The Science of Precision Prevention: Research Opportunities and Clinical Applications to Reduce Cardiovascular Health Disparities

Precision prevention embraces personalized prevention but includes broader factors such as social determinants of health to improve cardiovascular health. The quality, quantity, precision, and diversity of data relatable to individuals and communities continue to expand. New analytical methods can be applied to these data to create tools to attribute risk, which may allow a better understanding of cardiovascular health disparities. Interventions using these analytic tools should be evaluated to establish feasibility and efficacy for addressing cardiovascular disease disparities in diverse individuals and communities. Training in these approaches is important to create the next generation of scientists and practitioners in precision prevention. This state-of-the-art review is based on a workshop convened to identify current gaps in knowledge and methods used in precision prevention intervention research, discuss opportunities to expand trials of implementation science to close the health equity gaps, and expand the education and training of a diverse precision prevention workforce.

Proceedings From a National Heart, Lung, and Blood Institute and the Centers for Disease Control and Prevention Workshop to Control Hypertension

Hypertension treatment and control prevent more cardiovascular events than management of other modifiable risk factors. Although the age-adjusted proportion of US adults with controlled blood pressure (BP) defined as <140/90 mm Hg, improved from 31.8% in 1999-2000 to 48.5% in 2007-2008, it remained stable through 2013-2014 and declined to 43.7% in 2017-2018. To address the rapid decline in hypertension control, the National Heart, Lung, and Blood Institute and the Division for Heart Disease and Stroke Prevention of the Centers for Disease Control and Prevention convened a virtual workshop with multidisciplinary national experts. Also, the group sought to identify opportunities to reverse the adverse trend and further improve hypertension control. The workshop immediately preceded the Surgeon General's Call to Action to Control Hypertension, which recognized a stagnation in progress with hypertension control. The presentations and discussions included potential reasons for the decline and challenges in hypertension control, possible "big ideas," and multisector approaches that could reverse the current trend while addressing knowledge gaps and research priorities. The broad set of "big ideas" was comprised of various activities that may improve hypertension control, including: interventions to engage patients, promotion of self-measured BP monitoring with clinical support, supporting team-based care, implementing telehealth, enhancing community-clinical linkages, advancing precision population health, developing tailored public health messaging, simplifying hypertension treatment, using process and outcomes quality metrics to foster accountability and efficiency, improving access to high-quality health care, addressing social determinants of health, supporting cardiovascular public health and research, and lowering financial barriers to hypertension control.

SPRINT Revisited: Updated Results and Implications

The SPRINT (Systolic Blood Pressure Intervention Trial) results have influenced clinical practice but have also generated discussion regarding the validity, generalizability, and importance of the findings. Following the SPRINT primary results manuscript in 2015, additional results and analyses of the data have addressed these concerns. The primary objective of this article is to respond to key questions that have been raised.

Final Report of a Trial of Intensive versus Standard Blood-Pressure Control

BACKGROUND

In a previously reported randomized trial of standard and intensive systolic blood-pressure control, data on some outcome events had yet to be adjudicated and post-trial follow-up data had not yet been collected.

METHODS

We randomly assigned 9361 participants who were at increased risk for cardiovascular disease but did not have diabetes or previous stroke to adhere to an intensive treatment target (systolic blood pressure, <120 mm Hg) or a standard treatment target (systolic blood pressure, <140 mm Hg). The primary outcome was a composite of myocardial infarction, other acute coronary syndromes, stroke, acute decompensated heart failure, or death from cardiovascular causes. Additional primary outcome events occurring through the end of the intervention period (August 20, 2015) were adjudicated after data lock for the primary analysis. We also analyzed post-trial observational follow-up data through July 29, 2016.

RESULTS

At a median of 3.33 years of follow-up, the rate of the primary outcome and all-cause mortality during the trial were significantly lower in the intensive-treatment group than in the standard-treatment group (rate of the primary outcome, 1.77% per year vs. 2.40% per year; hazard ratio, 0.73; 95% confidence interval [CI], 0.63 to 0.86; all-cause mortality, 1.06% per year vs. 1.41% per year; hazard ratio, 0.75; 95% CI, 0.61 to 0.92). Serious adverse events of hypotension, electrolyte abnormalities, acute kidney injury or failure, and syncope were significantly more frequent in the intensive-treatment group. When trial and post-trial follow-up data were combined (3.88 years in total), similar patterns were found for treatment benefit and adverse events; however, rates of heart failure no longer differed between the groups.

CONCLUSIONS

Among patients who were at increased cardiovascular risk, targeting a systolic blood pressure of less than 120 mm Hg resulted in lower rates of major adverse cardiovascular events and lower all-cause mortality than targeting a systolic blood pressure of less than 140 mm Hg, both during receipt of the randomly assigned therapy and after the trial. Rates of some adverse events were higher in the intensive-treatment group. (Funded by the National Institutes of Health; SPRINT ClinicalTrials.gov number, NCT01206062.).

Cardiopulmonary Impact of Particulate Air Pollution in High-Risk Populations: JACC State-of-the-Art Review

Fine particulate air pollution <2.5 μm in diameter (PM2.5) is a major environmental threat to global public health. Multiple national and international medical and governmental organizations have recognized PM2.5 as a risk factor for cardiopulmonary diseases. A growing body of evidence indicates that several personal-level approaches that reduce exposures to PM2.5 can lead to improvements in health endpoints. Novel and forward-thinking strategies including randomized clinical trials are important to validate key aspects (e.g., feasibility, efficacy, health benefits, risks, burden, costs) of the various protective interventions, in particular among real-world susceptible and vulnerable populations. This paper summarizes the discussions and conclusions from an expert workshop, Reducing the Cardiopulmonary Impact of Particulate Matter Air Pollution in High Risk Populations, held on May 29 to 30, 2019, and convened by the National Institutes of Health, the U.S. Environmental Protection Agency, and the U.S. Centers for Disease Control and Prevention.

Trends in Blood Pressure Control Among US Adults With Hypertension, 1999-2000 to 2017-2018

IMPORTANCE

Controlling blood pressure (BP) reduces the risk for cardiovascular disease.

OBJECTIVE

To determine whether BP control among US adults with hypertension changed from 1999-2000 through 2017-2018.

DESIGN, SETTING, AND PARTICIPANTS

Serial cross-sectional analysis of National Health and Nutrition Examination Survey data, weighted to be representative of US adults, between 1999-2000 and 2017-2018 (10 cycles), including 18 262 US adults aged 18 years or older with hypertension defined as systolic BP level of 140 mm Hg or higher, diastolic BP level of 90 mm Hg or higher, or use of antihypertensive medication. The date of final data collection was 2018.

EXPOSURES

Calendar year.

MAIN OUTCOMES AND MEASURES

Mean BP was computed using 3 measurements. The primary outcome of BP control was defined as systolic BP level lower than 140 mm Hg and diastolic BP level lower than 90 mm Hg.

