De-implementation of expensive blood saving measures in hip and knee arthroplasties: study protocol for the LISBOA-II cluster randomized trial

Intraoperative use of balanced crystalloids versus 0.9% saline: a systematic review and meta-analysis of randomised controlled studies

BACKGROUND

The evidence regarding optimal crystalloid use in the perioperative period remains unclear. As the primary aim of this study, we sought to summarise the data from RCTs examining whether use of balanced crystalloids compared with 0.9% saline (saline) leads to differences in patient-important outcomes.

METHODS

We searched Ovid MEDLINE, Embase, the Cochrane library, and Clinicaltrials.gov, from inception until December 15, 2022, and included RCTs that intraoperatively randomised adult participants to receive either balanced fluids or saline. We pooled data using a random-effects model and present risk ratios (RRs) or mean differences (MDs), along with 95% confidence intervals (CIs). We assessed individual study risk of bias using the modified Cochrane tool, and certainty of evidence using GRADE.

RESULTS

Of 5959 citations, we included 38 RCTs (n=3776 patients). Pooled analysis showed that intraoperative use of balanced fluids compared with saline had an uncertain effect on postoperative mortality analysed at the longest point of follow-up (RR 1.51, 95% CI: 0.42-5.36) and postoperative need for renal replacement therapy (RR 0.95, 95% CI: 0.56-1.59), both very low certainty. Furthermore, use of balanced crystalloids probably leads to a higher postoperative serum pH (MD 0.05, 95% CI: 0.04-0.06), moderate certainty.

CONCLUSIONS

Use of balanced crystalloids, compared with saline, in the perioperative setting has an uncertain effect on mortality and need for renal replacement therapy but probably improves postoperative acid-base status. Further research is needed to determine whether balanced crystalloid use affects patient-important outcomes.

CLINICAL TRIAL REGISTRATION

CRD42022367593.

Effect of erythropoietin on perioperative blood transfusions in primary total hip arthroplasty: A systematic review

BACKGROUND

Primary total hip arthroplasty (THA) often requires blood transfusion. Transfusions are undesirable due to risks of infectious and noninfectious complications. This systematic review therefore studied the effectiveness of erythropoietin (EPO) in reducing allogeneic transfusion rate during THA.

METHODS

Using the MESH terms "Erythropoietin" AND "Total Hip" with restrictions to 'Randomized Controlled Trial', 'Clinical Trial', 'Humans', and 'English', a literature search was performed in PubMed and CINAHL. Articles were scanned by both authors and retained for further review if eligibility was met according to the inclusion criteria defined by the PICOS (population, intervention, comparator, outcomes, study design) configuration. Risk of bias was assessed using the Cochrane risk of bias criteria. Data extracted include patient demographics, intervention versus comparator arm, outcomes, laboratory data, and individual study characteristics. The primary outcome of focus was rate or amount of allogeneic blood transfusions intra- or postoperatively. In 6/8 studies, data permitted calculations of absolute risk reduction (ARR) in transfusion rate (%) and number needed to treat (NNT) to evade transfusions.

RESULTS

A total of 8 studies met all eligibility criteria and were retained for data extraction; risk of bias was low-moderate in 7/8 and high in 1/8. Allogeneic transfusion exposure was lowered by the intervention in 7/8 studies with ARR from 9.6% to 33.5% and NNT from 4 to 10.

CONCLUSIONS

In the blood conservation systems described, the addition of EPO was effective in reducing allogeneic transfusions. The studies included spanned a nearly 30-year period. Earlier studies incorporated preoperative autologous donation, a now outdated modality.

De-implementing Inhaled Corticosteroids to Improve Care and Safety in COPD Treatment: Primary Care Providers' Perspectives

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is among the most common medical diagnoses among Veterans. More than 50% of Veterans diagnosed with mild-to-moderate COPD are prescribed inhaled corticosteroids despite recommendations for use restricted to patients with frequent exacerbations.

OBJECTIVE

We explored primary care providers' experiences prescribing inhaled corticosteroids among patients with mild-to-moderate COPD as part of a quality improvement initiative.

