Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis

Background

The benefits of blood pressure lowering treatment for prevention of cardiovascular disease are well established. However, the extent to which these effects differ by baseline blood pressure, presence of comorbidities, or drug class is less clear. We therefore performed a systematic review and meta-analysis to clarify these differences.

Method

For this systematic review and meta-analysis, we searched MEDLINE for large-scale blood pressure lowering trials, published between Jan 1, 1966, and July 7, 2015, and we searched the medical literature to identify trials up to Nov 9, 2015. All randomised controlled trials of blood pressure lowering treatment were eligible for inclusion if they included a minimum of 1000 patient-years of follow-up in each study arm. No trials were excluded because of presence of baseline comorbidities, and trials of antihypertensive drugs for indications other than hypertension were eligible. We extracted summary-level data about study characteristics and the outcomes of major cardiovascular disease events, coronary heart disease, stroke, heart failure, renal failure, and all-cause mortality. We used inverse variance weighted fixed-effects meta-analyses to pool the estimates.

Results

We identified 123 studies with 613 815 participants for the tabular meta-analysis. Meta-regression analyses showed relative risk reductions proportional to the magnitude of the blood pressure reductions achieved. Every 10 mm Hg reduction in systolic blood pressure significantly reduced the risk of major cardiovascular disease events (relative risk [RR] 0·80, 95% CI 0·77–0·83), coronary heart disease (0·83, 0·78–0·88), stroke (0·73, 0·68–0·77), and heart failure (0·72, 0·67–0·78), which, in the populations studied, led to a significant 13% reduction in all-cause mortality (0·87, 0·84–0·91). However, the effect on renal failure was not significant (0·95, 0·84–1·07). Similar proportional risk reductions (per 10 mm Hg lower systolic blood pressure) were noted in trials with higher mean baseline systolic blood pressure and trials with lower mean baseline systolic blood pressure (all ptrend>0·05). There was no clear evidence that proportional risk reductions in major cardiovascular disease differed by baseline disease history, except for diabetes and chronic kidney disease, for which smaller, but significant, risk reductions were detected. β blockers were inferior to other drugs for the prevention of major cardiovascular disease events, stroke, and renal failure. Calcium channel blockers were superior to other drugs for the prevention of stroke. For the prevention of heart failure, calcium channel blockers were inferior and diuretics were superior to other drug classes. Risk of bias was judged to be low for 113 trials and unclear for 10 trials. Heterogeneity for outcomes was low to moderate; the I2 statistic for heterogeneity for major cardiovascular disease events was 41%, for coronary heart disease 25%, for stroke 26%, for heart failure 37%, for renal failure 28%, and for all-cause mortality 35%.

Interpretation

Blood pressure lowering significantly reduces vascular risk across various baseline blood pressure levels and comorbidities. Our results provide strong support for lowering blood pressure to systolic blood pressures less than 130 mm Hg and providing blood pressure lowering treatment to individuals with a history of cardiovascular disease, coronary heart disease, stroke, diabetes, heart failure, and chronic kidney disease.

Funding

National Institute for Health Research and Oxford Martin School.

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Association Between Hypertensive Disorders of Pregnancy and Later Risk of Cardiomyopathy

Importance  Women with hypertensive disorders of pregnancy, preeclampsia in particular, have an increased risk of cardiomyopathy during the peripartum period. Whether hypertensive disorders of pregnancy are also associated with cardiomyopathy later in life is unknown.

Objective  To determine whether hypertensive disorders of pregnancy are associated with cardiomyopathy beyond the peripartum period.

Design, Setting, and Participants  Nationwide register–based cohort study using Cox regression to compare rates of cardiomyopathy in women with and without a history of hypertensive disorders of pregnancy in a cohort of 1 075 763 women with at least 1 pregnancy ending in live birth or stillbirth in Denmark, 1978-2012, with follow-up through December 31, 2012.

Exposures  A hypertensive disorder of pregnancy (severe or moderate preeclampsia or gestational hypertension) registered in the National Patient Register.