RESULTS

Among the 51 761 participants included in this analysis, the mean (SD) age was 48 (19) years and 25 939 (50.1%) were women; 43.2% were non-Hispanic White adults; 21.6%, non-Hispanic Black adults; 5.3%, non-Hispanic Asian adults; and 26.1%, Hispanic adults. Among the 18 262 adults with hypertension, the age-adjusted estimated proportion with controlled BP increased from 31.8% (95% CI, 26.9%-36.7%) in 1999-2000 to 48.5% (95% CI, 45.5%-51.5%) in 2007-2008 (P < .001 for trend), remained stable and was 53.8% (95% CI, 48.7%-59.0%) in 2013-2014 (P = .14 for trend), and then declined to 43.7% (95% CI, 40.2%-47.2%) in 2017-2018 (P = .003 for trend). Compared with adults who were aged 18 years to 44 years, it was estimated that controlled BP was more likely among those aged 45 years to 64 years (49.7% vs 36.7%; multivariable-adjusted prevalence ratio, 1.18 [95% CI, 1.02-1.37]) and less likely among those aged 75 years or older (37.3% vs 36.7%; multivariable-adjusted prevalence ratio, 0.81 [95% CI, 0.65-0.97]). It was estimated that controlled BP was less likely among non-Hispanic Black adults vs non-Hispanic White adults (41.5% vs 48.2%, respectively; multivariable-adjusted prevalence ratio, 0.88; 95% CI, 0.81-0.96). Controlled BP was more likely among those with private insurance (48.2%), Medicare (53.4%), or government health insurance other than Medicare or Medicaid (43.2%) vs among those without health insurance (24.2%) (multivariable-adjusted prevalence ratio, 1.40 [95% CI, 1.08-1.80], 1.47 [95% CI, 1.15-1.89], and 1.36 [95% CI, 1.04-1.76], respectively). Controlled BP was more likely among those with vs those without a usual health care facility (48.4% vs 26.5%, respectively; multivariable-adjusted prevalence ratio, 1.48 [95% CI, 1.13-1.94]) and among those who had vs those who had not had a health care visit in the past year (49.1% vs 8.0%; multivariable-adjusted prevalence ratio, 5.23 [95% CI, 2.88-9.49]).

CONCLUSIONS AND RELEVANCE

In a series of cross-sectional surveys weighted to be representative of the adult US population, the prevalence of controlled BP increased between 1999-2000 and 2007-2008, did not significantly change from 2007-2008 through 2013-2014, and then decreased after 2013-2014.

Primary Prevention Trial Designs Using Coronary Imaging: A National Heart, Lung, and Blood Institute Workshop

Coronary artery calcium (CAC) is considered a useful test for enhancing risk assessment in the primary prevention setting. Clinical trials are under consideration. The National Heart, Lung, and Blood Institute convened a multidisciplinary working group on August 26 to 27, 2019, in Bethesda, Maryland, to review available evidence and consider the appropriateness of conducting further research on coronary artery calcium (CAC) testing, or other coronary imaging studies, as a way of informing decisions for primary preventive treatments for cardiovascular disease. The working group concluded that additional evidence to support current guideline recommendations for use of CAC in middle-age adults is very likely to come from currently ongoing trials in that age group, and a new trial is not likely to be timely or cost effective. The current trials will not, however, address the role of CAC testing in younger adults or older adults, who are also not addressed in existing guidelines, nor will existing trials address the potential benefit of an opportunistic screening strategy made feasible by the application of artificial intelligence. Innovative trial designs for testing the value of CAC across the lifespan were strongly considered and represent important opportunities for additional research, particularly those that leverage existing trials or other real-world data streams including clinical computed tomography scans. Sex and racial/ethnic disparities in cardiovascular disease morbidity and mortality, and inclusion of diverse participants in future CAC trials, particularly those based in the United States, would enhance the potential impact of these studies.

Effect of Intensive Blood Pressure Lowering on the Risk of Atrial Fibrillation

It remains uncertain whether intensive control of blood pressure (BP) results in a lower risk of atrial fibrillation (AF) in patients with hypertension. Using data from SPRINT (Systolic Blood Pressure Intervention Trial), which enrolled participants with hypertension at increased risk of cardiovascular disease, we examined whether intensive BP lowering (target systolic BP [SBP] <120 mm Hg), compared with standard BP lowering (target SBP<140 mm Hg), results in a lower risk of AF. This analysis included 8022 participants (4003 randomized to the intensive arm and 4019 to standard BP arm) who were free of AF at the time of enrollment and with available baseline and follow-up electrocardiographic data. AF was ascertained from standard 12-lead electrocardiograms recorded at biannual study examinations and an exit visit. During up to 5.2 years of follow-up and a total of 28 322 person-years, 206 incident AF cases occurred; 88 in the intensive BP-lowering arm and 118 in the standard BP-lowering arm. Intensive BP lowering was associated with a 26% lower risk of developing new AF (hazard ratio, 0.74 [95% CI, 0.56-0.98]; P=0.037). This effect was consistent among prespecified subgroups of SPRINT participants stratified by age, sex, race, SBP tertiles, prior cardiovascular disease, and prior chronic kidney disease when interactions between treatment effect and these subgroups were assessed using Hommel adjusted P values. In conclusion, intensive treatment to a target of SBP <120 mm Hg in patients with hypertension at high risk of cardiovascular disease has the potential to reduce the risk of AF. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

A new modeling and inference approach for the Systolic Blood Pressure Intervention Trial outcomes

Background/aims In clinical trials with time-to-event outcomes, usually the significance tests and confidence intervals are based on a proportional hazards model. Thus, the temporal pattern of the treatment effect is not directly considered. This could be problematic if the proportional hazards assumption is violated, as such violation could impact both interim and final estimates of the treatment effect. Methods We describe the application of inference procedures developed recently in the literature for time-to-event outcomes when the treatment effect may or may not be time-dependent. The inference procedures are based on a new model which contains the proportional hazards model as a sub-model. The temporal pattern of the treatment effect can then be expressed and displayed. The average hazard ratio is used as the summary measure of the treatment effect. The test of the null hypothesis uses adaptive weights that often lead to improvement in power over the log-rank test. Results Without needing to assume proportional hazards, the new approach yields results consistent with previously published findings in the Systolic Blood Pressure Intervention Trial. It provides a visual display of the time course of the treatment effect. At four of the five scheduled interim looks, the new approach yields smaller p values than the log-rank test. The average hazard ratio and its confidence interval indicates a treatment effect nearly a year earlier than a restricted mean survival time-based approach. Conclusion When the hazards are proportional between the comparison groups, the new methods yield results very close to the traditional approaches. When the proportional hazards assumption is violated, the new methods continue to be applicable and can potentially be more sensitive to departure from the null hypothesis.

Syncope, Hypotension, and Falls in the Treatment of Hypertension: Results from the Randomized Clinical Systolic Blood Pressure Intervention Trial

OBJECTIVE

To determine predictors of serious adverse events (SAEs) involving syncope, hypotension, and falls, with particular attention to age, in the Systolic Blood Pressure Intervention Trial.

DESIGN

Randomized clinical trial.

SETTING

Academic and private practices across the United States (N = 102).

PARTICIPANTS

Adults aged 50 and older with a systolic blood pressure (SBP) of 130 to 180 mmHg at high risk of cardiovascular disease events, but without diabetes, history of stroke, symptomatic heart failure or ejection fraction less than 35%, dementia, or standing SBP less than 110 mmHg (N = 9,361).

INTERVENTION

Treatment of SBP to a goal of less than 120 mmHg or 140 mmHg.

MEASUREMENTS

Outcomes were SAEs involving syncope, hypotension, and falls. Predictors were treatment assignment, demographic characteristics, comorbidities, baseline measurements, and baseline use of cardiovascular medications.

RESULTS

One hundred seventy-two (1.8%) participants had SAEs involving syncope, 155 (1.6%) hypotension, and 203 (2.2%) falls. Randomization to intensive SBP control was associated with greater risk of an SAE involving hypotension (hazard ratio (HR) = 1.67, 95% confidence interval (CI) = 1.21-2.32, P = .002), and possibly syncope (HR = 1.32, 95% CI = 0.98-1.79, P = .07), but not falls (HR = 0.98, 95% CI = 0.75-1.29, P = .90). Risk of all three outcomes was higher for participants with chronic kidney disease or frailty. Older age was also associated with greater risk of syncope, hypotension, and falls, but there was no age-by-treatment interaction for any of the SAE outcomes.