DESIGN

We used a sequential mixed-methods evaluation approach to understand factors influencing primary care providers' inhaled corticosteroid prescribing for patients with mild-to-moderate COPD. Participants were recruited to participate in qualitative interviews and structured surveys.

PARTICIPANTS

We used a purposive sample of primary care providers from 13 primary care clinics affiliated with two urban Veteran Health Administration healthcare systems.

MAIN MEASURES

Interviews were transcribed and analyzed using content analysis. Qualitative findings informed a subsequent survey. Surveys were administered through REDCap and analyzed descriptively. Key qualitative and quantitative findings were compared.

KEY RESULTS

Participants reported they were unaware of current evidence and recommendations for prescribing inhaled corticosteroids; for example, 46% of providers reported they were unaware of risks of pneumonia. Providers reported they are generally unable to keep up with the current literature due to the broad scope of primary care practice. We also found primary care providers may be reluctant to change inherited prescriptions, even if they thought inhaled corticosteroid therapy might not be appropriate.

CONCLUSIONS

Inhaled corticosteroid prescribing in this patient population is partly due to primary care providers' lack of knowledge about the potential harms and availability of alternative therapies. Our findings suggest that efforts to expand access by increasing the number of prescribing providers a patient potentially sees could make it more difficult to de-implement harmful prescriptions. Our findings also corroborate prior findings that awareness of current evidence-based guidelines is likely an important part of medical overuse.

De-implementation of low value castration for men with prostate cancer: protocol for a theory-based, mixed methods approach to minimizing low value androgen deprivation therapy (DeADT)

Background

Men with prostate cancer are often castrated with long-acting injectable drugs termed androgen deprivation therapy (ADT). Although many benefit, ADT is also used in patients with little or nothing to gain. The best ways to stop this practice are unknown, and range from blunt pharmacy restrictions to informed decision-making. This study will refine and pilot two different de-implementation strategies for reducing ADT use among those unlikely to benefit in preparation for a comparative effectiveness trial.

Methods/design

This innovative mixed methods research program has three aims. Aim 1: To assess preferences and barriers for de-implementation of chemical castration in prostate cancer. Guided by the theoretical domains framework (TDF), urologists and patients from facilities with the highest and lowest castration rates across the VA will be interviewed to identify key preferences and de-implementation barriers for reducing castration as prostate cancer treatment. This qualitative work will inform Aim 2 while gathering rich information for two proposed pilot intervention strategies. Aim 2: To use a discrete choice experiment (DCE), a novel barrier prioritization approach, for de-implementation strategy tailoring. The investigators will conduct national surveys of urologists to prioritize key barriers identified in Aim 1 for stopping incident castration as localized prostate cancer treatment using a DCE experiment design. These quantitative results will identify the most important barriers to be addressed through tailoring of two pilot de-implementation strategies in preparation for Aim 3 piloting. Aim 3: To pilot two tailored de-implementation strategies to reduce castration as localized prostate cancer treatment. Building on findings from Aims 1 and 2, two de-implementation strategies will be piloted. One strategy will focus on formulary restriction at the organizational level and the other on physician/patient informed decision-making at different facilities. Outcomes will include acceptability, feasibility, and scalability in preparation for an effectiveness trial comparing these two widely varying de-implementation strategies.

Discussion

Our innovative approach to de-implementation strategy development is directly aligned with state-of-the-art complex implementation intervention development and implementation science. This work will broadly advance de-implementation science for low value cancer care, and foster participation in our de-implementation evaluation trial by addressing barriers, facilitators, and concerns through pilot tailoring.

Trial registration

ClinicalTrials.gov Identifier: NCT03579680, First Posted July 6, 2018.

Changing behaviour 'more or less'-do theories of behaviour inform strategies for implementation and de-implementation? A critical interpretive synthesis

BACKGROUND

Implementing evidence-based care requires healthcare practitioners to do less of some things (de-implementation) and more of others (implementation). Variations in effectiveness of behaviour change interventions may result from failure to consider a distinction between approaches by which behaviour increases and decreases in frequency. The distinction is not well represented in methods for designing interventions. This review aimed to identify whether there is a theoretical rationale to support this distinction.