Main Outcomes and Measures  Cardiomyopathy more than 5 months after delivery (outside the peripartum period) up to 34 years 7 months.

Result  The women in the primary cohort had 2 067 633 eligible pregnancies during the study period, 76 108 of which were complicated by a hypertensive disorder of pregnancy. During follow-up, 1577 women (mean age, 48.5 years at cardiomyopathy diagnosis; 2.6% with multiple pregnancies) developed cardiomyopathy. Compared with women with normotensive pregnancies (18 211 603 person-years of follow-up; n = 1408 cardiomyopathy events, 7.7/100 000 person-years [95% CI, 7.3-8.2]), women with a history of hypertensive disorders of pregnancy had significantly increased rates of cardiomyopathy (in 173 062 person-years of follow-up among women with severe preeclampsia, n = 27 cardiomyopathy events; 15.6/100 000 person-years [95% CI, 10.7-22.7]; adjusted hazard ratio [HR], 2.20 [95% CI, 1.50-3.23]; in 697 447 person-years of follow-up among women with moderate preeclampsia, n = 102 cardiomyopathy events; 14.6/100 000 person-years [95% CI, 12.0-17.8]; adjusted HR, 1.89 [95% CI, 1.55-2.23]; in 213 197 person-years of follow-up among women with gestational hypertension, n = 40 cardiomyopathy events; 17.3/100 000 person-years [95% CI, 12.7-23.6]; adjusted HR, 2.06 [95% CI, 1.50-2.82]). These increases persisted more than 5 years after the latest pregnancy. Mediation analyses suggested that only about 50% of the association was an indirect association through postpregnancy chronic hypertension. In this cohort, 11% of all cardiomyopathy events occurred in women with a history of hypertensive disorders of pregnancy.

Conclusions and Relevance  Women with a history of hypertensive disorders of pregnancy, compared with women without such a history, had a small but statistically significant increased risk of cardiomyopathy more than 5 months after delivery. Further research is necessary to understand whether there is a causal mechanism behind this association.

By Ida Behrens et al, JAMA. 2016;315(10):1026-1033. doi:10.1001/jama.2016.1869.

Effect of Vitamin D Supplementation on Tibial Cartilage Volume and Knee Pain Among Patients With Symptomatic Knee Osteoarthritis

Importance  Observational studies suggest that vitamin D supplementation is associated with benefits for knee osteoarthritis, but current trial evidence is contradictory.

Objective  To compare the effects of vitamin D supplementation vs placebo on knee pain and knee cartilage volume in patients with symptomatic knee osteoarthritis and low vitamin D levels.

Design, Setting, and Participants  A multicenter randomized, double-blind, placebo-controlled clinical trial in Tasmania and Victoria, Australia. Participants with symptomatic knee osteoarthritis and low 25-hydroxyvitamin D (12.5-60 nmol/L) were enrolled from June 2010 to December 2011. The trial was completed in December 2013.

Interventions  Participants were randomly assigned to receive monthly treatment with oral vitamin D3(50 000 IU; n = 209) or an identical placebo (n = 204) for 2 years.

Main Outcomes and Measures  Primary outcomes were change in tibial cartilage volume (assessed using magnetic resonance imaging [MRI]) and change in the Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain score (0 [no pain] to 500 [worst pain]) from baseline to month 24. Secondary outcomes were cartilage defects and bone marrow lesions (assessed using MRI).

