Systematic reviews on tobacco control from Cochrane and the Community Guide: different methods, similar findings

Twenty-year health and economic impact of reducing cigarette use: Minnesota 1998-2017

Background

Adult smoking prevalence in Minnesota fell from 21.8% in 1997 to 15.2% in 2016. This reduction improved heart and lung health, prevented cancers, extended life and reduced healthcare costs, but quantifying these benefits is difficult.

Methods

1.3 million individuals were simulated in a tobacco policy model to estimate the gains to Minnesotans from 1998 to 2017 in health, medical spending reductions and productivity gains due to reduced cigarette smoking. A constant prevalence scenario was created to simulate the tobacco harms that would have occurred had smoking prevalence stayed at 1997 levels. Those harms were compared with tobacco harms from a scenario of actual smoking prevalence in Minnesota from 1998 to 2017.

Results

The simulation model predicts that reducing cigarette smoking from 1998 to 2017 has prevented 4560 cancers, 31 691 hospitalisations for cardiovascular disease and diabetes, 12 881 respiratory disease hospitalisations and 4118 smoking-attributable deaths. Minnesotans spent an estimated $2.7 billion less in medical care and gained $2.4 billion in paid and unpaid productivity, inflation adjusted to 2017 US$. In sensitivity analysis, medical care savings ranged from $1.7 to $3.6 billion.

Conclusions

Minnesota’s investment in comprehensive tobacco control measures has driven down smoking rates, saved billions in medical care and productivity costs and prevented tobacco related diseases of its residents. The simulation method employed in this study can be adapted to other geographies and time periods to bring to light the invisible gains of tobacco control.

The art and science of study identification: a comparative analysis of two systematic reviews

BACKGROUND

Systematic reviews (SRs) form the foundation for guidelines and evidence-based policy in medicine and public health. Although similar systematic reviews may include non-identical sets of studies, and it is recognized that different sets of studies may lead to different conclusions, little work has been published on why SR study cohorts differ.

METHODS

We took advantage of concurrent publication of two SRs on the same topic - prevention of child exposure to tobacco smoke - to understand why study cohorts differed in the two reviews. We identified all studies included in just one review, investigated validity of specified reasons for exclusions, and, using database records, explored reasons for study non-identification. We assessed review methods and discordancy, and attempted to assess whether changes in study cohorts would have changed conclusions.

RESULTS

Sixty-one studies were included in the two reviews. Thirty-five studies were present in just one review; of these, twenty were identified and excluded by the parallel review. Omissions were due to: review scope (9 studies, 26%), outcomes of interest not measured (8 studies, 23%), exclusion of reports with inadequate reporting (6 studies, 17%), mixed or unclear reasons (3 studies, 8%), search strategies concerning filters, tagging, and keywords (3 studies, 8%), search strategies regarding sources (PUBMED not searched) (2 studies, 6%); discordant interpretation of same eligibility criteria (2 studies, 6%), and non-identification due to non-specific study topic (2 studies, 6%). Review conclusions differed, but were likely due to differences in synthesis methods, not differences in study cohorts.

CONCLUSIONS

The process of study identification for SRs is part art and part science. While some differences are due to differences in review scope, outcomes measured, or reporting practices, others are caused by search methods or discrepancies in reviewer interpretations. Different study cohorts may or may not be a cause of differing SR results. Completeness of SR study cohorts could be enhanced by 1 - independent identification of studies by at least two reviewers, as recommended by recent guidelines, 2 - searching PUBMED with free-text keywords in addition to MEDLINE to identify recent studies, and 3 - Using validated search filters.

Coverage of mental health and substance misuse topics in the Cochrane review system

Aims. To assess the breadth of mental and substance coverage in the Cochrane review system. Methods. All mental health and substance entries were identified from the 2005 to April 2012 Cochrane Database of Systematic Reviews. Results. A total of 1019 entries focused on mental health or substance misuse, with 698 (68.5%) being completed reviews. One out of every five entries focused on serious mental illness/psychosis. Systematic reviews addressing unipolar depression, dementia and certain substance disorders also appeared well-represented. In contrast, a number of impairing disorders frequently seen in practice received less attention, with bipolar disorder, obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD) and autism spectrum disorders each accounting for less than 2% of the entries. The majority of interventions reviewed involved medication (57.1%), although this was not the case for a number of childhood-onset disorders. Some diagnostic areas (sleep, anxiety, mood and substance) were addressed by multiple Cochrane review groups (CRGs). Conclusions. The Cochrane Collaboration is well poised to be a strong guiding influence to those seeking to employ evidence-based mental health care. Broadening its diagnostic coverage and diversifying types of intervention reviewed would probably further maximize its impact. A more centralized and directed approach of prioritizing topics could help ensure more comprehensive coverage.

The effect of clinical interventions on hospital readmissions: a meta-review of published meta-analyses

BACKGROUND

The economic impact and ease of measurement of all-cause hospital readmission rates (HRR) have led to the current debate as to whether they are reducible, and whether they should be used as a publicly reported quality indicators of medical care.

OBJECTIVE

To assess the efficacy of broad clinical interventions in preventing HRR of patients with chronic diseases

METHOD

A meta-review of published systematic reviews of randomized controlled trials (RCTs) of clinical interventions that have included HRR among the patients' outcomes of interest.

MAIN FINDINGS

Meta-analyses of RCTs have consistently found that, in the community, disease management programs significantly reduced HRR in patients with heart failure, coronary heart disease and bronchial asthma, but not in patients with stroke and in unselected patients with chronic disorders. Inhospital interventions, such as discharge planning, pharmacological consultations and multidisciplinary care, and community interventions in patients with chronic obstructive pulmonary diseases had an inconsistent effect on HRR. MAIN STUDY LIMITATION: Despite their economic impact and ease of measurement, HRR are not the most important outcome of patient care, and efforts aimed at their reduction may compromise patients' health by reducing also justified re-admissions.

