Diagnostic value and cost-benefit analysis of 24 hours ambulatory blood pressure monitoring in primary care in Portugal

Supine blood pressure—A clinically relevant determinant of vascular target organ damage in hypertensive patients

Night‐time blood pressure (BP) is an important predictor of cardiovascular outcomes. Its assessment, however, remains challenging due to limited accessibility to ambulatory BP devices in many settings, costs, and other factors. We hypothesized that BP measured in a supine position during daytime may perform similarly to night‐time BP when modeling their association with vascular hypertension‐mediated organ damage (HMOD). Data from 165 hypertensive patients were used who as part of their routine clinic workup had a series of standardized BP measurements including seated attended office, seated and supine unattended office, and ambulatory BP monitoring. HMOD was determined by assessment of kidney function and pulse wave velocity. Correlation analysis was carried out, and univariate and multivariate models were fitted to assess the extent of shared variance between the BP modalities and their individual and shared contribution to HMOD variables. Of all standard non‐24‐hour systolic BP assessments, supine systolic BP shared the highest degree of variance with systolic night‐time BP. In univariate analysis, both systolic supine and night‐time BP were strong determinants of HMOD variables. In multivariate models, supine BP outperformed night‐time BP as the most significant determinant of HMOD. These findings indicate that supine BP may not only be a clinically useful surrogate for night‐time BP when ambulatory BP monitoring is not available, but also highlights the possibility that unattended supine BP may be more closely related to HMOD than other BP measurement modalities, a proposition that requires further investigations in prospective studies.

Long-term cardiovascular risk of white-coat hypertension with normal night-time blood pressure values

BACKGROUND

The prognostic impact of white-coat hypertension (WCHT) is still a matter of debate and controversy. Night-time blood pressure (NBP) is related strongly to cardiovascular (CV) prognosis, but this has not been considered currently in the definition of WCHT.

PATIENTS AND METHODS

We investigated the long-term CV prognosis of 2659 patients submitted at admission to 24 h-ambulatory blood pressure (BP) monitoring divided into three groups: normotension (NT) (n=812; 59% female; ageing 49±13 years), sustained hypertension (SHT) (n=1230; 56% female; ageing 51±13 years) and WCHT (n=617; 55% female; ageing 50±3 years) defined as office BP of at least 140/90 mmHg, daytime BP less than 135/85 mmHg and NBP less than 120/70 mmHg.

RESULTS

The median follow-up was 7.6 years (range: 0.4-24.4), during which a total of 257 CV events (36 fatal) occurred (46% strokes, 32% coronary and 22% others), 38 in NT, 31 in WCHT and 188 in SHT. The event rate per 100 patient-years was 0.60 in the WCHT group, 0.66 in the NT group and 2.09 in the SHT group. Cox's regression analysis adjusted for covariables showed a higher risk of CV events in patients with SHT than WCHT [hazard ratio (HR)=2.230, 95% confidence interval: 1.339-3.716, P=0.002], whereas there was no difference between WCHT and NT groups. Event-free survival was significantly different from SH versus WCHT and NT groups. Within the group of WCHT, 29% of patients received sustained antihypertensive medication during the follow-up, but the HR of CV events between WCHT either treated or not treated did not differ: HR=0.76 (95% confidence interval: 0.37-1.51, P=0.42).

CONCLUSION

In patients with WCHT defined by normal daytime and NBP values, the risk of CV events was significantly lower than that of SHT and similar to that of NT patients, suggesting that NBP should be included in the WCHT definition and in its prognostic stratification.

Validity of ambulatory blood pressure monitoring in daily primary healthcare practice in France

OBJECTIVE

The objective of the study was to assess 24-h ambulatory blood pressure monitoring (ABPM) validity in daily primary healthcare practice in France.

PATIENTS AND METHODS

An observational, longitudinal, prospective, multicenter study was performed in the Burgundy region, France. Participants were patients who had been prescribed ABPM by their general practitioner (GP), whatever its indication. ABPM was performed by employees of the healthcare providers group, which is publicly funded. The validity of ABPM was established according to the European Society of Cardiology (ESC) criteria. GPs interpretation of the ABPM results was collected and compared with the ESC recommendations. Determinants of ABPM validity were identified using logistic regression models.

RESULTS

Among the 531 patients included, 357 (67.23%) had a valid ABPM measurement. Multivariate analyses showed that ABPM validity was associated with nonmanual worker status [odds ratio (OR)=1.14; 95% confidence interval (CI)=1.04-1.23], participant's age of at least 65 years (OR=0.88; 95% CI=0.81-0.95) and participant's BMI above 30 kg/m (OR=0.90; 95% CI=0.81-0.99). GPs' interpretation of ABPM results was consistent with the ESC recommendation in 508 (95.67%) cases.