Results  Of 413 enrolled participants (mean age, 63.2 years; 50% women), 340 (82.3%) completed the study. The level of 25-hydroxyvitamin D increased more in the vitamin D group (40.6 nmol/L) than in the placebo group (6.7 nmol/L) (P < .001) over 2 years. There were no significant differences in annual change of tibial cartilage volume (−3.4% in the vitamin D group vs −4.2% in the placebo group [between-group difference, 0.8% {95% CI, −0.2% to 1.8%}]; P = .13) or WOMAC pain score (−49.9 in the vitamin D group vs −35.1 in the placebo group [between-group difference, −14.8 {95% CI, −32.5 to 2.9}]; P = .10). There were no significant differences in change of tibiofemoral cartilage defects (0.3 in the vitamin D group vs 0.5 in the placebo group [between-group difference, −0.2 {95% CI, −0.4 to 0.1}]; P = .21) or change in tibiofemoral bone marrow lesions (−0.1 in the vitamin D group vs 0.3 in the placebo group [between-group difference, −0.5 {95% CI, −0.9 to 0.0}]; P = .06). Adverse events (≥1 per patient) occurred in 56 participants in the vitamin D group and in 37 participants in the placebo group (P = .04).

Conclusions and Relevance  Among patients with symptomatic knee osteoarthritis and low serum 25-hydroxyvitamin D levels, vitamin D supplementation, compared with placebo, did not result in significant differences in change in MRI-measured tibial cartilage volume or WOMAC knee pain score over 2 years. These findings do not support the use of vitamin D supplementation for preventing tibial cartilage loss or improving WOMAC knee pain in patients with knee osteoarthritis.

Trial Registration  clinicaltrials.gov Identifier: NCT01176344; anzctr.org.au Identifier:ACTRN12610000495022

By Xingzhong Jin et al, JAMA. 2016;315(10):1005-1013. doi:10.1001/jama.2016.1961.

Effect of Naltrexone-Bupropion on Major Adverse Cardiovascular Events in Overweight and Obese Patients With Cardiovascular Risk Factors

Importance  Few cardiovascular outcomes trials have been conducted for obesity treatments. Withdrawal of 2 marketed drugs has resulted in controversy about the cardiovascular safety of obesity agents.

Objective  To determine whether the combination of naltrexone and bupropion increases major adverse cardiovascular events (MACE, defined as cardiovascular death, nonfatal stroke, or nonfatal myocardial infarction) compared with placebo in overweight and obese patients.

Design, Setting, and Participants  Randomized, multicenter, placebo-controlled, double-blind noninferiority trial enrolling 8910 overweight or obese patients at increased cardiovascular risk from June 13, 2012, to January 21, 2013, at 266 US centers. After public release of confidential interim data by the sponsor, the academic leadership of the study recommended termination of the trial and the sponsor agreed.

Interventions  An Internet-based weight management program was provided to all participants. Participants were randomized to receive placebo (n=4454) or naltrexone, 32 mg/d, and bupropion, 360 mg/d (n=4456).

Main Outcomes and Measures  Time from randomization to first confirmed occurrence of a MACE. The primary analysis planned to assess a noninferiority hazard ratio (HR) of 1.4 after 378 expected events, with a confidential interim analysis after approximately 87 events (25% interim analysis) to assess a noninferiority HR of 2.0 for consideration of regulatory approval.

Results  Among the 8910 participants randomized, mean age was 61.0 years (SD, 7.3 years), 54.5% were female, 32.1% had a history of cardiovascular disease, and 85.2% had diabetes, with a median body mass index of 36.6 (interquartile range, 33.1-40.9). For the 25% interim analysis, MACE occurred in 59 placebo-treated patients (1.3%) and 35 naltrexone-bupropion–treated patients (0.8%; HR, 0.59; 95% CI, 0.39-0.90). After 50% of planned events, MACE occurred in 102 patients (2.3%) in the placebo group and 90 patients (2.0%) in the naltrexone-bupropion group (HR, 0.88; adjusted 99.7% CI, 0.57-1.34). Adverse effects were more common in the naltrexone-bupropion group, including gastrointestinal events in 14.2% vs 1.9% (P < .001) and central nervous system symptoms in 5.1% vs 1.2% (P < .001).

