Disparities in Antihypertensive Prescribing After Stroke

Antihypertensive Medication Adherence and the Risk of Vascular Events and Falls After Stroke: A Real-World Effectiveness Study Using Linked Registry Data

BACKGROUND

Real-world evidence is limited on whether antihypertensive medications help avert major adverse cardiovascular events (MACE) after stroke without increasing the risk of falls. We investigated the association of adherence to antihypertensive medications on the incidence of MACE and falls requiring hospitalization after stroke.

METHODS

A retrospective cohort study of adults who were newly dispensed antihypertensive medications after an acute stroke (Australian Stroke Clinical Registry 2012-2016; Queensland and Victoria). Pharmaceutical dispensing records were used to determine medication adherence according to the proportion of days covered in the first 6 months poststroke. Outcomes between 6 and 18 months postdischarge included: (i) MACE, a composite outcome of all-cause death, recurrent stroke or acute coronary syndrome; and (ii) falls requiring hospitalization. Estimates were derived using Cox models, adjusted for >30 confounders using inverse probability treatment weights.

RESULTS

Among 4076 eligible participants (median age 68 years; 37% women), 55% had a proportion of days covered ≥80% within 6 months postdischarge. In the subsequent 12 months, 360 (9%) participants experienced a MACE and 337 (8%) experienced a fall requiring hospitalization. After achieving balance between groups, participants with a proportion of days covered ≥80% had a reduced risk of MACE (hazard ratio: 0.68; 95% CI: 0.54-0.84) and falls requiring hospitalization (subdistribution hazard ratio: 0.78; 95% CI: 0.62-0.98) than those with a proportion of days covered <80%.

CONCLUSIONS

High adherence to antihypertensive medications within 6 months poststroke was associated with reduced risks of both MACE and falls requiring hospitalization. Patients should be encouraged to adhere to their antihypertensive medications to maximize poststroke outcomes.

Long-Term Secondary Prevention: Management of Blood Pressure After a Transient Ischemic Attack or Stroke

Reducing blood pressure (BP) is a highly effective strategy for long-term stroke prevention. Despite overwhelmingly clear evidence from randomized trials that antihypertensive therapy substantially reduces the risk of stroke in primary prevention, uncertainty still surrounds the issue of BP lowering after cerebrovascular events, and the risk of recurrent stroke, coronary events, and vascular death remains significant. Important questions in a secondary prevention setting include should everyone be treated regardless of their poststroke BP, how soon after a stroke should BP-lowering treatment be commenced, how intensively should BP be lowered, what drugs are best, and how should long-term BP control be optimized and monitored. We review the evidence on BP control after a transient ischemic attack or stroke to address these unanswered questions and draw attention to some recent developments that hold promise to improve management of BP in current practice.

Cerebral hemodynamic effects of early blood pressure lowering after TIA and stroke in patients with carotid stenosis

BACKGROUND

Effects of early blood pressure (BP) lowering on cerebral perfusion in patients with moderate/severe occlusive carotid disease after transient ischemic attack (TIA) and non-disabling stroke are uncertain.

AIMS

We aimed to evaluate the changes in transcranial Doppler (TCD) indices in patients undergoing blood pressure lowering soon after TIA/non-disabling stroke.

METHODS

Consecutive eligible patients (1 November 2011 to 30 October 2018) attending a rapid-access clinic with TIA/non-disabling stroke underwent telemetric home blood pressure monitoring (HBPM) for 1 month and middle cerebral artery velocities measurements ipsilateral to carotid stenosis on TCD ultrasound in the acute setting and at 1 month. Hypertensive patients (HBPM ⩾ 135/85) underwent intensive BP-lowering guided by HBPM unless they had bilateral severe occlusive disease (⩾ 70%). Changes in BP and TCD parameters were compared in patients with extracranial moderate/severe carotid stenosis (between 50% and occlusion) versus those with no or mild (< 50%) stenosis.

RESULTS

Of 764 patients with repeated TCD measures, 42 had moderate/severe extracranial carotid stenosis without bilateral severe occlusive disease. HBPM was reduced from baseline to 1 month in hypertensive patients both with versus without moderate/severe carotid stenosis (-12.44/15.99 vs -13.2/12.2 mmHg, respectively, p-difference = 0.82), and changes in TCD velocities (4.69/14.94 vs 2.69/13.86 cm/s, respectively, p-difference = 0.52 for peak systolic velocity and 0.33/7.06 vs 1.75/6.84 cm/s, p-difference = 0.34 for end-diastolic velocity) were also similar, with no evidence of greater hemodynamic compromise in patients with stenosis/occlusion.

