Mm Hg Difference In Systolic Blood Pressure Research Articles

The Impact of APOL1 on Chronic Kidney Disease and Hypertension.

Essential hypertension is a clinical diagnosis based on the presence of an elevated systemic blood pressure on physical examination without a clear inciting cause. It has multiple etiologies and is not a homogeneous disorder. Hypertension contributes to the development and progression of atherosclerotic cardiovascular diseases, and antihypertensive treatment reduces the risk of fatal and nonfatal myocardial infarction, stroke, and congestive heart failure. Although hypertension is frequently present in nondiabetic individuals with low levels of proteinuria and chronic kidney disease, reducing blood pressures in this population does not reliably slow nephropathy progression. Many of these patients with recent African ancestry have the primary kidney disease "solidified glomerulosclerosis" that is strongly associated with renal-risk variants in the apolipoprotein L1 gene (APOL1). This kidney disease contributes to secondarily elevated blood pressures. The APOL1-associated spectrum of nondiabetic nephropathy also includes proteinuric kidney diseases, idiopathic focal segmental glomerulosclerosis, collapsing glomerulopathy, severe lupus nephritis, and sickle cell nephropathy. This article reviews relationships between mild to moderate essential hypertension and chronic kidney disease with a focus on the role of APOL1 in development of hypertension. Available evidence strongly supports that APOL1 renal-risk variants associate with glomerulosclerosis in African Americans, which then causes secondary hypertension, not with essential hypertension per se.

Abstract MP19: Can Clinical Measurements of Blood Pressure Replace Research-based Measurements?

Introduction: There is growing interest in embedding research protocols into clinical practice, including use of electronic health records (EHR) for measures of blood pressure (BP). However, the accuracy and reliability of EHR-derived BP compared to research-based BP are unknown. Hypothesis: We hypothesized EHR-derived measurements would overestimate systolic BP (SBP) and have higher variance compared to research measurements. Methods: We analyzed EHR-derived BP and research BP measurements in participants from a randomized trial, Five+ Nuts and Beans. EHR-derived measurements were made following the implementation of a standardized BP protocol, including the use of automated devices, clinical training, and systems support, to enhance the quality of clinic BP measurements. EHR-derived SBP measurements and change in SBP, calculated from closest clinic visits prior to the start and after the end of the trial period, were compared with measures obtained in the research setting. Results: Participants were 87% female (107 of 123); mean age was 58.6±9.7 yrs. Of the 123 participants, 118 had at least one primary care visit within 6 months of the research period. EHR-derived SBP were higher and more variable than research measurements, though these differences were attenuated for visits occurring within 7 days of research measurements (Table 1). EHR-based change in SBP was also more variable (SD=19.6) than research-based change (SD=14.0); using these SD’s, we estimate that a 2-arm trial conducted with clinic measurements would need to enroll 95% more participants (324 vs 166) to detect a 5 mmHg difference in SBP at a power of 0.9. Conclusions: Despite implementation of a standardized BP protocol, clinic measurements of SBP were higher and more variable than research protocol-based measurements. These results suggest that, in clinical trials, use of BP measurements obtained in clinical care, even if standardized, will reduce power and require greater sample size compared to measurements obtained in research settings.

Emerging Risk Factors for Stroke: What Have We Learned From Mendelian Randomization Studies?

