Effect of Allopurinol on Blood Pressure: A Systematic Review and Meta‐Analysis

J Clin Hypertens (Greenwich). 2013; 15:435–442 ©2012 Wiley Periodicals, Inc. Allopurinol is a potent xanthine oxidase inhibitor that is used in hyperuricemic patients to prevent gout. It has also been shown to decrease cardiovascular complications in a myriad of cardiovascular conditions. However, studies have reported conflicting evidence on its effects on blood pressure (BP). A systematic review was conducted using Medline, PubMed, Embase, and the Cochrane Library for all the longitudinal studies that assessed the efficacy of allopurinol on systolic and diastolic BP. A total of 10 clinical studies with 738 participants were included in the analysis. Compared with the control group, systolic BP decreased by 3.3 mm Hg (95% confidence interval [CI], 1.4–5.3 mm Hg; P=.001) and diastolic BP decreased by 1.3 mm Hg (95% CI, 0.1–2.5 mm Hg; P=.03) in patients treated with allopurinol. When analysis was restricted to the higher‐quality randomized controlled trials, similar changes in systolic and diastolic BPs were found: 3.3 mm Hg (95% CI, 0.8–5.8 mm Hg; P<.001) and 1.4 mm Hg (95% CI, 0.1–2.7 mm Hg; P=.04), respectively. Allopurinol is associated with a small but significant reduction in BP. This effect can be potentially exploited to aid in controlling BP in hypertensive patients with hyperuricemia.     

The effect of magnesium supplementation on blood pressure: a meta-analysis of randomized clinical trials

BACKGROUND: An increased intake of magnesium might lower blood pressure (BP), yet evidence from clinical trials is inconsistent, perhaps as a result of small sample size or heterogeneity in study design. METHODS: We performed a meta-analysis of randomized trials that tested the effects of magnesium supplementation on BP. Twenty trials meeting the inclusion criteria were identified. Random effects models and meta-regression methods were used to pool study results and to determine the dose-response relationship of magnesium to BP. RESULTS: The 20 studies included 14 of hypertensive and 6 of normotensive persons totaling 1220 participants. The doses of magnesium ranged from 10 to 40 mmol/day (median, 15.4 mmol/day). Magnesium supplementation resulted in only a small overall reduction in BP. The pooled net estimates of BP change (95% confidence interval [CI]) were -0.6 (-2.2 to 1.0) mm Hg for systolic BP and -0.8 (-1.9 to 0.4) mm Hg for diastolic BP. However, there was an apparent dose-dependent effect of magnesium, with reductions of 4.3 mm Hg systolic BP (95% CI 6.3 to 2.2; P < .001) and of 2.3 mm Hg diastolic BP (95% CI 4.9 to 0.0; P = .09) for each 10 mmol/day increase in magnesium dose. CONCLUSIONS: Our meta-analysis detected dose-dependent BP reductions from magnesium supplementation. However, adequately powered trials with sufficiently high doses of magnesium supplements need to be performed to confirm this relationship.     

On-treatment diastolic blood pressure and prognosis in systolic hypertension

BACKGROUND: It has been suggested that low diastolic blood pressure (BP) while receiving antihypertensive treatment (hereinafter called on-treatment BP) is harmful in older patients with systolic hypertension. We examined the association between on-treatment diastolic BP, mortality, and cardiovascular events in the prospective placebo-controlled Systolic Hypertension in Europe Trial. METHODS: Elderly patients with systolic hypertension were randomized into the double-blind first phase of the trial, after which all patients received active study drugs (phase 2). We assessed the relationship between outcome and on-treatment diastolic BP by use of multivariate Cox regression analysis during receipt of placebo (phase 1) and during active treatment (phases 1 and 2). RESULTS: Rates of noncardiovascular mortality, cardiovascular mortality, and cardiovascular events were 11.1, 12.0, and 29.4, respectively, per 1000 patient-years with active treatment (n = 2358) and 11.9, 12.6, and 39.0, respectively, with placebo (n = 2225). Noncardiovascular mortality, but not cardiovascular mortality, increased with low diastolic BP with active treatment (P < .005) and with placebo (P < .05); for example, hazard ratios for lower diastolic BP, that is, 65 to 60 mm Hg, were, respectively, 1.15 (95% confidence interval, 1.00-1.31) and 1.28 (95% confidence interval, 1.03-1.59). Low diastolic BP with active treatment was associated with increased risk of cardiovascular events, but only in patients with coronary heart disease at baseline (P < .02; hazard ratio for BP 65-60 mm Hg, 1.17; 95% confidence interval, 0.98-1.38). CONCLUSIONS: These findings support the hypothesis that antihypertensive treatment can be intensified to prevent cardiovascular events when systolic BP is not under control in older patients with systolic hypertension, at least until diastolic BP reaches 55 mm Hg. However, a prudent approach is warranted in patients with concomitant coronary heart disease, in whom diastolic BP should probably not be lowered to less than 70 mm Hg.     