CONCLUSIONS

Participants randomized to intensive SBP control had greater risk of hypotension and possibly syncope, but not falls. The greater risk of developing these events associated with intensive treatment did not vary according to age.

Blood Pressure Measurement in SPRINT (Systolic Blood Pressure Intervention Trial)

Recent publications have stated that the blood pressure (BP) measurement technique used in SPRINT (Systolic Blood Pressure Intervention Trial) was unattended. However, the SPRINT protocol does not address the issue of attendance. A survey was conducted immediately after SPRINT closeout visits were completed to inquire whether BP measurements were usually attended or unattended by staff. There were 4082 participants at 38 sites that measured BP after leaving the participant alone the entire time (always alone), 2247 at 25 sites that had personnel in the room the entire time (never alone), 1746 at 19 sites that left the participant alone only during the rest period (alone for rest), and 570 at 6 sites that left the participant alone only during the BP readings (alone for BP measurement). Similar systolic and diastolic BPs within randomized groups were noted during follow-up at the majority of visits in all 4 measurement categories. In the always alone and never alone categories, the intensive group had a similarly reduced risk for the primary outcome compared with the standard group (hazard ratio, 0.62; 95% confidence interval, 0.51-0.76 and hazard ratio, 0.64; 95% confidence interval, 0.46-0.91, respectively; pairwise interaction P value, 0.88); risk was not significantly reduced for the intensive group in the smaller alone-for-rest and the alone-for-BP-measurement categories. Similar BP levels and cardiovascular disease risk reduction were observed in the intensive group in SPRINT participants whether the measurement technique used was primarily attended or unattended.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Effect of Intensive Blood Pressure Treatment on Heart Failure Events in the Systolic Blood Pressure Reduction Intervention Trial

BACKGROUND

Acute decompensated heart failure (ADHF) was a frequent common outcome in SPRINT (Systolic Blood Pressure Intervention Trial). We examined whether there was differential reduction in ADHF events from intensive blood pressure [BP] treatment among the 6 key, prespecified subgroups in SPRINT: age ≥75 years, prior cardiovascular disease, chronic kidney disease, women, black race, and 3 levels of baseline systolic BP (≤132 versus >132 to <145 versus ≥145 mm Hg).

METHODS AND RESULTS

ADHF was defined as hospitalization for ADHF, confirmed and formally adjudicated by a blinded events committee using standardized protocols. At 3.29 years follow-up, there were 103 ADHF events (2.2%) among 4683 standard arm participants and 65 ADHF events (1.4%) among 4678 intensive arm participants (Cox proportional hazards ratio, 0.63; 95% confidence interval, 0.46-0.85; P value =0.003). In multivariable analyses, including treatment arm, baseline covariates that were significant predictors for ADHF included chronic kidney disease, cardiovascular disease, age≥75 years, body mass index, and higher systolic BP. The beneficial effect of the intervention on incident ADHF was consistent across all prespecified subgroups. Participants who had incident ADHF had markedly increased risk of subsequent cardiovascular events, including a 27-fold increase (P<0.001) in cardiovascular death.

CONCLUSIONS

Targeting a systolic BP<120 mm Hg, compared with <140 mm Hg, significantly reduced ADHF events, and the benefit was similar across all key, prespecified subgroups. Participants who developed ADHF had markedly increased risk for subsequent cardiovascular events and death, highlighting the importance of strategies aimed at prevention of ADHF, especially intensive BP reduction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Effect of Intensive Blood Pressure Lowering on Left Ventricular Hypertrophy in Patients With Hypertension: SPRINT (Systolic Blood Pressure Intervention Trial)

BACKGROUND

It is currently unknown whether intensive blood pressure (BP) lowering beyond that recommended would lead to more lowering of the risk of left ventricular hypertrophy (LVH) in patients with hypertension and whether reducing the risk of LVH explains the reported cardiovascular disease (CVD) benefits of intensive BP lowering in this population.

METHODS

This analysis included 8164 participants (mean age, 67.9 years; 35.3% women; 31.2% blacks) with hypertension but no diabetes mellitus from the SPRINT trial (Systolic Blood Pressure Intervention Trial): 4086 randomly assigned to intensive BP lowering (target SBP <120 mm Hg) and 4078 assigned to standard BP lowering (target SBP <140 mm Hg). Progression and regression of LVH as defined by Cornell voltage criteria derived from standard 12-lead ECGs recorded at baseline and biannually were compared between treatment arms during a median follow-up of 3.81 years. The effect of intensive (versus standard) BP lowering on the SPRINT primary CVD outcome (a composite of myocardial infarction, acute coronary syndrome, stroke, heart failure, and CVD death) was compared before and after adjustment for LVH as a time-varying covariate.

RESULTS

Among SPRINT participants without baseline LVH (n=7559), intensive (versus standard) BP lowering was associated with a 46% lower risk of developing LVH (hazard ratio=0.54; 95% confidence interval, 0.43-0.68). Similarly, among SPRINT participants with baseline LVH (n=605, 7.4%), those assigned to the intensive (versus standard) BP lowering were 66% more likely to regress/improve their LVH (hazard ratio=1.66; 95% confidence interval, 1.31-2.11). Adjustment for LVH as a time-varying covariate did not substantially attenuate the effect of intensive BP therapy on CVD events (hazard ratio of intensive versus standard BP lowering on CVD, 0.76 [95% confidence interval, 0.64-0.90] and 0.77 [95% confidence interval, 0.65-0.91] before and after adjustment for LVH as a time-varying covariate, respectively).

CONCLUSIONS

Among patients with hypertension but no diabetes mellitus, intensive BP lowering (target systolic BP <120 mm Hg) compared with standard BP lowering (target systolic BP <140 mm Hg) resulted in lower rates of developing new LVH in those without LVH and higher rates of regression of LVH in those with existing LVH. This favorable effect on LVH did not explain most of the reduction in CVD events associated with intensive BP lowering in the SPRINT trial.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01206062.

Decline in Cardiovascular Mortality: Possible Causes and Implications

If the control of infectious diseases was the public health success story of the first half of the 20th century, then the decline in mortality from coronary heart disease and stroke has been the success story of the century's past 4 decades. The early phase of this decline in coronary heart disease and stroke was unexpected and controversial when first reported in the mid-1970s, having followed 60 years of gradual increase as the US population aged. However, in 1978, the participants in a conference convened by the National Heart, Lung, and Blood Institute concluded that a significant recent downtick in coronary heart disease and stroke mortality rates had definitely occurred, at least in the US Since 1978, a sharp decline in mortality rates from coronary heart disease and stroke has become unmistakable throughout the industrialized world, with age-adjusted mortality rates having declined to about one third of their 1960s baseline by 2000. Models have shown that this remarkable decline has been fueled by rapid progress in both prevention and treatment, including precipitous declines in cigarette smoking, improvements in hypertension treatment and control, widespread use of statins to lower circulating cholesterol levels, and the development and timely use of thrombolysis and stents in acute coronary syndrome to limit or prevent infarction. However, despite the huge growth in knowledge and advances in prevention and treatment, there remain many questions about this decline. In fact, there is evidence that the rate of decline may have abated and may even be showing early signs of reversal in some population groups. The National Heart, Lung, and Blood Institute, through a request for information, is soliciting input that could inform a follow-up conference on or near the 40th anniversary of the original landmark conference to further explore these trends in cardiovascular mortality in the context of what has come before and what may lie ahead.