CONCLUSIONS

The efficacy of inhospital interventions in reducing HRR is in need of further study. In patients with heart diseases and bronchial asthma, HRR may be considered as a publicly reported quality indicator of community care, provided that future research confirms that efforts to reduce HRR do not adversely affect other patients' outcomes, such as mortality, functional capacity and quality of life. Future research should also focus on the reasons for the higher efficacy of community interventions in patients with heart diseases and bronchial asthma than in those with other chronic diseases.

A systematic review of randomized controlled trials: Web-based interventions for smoking cessation among adolescents, college students, and adults

INTRODUCTION

Web-based treatments can deliver broad reaching, relatively inexpensive, and clinically tested methods for smoking cessation. We performed a systematic review of randomized controlled trials (RCTs) of smoking cessation to evaluate the efficacy of Web-based interventions in adults, college students, and adolescents.

METHODS

MEDLINE, EMBASE, The Cochrane Library, CINAHL, and PsycINFO were searched from January 1, 1990 through February 12, 2010 for RCTs examining the efficacy of Web-based smoking cessation programs. Paired reviewers abstracted data on study design, patient characteristics, and outcomes sequentially and did quality assessments independently.

RESULTS

Twenty-one RCTs met eligibility criteria, with 15 conducted among adults. Among adults, 2 RCTs found that a multicomponent intervention with Web and non-Web-based elements was more efficacious than a self-help manual, and one of 2 RCTs found that Web-based interventions may be more effective than no treatment. Three trials provided insufficient evidence to demonstrate whether Web-based interventions were more efficacious than counseling. By contrast, tailored Web sites in 2 RCTs and greater Web site exposure in 6 of 7 RCTs were associated with higher rates of abstinence. Among college students, evidence supporting use of Web-based interventions was insufficient because the one RCT conducted was also a multicomponent intervention. Five RCTs among adolescents demonstrated mixed results, with insufficient evidence supporting their efficacy.

CONCLUSIONS

Evidence supporting the use of Web-based interventions for smoking cessation is insufficient to moderate in adults and insufficient in college students and adolescents. These RCTs have, however, elucidated clinical, methodological, and statistical practices that are likely to improve future trial design and treatment delivery.

A framework for developing an evidence-based, comprehensive tobacco control program

Background

Tobacco control is an area where the translation of evidence into policy would seem to be straightforward, given the wealth of epidemiological, behavioural and other types of research available. Yet, even here challenges exist. These include information overload, concealment of key (industry-funded) evidence, contextualization, assessment of population impact, and the changing nature of the threat.

Methods

In the context of Israel's health targeting initiative, Healthy Israel 2020, we describe the steps taken to develop a comprehensive tobacco control strategy. We elaborate on the following: a) scientific issues influencing the choice of tobacco control strategies; b) organization of existing evidence of effectiveness of interventions into a manageable form, and c) consideration of relevant philosophical and political issues. We propose a framework for developing a plan and illustrate this process with a case study in Israel.

Results

Broad consensus exists regarding the effectiveness of most interventions, but current recommendations differ in the emphasis they place on different strategies. Scientific challenges include integration of complex and sometimes conflicting information from authoritative sources, and lack of estimates of population impact of interventions. Philosophical and political challenges include the use of evidence-based versus innovative policymaking, the importance of individual versus governmental responsibility, and whether and how interventions should be prioritized.

The proposed framework includes: 1) compilation of a list of potential interventions 2) modification of that list based on local needs and political constraints; 3) streamlining the list by categorizing interventions into broad groupings of related interventions; together these groupings form the basis of a comprehensive plan; and 4) refinement of the plan by comparing it to existing comprehensive plans.

Conclusions

Development of a comprehensive tobacco control plan is a complex endeavour, involving crucial decisions regarding intervention components. "Off the shelf" plans, which need to be adapted to local settings, are available from a variety of sources, and a multitude of individual recommendations are available. The proposed framework for adapting existing approaches to the local social and political climate may assist others planning for smoke-free societies. Additionally, this experience has implications for development of evidence-based health plans addressing other risk factors.

Missing the forest (plot) for the trees? A critique of the systematic review in tobacco control

BACKGROUND

The systematic review (SR) lies at the core of evidence-based medicine. While it may appear that the SR provides a reliable summary of existing evidence, standards of SR conduct differ. The objective of this research was to examine systematic review (SR) methods used by the Cochrane Collaboration ("Cochrane") and the Task Force on Community Preventive Services ("the Guide") for evaluation of effectiveness of tobacco control interventions.

METHODS

We searched for all reviews of tobacco control interventions published by Cochrane (4th quarter 2008) and the Guide. We recorded design rigor of included studies, data synthesis method, and setting.

RESULTS

About a third of the Cochrane reviews and two thirds of the Guide reviews of interventions in the community setting included uncontrolled trials. Most (74%) Cochrane reviews in the clinical setting, but few (15%) in the community setting, provided pooled estimates from RCTs. Cochrane often presented the community results narratively. The Guide did not use inferential statistical approaches to assessment of effectiveness.

CONCLUSIONS

Policy makers should be aware that SR methods differ, even among leading producers of SRs and among settings studied. The traditional SR approach of using pooled estimates from RCTs is employed frequently for clinical but infrequently for community-based interventions. The common lack of effect size estimates and formal tests of significance limit the contribution of some reviews to evidence-based decision making. Careful exploration of data by subgroup, and appropriate use of random effects models, may assist researchers in overcoming obstacles to pooling data.