Influence of weight reduction on blood pressure: a meta-analysis of randomized controlled trials

Increased body weight is a strong risk factor for hypertension. A meta-analysis of randomized controlled trials was performed to estimate the effect of weight reduction on blood pressure overall and in population subgroups. Twenty-five randomized, controlled trials (comprising 34 strata) published between 1966 and 2002 with a total of 4874 participants were included. A random-effects model was used to account for heterogeneity among trials. A net weight reduction of -5.1 kg (95% confidence interval [CI], -6.03 to -4.25) by means of energy restriction, increased physical activity, or both reduced systolic blood pressure by -4.44 mm Hg (95% CI, -5.93 to -2.95) and diastolic blood pressure by -3.57 mm Hg (95% CI, -4.88 to -2.25). Blood pressure reductions were -1.05 mm Hg (95% CI, -1.43 to -0.66) systolic and -0.92 mm Hg (95% CI, -1.28 to -0.55) diastolic when expressed per kilogram of weight loss. As expected, significantly larger blood pressure reductions were observed in populations with an average weight loss >5 kg than in populations with less weight loss, both for systolic (-6.63 mm Hg [95% CI, -8.43 to -4.82] vs -2.70 mm Hg [95% CI, -4.59 to -0.81]) and diastolic (-5.12 mm Hg [95% CI, -6.48 to -3.75] vs -2.01 mm Hg [95% CI, -3.47 to -0.54]) blood pressure. The effect on diastolic blood pressure was significantly larger in populations taking antihypertensive drugs than in untreated populations (-5.31 mm Hg [95% CI, -6.64 to -3.99] vs -2.91 mm Hg [95% CI, -3.66 to -2.16]). This meta-analysis clearly shows that weight loss is important for the prevention and treatment of hypertension.     

Effect of the dietary approaches to stop hypertension diet and reduced sodium intake on blood pressure control

The authors hypothesized that the Dietary Approaches to Stop Hypertension (DASH) diet and reduced sodium intake would control stage 1 hypertension and reduce high-normal blood pressure (BP) to optimal levels. Adults with systolic BP 120-159 mm Hg and diastolic BP 80-95 mm Hg were randomly assigned to receive the DASH diet or a typical American (control) diet, consuming three different sodium intakes (higher=142 mmol/d, intermediate=107 mmol/d, and lower=65 mmol/d) for 30 days each. BP control was defined as systolic BP <140 mm Hg and diastolic BP <90 mm Hg. Among subjects with hypertension at baseline, at higher sodium intake the DASH diet increased BP control two-fold over control (63% vs. 32%; 95% confidence interval, 1.4-2.9). Reducing sodium intake in the control diet group increased BP control 2.3-fold (74% vs. 32%; 95% confidence interval, 1.7-3.2). The maximum BP control rate (84%) was achieved with the DASH/lower sodium diet. BP became normal or optimal in 71% of persons consuming the control/lower sodium diet and 77% of persons consuming the DASH/lower sodium diet. Both the DASH diet and reduced sodium intake improved BP control.     