METHODS

Using Critical Interpretative Synthesis, this conceptual review included papers from a broad range of fields (biology, psychology, education, business) likely to report approaches for increasing or decreasing behaviour. Articles were identified from databases using search terms related to theory and behaviour change. Articles reporting changes in frequency of behaviour and explicit use of theory were included. Data extracted were direction of behaviour change, how theory was operationalised, and theory-based recommendations for behaviour change. Analyses of extracted data were conducted iteratively and involved inductive coding and critical exploration of ideas and purposive sampling of additional papers to explore theoretical concepts in greater detail.

RESULTS

Critical analysis of 66 papers and their theoretical sources identified three key findings: (1) 9 of the 15 behavioural theories identified do not distinguish between implementation and de-implementation (5 theories were applied to only implementation or de-implementation, not both); (2) a common strategy for decreasing frequency was substituting one behaviour with another. No theoretical basis for this strategy was articulated, nor were methods proposed for selecting appropriate substitute behaviours; (3) Operant Learning Theory makes an explicit distinction between techniques for increasing and decreasing frequency.

DISCUSSION

Behavioural theories provide little insight into the distinction between implementation and de-implementation. Operant Learning Theory identified different strategies for implementation and de-implementation, but these strategies may not be acceptable in health systems. Additionally, if behaviour substitution is an approach for de-implementation, further investigation may inform methods or rationale for selecting the substitute behaviour.

Towards a systematic approach for (de)implementation of patient blood management strategies

Despite the increasing availability of evidence in transfusion medicine literature, this evidence does not automatically find its way into practice. This is also applicable to patient blood management (PBM). It may concern the lack of implementation of effective new techniques or treatments, or it may apply to the (over)use of techniques and treatments (e.g. inappropriate transfusions) that have proven to be of limited benefit for patients (low-value care) and could be abandoned (de-implementation). In PBM literature, the implementation of restrictive transfusion thresholds and the de-implementation of inappropriate transfusions are described. However, most implementation strategies were not preceded by the identification of relevant barriers, and the used strategies were not often supported by literature on behavioural changes. In this article, we describe implementation vs de-implementation, highlight the current situation of (de)implementation in PBM and describe a systematic approach for (de)implementation illustrated by an example of a PBM de-implementation study regarding '(cost-) effective patient blood management in total hip and knee arthroplasty'. The systematic approach used for (de)implementation is based on the implementation model of Grol, which consists of the following five steps: the detection of improvement goals, a problem analysis, the selection of (de)implementation strategies, the execution of the (de)implementation strategy and an evaluation. Based on the description of the current situation and the experiences in our de-implementation study, we can conclude that de-implementation may be more difficult than expected as other factors may play a role in effective de-implementation compared to implementation.

Variation in Research Designs Used to Test the Effectiveness of Dissemination and Implementation Strategies: A Review

Background

The need for optimal study designs in dissemination and implementation (D&I) research is increasingly recognized. Despite the wide range of study designs available for D&I research, we lack understanding of the types of designs and methodologies that are routinely used in the field. This review assesses the designs and methodologies in recently proposed D&I studies and provides resources to guide design decisions.

Methods

We reviewed 404 study protocols published in the journal Implementation Science from 2/2006 to 9/2017. Eligible studies tested the efficacy or effectiveness of D&I strategies (i.e., not effectiveness of the underlying clinical or public health intervention); had a comparison by group and/or time; and used ≥1 quantitative measure. Several design elements were extracted: design category (e.g., randomized); design type [e.g., cluster randomized controlled trial (RCT)]; data type (e.g., quantitative); D&I theoretical framework; levels of treatment assignment, intervention, and measurement; and country in which the research was conducted. Each protocol was double-coded, and discrepancies were resolved through discussion.