Effect of Intensive Versus Standard Clinic-Based Hypertension Management on Ambulatory Blood Pressure: Results From the SPRINT (Systolic Blood Pressure Intervention Trial) Ambulatory Blood Pressure Study

The effect of clinic-based intensive hypertension treatment on ambulatory blood pressure (BP) is unknown. The goal of the SPRINT (Systolic Blood Pressure Intervention Trial) ambulatory BP ancillary study was to evaluate the effect of intensive versus standard clinic-based BP targets on ambulatory BP. Ambulatory BP was obtained within 3 weeks of the 27-month study visit in 897 SPRINT participants. Intensive treatment resulted in lower clinic systolic BP (mean difference between groups=16.0 mm Hg; 95% confidence interval, 14.1-17.8 mm Hg), nighttime systolic BP (mean difference=9.6 mm Hg; 95% confidence interval, 7.7-11.5 mm Hg), daytime systolic BP (mean difference=12.3 mm Hg; 95% confidence interval, 10.6-13.9 mm Hg), and 24-hour systolic BP (mean difference=11.2 mm Hg; 95% confidence interval, 9.7-12.8 mm Hg). The night/day systolic BP ratio was similar between the intensive (0.92±0.09) and standard-treatment groups (0.91±0.09). There was considerable lack of agreement within participants between clinic systolic BP and daytime ambulatory systolic BP with wide limits of agreement on Bland-Altman plots. In conclusion, targeting a systolic BP of <120 mm Hg, when compared with <140 mm Hg, resulted in lower nighttime, daytime, and 24-hour systolic BP, but did not change the night/day systolic BP ratio. Ambulatory BP monitoring may be required to assess the effect of targeted hypertension therapy on out of office BP. Further studies are needed to assess whether targeting hypertension therapy based on ambulatory BP improves clinical outcomes.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01835249.

SPRINT and Implications for Target Organ Protection in African Americans

<em>Ethn Dis.</em> 2016;26(3):271-274; doi:10.18865/ed.26.3.271

The Productivity of NHLBI-Funded Obesity Research, 1983-2013

OBJECTIVE

To describe and elucidate the time trends of the academic productivity of NHLBI's obesity-related research funding via bibliometric analysis of 30 years of NHLBI-supported obesity-related publications.

METHODS

In total, 3,545 NHLBI-funded obesity-related publications were identified in the Thomson Reuters InCites™ database. Shared references in a community detection algorithm were used to identify publication topics. Characteristics of publications and topical communities were analyzed based on citation count and percentile rank. A percentile rank >90 was considered "highly cited."

RESULTS

Obesity-related publications increased more than 10-fold over 30 years, whereas NHLBI-funded publications only increased twofold NHLBI-funded obesity publications were cited a median of 23 times (IQR 8-55, range 0-2,047, mean 52). Thirty percent of these publications were highly cited compared to the expected ten percent. Six topical communities were present in 1983 compared to 16 in 2013. The most highly cited topical areas were sleep (n = 199 publications, 38% highly cited), cardiovascular morbidity and mortality (n = 277, 36%), obesity correlates and consequences (n = 588, 35%), and asthma and inflammation (n = 283, 35%).

CONCLUSIONS

NHLBI-funded obesity publications have contributed substantially to the obesity literature, with many highly cited. Publications grew in number and topical diversity over 30 years and grew at a faster rate than total NHLBI publications.

A Randomized Trial of Intensive versus Standard Blood-Pressure Control

BACKGROUND

The most appropriate targets for systolic blood pressure to reduce cardiovascular morbidity and mortality among persons without diabetes remain uncertain.

METHODS

We randomly assigned 9361 persons with a systolic blood pressure of 130 mm Hg or higher and an increased cardiovascular risk, but without diabetes, to a systolic blood-pressure target of less than 120 mm Hg (intensive treatment) or a target of less than 140 mm Hg (standard treatment). The primary composite outcome was myocardial infarction, other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes.

RESULTS

At 1 year, the mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard-treatment group. The intervention was stopped early after a median follow-up of 3.26 years owing to a significantly lower rate of the primary composite outcome in the intensive-treatment group than in the standard-treatment group (1.65% per year vs. 2.19% per year; hazard ratio with intensive treatment, 0.75; 95% confidence interval [CI], 0.64 to 0.89; P<0.001). All-cause mortality was also significantly lower in the intensive-treatment group (hazard ratio, 0.73; 95% CI, 0.60 to 0.90; P=0.003). Rates of serious adverse events of hypotension, syncope, electrolyte abnormalities, and acute kidney injury or failure, but not of injurious falls, were higher in the intensive-treatment group than in the standard-treatment group.

CONCLUSIONS

Among patients at high risk for cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg, resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause, although significantly higher rates of some adverse events were observed in the intensive-treatment group. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01206062.).

The design and rationale of a multicenter clinical trial comparing two strategies for control of systolic blood pressure: the Systolic Blood Pressure Intervention Trial (SPRINT)

BACKGROUND

High blood pressure is an important public health concern because it is highly prevalent and a risk factor for adverse health outcomes, including coronary heart disease, stroke, decompensated heart failure, chronic kidney disease, and decline in cognitive function. Observational studies show a progressive increase in risk associated with blood pressure above 115/75 mm Hg. Prior research has shown that reducing elevated systolic blood pressure lowers the risk of subsequent clinical complications from cardiovascular disease. However, the optimal systolic blood pressure to reduce blood pressure-related adverse outcomes is unclear, and the benefit of treating to a level of systolic blood pressure well below 140 mm Hg has not been proven in a large, definitive clinical trial.

PURPOSE

To describe the design considerations of the Systolic Blood Pressure Intervention Trial (SPRINT) and the baseline characteristics of trial participants.

METHODS

The Systolic Blood Pressure Intervention Trial is a multicenter, randomized, controlled trial that compares two strategies for treating systolic blood pressure: one targets the standard target of <140 mm Hg, and the other targets a more intensive target of <120 mm Hg. Enrollment focused on volunteers of age ≥50 years (no upper limit) with an average baseline systolic blood pressure ≥130 mm Hg and evidence of cardiovascular disease, chronic kidney disease, 10-year Framingham cardiovascular disease risk score ≥15%, or age ≥75 years. The Systolic Blood Pressure Intervention Trial recruitment also targeted three pre-specified subgroups: participants with chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m(2)), participants with a history of cardiovascular disease, and participants 75 years of age or older. The primary outcome is first the occurrence of a myocardial infarction (MI), acute coronary syndrome, stroke, heart failure, or cardiovascular disease death. Secondary outcomes include all-cause mortality, decline in kidney function or development of end-stage renal disease, incident dementia, decline in cognitive function, and small-vessel cerebral ischemic disease.

RESULTS

Between 8 November 2010 and 15 March 2013, Systolic Blood Pressure Intervention Trial recruited and randomized 9361 people at 102 clinics, including 3331 women, 2648 with chronic kidney disease, 1877 with a history of cardiovascular disease, 3962 minorities, and 2636 ≥75 years of age.

LIMITATIONS

Although the overall recruitment target was met, the numbers recruited in the high-risk subgroups were lower than planned.

CONCLUSIONS

The Systolic Blood Pressure Intervention Trial will provide important information on the risks and benefits of intensive blood pressure treatment targets in a diverse sample of high-risk participants, including those with prior cardiovascular disease, chronic kidney disease, and those aged ≥75 years.