The association of nocturnal hypertension and nondipping blood pressure with treatment‐resistant hypertension: The Jackson Heart Study

Apparent treatment‐resistant hypertension (aTRH), nocturnal hypertension, and nondipping blood pressure (BP) have shared risk factors. The authors studied the association between aTRH and nocturnal hypertension and aTRH and nondipping BP among 524 black Jackson Heart Study participants treated for hypertension. Nocturnal hypertension was defined by mean nighttime systolic BP ≥120 mm Hg or diastolic BP ≥70 mm Hg. Nondipping BP was defined by mean nighttime to daytime systolic BP ratio >0.90. aTRH was defined by mean clinic systolic BP ≥140 mm Hg and/or diastolic BP ≥90 mm Hg with three medication classes or treatment with four or more classes. The risk for developing aTRH associated with nondipping BP and nocturnal hypertension was estimated. After multivariable adjustment, participants with aTRH were more likely to have nocturnal hypertension (prevalence ratio, 1.20; 95% confidence interval, 1.03–1.39) and nondipping (prevalence ratio, 1.25; 95% confidence interval, 1.09–1.43). Over a median 7.3 years of follow‐up, nocturnal hypertension and nondipping BP at baseline were not associated with developing aTRH after adjustment.     

The effect of conjugated linoleic acid, a natural trans fat from milk and meat, on human blood pressure: results from a randomized crossover feeding study

Cis-9, trans-11 conjugated linoleic acid (CLA) is a natural trans fatty acid that is largely restricted to ruminant fats and consumed in foods and supplements. Its role in blood pressure (BP) regulation is still unclear. We examined the effect of cis-9, trans-11 CLA on BP compared with oleic acid. A total of 61 healthy volunteers were sequentially fed each of 3 diets for 3 weeks, in random order, for a total of 9 weeks. The diets were identical except for 7% of energy (18.9?g in a diet of 10?MJ?day(-1)) that was provided either by oleic acid, by industrial trans fatty acids or by cis-9, trans-11 CLA. We measured BP on two separate days at the end of each intervention period. At baseline, mean BP was 113.8±14.4?mm?Hg systolic and 66.3±9.6?mm?Hg diastolic. The effect of the CLA diet compared with the oleic acid diet was 0.11?mm?Hg (95% confidence interval: -1.27, 1.49) systolic and -0.45?mm?Hg (-1.63, 0.73) diastolic. After the industrial trans fatty acid diet, the effect was 1.13?mm?Hg (-0.25, 2.51) systolic and -0.44?mm?Hg (-1.62, 0.73) diastolic compared with the oleic acid diet. Our study suggests that short-term high intakes of cis-9,trans-11 CLA do not affect BP in healthy volunteers.     

Blood pressure response to calcium supplementation: a meta-analysis of randomized controlled trials

Calcium plays a role in blood pressure (BP) regulation, but the importance of supplemental calcium intake for the prevention of hypertension is still debated. We conducted a meta-analysis of randomized controlled trials to determine the effect of calcium supplementation on BP. A systematic search for randomized trials of calcium supplementation and BP in non-pregnant subjects was performed in Medline from 1966 to June 2003. Seventy-one trials were identified, 40 of which met the criteria for meta-analysis (total of 2492 subjects). Two persons independently extracted data from original publications on changes in calcium intake and BP. In addition, data were collected on subjects' characteristics, that is, age, gender, initial BP and initial calcium intake. A random effects model was used to obtain the effect of calcium supplementation on BP, overall and in predefined population subgroups. Calcium supplementation (mean daily dose: 1200 mg) reduced systolic BP by -1.86 mm Hg (95% confidence interval: -2.91 to -0.81) and diastolic BP by -0.99 mm Hg (-1.61 to -0.37). In people with a relatively low calcium intake (< or =800 mg per day) somewhat larger BP estimates were obtained, that is, -2.63 (-4.03 to -1.24) for systolic BP and -1.30 (-2.13 to -0.47) for diastolic BP. Our study suggests that an adequate intake of calcium should be recommended for the prevention of hypertension. More research on BP in people with calcium-deficient diets is warranted.     

