Distribution of lifespan gain from primary prevention intervention

Quantifying the benefit of nonselective beta-blockers in the prevention of hepatic decompensation: A Bayesian reanalysis of the PREDESCI trial

BACKGROUND AND AIMS

Beta-blockers have been studied for the prevention of variceal bleeding and, more recently, for the prevention of all-cause decompensation. Some uncertainties regarding the benefit of beta-blockers for the prevention of decompensation remain. Bayesian analyses enhance the interpretation of trials. The purpose of this study was to provide clinically meaningful estimates of both the probability and magnitude of the benefit of beta-blocker treatment across a range of patient types.

APPROACH AND RESULTS

We undertook a Bayesian reanalysis of PREDESCI incorporating 3 priors (moderate neutral, moderate optimistic, and weak pessimistic). The probability of clinical benefit was assessed considering the prevention of all-cause decompensation. Microsimulation analyses were done to determine the magnitude of the benefit. In the Bayesian analysis, the probability that beta-blockers reduce all-cause decompensation was >0.93 for all priors. The Bayesian posterior hazard ratios (HR) for decompensation ranged from 0.50 (optimistic prior, 95% credible interval 0.27-0.93) to 0.70 (neutral prior, 95% credible interval 0.44-1.12). Exploring the benefit of treatment using microsimulation highlights substantial treatment benefits. For the neutral prior derived posterior HR and a 5% annual incidence of decompensation, at 10 years, an average of 497 decompensation-free years per 1000 patients were gained with treatment. In contrast, at 10 years 1639 years per 1000 patients were gained from the optimistic prior derived posterior HR and a 10% incidence of decompensation.

CONCLUSIONS

Beta-blocker treatment is associated with a high probability of clinical benefit. This likely translates to a substantial gain in decompensation-free life years at the population level.

Adjusted restricted mean survival times in observational studies

In observational studies with censored data, exposure-outcome associations are commonly measured with adjusted hazard ratios from multivariable Cox proportional hazards models. The difference in restricted mean survival times (RMSTs) up to a pre-specified time point is an alternative measure that offers a clinically meaningful interpretation. Several regression-based methods exist to estimate an adjusted difference in RMSTs, but they digress from the model-free method of taking the area under the survival function. We derive the adjusted RMST by integrating an adjusted Kaplan-Meier estimator with inverse probability weighting (IPW). The adjusted difference in RMSTs is the area between the two IPW-adjusted survival functions. In a Monte Carlo-type simulation study, we demonstrate that the proposed estimator performs as well as two regression-based approaches: the ANCOVA-type method of Tian et al and the pseudo-observation method of Andersen et al. We illustrate the methods by reexamining the association between total cholesterol and the 10-year risk of coronary heart disease in the Framingham Heart Study.

How Knowledge Is Constructed and Exchanged in Virtual Communities of Physicians: Qualitative Study of Mindlines Online

BACKGROUND

As a response to the criticisms evidence-based practice currently faces, groups of health care researchers and guideline makers have started to call for the appraisal and inclusion of different kinds of knowledge in guideline production (other than randomized controlled trials [RCTs]) to better link with the informal knowledge used in clinical practice. In an ethnographic study, Gabbay and Le May showed that clinicians in everyday practice situations do not explicitly or consciously use guidelines. Instead, they use mindlines: collectively shared, mostly tacit knowledge that is shaped by many sources, including accumulated personal experiences, education (formal and informal), guidance, and the narratives about patients that are shared among colleagues. In this study on informal knowledge, we consider virtual networks of clinicians as representative of the mindlines in the wider medical community, as holders of knowledge, as well as catalysts of knowing.

OBJECTIVE

The aim of this study was to explore how informal knowledge and its creation in communities of clinicians can be characterized as opposed to the more structured knowledge produced in guideline development.

METHODS

This study included a qualitative study of postings on three large virtual networks for physicians in the United Kingdom, the Netherlands, and Norway, taking the topic of statins as a case study and covering more than 1400 posts. Data were analyzed thematically with reference to theories of collaborative knowledge construction and communities of practice.

