Comparing the cost-effectiveness of four novel risk markers for screening asymptomatic individuals to prevent cardiovascular disease (CVD) in the US population.

BACKGROUND: High sensitivity CRP (hsCRP), coronary artery calcification on CT (CT calcium), carotid artery intima media thickness on ultrasound (cIMT) and ankle-brachial index (ABI) improve prediction of cardiovascular disease (CVD) risk, but the benefit of screening with these novel risk markers in the U.S. population is unclear. METHODS AND RESULTS: A microsimulation model evaluating lifelong cost-effectiveness for individuals aged 40-85 at intermediate risk of CVD, using 2003-2004 NHANES-III (N=3736), Framingham Heart Study, U.S. Vital Statistics, meta-analyses of independent predictive effects of the four novel risk markers and treatment effects was constructed. Using both an intention-to-treat (assumes adherence <100% and incorporates disutility from taking daily medications) and an as-treated (100% adherence and no disutility) analysis, quality adjusted life years (QALYs), lifetime costs (2014 US $), and incremental cost-effectiveness ratios (ICER in $/QALY gained) of screening with hsCRP, CT coronary calcium, cIMT and ABI were established compared with current practice, full adherence to current guidelines, and ubiquitous statin therapy. In the intention-to-treat analysis in men, screening with CT calcium was cost effective ($32,900/QALY) compared with current practice. In women, screening with hsCRP was cost effective ($32,467/QALY). In the as-treated analysis, statin therapy was both more effective and less costly than all other strategies for both men and women. CONCLUSIONS: When a substantial disutility from taking daily medication is assumed, screening men with CT coronary calcium is likely to be cost-effective whereas screening with hsCRP has value in women. The individual perceived disutility for taking daily medication should play a key role in the decision.

Risk factors for inguinal hernia in middle-aged and elderly men: results from the Rotterdam Study.

BACKGROUND: Prospective data on risk factors and the incidence of inguinal hernia are sparse, especially in an elderly population. The aim of this study was to determine the incidence of and risk factors for inguinal hernia. METHODS: We analyzed data from the Rotterdam Study, a prospective cohort study that observed the general population aged ≥45 years of Ommoord, a district in Rotterdam, from baseline (1990) over a period of >20 years. Diagnoses of inguinal hernia were obtained from hospital discharge records and records from general practitioners. Multivariate regression analysis was performed to determine risk factors for inguinal hernia development. RESULTS: Among 5,780 men, with a total of 50,802 person-years, who did not have a hernia at baseline, 416 cases of inguinal hernia (7.2%) occurred. The 20-year cumulative incidence was 14%. Age-adjusted hazard ratio (HR) for inguinal hernia for men relative to women was 12.4 (95% CI, 9.5-16.3; P < .001). On multivariate analysis, the risk of inguinal hernia increased with advancing age (HR per 1-year increase in age, 1.03; 95% CI, 1.02-1.04; P < .001). Participants with a body mass index (BMI) of 25-30 kg/m2 had an HR of 0.72 (95% CI, 0.58-0.89; P = .003) compared with a BMI of <25; a BMI of >30 had an associated HR of 0.63 (95% CI, 0.42-0.94; P = .025). CONCLUSION: Inguinal hernia is common in the middle-aged and elderly male population and its incidence increases with advancing age. Overweight or obese patients have a lesser risk of developing an inguinal hernia.

Incisional hernia after liver transplantation: risk factors and health-related quality of life.

The aim of this cross-sectional study was to analyze the incidence of incisional hernia after liver transplantation (LT), to determine potential risk factors for their development, and to assess their impact on health-related quality of life (HRQoL). Patients who underwent LT through a J-shaped incision with a minimum follow-up of three months were included. Follow-up was conducted at the outpatient clinic. Short Form 36 (SF-36) and body image questionnaire (BIQ) were used for the assessment of HRQoL. A total of 140 patients was evaluated. The mean follow-up period was 33 (SD 20) months. Sixty patients (43%) were diagnosed with an incisional hernia. Multivariate analysis revealed surgical site infection (OR 5.27, p = 0.001), advanced age (OR 1.05, p = 0.003), and prolonged ICU stay (OR 1.54, p = 0.022) to be independent risk factors for development of incisional hernia after LT. Patients with an incisional hernia experienced significantly diminished HRQoL with respect to physical, social, and mental aspects. In conclusion, patients who undergo LT exhibit a high incidence of incisional hernia, which has a considerable impact on HRQoL. Development of incisional hernia was shown to be related to surgical site infection, advanced age, and prolonged ICU stay.

Separate prediction of intracerebral hemorrhage and ischemic stroke.