Establishing new approaches for the prevention and treatment of stroke relies on identifying modifiable risk factors that contribute to the development of this complex disease. Mendelian randomization (MR) studies, analogous to naturally occurring randomized trials, can assess causality of potentially modifiable biomarkers and offer new insights into biological pathways. Stroke is the second leading cause of death worldwide and the chief determinant of long-term disability. Stroke is a heterogeneous disease arising from several distinct underlying pathologies and is typically classified as ischemic or hemorrhagic, and further subclassified using imaging data. Ischemic stroke (IS), including its 3 main subtypes: small vessel disease, large vessel disease, and cardioembolic stroke, accounts for ≈80% of stroke and is the result of an interrupted blood supply, leading to localized areas of ischemia in the brain. Small vessel disease may be a consequence of nonatherosclerotic, as well as atherosclerotic, mechanisms that result in an occlusion of the small perforating arteries, whereas large vessel disease results from occlusions or emboli from plaque rupture in larger vessels, such as a carotid artery. Cardioembolic stroke arises typically from emboli from the heart. By contrast, hemorrhagic stroke is a consequence of intracerebral hemorrhage (bleeding into the brain) or subarachnoid hemorrhage (bleeding into the subarachnoid space). These diverse stroke subtypes have distinct underlying pathologies reflecting different risk factor distributions. MR studies, using genetic variants as instrumental variables, afford a powerful approach to assessing causality of risk factors and avoid biases inherent in observational studies, including confounding and reverse causation. This review considers the contribution of MR studies to stroke epidemiology and their relevance to understanding risk factors and new therapeutic targets for stroke. Meta-analyses of large prospective studies have enhanced our knowledge of classical and emerging risk factors for stroke.1–4 Classical risk factors for stroke include nonmodifiable characteristics, …

The QICKD study protocol: a cluster randomised trial to compare quality improvement interventions to lower systolic BP in chronic kidney disease (CKD) in primary care

BackgroundChronic kidney disease (CKD) is a relatively newly recognised but common long-term condition affecting 5 to 10% of the population. Effective management of CKD, with emphasis on strict blood pressure (BP) control, reduces cardiovascular risk and slows the progression of CKD. There is currently an unprecedented rise in referral to specialist renal services, which are often located in tertiary centres, inconvenient for patients, and wasteful of resources. National and international CKD guidelines include quality targets for primary care. However, there have been no rigorous evaluations of strategies to implement these guidelines. This study aims to test whether quality improvement interventions improve primary care management of elevated BP in CKD, reduce cardiovascular risk, and slow renal disease progressionDesignCluster randomised controlled trial (CRT)MethodsThis three-armed CRT compares two well-established quality improvement interventions with usual practice. The two interventions comprise: provision of clinical practice guidelines with prompts and audit-based education.The study population will be all individuals with CKD from general practices in eight localities across England. Randomisation will take place at the level of the general practices. The intended sample (three arms of 25 practices) powers the study to detect a 3 mmHg difference in systolic BP between the different quality improvement interventions. An additional 10 practices per arm will receive a questionnaire to measure any change in confidence in managing CKD. Follow up will take place over two years. Outcomes will be measured using anonymised routinely collected data extracted from practice computer systems. Our primary outcome measure will be reduction of systolic BP in people with CKD and hypertension at two years. Secondary outcomes will include biomedical outcomes and markers of quality, including practitioner confidence in managing CKD.A small group of practices (n = 4) will take part in an in-depth process evaluation. We will use time series data to examine the natural history of CKD in the community. Finally, we will conduct an economic evaluation based on a comparison of the cost effectiveness of each intervention.Clinical Trials RegistrationISRCTN56023731. ClinicalTrials.gov identifier.

Reproducibility of 24-hour non-invasive ambulatory blood pressure monitoring using the Suntech Accutracker.

1. The reproducibility of 24-hour non-invasive ambulatory blood pressure monitoring (ABPM) using the 'Accutracker' (AC) (Suntech Medical Instruments, NC) was determined to evaluate the AC's suitability for clinical trials investigating the effects of environmental determinants on blood pressure. 2. Six healthy males from the University Department of Medicine underwent 24 h ABPM on the same working day of the week on six occasions. Reproducibility of hourly mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) was determined using analysis of variance. 3. No familiarization effect of measurement with the AC was detected. 4. When comparing four time periods (0000-0759 h, 0800-1259 h, 1300-1859 h and 1900-2359 h), reproducibility of SBP was highest during the afternoon (1300-1859 h) whereas reproducibility of DBP was highest during late morning (0800-1259 h). 5. Hourly mean SBP was significantly lower during late morning (0800-1259 h) than in the afternoon (1300-1859 h) or at night (1900-2359 h). Hourly mean SBP and DBP was significantly lower during sleep. 6. Based on a select sample of volunteers, the AC is suitable for clinical trials involving paired measurements, particularly between 0800 and 1900 h when only 10-15 subjects would provide 80% power to demonstrate a 5 mmHg difference in SBP and DBP significant at the 0.05 level.