CONCLUSION

There was no evidence of worsening of TCD hemodynamic indices in patients with moderate/severe occlusive carotid disease treated with BP-lowering soon after TIA/non-disabling stroke, suggesting that antihypertensive treatment in this group of patients is safe in the acute setting of TIA clinics.

Age-specific cerebral haemodynamic effects of early blood pressure lowering after transient ischaemic attack and non-disabling stroke

INTRODUCTION

There is limited knowledge of the effects of blood pressure (BP) lowering on cerebral haemodynamics after transient ischaemic attack (TIA) and non-disabling stroke, particularly at older ages. We aimed to evaluate changes in transcranial Doppler (TCD) haemodynamic indices in patients undergoing early blood pressure lowering after TIA/non-disabling stroke, irrespective of age.

PATIENTS AND METHODS

Among consecutive eligible patients attending a rapid-access clinic with suspected TIA/non-disabling stroke and no evidence of extra/intracranial stenosis, hypertensive ones underwent intensive BP-lowering guided by daily home telemetric blood pressure monitoring (HBPM). Clinic-based BP, HBPM, End-tidal CO2 and bilateral middle cerebral artery (MCA) velocity on TCD were compared in the acute setting versus one-month follow-up; changes were stratified by baseline hypertension (clinic-BP≥140/90) and by age (<65, 65-79 and ≥80).

RESULTS

In 697 patients with repeated TCD measures, mean/SD baseline systolic-BP (145.0/21.3 mmHg) was reduced by an average of 11.3/19.9 mmHg (p < 0.0001) at one-month (133.7/17.4 mmHg), driven by patients hypertensive at baseline (systolic-BP change = -19.0/19.2 mmHg, p < 0.001; vs -0.5/15.4, p = 0.62 in normotensives). Compared with baseline, a significant change was observed at one-month only in mean/SD MCA end diastolic velocity (EDV) (0.77/7.26 cm/s, p = 0.005) and in resistance index (RI) (-0.005/0.051, p = 0.016), driven by hypertensive patients (mean/SD EDV change: 1.145/6.96 cm/s p = 0.001, RI change -0.007/0.06, p = 0.014). Findings were similar at all ages (EDV change - ptrend=0.357; RI change - ptrend=0.225), including 117 patients aged ≥80. EDV and RI changes were largest in 100 patients with clinic systolic-BP decrease ≥30 mmHg (mean/SD EDV change = 2.49/7.47 cm/s, p = 0.001; RI change -0.024/0.063, p < 0.0001).

CONCLUSION

There was no evidence of worsening of TCD haemodynamic indices associated with BP-lowering soon after TIA/non-disabling stroke, irrespective of age and degree of BP reduction. In fact, EDV increase and RI decrease observed after treatment of hypertensive patients suggest a decrease in distal vascular resistance.

Trends in Antihypertensive Medication Use Among Individuals With a History of Stroke and Hypertension, 2005 to 2016

Importance

Hypertension is a well-established, modifiable risk factor for stroke. National hypertension management trends among stroke survivors may provide important insight into secondary preventive treatment gaps.

Objective

To investigate the adequacy of blood pressure control among stroke survivors and antihypertensive treatment trends using National Health and Nutrition Examination Survey (NHANES) data.

Design, Setting, and Participants

Cross-sectional surveys conducted between 2005 and 2016 of nationally representative samples of the civilian US population were analyzed from March 2019 to January 2020. The NHANES is a large, nationally representative cross-sectional survey conducted in 2-year cycles in the United States. Evaluations include interviews, medication lists, physical examinations, and laboratory tests on blood samples. Among 221 982 140 adults 20 years or older in the NHANES from 2005 through 2016, a total of 4 971 136 had stroke and hypertension and were included in this analysis, with 217 011 004 excluded from the primary analysis.

Exposures

Hypertension was defined by self-report, antihypertensive medication use, or uncontrolled blood pressure (>140/90 mm Hg) on physical examination. Antihypertensive medication was classified as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, diuretics, β-blockers, calcium channel blockers, or other.

Main Outcomes and Measures

Weighted frequencies and means were reported using NHANES methods, estimating the proportion of individuals with stroke and hypertension. For all other analyses, 4 971 136 individuals with stroke and hypertension were examined, summarizing number and classes of antihypertensive medications, frequency of uncontrolled hypertension, and associations between antihypertensive classes and blood pressure control. Trends in antihypertensive medication use over time were examined.