CONCLUSION

ABPM is feasible in daily primary healthcare practice in the studied condition, that is to say relying on trained employees. GPs should be careful when prescribing ABPM to patients aged 65 years and older, to those with BMI over 30 or to manual workers.

Predicting Out-of-Office Blood Pressure in the Clinic for the Diagnosis of Hypertension in Primary Care: An Economic Evaluation

Clinical guidelines in the United States and United Kingdom recommend that individuals with suspected hypertension should have ambulatory blood pressure (BP) monitoring to confirm the diagnosis. This approach reduces misdiagnosis because of white coat hypertension but will not identify people with masked hypertension who may benefit from treatment. The Predicting Out-of-Office Blood Pressure (PROOF-BP) algorithm predicts masked and white coat hypertension based on patient characteristics and clinic BP, improving the accuracy of diagnosis while limiting subsequent ambulatory BP monitoring. This study assessed the cost-effectiveness of using this tool in diagnosing hypertension in primary care. A Markov cost-utility cohort model was developed to compare diagnostic strategies: the PROOF-BP approach, including those with clinic BP ≥130/80 mm Hg who receive ambulatory BP monitoring as guided by the algorithm, compared with current standard diagnostic strategies including those with clinic BP ≥140/90 mm Hg combined with further monitoring (ambulatory BP monitoring as reference, clinic, and home monitoring also assessed). The model adopted a lifetime horizon with a 3-month time cycle, taking a UK Health Service/Personal Social Services perspective. The PROOF-BP algorithm was cost-effective in screening all patients with clinic BP ≥130/80 mm Hg compared with current strategies that only screen those with clinic BP ≥140/90 mm Hg, provided healthcare providers were willing to pay up to £20 000 ($26 000)/quality-adjusted life year gained. Deterministic and probabilistic sensitivity analyses supported the base-case findings. The PROOF-BP algorithm seems to be cost-effective compared with the conventional BP diagnostic options in primary care. Its use in clinical practice is likely to lead to reduced cardiovascular disease, death, and disability.

Cost-effectiveness of ambulatory blood pressure monitoring in the management of hypertension

INTRODUCTION AND OBJECTIVES

The prevalence of hypertension in Portugal is between 29.1% and 42.2%. International studies show that 13% of individuals have masked hypertension and 13% of diagnoses based on office blood pressure measurements are in fact white coat hypertension. More sensitive and specific blood pressure measuring methods could avoid costs associated with misdiagnosis. The aim of this study was to review the cost-effectiveness of ambulatory blood pressure monitoring (ABPM) compared to other methods in the management of hypertension.

METHODS

We performed a literature search in CMA Infobase, Guidelines Finder, National Guideline Clearinghouse, Bandolier, BMJ Clinical Evidence, the Cochrane Library, DARE, Medline, the Trip Database, SUMSearch and Índex das Revistas Médicas Portuguesas. We researched articles published between January 2005 and August 2015 in Portuguese, English and Spanish, using the MeSH terms "Hypertension", "Blood Pressure Monitoring, Ambulatory" and "Cost-Benefit Analysis" and the Portuguese search terms "Hipertensão", "Monitorização Ambulatorial da Pressão Arterial" and "Análise Custo-Benefício". Levels of evidence and grades of recommendation were attributed according to the Oxford Centre for Evidence-Based Medicine scale.

RESULTS

Five hundred and twenty-five articles were identified. We included five original studies and one clinical practice guideline. All of them state that ABPM is the most cost-effective method. Two report better blood pressure control, and a Portuguese study revealed a saving of 23%.

CONCLUSIONS

The evidence shows that ABPM is cost-effective, avoiding iatrogenic effects and reducing expenditure on treatment (grade of recommendation B). The included studies provide a solid basis, but further evidence of reproducibility is needed in research that is not based mainly on analytical models.

Impact of Different Normality Thresholds for 24-hour ABPM at the Primary Health Care Level

Background

Hypertension is an important risk factor for cardiovascular outcomes. Primary health care (PHC) physicians should be prepared to act appropriately in the prevention of cardiovascular risk factors. However, the rates of patients with control of blood pressure (BP) remain low. The impact of the reclassification of high BP by 24-hour ambulatory BP monitoring (ABPM) can lead to different medical decisions in PHC.

Objective

To evaluate the agreement between the BP measured by a conventional method by PHC physicians and by 24-hour ABPM, considering different BP normal thresholds for the 24-hour ABPM according to the V Brazilian ABPM Guidelines and the European Society of Hypertension Guidelines.