Conclusions and Relevance  Among overweight or obese patients at increased cardiovascular risk, based on the interim analyses performed after 25% and 50% of planned events, the upper limit of the 95% CI of the HR for MACE for naltrexone-bupropion treatment, compared with placebo, did not exceed 2.0. However, because of the unanticipated early termination of the trial, it is not possible to assess noninferiority for the prespecified upper limit of 1.4. Accordingly, the cardiovascular safety of this treatment remains uncertain and will require evaluation in a new adequately powered outcome trial.

Trial Registration  clinicaltrials.gov Identifier: NCT01601704

By Steven E. Nissen et al, JAMA. 2016;315(10):990-1004. doi:10.1001/jama.2016.1558.

Primary prevention and risk factor reduction in coronary heart disease mortality among working aged men and women in eastern Finland over 40 years: population based observational study

Objective To estimate how much changes in the main risk factors of cardiovascular disease (smoking prevalence, serum cholesterol, and systolic blood pressure) can explain the reduction in coronary heart disease mortality observed among working aged men and women in eastern Finland.

Design Population based observational study.

Setting Eastern Finland.

Participants 34 525 men and women aged 30-59 years who participated in the national FINRISK studies between 1972 and 2012.

Interventions Change in main cardiovascular risk factors through population based primary prevention.

Main outcome measures Predicted and observed age standardised mortality due to coronary heart disease. Predicted change was estimated with a logistic regression model using risk factor data collected in nine consecutive, population based, risk factor surveys conducted every five years since 1972. Data on observed mortality were obtained from the National Causes of Death Register.

Results During the 40 year study period, levels of the three major cardiovascular risk factors decreased except for a small increase in serum cholesterol levels between 2007 and 2012. From years 1969-1972 to 2012, coronary heart disease mortality decreased by 82% (from 643 to 118 deaths per 100 000 people) and 84% (114 to 17) among men and women aged 35-64 years, respectively. During the first 10 years of the study, changes in these three target risk factors contributed to nearly all of the observed mortality reduction. Since the mid-1980s, the observed reduction in mortality has been larger than predicted. In the last 10 years of the study, about two thirds (69% in men and 66% in women) of the reduction could be explained by changes in the three main risk factors, and the remaining third by other factors.

Conclusion Reductions in disease burden and mortality due to coronary heart disease can be achieved through the use of population based primary prevention programmes. Secondary prevention among high risk individuals and treatment of acute events of coronary heart disease could confer additional benefit.

By Pekka Jousilahti et al, BMJ 2016;352:i721

Does happiness itself directly affect mortality? The prospective UK Million Women Study

Background

Poor health can cause unhappiness and poor health increases mortality. Previous reports of reduced mortality associated with happiness could be due to the increased mortality of people who are unhappy because of their poor health. Also, unhappiness might be associated with lifestyle factors that can affect mortality. We aimed to establish whether, after allowing for the poor health and lifestyle of people who are unhappy, any robust evidence remains that happiness or related subjective measures of wellbeing directly reduce mortality.

Methods

The Million Women Study is a prospective study of UK women recruited between 1996 and 2001 and followed electronically for cause-specific mortality. 3 years after recruitment, the baseline questionnaire for the present report asked women to self-rate their health, happiness, stress, feelings of control, and whether they felt relaxed. The main analyses were of mortality before Jan 1, 2012, from all causes, from ischaemic heart disease, and from cancer in women who did not have heart disease, stroke, chronic obstructive lung disease, or cancer at the time they answered this baseline questionnaire. We used Cox regression, adjusted for baseline self-rated health and lifestyle factors, to calculate mortality rate ratios (RRs) comparing mortality in women who reported being unhappy (ie, happy sometimes, rarely, or never) with those who reported being happy most of the time.

Findings

Of 719 671 women in the main analyses (median age 59 years [IQR 55–63]), 39% (282 619) reported being happy most of the time, 44% (315 874) usually happy, and 17% (121 178) unhappy. During 10 years (SD 2) follow-up, 4% (31 531) of participants died. Self-rated poor health at baseline was strongly associated with unhappiness. But after adjustment for self-rated health, treatment for hypertension, diabetes, asthma, arthritis, depression, or anxiety, and several sociodemographic and lifestyle factors (including smoking, deprivation, and body-mass index), unhappiness was not associated with mortality from all causes (adjusted RR for unhappy vs happy most of the time 0·98, 95% CI 0·94–1·01), from ischaemic heart disease (0·97, 0·87–1·10), or from cancer (0·98, 0·93–1·02). Findings were similarly null for related measures such as stress or lack of control.