Effect of long-chain ω-3 fatty acids and lutein + zeaxanthin supplements on cardiovascular outcomes: results of the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial

IMPORTANCE

Dietary supplements have been proposed as a mechanism to improve health and prevent disease.

OBJECTIVE

To determine if supplementing diet with long-chain ω-3 polyunsaturated fatty acids or with macular xanthophylls results in a reduced rate of cardiovascular disease (CVD).

DESIGN, SETTING, AND PARTICIPANTS

The Cardiovascular Outcome Study (COS) was an ancillary study of the Age-Related Eye Disease Study 2 (AREDS2), a factorial-designed randomized clinical trial of 4203 participants recruited from 82 US academic and community ophthalmology clinics, who were followed up for a median of 4.8 years. Individuals were eligible to participate if they were between the ages of 50 and 85 years, had intermediate or advanced age-related macular degeneration in 1 eye, and were willing to be randomized. Participants with stable, existing CVD (>12 months since initial event) were eligible to participate. Participants, staff, and outcome assessors were masked to intervention.

INTERVENTIONS

Daily supplementation with long-chain ω-3 polyunsaturated fatty acids (350-mg docosahexaenoic acid [DHA] + 650-mg eicosapentaenoic acid [EPA]), macular xanthophylls (10-mg lutein + 2-mg zeaxanthin), combination of the two, or matching placebos. These treatments were added to background therapy of the AREDS vitamin and mineral formulation for macular degeneration. MAIN OUTCOMES AND MEASURES A composite outcome of myocardial infarction, stroke, and cardiovascular death with 4 prespecified secondary combinations of the primary outcome with hospitalized heart failure, revascularization, or unstable angina.

RESULTS

Study participants were primarily white, married, and highly educated, with a median age at baseline of 74 years. A total of 602 cardiovascular events were adjudicated, and 459 were found to meet 1 of the study definitions for a CVD outcome. In intention-to-treat analysis, no reduction in the risk of CVD or secondary CVD outcomes was seen for the DHA + EPA (primary outcome: hazard ratio [HR], 0.95; 95% CI, 0.78-1.17) or lutein + zeaxanthin (primary outcome: HR, 0.94; 95% CI, 0.77-1.15) groups. No differences in adverse events or serious adverse event were seen by treatment group. The sample size was sufficient to detect a 25% reduction in CVD events with 80% power.

CONCLUSIONS AND RELEVANCE

Dietary supplementation of long-chain ω-3 polyunsaturated fatty acids or macular xanthophylls in addition to daily intake of minerals and vitamins did not reduce the risk of CVD in elderly participants with age-related macular degeneration.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00345176.

Depression predicts all-cause mortality: epidemiological evaluation from the ACCORD HRQL substudy

OBJECTIVE

Depression affects up to 20-25% of adults with type 2 diabetes and may increase all-cause mortality, but few well-designed studies have examined the effects of depression on the full range of cardiovascular disease outcomes in type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 2,053 participants in the ACCORD (Action to Control Cardiovascular Risk in Diabetes) Health-Related Quality of Life substudy completed the Patient Health Questionnaire (PHQ)-9 measure of depression symptoms at baseline and 12, 36, and 48 months. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) (95% CI) for the time-varying impact of depression on protocol-defined clinical outcomes with and without adjustment for demographic, trial-related, clinical, and behavioral variables.

RESULTS

In fully adjusted models, depression was not significantly related to the ACCORD primary composite outcome (cardiovascular death, nonfatal heart attack, or stroke) (HR 1.53 [95% CI 0.85-2.73]) or to the ACCORD microvascular composite outcome (0.93 [0.53-1.62]), but all-cause mortality was significantly increased both in those with PHQ-assessed probable major depression (2.24 [1.24-4.06]) and PHQ score of ≥ 10 (1.84 [1.17-2.89]). The effect of depression on all-cause mortality was not related to previous cardiovascular events or to assignment to intensive or standard glycemia control. Probable major depression (by PHQ-9) had a borderline impact on the ACCORD macrovascular end point (1.42 [0.99-2.04]).

CONCLUSIONS

Depression increases the risk of all-cause mortality and may increase the risk of macrovascular events among adults with type 2 diabetes at high risk for cardiovascular events.

Long-term renal and cardiovascular outcomes in Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants by baseline estimated GFR

BACKGROUND AND OBJECTIVES

CKD is common among older patients. This article assesses long-term renal and cardiovascular outcomes in older high-risk hypertensive patients, stratified by baseline estimated GFR (eGFR), and long-term outcome efficacy of 5-year first-step treatment with amlodipine or lisinopril, each compared with chlorthalidone.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a long-term post-trial follow-up of hypertensive participants (n=31,350), aged ≥55 years, randomized to receive chlorthalidone, amlodipine, or lisinopril for 4-8 years at 593 centers. Participants were stratified by baseline eGFR (ml/min per 1.73 m(2)) as follows: normal/increased (≥90; n=8027), mild reduction (60-89; n=17,778), and moderate/severe reduction (<60; n=5545). Outcomes were cardiovascular mortality (primary outcome), total mortality, coronary heart disease, cardiovascular disease, stroke, heart failure, and ESRD.

RESULTS

After an average 8.8-year follow-up, total mortality was significantly higher in participants with moderate/severe eGFR reduction compared with those with normal and mildly reduced eGFR (P<0.001). In participants with an eGFR <60, there was no significant difference in cardiovascular mortality between chlorthalidone and amlodipine (P=0.64), or chlorthalidone and lisinopril (P=0.56). Likewise, no significant differences were observed for total mortality, coronary heart disease, cardiovascular disease, stroke, or ESRD.

CONCLUSIONS

CKD is associated with significantly higher long-term risk of cardiovascular events and mortality in older hypertensive patients. By eGFR stratum, 5-year treatment with amlodipine or lisinopril was not superior to chlorthalidone in preventing cardiovascular events, mortality, or ESRD during 9-year follow-up. Because data on proteinuria were not available, these findings may not be extrapolated to proteinuric CKD.

Relationships between changes in patient-reported health status and functional capacity in outpatients with heart failure

BACKGROUND

Heart failure trials use a variety of measures of functional capacity and quality of life. Lack of formal assessments of the relationships between changes in multiple aspects of patient-reported health status and measures of functional capacity over time limits the ability to compare results across studies.

METHODS

Using data from HF-ACTION (N = 2331), we used the Pearson correlation coefficients and predicted change scores from linear mixed-effects modeling to demonstrate the associations between changes in patient-reported health status measured with the EQ-5D visual analog scale and the Kansas City Cardiomyopathy Questionnaire (KCCQ) and changes in peak VO(2) and 6-minute walk distance at 3 and 12 months. We examined a 5-point change in KCCQ within individuals to provide a framework for interpreting changes in these measures.

RESULTS

After adjustment for baseline characteristics, correlations between changes in the visual analog scale and changes in peak VO(2) and 6-minute walk distance ranged from 0.13 to 0.28, and correlations between changes in the KCCQ overall and subscale scores and changes in peak VO(2) and 6-minute walk distance ranged from 0.18 to 0.34. A 5-point change in KCCQ was associated with a 2.50-mL kg(-1) min(-1) change in peak VO(2) (95% CI 2.21-2.86) and a 112-m change in 6-minute walk distance (95% CI 96-134).

CONCLUSIONS

Changes in patient-reported health status are not highly correlated with changes in functional capacity. Our findings generally support the current practice of considering a 5-point change in the KCCQ within individuals to be clinically meaningful.