Results

Of the 404 protocols reviewed, 212 (52%) studies tested one or more implementation strategy across 208 manuscripts, therefore meeting inclusion criteria. Of the included studies, 77% utilized randomized designs, primarily cluster RCTs. The use of alternative designs (e.g., stepped wedge) increased over time. Fewer studies were quasi-experimental (17%) or observational (6%). Many study design categories (e.g., controlled pre-post, matched pair cluster design) were represented by only one or two studies. Most articles proposed quantitative and qualitative methods (61%), with the remaining 39% proposing only quantitative. Half of protocols (52%) reported using a theoretical framework to guide the study. The four most frequently reported frameworks were Consolidated Framework for Implementing Research and RE-AIM (n = 16 each), followed by Promoting Action on Research Implementation in Health Services and Theoretical Domains Framework (n = 12 each).

Conclusion

While several novel designs for D&I research have been proposed (e.g., stepped wedge, adaptive designs), the majority of the studies in our sample employed RCT designs. Alternative study designs are increasing in use but may be underutilized for a variety of reasons, including preference of funders or lack of awareness of these designs. Promisingly, the prevalent use of quantitative and qualitative methods together reflects methodological innovation in newer D&I research.

How the dual process model of human cognition can inform efforts to de-implement ineffective and harmful clinical practices: A preliminary model of unlearning and substitution

RATIONALE AND OBJECTIVES

One way to understand medical overuse at the clinician level is in terms of clinical decision-making processes that are normally adaptive but become maladaptive. In psychology, dual process models of cognition propose 2 decision-making processes. Reflective cognition is a conscious process of evaluating options based on some combination of utility, risk, capabilities, and/or social influences. Automatic cognition is a largely unconscious process occurring in response to environmental or emotive cues based on previously learned, ingrained heuristics. De-implementation strategies directed at clinicians may be conceptualized as corresponding to cognition: (1) a process of unlearning based on reflective cognition and (2) a process of substitution based on automatic cognition.

RESULTS

We define unlearning as a process in which clinicians consciously change their knowledge, beliefs, and intentions about an ineffective practice and alter their behaviour accordingly. Unlearning has been described as "the questioning of established knowledge, habits, beliefs and assumptions as a prerequisite to identifying inappropriate or obsolete knowledge underpinning and/or embedded in existing practices and routines." We hypothesize that as an unintended consequence of unlearning strategies clinicians may experience "reactance," ie, feel their professional prerogative is being violated and, consequently, increase their commitment to the ineffective practice. We define substitution as replacing the ineffective practice with one or more alternatives. A substitute is a specific alternative action or decision that either precludes the ineffective practice or makes it less likely to occur. Both approaches may work independently, eg, a substitute could displace an ineffective practice without changing clinicians' knowledge, and unlearning could occur even if no alternative exists. For some clinical practice, unlearning and substitution strategies may be most effectively used together.

CONCLUSIONS

By taking into account the dual process model of cognition, we may be able to design de-implementation strategies matched to clinicians' decision-making processes and avoid unintended consequence.

Hospital variation in allogeneic transfusion and extended length of stay in primary elective hip and knee arthroplasty: a cross-sectional study

OBJECTIVES

Outcomes in total hip and knee arthroplasty (THA and TKA), such as allogeneic transfusions or extended length of stay (LoS), can be used to compare the performance of hospitals. However, there is much variation in these outcomes. This study aims to rank hospitals and to assess hospital differences of two outcomes in THA and TKA: allogeneic transfusions and extended LoS, and to additionally identify factors associated with these differences.

DESIGN

Cross-sectional medical record review study.

SETTING

Data were gathered in 23 Dutch hospitals.

PARTICIPANTS

1163 THA and 986 TKA patient admissions.

OUTCOMES

Hospitals were ranked based on their observed/expected (O/E) ratios regarding allogeneic transfusion and extended LoS percentages (extended LoS was defined by postoperative stay >4 days). To assess the reliability of these rankings, we calculated which percentage of the existing variation was based on differences between hospitals as compared with random variation (after adjustment for variation in patient characteristics). Associations between hospital-specific factors and O/E ratios were used to explore potential sources of differences.