Comparison of the efficacy and safety of azilsartan with that of candesartan cilexetil in Japanese patients with grade I-II essential hypertension: a randomized, double-blind clinical study

Azilsartan is a novel angiotensin receptor blocker being developed for hypertension treatment. This 16-week, multicenter, randomized, double-blind study compared the efficacy and safety of azilsartan (20-40 mg once daily by forced titration) and its ability to provide 24-h blood pressure (BP) control, with that of candesartan cilexetil (candesartan; 8-12 mg once daily by forced titration) in 622 Japanese patients with grade I-II essential hypertension. Efficacy was evaluated by clinic-measured sitting BP, and by ambulatory BP monitoring (ABPM) at week 14. Participants (mean age: 57 years, 61% males) had a mean baseline sitting BP of 159.8/100.4 mm Hg. The mean change from baseline in sitting diastolic BP at week 16 (primary endpoint) was -12.4 mm Hg in the azilsartan group and -9.8 mm Hg in the candesartan group, demonstrating a statistically significant greater reduction with azilsartan vs. candesartan (difference: -2.6 mm Hg, 95% confidence interval (CI): -4.08 to -1.22 mm Hg, P=0.0003). The week 16 (secondary endpoint) mean change from baseline in sitting systolic BP was -21.8 mm Hg and -17.5 mm Hg, respectively, a significant decrease with azilsartan vs. candesartan (difference: -4.4 mm Hg, 95% CI: -6.53 to -2.20 mm Hg, P<0.0001). On ABPM, the week 14 mean changes from baseline in diastolic and systolic BP were also significantly greater with azilsartan over a 24-h period, and during the daytime, night-time and early morning. Safety and tolerability were similar among the two groups. These data demonstrate that once-daily azilsartan provides a more potent 24-h sustained antihypertensive effect than that of candesartan but with equivalent safety.     

Effects of naproxcinod on blood pressure in patients with osteoarthritis

Nonsteroidal anti-inflammatory drugs are associated with increases in blood pressure (BP), particularly in patients treated with antihypertensive therapy. Naproxcinod is a nitric oxide-donating cyclooxygenase inhibitor in development for osteoarthritis (OA). Thus, we characterized the effects of naproxcinod on BP in an integrated safety analysis of 3 pivotal trials of patients with OA of the hip or knee involving 2,734 patients. The changes from baseline in the systolic BP after 13 weeks of therapy with naproxcinod (375 and 750 mg), naproxen 500 mg (equipotent to naproxcinod 750 mg), or placebo twice daily were evaluated in all patients and in the subgroup taking renin-angiotensin system inhibitors. Heterogeneity testing showed no treatment-by-study interaction. The effects of naproxcinod 750 mg on the systolic BP was not different from placebo (mean change from baseline vs placebo -0.4 mm Hg, 95% confidence interval -1.6 to 0.8). Naproxen increased the systolic BP relative to placebo (mean change from baseline vs placebo +1.4 mm Hg, 95% confidence interval 0.1 to 2.7). In the renin-angiotensin system inhibitor-treated patients, the effect of naproxcinod 750 mg compared to naproxen 500 mg in the changes from baseline in the systolic BP was -4.3 mm Hg (95% confidence interval -8.5 to -0.0). In conclusion, naproxcinod had effects on BP similar to that of placebo in patients with OA. These results imply that naproxcinod would be less likely to alter systolic BP control in patients with OA than a conventional nonsteroidal anti-inflammatory drug, particularly in those treated with renin-angiotensin system inhibitor agents.     

Effects of sodium-glucose co-transporter 2 inhibitors on blood pressure: A systematic review and meta-analysis

Sodium-glucose co-transporter 2 (SGLT2) inhibitors represent a new class of antihyperglycemic agents that block renal sodium and glucose reabsorption and may reduce blood pressure (BP). We assessed the BP lowering ability of these agents using meta-analytic techniques. PubMed, SCOPUS, and Cochrane Central were searched through October 2013. We included fully published randomized controlled trials (RCTs) that evaluated SGLT2 inhibitors in patients with type-2 diabetes mellitus and reported change in systolic and/or diastolic BP. Subgroup analyses were performed for placebo-controlled trials and those with active controls. We also conducted meta-regression to assess for a dose-response effect, and whether baseline BP, changes in body weight, heart rate, and hematocrit were associated with the BP effects. Twenty-seven RCTs (n = 12,960 participants) were included. SGLT2 inhibitors significantly reduced both systolic BP (weighted mean difference, −4.0 mm Hg; 95% confidence interval, −4.4 to −3.5) and diastolic BP (weighted mean difference, −1.6 mm Hg; 95% confidence interval, −1.9 to −1.3) from baseline. Only canagliflozin had a significant dose-response relationship with SBP (P = .008). Significant reductions in body weight and hematocrit were seen with the SGLTs. SGLTs had no significant effect on the incidence of orthostatic hypotension (P > .05). SGLT2 inhibitors significantly reduce BP in patients with type 2 diabetes.     