Results

Among 4 971 136 individuals with a history of stroke and hypertension, the mean age was 67.1 (95% CI, 66.1-68.1) years, and 2 790 518 (56.1%) were women. In total, 37.1% (33.5%-40.8%) had uncontrolled blood pressure on examination, with 80.4% (82.0%-87.5%) taking antihypertensive medication. The most commonly used antihypertensive medications were angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (59.2%; 95% CI, 54.9%-63.4%) and β-blockers (43.8%; 95% CI, 40.3%-47.3%). Examining trends over time, diuretics have become statistically significantly less commonly used (49.4% in 2005-2006 vs 35.7% in 2015-2016, P = .005), with frequencies of other antihypertensive classes remaining constant.

Conclusions and Relevance

In this cross-sectional study that used national survey data, substantial undertreatment of hypertension was found in individuals with a history of stroke, and more than one-third had uncontrolled hypertension. Because hypertension is a major risk factor for stroke, these data demonstrate a missed opportunity nationally for secondary stroke prevention.

A Versatile Big Data Health System for Australia: Driving Improvements in Cardiovascular Health

Cardiovascular diseases (CVD) are leading causes of death and morbidity in Australia and worldwide. Despite improvements in treatment, there remain large gaps in our understanding to prevent, treat and manage CVD events and associated morbidities. This article lays out a vision for enhancing CVD research in Australia through the development of a Big Data system, bringing together the multitude of rich administrative and health datasets available. The article describes the different types of Big Data available for CVD research in Australia and presents an overview of the potential benefits of a Big Data system for CVD research and some of the major challenges in establishing the system for Australia. The steps for progressing this vision are outlined.

Regional differences in the care and outcomes of acute stroke patients in Australia: an observational study using evidence from the Australian Stroke Clinical Registry (AuSCR)

OBJECTIVE

To compare the processes and outcomes of care in patients who had a stroke treated in urban versus rural hospitals in Australia.

DESIGN

Observational study using data from a multicentre national registry.

SETTING

Data from 50 acute care hospitals in Australia (25 urban, 25 rural) which participated in the Australian Stroke Clinical Registry during the period 2010-2015.

PARTICIPANTS

Patients were divided into two groups (urban, rural) according to the Australian Standard Geographical Classification Remoteness Area classification. Data pertaining to 28 115 patients who had a stroke were analysed, of whom 8159 (29%) were admitted to hospitals located within rural areas.

PRIMARY AND SECONDARY OUTCOME MEASURES

Regional differences in processes of care (admission to a stroke unit, thrombolysis for ischaemic stroke, discharge on antihypertensive medication and provision of a care plan), and survival analyses up to 180 days and health-related quality of life at 90-180 days.

RESULTS

Compared with those admitted to urban hospitals, patients in rural hospitals less often received thrombolysis (urban 12.7% vs rural 7.5%, p<0.001) or received treatment in stroke units (urban 82.2% vs rural 76.5%, p<0.001), and fewer were discharged with a care plan (urban 61.3% vs rural 44.7%, p<0.001). No significant differences were found in terms of survival or overall self-reported quality of life.

CONCLUSIONS

Rural access to recommended components of acute stroke care was comparatively poorer; however, this did not appear to impact health outcomes at approximately 6 months.

Age-Related Disparities in the Quality of Stroke Care and Outcomes in Rehabilitation Hospitals: The Australian National Audit

INTRODUCTION

Stroke affects all ages. Despite increased incidence in those <65 years, little is known about age-based differences in inpatient rehabilitation management and outcomes.

OBJECTIVES

To investigate management and outcomes, comparing younger (<65 years) and older (≥65 years) patients with stroke, who received inpatient rehabilitation.

METHODS

Multicentre, cross-sectional study using data from Australian hospitals who participated in the Stroke Foundation national stroke rehabilitation audit (2016-2018). Chi-square tests compared characteristics and care by age. Multivariable regression models were used to compare outcomes by age (e.g. length of stay). Models were adjusted for sex, stroke type and severity factors.