OBJECTIVES: To develop and validate 10-year cumulative incidence functions of intracerebral hemorrhage (ICH) and ischemic stroke (IS). METHODS: We used data on 27,493 participants from 3 population-based cohort studies: the Atherosclerosis Risk in Communities Study, median age 54 years, 45% male, median follow-up 20.7 years; the Rotterdam Study, median age 68 years, 38% male, median follow-up 14.3 years; and the Cardiovascular Health Study, median age 71 years, 41% male, median follow-up 12.8 years. Among these participants, 325 ICH events, 2,559 IS events, and 9,909 nonstroke deaths occurred. We developed 10-year cumulative incidence functions for ICH and IS using stratified Cox regression and competing risks analysis. Basic models including only established nonlaboratory risk factors were extended with diastolic blood pressure, total cholesterol/high-density lipoprotein cholesterol ratio, body mass index, waist-to-hip ratio, and glomerular filtration rate. The cumulative incidence functions' performances were cross-validated in each cohort separately by Harrell C-statistic and calibration plots. RESULTS: High total cholesterol/high-density lipoprotein cholesterol ratio decreased the ICH rates but increased IS rates (p for difference across stroke types <0.001). For both the ICH and IS models, C statistics increased more by model extension in the Atherosclerosis Risk in Communities and Cardiovascular Health Study cohorts. Improvements in C statistics were reproduced by cross-validation. Models were well calibrated in all cohorts. Correlations between 10-year ICH and IS risks were moderate in each cohort. CONCLUSIONS: We developed and cross-validated cumulative incidence functions for separate prediction of 10-year ICH and IS risk. These functions can be useful to further specify an individual's stroke risk.

Predictive value of updating Framingham risk scores with novel risk markers in the U.S. general population.

BACKGROUND: According to population-based cohort studies CT coronary calcium score (CTCS), carotid intima-media thickness (cIMT), high-sensitivity C- reactive protein (CRP), and ankle-brachial index (ABI) are promising novel risk markers for improving cardiovascular risk assessment. Their impact in the U.S. general population is however uncertain. Our aim was to estimate the predictive value of four novel cardiovascular risk markers for the U.S. general population. METHODS AND FINDINGS: Risk profiles, CRP and ABI data of 3,736 asymptomatic subjects aged 40 or older from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 exam were used along with predicted CTCS and cIMT values. For each subject, we calculated 10-year cardiovascular risks with and without each risk marker. Event rates adjusted for competing risks were obtained by microsimulation. We assessed the impact of updated 10-year risk scores by reclassification and C-statistics. In the study population (mean age 56±11 years, 48% male), 70% (80%) were at low (<10%), 19% (14%) at intermediate (≥10-<20%), and 11% (6%) at high (≥20%) 10-year CVD (CHD) risk. Net reclassification improvement was highest after updating 10-year CVD risk with CTCS: 0.10 (95%CI 0.02-0.19). The C-statistic for 10-year CVD risk increased from 0.82 by 0.02 (95%CI 0.01-0.03) with CTCS. Reclassification occurred most often in those at intermediate risk: with CTCS, 36% (38%) moved to low and 22% (30%) to high CVD (CHD) risk. Improvements with other novel risk markers were limited. CONCLUSIONS: Only CTCS appeared to have significant incremental predictive value in the U.S. general population, especially in those at intermediate risk. In future research, cost-effectiveness analyses should be considered for evaluating novel cardiovascular risk assessment strategies.

Performance of Framingham cardiovascular disease (CVD) predictions in the Rotterdam Study taking into account competing risks and disentangling CVD into coronary heart disease (CHD) and stroke.

BACKGROUND: To evaluate the performance of Framingham predictions of cardiovascular disease (CVD) risk corrected for the competing risk of non-CVD death, in an independent European cohort of older individuals and subsequently extend the predictions by disentangling CVD into coronary heart disease (CHD) and stroke separately. METHODS: We used the Rotterdam Study data, a prospective cohort study of individuals aged 55 years and older (N=6004), to validate the Framingham predictions of CVD, defined as first occurrence of myocardial infarction, coronary death or stroke during 15 years of follow-up, corrected for the competing risk of non-CVD death. We subsequently estimated the risks of CHD and stroke separately, and used the sum as a predictor for the total CVD risk. Calibration plots and c-statistics were used to evaluate the performance of the models. RESULTS: Performance of the Framingham predictions was good in the low- to intermediate risk (≤30%, 15-year CVD risk) (17.5% observed vs. 16.6% expected) but poorer in the higher risk (>30%) categories (36.3% observed vs. 44.1% expected). The c-statistic increased from 0.66 to 0.69 after refitting. Separately estimating CHD and stroke revealed considerable heterogeneity with regard to the contribution of CHD and stroke to total CVD risk. CONCLUSIONS: Framingham CVD risk predictions perform well in the low- to intermediate risk categories in the Rotterdam Study. Disentangling CVD into CHD and stroke separately provides additional information about the individual contribution of CHD and stroke to total individual CVD risk.