Aliskiren alone or in combination with hydrochlorothiazide in patients with the lower ranges of stage 2 hypertension: The ACQUIRE randomized double-blind study

Patients with stage 2 hypertension (systolic blood pressure [SBP] ≥160mm Hg and/or diastolic blood pressure [DBP] ≥100mm Hg) are at high cardiovascular risk and require intensive blood pressure (BP)-lowering therapy. This randomized double-blind study is the first prospective trial specifically designed to evaluate the direct renin inhibitor aliskiren in patients with a mean sitting SBP ≥160 mm Hg and <180mm Hg (the lower ranges of stage 2 systolic hypertension). After a 2- to 4-week washout period, 688 patients were randomized to once-daily aliskiren/hydrochlorothiazide (HCT) 150/12.5mg or aliskiren 150mg for 1 week and then double the doses for 11 weeks. Baseline BP was 167.1/95.0mm Hg. At week 12, both aliskiren/HCT and aliskiren provided substantial BP reductions from baseline (30.0/12.6 mm Hg and 20.3/8.2 mm Hg, respectively). Aliskiren/HCT lowered BP significantly more than aliskiren (least-squares mean between-treatment differences [95% confidence interval] were -9.7 [-12.0 to -7.4] for SBP and -4.5 [-5.8 to -3.2] for DBP; both P<.0001). Similar BP reductions were seen in the subgroups of patients with isolated systolic hypertension and obesity. Aliskiren, with or without HCT, provides clinically significant BP reductions and may therefore be an effective treatment option in patients with stage 2 hypertension.     

Coenzyme Q10 in the treatment of hypertension: a meta-analysis of the clinical trials

Our objective was to review all published trials of coenzyme Q10 for hypertension, assess overall efficacy and consistency of therapeutic action and side effect incidence. Meta-analysis was performed in 12 clinical trials (362 patients) comprising three randomized controlled trials, one crossover study and eight open label studies. In the randomized controlled trials (n=120), systolic blood pressure in the treatment group was 167.7 (95% confidence interval, CI: 163.7-171.1) mm Hg before, and 151.1 (147.1-155.1) mm Hg after treatment, a decrease of 16.6 (12.6-20.6, P<0.001) mm Hg, with no significant change in the placebo group. Diastolic blood pressure in the treatment group was 103 (101-105) mm Hg before, and 94.8 (92.8-96.8) mm Hg after treatment, a decrease of 8.2 (6.2-10.2, P<0.001) mm Hg, with no significant change in the placebo group. In the crossover study (n=18), systolic blood pressure decreased by 11 mm Hg and diastolic blood pressure by 8 mm Hg (P<0.001) with no significant change with placebo. In the open label studies (n=214), mean systolic blood pressure was 162 (158.4-165.7) mm Hg before, and 148.6 (145-152.2) mm Hg after treatment, a decrease of 13.5 (9.8-17.1, P<0.001) mm Hg. Mean diastolic blood pressure was 97.1 (95.2-99.1) mm Hg before, and 86.8 (84.9-88.8) mm Hg after treatment, a decrease of 10.3 (8.4-12.3, P<0.001) mm Hg. We conclude that coenzyme Q10 has the potential in hypertensive patients to lower systolic blood pressure by up to 17 mm Hg and diastolic blood pressure by up to 10 mm Hg without significant side effects.     

A meta-analysis of randomised controlled trials (RCT) among healthy normotensive and essential hypertensive elderly patients to determine the effect of high salt (NaCl) diet of blood pressure.