RESULTS

7,165 audited cases from 127 hospitals; 23% <65 years (66% male; 72% ischaemic stroke). When compared to older patients, younger patients were more likely male (66% vs 52%); identify as Aboriginal or Torres Strait Islander (6% vs 1%); be less disabled on admission; receive psychology (46% vs 34%) input, and community reintegration support, including return to work (OR 1.47, 95% CI 1.03, 2.11), sexuality (OR 1.60, 95% CI 1.39, 1.84) and self-management (OR 1.39, 95% CI 1.23, 1.57) advice. Following adjustment, younger patients had longer lengths of stay (coeff 3.54, 95% CI 2.27, 4.81); were more likely to be independent on discharge (aOR 1.96, 95% CI 1.68, 2.28); be discharged to previous residences (aOR 1.64, 95% CI 1.41, 1.91) and receive community rehabilitation (aOR: 2.27, 95% CI 1.91, 2.70).

CONCLUSIONS

Age-related differences exist in characteristics, management and outcomes for inpatients with stroke accessing rehabilitation in Australia.

Prescription of blood pressure lowering treatment after intracerebral haemorrhage: Prospective, population-based cohort study

Introduction

Blood pressure (BP) lowering reduces the risk of recurrent stroke after intracerebral haemorrhage (ICH). However, implementation of BP lowering in clinical practice in the UK is unknown.

Patients and methods

We identified adults with first-ever incident ICH to quantify the proportion who survived >14 days after hospital discharge and were prescribed BP-lowering medication in a prospective, population-based, inception cohort study in the Lothian region of Scotland during June 2010–May 2012 and January–December 2019. After the first cohort, we analysed reasons for avoiding BP-lowering medication in a sample from the Lothian region of the Scottish Stroke Care Audit during January 2017–November 2017, which informed a quality improvement intervention that was implemented in the second cohort.

Results

After efforts to improve monitoring and lowering of BP amongst ICH survivors, there was an increase in the proportion of patients prescribed BP-lowering medication at hospital discharge between the first and second population-based cohorts (81/130 [62%] vs. 68/89 [76%]; P = 0.028). Compared with patients not prescribed BP-lowering medication at hospital discharge, patients prescribed BP-lowering medication presented with higher systolic BP (177 vs. 156 mm Hg, P = 0.002 and 180 vs. 149 mm Hg, P < 0.001, in the first and second population-based cohorts, respectively), and were more likely to have pre-morbid hypertension (85% vs. 33%, P < 0.001 and 72% vs. 29%, P < 0.001) and atrial fibrillation (35% vs. 4%, P < 0.001 and 26% vs. 5%, P < 0.034).

Conclusion

In this population-based study, the proportion of patients with ICH who were prescribed BP-lowering medication at hospital discharge increased after a quality improvement intervention.

Patterns of Use and Discontinuation of Secondary Prevention Medications After Stroke

OBJECTIVE

To investigate whether certain patient, acute care, or primary care factors are associated with medication initiation and discontinuation in the community after stroke or TIA.

METHODS

This is a retrospective cohort study using prospective data on adult patients with first-ever acute stroke/TIA from the Australian Stroke Clinical Registry (April 2010 to June 2014), linked with nationwide medication dispensing and Medicare claims data. Medication users were those with ≥1 dispensing in the year postdischarge. Discontinuation was assessed among medication users and defined as having no medication supply for ≥90 days in the year postdischarge. Multivariable competing risks regression, accounting for death during the observation period, was conducted to investigate factors associated with time to medication discontinuation.

RESULTS

Among 17,980 registry patients with stroke/TIA, 91.4% were linked to administrative datasets. Of these, 9,817 adults with first-ever stroke/TIA were included (45.4% female, 47.6% aged ≥75 years, and 11.4% intracerebral hemorrhage). While most patients received secondary prevention medications (79.3% antihypertensive, 81.8% antithrombotic, and 82.7% lipid-lowering medication), between one-fifth and one-third discontinued treatment over the subsequent year postdischarge (20.9% antihypertensive, 34.1% antithrombotic, and 28.5% lipid-lowering medications). Prescription at hospital discharge (sub-hazard ratio [SHR] 0.70; 95% confidence interval [CI] 0.62-0.79), quarterly contact with a primary care physician (SHR 0.62; 95% CI 0.57-0.67), and prescription by a specialist physician (SHR 0.87; 95% CI 0.77-0.98) were all inversely associated with antihypertensive discontinuation.

CONCLUSIONS

Patterns of use of secondary prevention medications after stroke/TIA are not optimal, with many survivors discontinuing treatment within 1 year postdischarge. Improving postdischarge care for patients with stroke/TIA is needed to minimize unwarranted discontinuation.