Interpretation

In middle-aged women, poor health can cause unhappiness. After allowing for this association and adjusting for potential confounders, happiness and related measures of wellbeing do not appear to have any direct effect on mortality.

Funding

UK Medical Research Council, Cancer Research UK.

By Bette Liu et al, The Lancet, Volume 387, No. 10021, p874–881, 27 February 2016

Effect of Insulin Glargine Up-titration vs Insulin Degludec/Liraglutide on Glycated Hemoglobin Levels in Patients With Uncontrolled Type 2 Diabetes

Importance  Achieving glycemic control remains a challenge for patients with type 2 diabetes, even with insulin therapy.

Objective  To assess whether a fixed ratio of insulin degludec/liraglutide was noninferior to continued titration of insulin glargine in patients with uncontrolled type 2 diabetes treated with insulin glargine and metformin.

Design, Setting, and Participants  Phase 3, multinational, multicenter, 26-week, randomized, open-label, 2-group, treat-to-target trial conducted at 75 centers in 10 countries from September 2013 to November 2014 among 557 patients with uncontrolled diabetes treated with glargine (20-50 U) and metformin (≥1500 mg/d) with glycated hemoglobin (HbA1c) levels of 7% to 10% and a body mass index of 40 or lower.

Interventions  1:1 randomization to degludec/liraglutide (n = 278; maximum dose, 50 U of degludec/1.8 mg of liraglutide) or glargine (n = 279; no maximum dose), with twice-weekly titration to a glucose target of 72 to 90 mg/dL.

Main Outcomes and Measures  Primary outcome measure was change in HbA1c level after 26 weeks, with a noninferiority margin of 0.3% (upper bound of 95% CI, <0.3%). If noninferiority of degludec/liraglutide was achieved, secondary end points were tested for statistical superiority and included change in HbA1c level, change in body weight, and rate of confirmed hypoglycemic episodes.

Results  Among 557 randomized patients (mean: age, 58.8 years; women, 49.7%), 92.5% of patients completed the trial and provided data at 26 weeks. Baseline HbA1c level was 8.4% for the degludec/liraglutide group and 8.2% for the glargine group. HbA1c level reduction was greater with degludec/liraglutide vs glargine (−1.81% for the degludec/liraglutide group vs −1.13% for the glargine group; estimated treatment difference [ETD], –0.59% [95% CI, –0.74% to –0.45%]), meeting criteria for noninferiority (P < .001), and also meeting criteria for statistical superiority (P < .001). Treatment with degludec/liraglutide was also associated with weight loss compared with weight gain with glargine (–1.4 kg for degludec/liraglutide vs 1.8 kg for glargine; ETD, –3.20 kg [95% CI, –3.77 to –2.64],P < .001) and fewer confirmed hypoglycemic episodes (episodes/patient-year exposure, 2.23 for degludec/liraglutide vs 5.05 for glargine; estimated rate ratio, 0.43 [95% CI, 0.30 to 0.61],P < .001). Overall and serious adverse event rates were similar in the 2 groups, except for more nonserious gastrointestinal adverse events reported with degludec/liraglutide (adverse events, 79 for degludec/liraglutide vs 18 for glargine).

Conclusions and Relevance  Among patients with uncontrolled type 2 diabetes taking glargine and metformin, treatment with degludec/liraglutide compared with up-titration of glargine resulted in noninferior HbA1c levels, with secondary analyses indicating greater HbA1c level reduction after 26 weeks of treatment. Further studies are needed to assess longer-term efficacy and safety.

Trial Registration  clinicaltrials.gov Identifier: NCT01952145