Relation among body mass index, exercise training, and outcomes in chronic systolic heart failure

Exercise training (ET) in patients with heart failure (HF), as demonstrated in the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION), was associated with improved exercise tolerance and health status and a trend toward reduced mortality or hospitalization. The present analysis of the HF-ACTION cohort examined the effect of ET in overweight and obese subjects compared to normal weight subjects with HF. Of 2,331 subjects with systolic HF randomized to aerobic ET versus usual care in the HF-ACTION, 2,314 were analyzed to determine the effect of ET on all-cause mortality, hospitalizations, exercise parameters, quality of life, and body weight changes by subgroups of body mass index (BMI). The strata included normal weight (BMI 18.5 to 24.9 kg/m(2)), overweight (BMI 25.0 to 29.9 kg/m(2)), obese I (BMI 30 to 34.9 kg/m(2)), obese II (BMI 35 to 39.9 kg/m(2)), and obese III (BMI ≥40 kg/m(2)). At enrollment, 19.4% of subjects were normal weight, 31.3% were overweight, and 49.4% were obese. A greater BMI was associated with a nonsignificant increase in all-cause mortality or hospitalization. ET was associated with nonsignificant reductions in all-cause mortality and hospitalization in each weight category (hazard ratio 0.98, 0.95, 0.92, 0.89, and 0.86 in the normal weight, overweight, obese I, obese II, and obese III categories, respectively; all p >0.05). Modeled improvement in exercise capacity (peak oxygen consumption) and quality of life in the ET group was seen in all BMI categories. In conclusion, aerobic ET in subjects with HF was associated with a nonsignificant trend toward decreased mortality and hospitalization and a significant improvement in quality of life across the range of BMI categories.

Factors related to morbidity and mortality in patients with chronic heart failure with systolic dysfunction: the HF-ACTION predictive risk score model

BACKGROUND

We aimed to develop a multivariable statistical model for risk stratification in patients with chronic heart failure with systolic dysfunction, using patient data that are routinely collected and easily obtained at the time of initial presentation.

METHODS AND RESULTS

In a cohort of 2331 patients enrolled in the HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise TraiNing) study (New York Heart Association class II-IV, left ventricular ejection fraction ≤0.35, randomized to exercise training and usual care versus usual care alone, median follow-up of 2.5 years), we performed risk modeling using Cox proportional hazards models and analyzed the relationship between baseline clinical factors and the primary composite end point of death or all-cause hospitalization and the secondary end point of all-cause death alone. Prognostic relationships for continuous variables were examined using restricted cubic spline functions, and key predictors were identified using a backward variable selection process and bootstrapping methods. For ease of use in clinical practice, point-based risk scores were developed from the risk models. Exercise duration on the baseline cardiopulmonary exercise test was the most important predictor of both the primary end point and all-cause death. Additional important predictors for the primary end point risk model (in descending strength) were Kansas City Cardiomyopathy Questionnaire symptom stability score, higher serum urea nitrogen, and male sex (all P<0.0001). Important additional predictors for the mortality risk model were higher serum urea nitrogen, male sex, and lower body mass index (all P<0.0001).

CONCLUSIONS

Risk models using simple, readily obtainable clinical characteristics can provide important prognostic information in ambulatory patients with chronic heart failure with systolic dysfunction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00047437.

Effects of medical therapies on retinopathy progression in type 2 diabetes

BACKGROUND

We investigated whether intensive glycemic control, combination therapy for dyslipidemia, and intensive blood-pressure control would limit the progression of diabetic retinopathy in persons with type 2 diabetes. Previous data suggest that these systemic factors may be important in the development and progression of diabetic retinopathy.

METHODS

In a randomized trial, we enrolled 10,251 participants with type 2 diabetes who were at high risk for cardiovascular disease to receive either intensive or standard treatment for glycemia (target glycated hemoglobin level, <6.0% or 7.0 to 7.9%, respectively) and also for dyslipidemia (160 mg daily of fenofibrate plus simvastatin or placebo plus simvastatin) or for systolic blood-pressure control (target, <120 or <140 mm Hg). A subgroup of 2856 participants was evaluated for the effects of these interventions at 4 years on the progression of diabetic retinopathy by 3 or more steps on the Early Treatment Diabetic Retinopathy Study Severity Scale (as assessed from seven-field stereoscopic fundus photographs, with 17 possible steps and a higher number of steps indicating greater severity) or the development of diabetic retinopathy necessitating laser photocoagulation or vitrectomy.

RESULTS

At 4 years, the rates of progression of diabetic retinopathy were 7.3% with intensive glycemia treatment, versus 10.4% with standard therapy (adjusted odds ratio, 0.67; 95% confidence interval [CI], 0.51 to 0.87; P=0.003); 6.5% with fenofibrate for intensive dyslipidemia therapy, versus 10.2% with placebo (adjusted odds ratio, 0.60; 95% CI, 0.42 to 0.87; P=0.006); and 10.4% with intensive blood-pressure therapy, versus 8.8% with standard therapy (adjusted odds ratio, 1.23; 95% CI, 0.84 to 1.79; P=0.29).

CONCLUSIONS

Intensive glycemic control and intensive combination treatment of dyslipidemia, but not intensive blood-pressure control, reduced the rate of progression of diabetic retinopathy. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov numbers, NCT00000620 for the ACCORD study and NCT00542178 for the ACCORD Eye study.)

Outcomes, health policy, and managed care: relationships between patient-reported outcome measures and clinical measures in outpatients with heart failure

BACKGROUND

Patient-reported outcomes are increasingly used to assess the efficacy of new treatments. Understanding relationships between these and clinical measures can facilitate their interpretation. We examined associations between patient-reported measures of health-related quality of life and clinical indicators of disease severity in a large, heterogeneous sample of patients with heart failure.

METHODS

Patient-reported measures, including the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the EuroQol Visual Analog Scale (VAS), and clinical measures, including peak VO(2), 6-minute walk distance, and New York Heart Association (NYHA) class, were assessed at baseline in 2331 patients with heart failure. We used general linear models to regress patient-reported measures on each clinical measure. Final models included for significant sociodemographic variables and 2-way interactions.

RESULTS

The KCCQ was correlated with peak VO(2) (r = .21) and 6-minute walk distance (r = .27). The VAS was correlated with peak VO(2) (r = .09) and 6-minute walk distance (r = .11). Using the KCCQ as the response variable, a 1-SD difference in peak Vo(2) (4.7 mL/kg/min) was associated with a 2.86-point difference in the VAS (95% CI, 1.98-3.74) and a 4.75-point difference in the KCCQ (95% CI, 3.78-5.72). A 1-SD difference in 6-minute walk distance (105 m) was associated with a 2.78-point difference in the VAS (95% CI, 1.92-3.64) and a 5.92-point difference in the KCCQ (95% CI, 4.98-6.87); NYHA class III was associated with an 8.26-point lower VAS (95% CI, 6.59-9.93) and a 12.73-point lower KCCQ (95% CI, 10.92-14.53) than NYHA class II.

CONCLUSIONS

These data may inform deliberations about how to best measure benefits of heart failure interventions, and they generally support the practice of considering a 5-point difference on the KCCQ and a 3-point difference on the VAS to be clinically meaningful.

Effects of exercise training on health status in patients with chronic heart failure: HF-ACTION randomized controlled trial

CONTEXT

Findings from previous studies of the effects of exercise training on patient-reported health status have been inconsistent.

OBJECTIVE

To test the effects of exercise training on health status among patients with heart failure.