RESULTS

The dataset showed very few postings referring to, or seeking to adhere to, explicit guidance and recommendations. Participants presented many instances of individual case narratives that highlighted quantitative test results and clinical examination findings. There was an emphasis on outliers and the material, regulatory, and practical constraints on knowledge use by clinicians. Participants conveyed not-so-explicit knowledge as tacit and practical knowledge and used a prevailing style of pragmatic reasoning focusing on what was likely to work in a particular case. Throughout the discussions, a collective conceptualization of statins was generated and reinforced in many contexts through stories, jokes, and imagery.

CONCLUSIONS

Informal knowledge and knowing in clinical communities entail an inherently collective dynamic practice that includes explicit and nonexplicit components. It can be characterized as knowledge-in-context in practice, with a strong focus on casuistry. Validity of knowledge appears not to be based on criteria of consensus, coherence, or correspondence but on a more polyphonic understanding of truth. We contend that our findings give enough ground for further research on how exploring mindlines of clinicians online could help improve guideline development processes.

Cultural primer for cardiometabolic health: health disparities, structural factors, community, pathways to improvement, and clinical applications

The quest to optimize cardiometabolic health has created great interest in nonmedical health variables in the population, community-based research and coordination, and addressing social, ethnic, and cultural barriers. All of these may be of equal or even greater importance than classical health care delivery in achieving individual well-being. One dominant issue is health disparity - causes, methods of reduction, and community versus other levels of solutions. This communication summarizes some major views regarding social structures, followed by amplification and synthesis of central ideas in the literature. The role of community involvement, tools, and partnerships is also presented in this Primer. Recent views of how these approaches could be incorporated into cardiometabolic initiatives and strategies follow, with implications for research. Two examples comparing selected aspects of community leverage and interventions in relation to individual approaches to health care equity are examined in depth: overall performance in reducing cardiovascular risk and mortality, and the recent National Diabetes Prevention Program, both touching upon healthy diets and adherence. Finally, the potential that precision medicine offers, and possible effects on disparities are also discussed.

Polypharmacy: a challenge for the primary health care of the Brazilian Unified Health System

OBJECTIVE

To characterize the polypharmacy in primary health care patients and to identify its associated factors.

METHODS

This is a cross-sectional, exploratory, and evaluative study, part of the Pesquisa Nacional sobre Acesso, Utilização e Promoção do Uso Racional de Medicamentos - Serviços, 2015 (PNAUM - National Survey on Access, Use and Promotion of Rational Use of Medicines - Services, 2015). The variable of interest was polypharmacy, defined as the use of five or more medicines. We sought to identify the association of sociodemographic variables and indicators of health conditions to polypharmacy. For group comparison, the Pearson's Chi-square test was used. The association between polypharmacy and explanatory variables was evaluated by logistic regression model (p < 0.05). The quality of the adjustment was verified by Hosmer-Lemeshow test.

RESULTS

The prevalence of polypharmacy among medicine users was 9.4% (95%CI 7.8-12.0) in the general population and 18.1% (95%CI 13.6-22.8) in older adults above 65 years old. We found statistically significant association between polypharmacy and age above 45 years, lower self-perception of health, presence of chronic diseases, having health insurance, care in emergency services, and region of the Country. South users presented the highest chances to polypharmacy. The most used medicines were those of the cardiovascular system, being compatible with the national epidemiological profile.

CONCLUSIONS

Polypharmacy is a reality in the population met within the primary care of Brazilian Unified Health System and may be related to excessive or inappropriate use of medicines. The main challenge to qualify health care is to ensure that prescription of multiple medicines be appropriate and safe.