To examine the effect of chronic NaCl ingestion on blood pressure (BP) in the elderly, a meta-analysis was undertaken of 11 randomised controlled trials of which five included patients > or =60 years of age only and six included patients with a mean age close to 60 years. The following databases were used: Medline, Embase, Current Contents, The Cochrane Library, the AMI and IPA databases. Mean erect systolic and diastolic blood pressures (SBP/DBP) on chronic (> or =9 weeks) high and low NaCl diets were recorded, the pooled mean effect, the pooled standard error and 95% confidence intervals (Cl) were calculated and linear regression was used to evaluate the potential association between NaCl intake and BP. When all trials were pooled, a chronic high NaCl diet significantly increased mean SBP and DBP by 5.58 mm Hg (95%Cl 4.31-6.85) and 3.5 mm Hg (95%Cl 2.62-4.38) respectively. There was a significant association between the level of NaCl intake and SBP (P = 0.05, r2 = 0.37) but not DBP (P = 0.76, r2 = 0.01). When trials were pooled separately, a chronic high NaCl diet increased SBP by 5.46 mm Hg (95%Cl 3.56-7.36) and DBP by 2.63 mm Hg (95%Cl 1.18-4.08) in trials including patients > or =60 years of age only, and increased SBP by 3.27 mm Hg (95%Cl 1.23-5.31) and DBP by 2.69 mm Hg (95%Cl 1.44-3.94) in trials including patients with a mean age close to 60 years. These data suggest that a chronic high NaCl diet in elderly patients with essential hypertension is associated with an increase in SBP and DBP, the association is significant for both SBP and DBP but more marked for SBP than DBP, the effect is more pronounced the older the patient and NaCl dose strongly predicts SBP in older patients.     

Effects of thiazolidinediones on blood pressure

Peroxisome-proliferator-activated receptor-γ (PPAR-γ) agonists (known as thiazolidinediones; TDZs) activate nuclear receptors that regulate gene expression; they were developed as insulin-sensitizing drugs to treat type 2 diabetes mellitus. Although the prototypic TZD troglitazone was withdrawn from the market due to hepatic toxicity, rosiglitazone and pioglitazone are mainstays in managing type 2 diabetes mellitus. TZDs exert their hypoglycemic effect by reducing insulin resistance, hence improving insulin sensitivity. However, TZDs also exhibit a broad range of cardiovascular actions, with the clinical consequence of reduction in blood pressure (BP), observed in animal models and human diabetic subjects. The magnitude of reduction appears to be about 4 to 5 mm Hg in systolic and 2 to 4 mm Hg in diastolic BP—sufficient to significantly reduce subsequent cardiovascular event rates. But these BP-reducing properties, which are not present with metformin or sulfonylureas, are particularly important when viewed in conjunction with hypoglycemic effects. A significant proportion of patients with type 2 diabetes mellitus and BP mildly above target range might be successfully treated for both processes with a single drug.     

Elevation of C-reactive protein in people with prehypertension

The objective of this study was to determine the relationship of C-reactive protein (CRP) and blood pressure (BP) across the range of BP categories including prehypertension. The Third National Health and Nutrition Examination Survey (NHANES III) data collected from 1988 to 1994 were analyzed. In unadjusted analyses, there was a step-wise increase in the probability of elevated CRP across a wide range of BP categories. Prehypertensive participants had a higher prevalence of elevated CRP than normotensive people (27.4% vs. 19.8%; p<05). After adjustment for age, gender, race, smoking, body mass index, exercise, diabetes, and medication usage, participants with systolic BP 120-139 mm Hg or diastolic BP 80-89 mm Hg were more likely to have elevated CRP than people with systolic BP <120 (odds ratio, 1.36; 95% confidence interval, 1.14-1.62; odds ratio, 1.20; 95% confidence interval, 1.02-1.41, respectively). CRP and BP are positively related across a wide range of BP categories. A substantial proportion of prehypertensive individuals have elevated CRP independent of multiple confounders.     

Dietary fiber and blood pressure: a meta-analysis of randomized placebo-controlled trials

BACKGROUND: Dietary fiber is part of a healthy diet and may exert a protective effect in the cardiovascular system. The effect of fiber intake on blood pressure (BP) has not yet been established. METHODS: We performed a meta-analysis of randomized placebo-controlled trials to estimate the effect of fiber supplementation on BP overall and in population subgroups. Original articles published between January 1, 1966, and January 1, 2003, were retrieved for 24 trials that fulfilled criteria for meta-analysis. Data were abstracted on fiber dose, fiber type, BP changes, study design features, and study population characteristics. A random-effects model was used for meta-analysis. RESULTS: Fiber supplementation (average dose, 11.5 g/d) changed systolic BP by -1.13 mm Hg (95% confidence interval: -2.49 to 0.23) and diastolic BP by -1.26 mm Hg (-2.04 to -0.48). Reductions in BP tended to be larger in older (>40 years) and in hypertensive populations than in younger and in normotensive ones. CONCLUSION: Increasing the intake of fiber in Western populations, where intake is far below recommended levels, may contribute to the prevention of hypertension.     