Methods

A cross-sectional study including 569 hypertensive patients. The BP was initially measured by the PHC physicians and, later, by 24-hour ABPM. The BP measurements were obtained independently between the two methods. The therapeutic targets for the conventional BP followed the guidelines by the Eighth Joint National Committee (JNC 8), the V ABPM Brazilian Guidelines, and the 2013 European Hypertension Guidelines.

Results

There was an accuracy of 54.8% (95% confidence interval [95%CI] 0.51 - 0.58%) for the BP measured with the conventional method when compared with the 24-hour ABPM, with a sensitivity of 85% (95%CI 80.8 - 88.6%), specificity of 31.9% (95%CI 28.7 - 34.7%), and kappa value of 0.155, when considering the European Hypertension Guidelines. When using more stringent thresholds to characterize the BP as "normal" by ABPM, the accuracy was 45% (95%CI 0.41 - 0.47%) for conventional measurement when compared with 24-hour ABPM, with a sensitivity of 86.7% (95%CI 0.81 - 0.91%), specificity of 29% (95%CI 0.26 - 0.30%), and kappa value of 0.103.

Conclusion

The BP measurements obtained by PHC physicians showed low accuracy when compared with those obtained by 24-hour ABPM, regardless of the threshold set by the different guidelines.

Screening for high blood pressure in adults: U.S. Preventive Services Task Force recommendation statement

DESCRIPTION

Update of the 2007 U.S. Preventive Services Task Force (USPSTF) reaffirmation recommendation statement on screening for high blood pressure in adults.

METHODS

The USPSTF reviewed the evidence on the diagnostic accuracy of different methods for confirming a diagnosis of hypertension after initial screening and the optimal rescreening interval for diagnosing hypertension.

POPULATION

This recommendation applies to adults aged 18 years or older without known hypertension.

RECOMMENDATION

The USPSTF recommends screening for high blood pressure in adults aged 18 years or older. (A recommendation) The USPSTF recommends obtaining measurements outside of the clinical setting for diagnostic confirmation before starting treatment.

Clinical value of ambulatory blood pressure: Is it time to recommend for all patients with hypertension?

Hypertension is a very common disease, and office measurements of blood pressure are frequently inaccurate. Ambulatory Blood Pressure Monitoring (ABPM) offers a more accurate diagnosis, more detailed readings of average blood pressures, better blood pressure measurement during sleep, fewer false positives by detecting more white-coat hypertension, and fewer false negatives by detecting more masked hypertension. ABPM offers better management of clinical outcomes. For example, based on more accurate measurements of blood pressure variability, ABPM demonstrates that taking antihypertensive medication at night leads to better controlled nocturnal blood pressure, which translates into less end organ damage and fewer clinical complications of hypertension. For these reasons, albeit some shortcomings which were discussed, ABPM should be considered as a first-line tool for diagnosing and managing hypertension.

Diagnostic and predictive accuracy of blood pressure screening methods with consideration of rescreening intervals: a systematic review for the U.S. Preventive Services Task Force

BACKGROUND

Elevated blood pressure (BP) is the largest contributing risk factor to all-cause and cardiovascular mortality.

PURPOSE

To update a systematic review on the benefits and harms of screening for high BP in adults and to summarize evidence on rescreening intervals and diagnostic and predictive accuracy of different BP methods for cardiovascular events.

DATA SOURCES

Selected databases searched through 24 February 2014.

STUDY SELECTION

Fair- and good-quality trials and diagnostic accuracy and cohort studies conducted in adults and published in English.

DATA EXTRACTION

One investigator abstracted data, and a second checked for accuracy. Study quality was dual-reviewed.

DATA SYNTHESIS

Ambulatory BP monitoring (ABPM) predicted long-term cardiovascular outcomes independently of office BP (hazard ratio range, 1.28 to 1.40, in 11 studies). Across 27 studies, 35% to 95% of persons with an elevated BP at screening remained hypertensive after nonoffice confirmatory testing. Cardiovascular outcomes in persons who were normotensive after confirmatory testing (isolated clinic hypertension) were similar to outcomes in those who were normotensive at screening. In 40 studies, hypertension incidence after rescreening varied considerably at each yearly interval up to 6 years. Intrastudy comparisons showed at least 2-fold higher incidence in older adults, those with high-normal BP, overweight and obese persons, and African Americans.

LIMITATION

Few diagnostic accuracy studies of office BP methods and protocols in untreated adults.

CONCLUSION

Evidence supports ABPM as the reference standard for confirming elevated office BP screening results to avoid misdiagnosis and overtreatment of persons with isolated clinic hypertension. Persons with BP in the high-normal range, older persons, those with an above-normal body mass index, and African Americans are at higher risk for hypertension on rescreening within 6 years than are persons without these risk factors.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.