DESIGN, SETTING, AND PATIENTS

Multicenter, randomized controlled trial among 2331 medically stable outpatients with heart failure with left ventricular ejection fraction of 35% or less. Patients were randomized from April 2003 through February 2007.

INTERVENTIONS

Usual care plus aerobic exercise training (n = 1172), consisting of 36 supervised sessions followed by home-based training, vs usual care alone (n = 1159). Randomization was stratified by heart failure etiology, which was a covariate in all models.

MAIN OUTCOME MEASURES

Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary scale and key subscales at baseline, every 3 months for 12 months, and annually thereafter for up to 4 years. The KCCQ is scored from 0 to 100 with higher scores corresponding to better health status. Treatment group effects were estimated using linear mixed models according to the intention-to-treat principle.

RESULTS

Median follow-up was 2.5 years. At 3 months, usual care plus exercise training led to greater improvement in the KCCQ overall summary score (mean, 5.21; 95% confidence interval, 4.42 to 6.00) compared with usual care alone (3.28; 95% confidence interval, 2.48 to 4.09). The additional 1.93-point increase (95% confidence interval, 0.84 to 3.01) in the exercise training group was statistically significant (P < .001). After 3 months, there were no further significant changes in KCCQ score for either group (P = .85 for the difference between slopes), resulting in a sustained, greater improvement overall for the exercise group (P < .001). Results were similar on the KCCQ subscales, and no subgroup interactions were detected.

CONCLUSIONS

Exercise training conferred modest but statistically significant improvements in self-reported health status compared with usual care without training. Improvements occurred early and persisted over time.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00047437.

Study designs for effectiveness and translation research :identifying trade-offs

BACKGROUND

Practitioners and policymakers need credible evidence of effectiveness to justify allocating resources to complex, expensive health programs. Investigators, however, face challenges in designing sound effectiveness and translation research with relevance for "real-world" settings.

METHODS

Research experts and federal and foundation funders (n= approximately 120) prepared for and participated in a symposium, held May 4-5, 2004, to weigh the strengths, limitations, and trade-offs between alternate designs for studying the effectiveness and translation of complex, multilevel health interventions.

RESULTS

Symposium attendees acknowledged that research phases (hypothesis generating, efficacy, effectiveness, translation) are iterative and cyclical, not linear, since research in advanced phases may reveal unanswered questions in earlier phases. Research questions thus always need to drive the choice of study design. When randomization and experimental control are feasible, participants noted that the randomized controlled trial with individual random assignment remains the gold standard for safeguarding internal validity. Attendees highlighted trade-offs of randomized controlled trial variants, quasi-experimental designs, and natural experiments for use when randomization or experimental control or both are impossible or inadequately address external validity. Participants discussed enhancements to all designs to increase confidence in causal inference while accommodating greater external validity. Since no single study can establish causality, participants encouraged replication of studies and triangulation using different study designs. Participants also recommended participatory research approaches for building population relevance, acceptability, and usefulness.

CONCLUSIONS

Consideration of the study design choices, trade-offs, and enhancements discussed here can guide the design, funding, completion, and publication of appropriate policy- and practice-oriented effectiveness and translational research for complex, multilevel health interventions.

Health care charges associated with physical inactivity, overweight, and obesity

INTRODUCTION

Physical inactivity, overweight, and obesity are associated with increased morbidity and mortality. The objective of this study was to estimate the proportion of total health care charges associated with physical inactivity, overweight, and obesity among U.S. populations aged 40 years and older.

METHODS

A predictive model of health care charges was developed using data from a cohort of 8000 health plan members aged 40 and older. Model cells were defined by physical activity status, body mass index, age, sex, smoking status, and selected chronic diseases. Total health care charges were estimated by multiplying the percentage of the population in each cell by the predicted charges per cell. Counterfactual estimates were computed by reclassifying all individuals as physically active and of normal weight while leaving other characteristics unchanged. Charges associated with physical inactivity, overweight, and obesity were computed as the difference between current risk profile total charges and counterfactual total charges. National population percentage estimates were derived from the National Health Interview Survey; those estimates were multiplied by the predicted charges per cell from the health plan analysis.

RESULTS

Physical inactivity, overweight, and obesity were associated with 23% (95% confidence interval [CI], 10%-34%) of health plan health care charges and 27% (95% CI, 10%-37%) of national health care charges. Although charges associated with these risk factors were highest for the oldest group (aged 65 years and older) and for individuals with chronic conditions, nearly half of aggregate charges were generated from the group aged 40 to 64 years without chronic disease.

CONCLUSION

Charges associated with physical inactivity, overweight, and obesity constitute a significant portion of total medical expenditures. The results underscore the importance of addressing these risk factors in all segments of the population.

Prevalence of multiple chronic disease risk factors. 2001 National Health Interview Survey

BACKGROUND

Four common factors--cigarette smoking, risky drinking of alcoholic beverages, physical inactivity, and overweight--contribute substantially to chronic disease prevalence.

METHODS

We used data from the 2001 National Health Interview Survey to provide an up-to-date picture of multiple risk factor prevalence and clustering in the U.S. population. We conducted a multinomial logit analysis to examine the independent association between each covariate and the dependent ordinal risk factor variable with three levels (none or one risk factor, two risk factors, and three or four risk factors).

RESULTS

Seventeen percent of the sample of 29,183 subjects had three or more risk factors. For the entire sample, the mean number of risk factors was 1.68 (95% confidence interval [CI]=1.66-1.70). Many demographic and health factors were significantly associated with the mean number of risk factors including gender, age, ethnic/racial categories, education, martial status, presence of chronic diseases, level of mental distress, country of birth, and presence and type of health insurance. Using the risk factor score as the ordinal dependent variable, adjusted odds for having a risk score of three or four versus zero or one were as follows: men aged <65, 2.49 (95% CI=2.29-2.72); education attainment of high school graduate or less, 3.24 (95% CI=2.86-3.67); and individuals with high levels of mental distress, 2.06 (95% CI=1.65-2.58).

CONCLUSIONS

Our analyses confirm earlier reports of the high prevalence of multiple, clustered behavioral risk factors and underline the challenge this presents for primary care and public health systems.

Shoulder disorders and postural stress in automobile assembly work

OBJECTIVES

A case-referent study was conducted in an automobile assembly plant to evaluate the risk of shoulder disorders associated with nonneutral postures.

METHODS

The cases were workers who reported shoulder pain to the plant clinic during a 10-month period and met symptom criteria (pain frequency or duration in the past year) in an interview; more than one-half also had positive findings in a physical examination. The referents were randomly selected workers who were free of shoulder disorders according to the clinic records, the interview, and the physical examination. For each of the 79 cases and 124 referents, 1 job was analyzed for postural and biomechanical demands by an analyst blinded to the case-referent status.

RESULTS

Forty-one percent of the subjects flexed or abducted the right arm "severely" (above 90 degrees) during the job cycle, and 35% did so with the left arm. The peak torques at the shoulder were rather low. Shoulder disorders were associated with severe flexion or abduction of the left [odds ratio (OR) 3.2, 95% confidence interval (95% CI) 1.5-6.5] and the right (OR 2.3, 95% CI 1.2-4.8) shoulder. The risk increased as the proportion of the work cycle exposed increased. The relationships were similar for the cases with and without physical findings. Use of hand-held tools increased the risk and also modified the association with postural stress, although the joint exposure distributions limited full analysis of this finding.

CONCLUSIONS

The findings support the conclusion that severe shoulder flexion or abduction, especially for 10% or more of the work cycle, is predictive of chronic or recurrent shoulder disorders.