Meta-analysis of primary mesh augmentation as prophylactic measure to prevent incisional hernia.

BACKGROUND: Incisional hernia (IH) remains one of the most frequent postoperative complications after abdominal surgery. As a consequence, primary mesh augmentation (PMA), a technique to strengthen the abdominal wall, has been gaining popularity. This meta-analysis was conducted to evaluate the prophylactic effect of PMA on the incidence of IH compared to primary suture (PS). METHODS: A meta-analysis was conducted according to the PRISMA guidelines. Randomized controlled trials (RCTs) comparing PMA and PS for closing the abdominal wall after surgery were included. RESULTS: Out of 576 papers, 5 RCTs were selected comprising 346 patients. IH occurred significantly less in the PMA group (RR 0.25, 95% CI 0.12-0.52, I(2)0%; p < 0.001). No difference could be observed with regard to wound infection (RR 0.86, 95% CI 0.39-1.91, I(2) 0%; p = 0.71) or seroma (RR 1.22, 95% CI 0.64-2.33, I(2) 0%; p = 0.55). A trend was observed for chronic pain in favor of the PS group (RR 5.95, 95% CI 0.74-48.03, I(2)0%; p = 0.09). CONCLUSION: The use of PMA for abdominal wall closure is associated with significantly lower incidence of IH compared to PS.

Validation of a model to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD: the rotterdam ischemic heart disease and stroke computer simulation (RISC) model.

BACKGROUND: We developed a Monte Carlo Markov model designed to investigate the effects of modifying cardiovascular disease (CVD) risk factors on the burden of CVD. Internal, predictive, and external validity of the model have not yet been established. METHODS: The Rotterdam Ischemic Heart Disease and Stroke Computer Simulation (RISC) model was developed using data covering 5 years of follow-up from the Rotterdam Study. To prove 1) internal and 2) predictive validity, the incidences of coronary heart disease (CHD), stroke, CVD death, and non-CVD death simulated by the model over a 13-year period were compared with those recorded for 3,478 participants in the Rotterdam Study with at least 13 years of follow-up. 3) External validity was verified using 10 years of follow-up data from the European Prospective Investigation of Cancer (EPIC)-Norfolk study of 25,492 participants, for whom CVD and non-CVD mortality was compared. RESULTS: At year 5, the observed incidences (with simulated incidences in brackets) of CHD, stroke, and CVD and non-CVD mortality for the 3,478 Rotterdam Study participants were 5.30% (4.68%), 3.60% (3.23%), 4.70% (4.80%), and 7.50% (7.96%), respectively. At year 13, these percentages were 10.60% (10.91%), 9.90% (9.13%), 14.20% (15.12%), and 24.30% (23.42%). After recalibrating the model for the EPIC-Norfolk population, the 10-year observed (simulated) incidences of CVD and non-CVD mortality were 3.70% (4.95%) and 6.50% (6.29%). All observed incidences fell well within the 95% credibility intervals of the simulated incidences. CONCLUSIONS: We have confirmed the internal, predictive, and external validity of the RISC model. These findings provide a basis for analyzing the effects of modifying cardiovascular disease risk factors on the burden of CVD with the RISC model.

Do different methods of modeling statin treatment effectiveness influence the optimal decision?

PURPOSE: Modeling studies that evaluate statin treatment for the prevention of cardiovascular disease (CVD) use different methods to model the effect of statins. The aim of this study was to evaluate the impact of using different modeling methods on the optimal decision found in such studies. METHODS: We used a previously developed and validated Monte Carlo-Markov model based on the Rotterdam study (RISC model). The RISC model simulates coronary heart disease (CHD), stroke, cardiovascular death, and death due to other causes. Transition probabilities were based on 5-year risks predicted by Cox regression equations, including (among others) total and high-density lipoprotein (HDL) cholesterol as covariates. In a cost-effectiveness analysis of implementing the ATP-III guidelines, we evaluated the impact of using 3 different modeling methods of statin effectiveness: 1) through lipid level modification: statins lower total cholesterol and increase HDL cholesterol, which through the covariates in the Cox regression equations leads to a lower incidence of CHD and stroke events; 2) fixed risk reduction of CVD events: statins decrease the odds of CHD and stroke with an associated odds ratio that is assumed to be the same for each individual; 3) risk reduction of CVD events proportional to individual change in low-density lipoprotein (LDL) cholesterol: the relative risk reduction with statin therapy on the incidence of CHD and stroke was assumed to be proportional to the absolute reduction in LDL cholesterol levels for each individual. The probability that the ATP-III strategy was cost-effective, compared to usual care as observed in the Rotterdam study, was calculated for each of the 3 modeling methods for varying willingness-to-pay thresholds. RESULTS: Incremental cost-effectiveness ratios for the ATP-III strategy compared with the reference strategy were €56,642/quality-adjusted life year (QALY), €21,369/QALY, and €22,131/QALY for modeling methods 1, 2, and 3, respectively. At a willingness-to-pay threshold of €50,000/QALY, the probability that the ATP-III strategy was cost-effective was about 40% for modeling method 1 and more than 90% for both methods 2 and 3. Differences in results between the modeling methods were sensitive to both the time horizon modeled and age distribution of the target CONCLUSIONS: Modeling the effect of statins on CVD through the modification of lipid levels produced different results and associated uncertainty than modeling it directly through a risk reduction of events. This was partly attributable to the modeled effect of cholesterol on the incidence of stroke.

