes of exercise at an initial workload of 600 kpm/min. These 304 men had an excessive risk of myocardial infarction (18.8% versus 9.5% among the 1294 men with casual blood pressure < 140 mm Hg and exercise blood pressure < 200 mm Hg; P < .001). As many as 58% of those with myocardial infarction in this group died, compared with 33% (range, 26% to 35%) for all other groups (P=.0011), including those with casual blood pressure > or = 140 mm Hg and exercise blood pressure < 200 mm Hg. Thus, exercise blood pressure is a stronger predictor than casual blood pressure of morbidity and mortality from myocardial infarction, and an early rise in systolic blood pressure during exercise adds prognostic information about mortality from myocardial infarction among otherwise healthy middle-aged men with mildly elevated casual blood pressure. We suggest that blood pressure taken during standardized exercise testing may distinguish between severe and less severe hypertension.

Clinic blood pressure measurements and blood pressure load in the diagnosis of hypertension

We have retrospectively compared the blood pressure load derived from 24 hour ambulatory blood pressure monitoring in patients with all clinic blood pressure readings elevated with those with only some elevated pressures to establish whether clinic readings alone are good predictors of blood pressure status. Fifty-seven patients attending a district general hospital hypertension clinic who were not on anti-hypertensive treatment were selected. Between two and six clinic readings were taken over a period of 1-6 months. Forty out of 57 patients had at least one clinic diastolic blood pressure reading of < 90 mmHg and, of these, 14 (35%) had a high blood pressure load and 26 (65%) had a normal blood pressure load. Patients with all diastolic blood pressure readings > 90 mmHg totalled 17 and of these 11 (65%) had high load and six (35%) had normal load. Patients with clinic diastolic blood pressure > 90 mmHg were significantly more likely to be truly hypertensive on the basis of blood pressure load than if one or more clinic readings was below 90 mmHg (P < 0.05). Diastolic pressures have some predictive power as to the blood pressure status defined by blood pressure load, but even consistently raised diastolic pressures do not necessarily indicate hypertension. Likewise one or more clinic diastolic blood pressure < 90 mmHg does not assuredly indicate normotension. Twenty-four hour ambulatory blood pressure monitoring may have an increasingly important role in the assessment of hypertension.

1993 guidelines for the management of mild hypertension: memorandum from a WHO/ISH meeting

The present guidelines were prepared by the Guidelines Sub-Committee of the WHO/ISH (International Society of Hypertension) Mild Hypertension Liaison Committee. They represent the third revision of the WHO/ISH guidelines and were finalized after discussions at the Sixth WHO/ISH Meeting on Mild Hypertension in Chantilly, France, on 28-31 March 1993. The new guidelines discuss the cardiovascular risk in patients with hypertension, the definition and classification of mild hypertension, drug treatment (including the elderly) and non-drug measures, cost-effectiveness, and further research.