The Evolution of a Canadian Hypertension Education Program Recommendation: The Impact of Resistance Training on Resting Blood Pressure in Adults as an Example

Ever since the first set of hypertension recommendations which were generated from the Canadian Hypertension Education Program, lifestyle and health behaviour have been a key focus. An initial recommendation focused on the benefits of aerobic exercise to reduce resting blood pressure (BP). However, until the 2013 edition, resistance exercise (RT) was not included. The current article describes a meta-analysis that was conducted which helped inform the creation of the newly introduced recommendation. Literature searches were conducted in 4 electronic databases. Inclusion criteria included: (1) randomized controlled trials with 4-week minimum, RT-alone intervention arms; (2) BP-lowering as the primary outcome; (3) human, adult participants; and (4) reporting control data, baseline, and postintervention resting systolic BP and diastolic BP. Nine studies (11 intervention groups, 452 participants) were identified. The analyses indicated that diastolic BP was significantly reduced (−2.2 mm Hg; 95% confidence interval, −3.9 to −0.5) in those randomized to RT compared with control participants. In contrast, no statistically significant change in systolic BP (−1.0 mm Hg; 95% confidence interval, −3.4 to 1.4) was observed. None of the studies found RT to increase BP and no adverse effects of RT were explicitly reported. Results suggest that participation in RT is not harmful and does not increase BP. However, more evidence is needed before recommending RT as a specific BP-lowering therapy.     

A cluster randomized trial to evaluate physician/pharmacist collaboration to improve blood pressure control

This was a prospective, cluster randomized controlled trial in patients with uncontrolled hypertension aged 21 to 85 years (mean, 61 years). Pharmacists made recommendations to physicians for patients in the intervention clinics (n=101) but not patients in the control clinics (n=78). The mean adjusted difference in systolic blood pressure (BP) between the control and intervention groups was 8.7 mm Hg (95% confidence interval [CI], 4.4-12.9), while the difference in diastolic BP was 5.4 mm Hg (CI, 2.8-8.0) at 9 months. The 24-hour BP levels showed similar effects, with a mean systolic BP level that was 8.8 mm Hg lower (CI, 5.0-12.6) and a mean diastolic BP level that was 4.6 mm Hg (CI, 2.4-6.8) lower in the intervention group. BP was controlled in 89.1% of patients in the intervention group and 52.9% in the control group (adjusted odds ratio, 8.9; CI, 3.8-20.7; P<.001). Physician/pharmacist collaboration achieved significantly better mean BP values and overall BP control rates, primarily by intensification of medication therapy and improving patient adherence.     

BpTRUth: Do automated blood pressure monitors outperform mercury?

Manual measurement of blood pressure (BP) in the office (MOBP) is inferior in accuracy when compared with ambulatory BP measurements (ABPM) since it misses white coat and masked effects on BP. BpTRU, an automated office BP device (AOBP), has been reported to reduce white coat effect. We performed a retrospective review of the diagnostic accuracy of MOBP (taken by a trained nurse in clinical hypertension) and AOBP using the Bland-Altman method in hypertensive patients referred to a Renal Hypertension Clinic. In 329 hypertensive patients, the 95% limits of agreement between systolic AOBP and ABPM were ?31 mm Hg to 33 mm Hg and for MOBP and ABPM were ?27.8 mm Hg to 37.4 mm Hg. The bias between systolic MOBP and systolic ABPM was 4.9 mm Hg (95% confidence interval, 3.0–6.6 mm Hg) whereas the bias between the systolic AOBP and the systolic ABPM was ?3.2 (95% confidence interval, ?1.3 to ?5.0). AOBP did not improve treatment relevant classification errors compared with MOBP (28% vs. 23%; P = .052). Our data support findings by others showing that AOBP improves, but does not eliminate, white coat effect. The increased detection of white coat effect appears related to systematic downward bias by BpTRU. As a result, detection of masked effect is undermined by BpTRU.