Personalized prediction of lifetime benefits with statin therapy for asymptomatic individuals: a modeling study.

BACKGROUND: Physicians need to inform asymptomatic individuals about personalized outcomes of statin therapy for primary prevention of cardiovascular disease (CVD). However, current prediction models focus on short-term outcomes and ignore the competing risk of death due to other causes. We aimed to predict the potential lifetime benefits with statin therapy, taking into account competing risks. METHODS AND FINDINGS: A microsimulation model based on 5-y follow-up data from the Rotterdam Study, a population-based cohort of individuals aged 55 y and older living in the Ommoord district of Rotterdam, the Netherlands, was used to estimate lifetime outcomes with and without statin therapy. The model was validated in-sample using 10-y follow-up data. We used baseline variables and model output to construct (1) a web-based calculator for gains in total and CVD-free life expectancy and (2) color charts for comparing these gains to the Systematic Coronary Risk Evaluation (SCORE) charts. In 2,428 participants (mean age 67.7 y, 35.5% men), statin therapy increased total life expectancy by 0.3 y (SD 0.2) and CVD-free life expectancy by 0.7 y (SD 0.4). Age, sex, smoking, blood pressure, hypertension, lipids, diabetes, glucose, body mass index, waist-to-hip ratio, and creatinine were included in the calculator. Gains in total and CVD-free life expectancy increased with blood pressure, unfavorable lipid levels, and body mass index after multivariable adjustment. Gains decreased considerably with advancing age, while SCORE 10-y CVD mortality risk increased with age. Twenty-five percent of participants with a low SCORE risk achieved equal or larger gains in CVD-free life expectancy than the median gain in participants with a high SCORE risk. CONCLUSIONS: We developed tools to predict personalized increases in total and CVD-free life expectancy with statin therapy. The predicted gains we found are small. If the underlying model is validated in an independent cohort, the tools may be useful in discussing with patients their individual outcomes with statin therapy.

Comparative effectiveness and cost-effectiveness of computed tomography screening for coronary artery calcium in asymptomatic individuals.

OBJECTIVES: The aim of this study was to assess the (cost-) effectiveness of screening asymptomatic individuals at intermediate risk of coronary heart disease (CHD) for coronary artery calcium with computed tomography (CT). BACKGROUND: Coronary artery calcium on CT improves prediction of CHD. METHODS: A Markov model was developed on the basis of the Rotterdam Study. Four strategies were evaluated: 1) current practice; 2) current prevention guidelines for cardiovascular disease; 3) CT screening for coronary calcium; and 4) statin therapy for all individuals. Asymptomatic individuals at intermediate risk of CHD were simulated over their remaining lifetime. Quality-adjusted life years (QALYs), costs, and incremental cost-effectiveness ratios were calculated. RESULTS: In men, CT screening was more effective and more costly than the other 3 strategies (CT vs. current practice: +0.13 QALY [95% confidence interval (CI): 0.01 to 0.26], +$4,676 [95% CI: $3,126 to $6,339]; CT vs. statin therapy: +0.04 QALY [95% CI: -0.02 to 0.13], +$1,951 [95% CI: $1,170 to $2,754]; and CT vs. current guidelines: +0.02 QALY [95% CI: -0.04 to 0.09], +$44 [95% CI: -$441 to $486]). The incremental cost-effectiveness ratio of CT calcium screening was $48,800/QALY gained. In women, CT screening was more effective and more costly than current practice (+0.13 QALY [95% CI: 0.02 to 0.28], +$4,663 [95% CI: $3,120 to $6,277]) and statin therapy (+0.03 QALY [95% CI: -0.03 to 0.12], +$2,273 [95% CI: $1,475 to $3,109]). However, implementing current guidelines was more effective compared with CT screening (+0.02 QALY [95% CI: -0.03 to 0.07]), only a little more expensive (+$297 [95% CI: -$8 to $633]), and had a lower cost per additional QALY ($33,072/QALY vs. $35,869/QALY). Sensitivity analysis demonstrated robustness of results in women but considerable uncertainty in men. CONCLUSIONS: Screening for coronary artery calcium with CT in individuals at intermediate risk of CHD is probably cost-effective in men but is unlikely to be cost-effective in women.