Evaluation of the revised NIOSH lifting equation. A cross-sectional epidemiologic study

STUDY DESIGN

A cross-sectional study of the 1-year prevalence of low back pain was conducted in workers employed in manual lifting jobs.

OBJECTIVES

To provide epidemiologic data to determine the correlation between the prevalence of low back pain and exposure to manual lifting stressors, measured with the lifting index component of the revised lifting equation from the National Institute for Occupational Safety and Health (NIOSH).

SUMMARY OF BACKGROUND DATA

The NIOSH lifting equation has been proposed as a practical, yet valid tool for assessing the risks of low back pain caused by manual lifting. To date, however, there have been few studies in which the effectiveness of the equation to identify jobs with elevated rates of low back pain has been evaluated.

METHODS

Fifty jobs from four industrial sites were evaluated with the NIOSH lifting equation. A symptom and occupational history questionnaire was administered to 204 people employed in lifting jobs and 80 people employed in nonlifting jobs. Regression analysis was used to determine whether there was a correlation between the lifting index and reported low back pain.

RESULTS

As the lifting index increased from 1.0 to 3.0, the odds of low back pain increased, with a peak and statistically significant odds ratio occurring in the 2 < lifting index < or = 3 category (odds ratio = 2.45). For jobs with a lifting index higher than 3.0, however, the odds ratio was lower (odds ratio = 1.45).

CONCLUSIONS

Although low back pain is a common disorder, the lifting index appears be a useful indicator for determining the risk of low back pain caused by manual lifting.

Surveillance and occupational health

This report explains the basics of two important uses of surveillance data: determining the magnitude of a specific occupational health or injury problem and examining temporal trends to determine whether the problem is increasing or decreasing. Types of data available for the purpose and some of their strengths and weaknesses are described. The utility of surveillance data is illustrated with examples from surveillance of acute injuries, musculoskeletal disorders, lead overexposures, and hazard surveillance data sets. Increasingly, surveillance systems may be used to evaluate the effectiveness of interventions. Surveillance is most important in times of rapid change in the economy and when resources for prevention may be limited. Both conditions are common in the world today.

The effectiveness of commonly used lifting assessment methods to identify industrial jobs associated with elevated risk of low-back disorders

Low-back disorders (LBD) continue to be the most costly and common musculoskeletal problem facing society today. Investigators have developed tools or measures that are intended to identify jobs that will probably be associated with an elevated risk of low-back disorders. However, an important and not widely discussed issue associated with these tools and procedures has been that of the validity or effectiveness of the tools. Therefore the objective of this study was to evaluate the validity and effectiveness of two commonly used types of LBD assessment methods in terms of their ability to correctly associate jobs with LBD risk. The 1981 NIOSH Work Practices Guide for Manual Lifting and the 1991 NIOSH revised lifting equation, along with psychophysical measures were assessed for their ability to correctly identify high-, medium-, and low-risk (of LBD) jobs. Risk was defined according to a database of 353 industrial jobs representing over 21 million person-hours of exposure. The results indicated that both NIOSH measures were predictive and resulted in odds ratios between 3.1 and 4.6. Higher odds ratios were found when the maximum horizontal distance was used to assess a job compared to the average horizontal distance. Further analyses indicated that the two NIOSH assessment methods classified risk in very different ways. The 1981 NIOSH Guide demonstrated good specificity (91%) in that it identified low-risk jobs well but it also displayed low sensitivity by only correctly identifying 10% of the high-risk jobs. The 1993 NIOSH revised lifting equation, on the other hand, had better sensitivity. It correctly identified 73% of the high-risk jobs but did not identify low- and medium-risk jobs well. Using psychophysical criteria it was observed that 60% of the high-risk jobs would be judged to be acceptable, whereas, 64% and 91% of the medium- and low-risk jobs, respectively, would be judged to be acceptable. This study indicates that the different measures have various strengths and weaknesses. When controlling for occupational LBD it should be recognized that a variety of measures exist and that the measure that most appropriately assesses risk depends upon the characteristics of the job.

Cancer risks among workers exposed to metalworking fluids: a systematic review

Metalworking fluids (MWFs) are commonly used in a variety of industrial machining and grinding operations. The National Institute for Occupational Safety and Health (NIOSH) estimates that more that one million workers are exposed to MWFs. NIOSH conducted a comprehensive and systematic review of the epidemiologic studies that examined the association between MWF exposure and cancer. Substantial evidence was found for an increased risk of cancer at several sites (larynx, rectum, pancreas, skin, scrotum, and bladder) associated with at least some MWFs used prior to the mid-1970s. This paper provides the evidence pertaining to cancer at these sites. Cancer at those sites found to have more limited or less consistent evidence for an association with MWF (stomach, esophagus, lung, prostate, brain, colon, and hematopoietic system) will not be discussed in this paper but are discussed in the recent NIOSH Criteria for a Recommended Standard-Occupational Exposure to MWFs. Because the changes in MWF composition that have occurred over the last several decades may not be sufficient to eliminate the cancer risks associated with MWF exposure, reductions in airborne MWF exposures are recommended.

Design and conduct of occupational injury intervention studies: a review of evaluation strategies

Occupational injuries continue to exact a great toll on American workers and their employers--the physical and financial costs are enormous. However, in the current political climate, few employers or regulatory agencies will implement injury prevention interventions without specific evidence of their effectiveness. This paper reviews the literature on the design, conduct, and evaluation of occupational injury interventions. Our review suggests that randomized controlled trials are rare and also notes that the quasi-experimental studies in the literature often use the weakest designs. We recommend a hierarchical approach to evaluating occupational injury interventions--beginning with qualitative studies, following up with simple quasi-experimental designs using historical controls, continuing with more elaborate quasi-experimental designs comparing different firms' experience, and, when necessary, implementing randomized controlled trials.

Work-related musculoskeletal disorders: comparison of data sources for surveillance

Work-related upper extremity musculoskeletal disorders "associated with repeated trauma" account for more than 60% of all newly reported occupational illness, 332,000 in 1994 according to the U.S. Department of Labor. These numbers do not include, for example, those disorders categorized as "injuries due to overexertion in lifting," approximately 370,000. Early identification of potential disorders and associated risk factors is needed to reduce these disorders. There are a number of possible methods for conducting surveillance for work-related musculoskeletal disorders (WMDs) based on health outcome: workers' compensation, sickness and accident insurance, OSHA 200 logs, plant medical records, self-administered questionnaires, professional interviews, and physical examinations. In addition, hazard surveillance based on evaluation of job exposures to physical stressors by nonoccupational health personnel is possible. As part of a large labor-management-initiated intervention study to reduce the incidence of WMDs in four automotive plants, we were able to compare the strengths and limitations of each of these surveillance tools. University administered health interviews yielded the highest rate of symptoms; combined physical examinations plus interview (point prevalence) rates were similar to self-administered questionnaires (period prevalence) rates. Plant medical records yielded the lowest rate of WMDs. WMD status on self-administered questionnaire and on physical examination were associated with risk factor exposure scores. This study suggests that symptoms questionnaires and checklist-based hazard surveillance are feasible within the context of joint labor-management ergonomics programs and are more sensitive indicators of ergonomic problems than pre-existing data sources.

The importance of information dissemination in the prevention of occupational cancer

It is assumed that prevention of occupational cancer depends upon dissemination of research findings, resulting in changes in work processes and reduction of occupational exposures to carcinogens. Examples of successes and failures of information dissemination are found in the results of research on silicosis. Better assessment of the effectiveness of information dissemination is needed, along with greater understanding of the barriers to implementation of the information by workers and management and improved hazard surveillance.