From evidence-based medicine to personalized medicine, with particular emphasis on drug-safety monitoring

Nowadays, guidelines are derived from the findings of randomized controlled therapeutic trials. However, an overall significant P value does not exclude that some patients may be harmed by or will not respond to the therapeutic agent being studied. Trials in patients with a low risk of events and/or a limited chance of providing significant differences in therapeutic effects require a large patient population to demonstrate a beneficial effect. Composite efficacy endpoints are often employed to obviate the need for a large patient population when low rates of events or limited therapeutic efficacy are anticipated. Results of randomized controlled therapeutic trials are commonly expressed in terms of relative risk reduction, whereas absolute risk reduction allows the calculation of the "number needed to treat" to prevent an adverse outcome. The number needed to treat is a far more clinically relevant variable than relative risk reduction. The clinician's mission is to match treatment to patient with the goal of achieving optimal therapeutic response. Drug-safety monitoring is also of major importance to avoid exposing patients to irreversible adverse effects. Unfortunately, drug-safety monitoring is often overlooked in routine clinical practice. Finally, the lack of long-term therapeutic data (>5-10 years) is an unsolved dilemma, as most trials are limited to a duration of a few months or years.

Patient preferences for cardiovascular preventive medication: a systematic review

OBJECTIVE

To systematically review current evidence regarding the minimum acceptable risk reduction of a cardiovascular event that patients feel would justify daily intake of a preventive medication.

METHODS

We used the Web of Science to track the forward and backward citations of a set of five key articles until 15 November 2016. Studies were eligible if they quantitatively assessed the minimum acceptable benefit-in absolute values-of a cardiovascular disease preventive medication among a sample of the general population and required participants to choose if they would consider taking the medication.

RESULTS

Of 341 studies screened, we included 22, involving a total of 17 751 participants: 6 studied prolongation of life (POL), 12 studied absolute risk reduction (ARR) and 14 studied number needed to treat (NNT) as measures of risk reduction communicated to the patients. In studies framed using POL, 39%-54% (average: 48%) of participants would consider taking a medication if it prolonged life by <8 months and 56%-73% (average: 64%) if it prolonged life by ≥8 months. In studies framed using ARR, 42%-72% (average: 54%) of participants would consider taking a medication that reduces their 5-year cardiovascular disease (CVD) risk by <3% and 50%-89% (average: 77%) would consider taking a medication that reduces their 5-year CVD risk by ≥3%. In studies framed using 5-year NNT, 31%-81% (average: 60%) of participants would consider taking a medication with an NNT of >30 and 46%-87% (average: 71%) with an NNT of ≤30.

CONCLUSIONS

Many patients require a substantial risk reduction before they consider taking a daily medication worthwhile, even when the medication is described as being side effect free and costless.

Time to improve statin prescription guidelines in low-risk patients?

Background

The challenge of the primary prevention of cardiovascular disease (CVD) is to identify patients who would benefit from treatment with statins. Statins are currently prescribed to many patients, even those at a low 10-year risk of CVD. These latter patients may not be eligible for statins according to current guidelines.

Design

This study investigated the prescription of guideline-consistent (according to guidelines) and guideline-inconsistent (not according to guidelines) lipid-lowering treatment in primary prevention in a large contemporary Dutch cohort study (Lifelines).

Methods

Lifelines is a large cohort study from the Netherlands. Participants were recruited between 2006 and 2013. They completed questionnaires and underwent a physical examination. Participants with previous CVD were excluded. Statins and ezetimibe were grouped as statin treatment. The Dutch guideline on cardiovascular management was used to assess eligibility for statins.

Results

Of 147,785 participants, 7092 (4.8%) reported statin treatment. In 4667 (66%) participants, statin treatment was inconsistent with the Dutch guideline. A total of 78% of these participants had a low 10-year predicted CVD risk. Multivariable logistic regression analysis showed that female sex and smoking were strongly associated with guideline-inconsistent treatment. Interestingly, 65% of the these participants had low-density lipoprotein cholesterol levels above the 95^th percentile, adjusted for age and sex, two or more major risk factors of CVD or a positive family history of premature CVD. Therefore treatment might be reasonable.

Conclusions

There is a large inconsistency between guideline recommendations and the prescription of statins in clinical practice in the Netherlands. This is especially true for patients with low CVD risk. Many of these patients probably had risk-increasing circumstances justifying treatment.