RESULTS

The variation in O/E ratios between hospitals ranged from 0 to 4.4 for allogeneic transfusion, and from 0.08 to 2.7 for extended LoS. Variation in transfusion could in 21% be explained by hospital differences in THA and 34% in TKA. For extended LoS this was 71% in THA and 78% in TKA. Better performance (low O/E ratios) in transfusion was associated with more frequent tranexamic acid (TXA) use in TKA (R=-0.43, p=0.04). Better performance in extended LoS was associated with more frequent TXA use in THA (R=-0.45, p=0.03) and TKA (R=-0.65, p<0.001) and local infiltration analgesia (LIA) in TKA (R=-0.60, p=0.002).

CONCLUSIONS

Ranking hospitals based on allogeneic transfusion is unreliable due to small percentages of variation explained by hospital differences. Ranking based on extended LoS is more reliable. Hospitals using TXA and LIA have relatively fewer patients with transfusions and extended LoS.

The effectiveness of a de-implementation strategy to reduce low-value blood management techniques in primary hip and knee arthroplasty: a pragmatic cluster-randomized controlled trial

Background

Perioperative autologous blood salvage and preoperative erythropoietin are not (cost) effective to reduce allogeneic transfusion in primary hip and knee arthroplasty, but are still used. This study aimed to evaluate the effectiveness of a theoretically informed multifaceted strategy to de-implement these low-value blood management techniques.

Methods

Twenty-one Dutch hospitals participated in this pragmatic cluster-randomized trial. At baseline, data were gathered for 924 patients from 10 intervention and 1040 patients from 11 control hospitals undergoing hip or knee arthroplasty. The intervention included a multifaceted de-implementation strategy which consisted of interactive education, feedback on blood management performance, and a comparison with benchmark hospitals, aimed at orthopedic surgeons and anesthesiologists. After the intervention, data were gathered for 997 patients from the intervention and 1096 patients from the control hospitals. The randomization outcome was revealed after the baseline measurement. Primary outcomes were use of blood salvage and erythropoietin. Secondary outcomes included postoperative hemoglobin, length of stay, allogeneic transfusions, and use of local infiltration analgesia (LIA) and tranexamic acid (TXA).

Results

The use of blood salvage (OR 0.08, 95% CI 0.02 to 0.30) and erythropoietin (OR 0.30, 95% CI 0.09 to 0.97) reduced significantly over time, but did not differ between intervention and control hospitals (blood salvage OR 1.74 95% CI 0.27 to 11.39, erythropoietin OR 1.33, 95% CI 0.26 to 6.84). Postoperative hemoglobin levels were significantly higher (β 0.21, 95% CI 0.08 to 0.34) and length of stay shorter (β −0.36, 95% CI −0.64 to −0.09) in hospitals receiving the multifaceted strategy, compared with control hospitals and after adjustment for baseline. Transfusions did not differ between the intervention and control hospitals (OR 1.06, 95% CI 0.63 to 1.78). Both LIA (OR 0.0, 95% CI 0.0 to 0.0) and TXA (OR 0.3, 95% CI 0.2 to 0.5) were significantly associated with the reduction in blood salvage over time.

Conclusions

Blood salvage and erythropoietin use reduced over time, but not differently between intervention and control hospitals. The reduction in blood salvage was associated with increased use of local infiltration analgesia and tranexamic acid, suggesting that de-implementation is assisted by the substitution of techniques. The reduction in blood salvage and erythropoietin did not lead to a deterioration in patient-related secondary outcomes.

Trial registration

www.trialregister.nl, NTR4044

Electronic supplementary material

The online version of this article (doi:10.1186/s13012-017-0601-0) contains supplementary material, which is available to authorized users.

The Exnovation of Chronic Care Management Processes by Physician Organizations

Policy Points The rate of adoption of chronic care management processes (CMPs) by physician organizations has been fairly slow in spite of demonstrated effectiveness of CMPs in improving outcomes of chronic care. Exnovation (ie, removal of innovations) by physician organizations largely explains the slow population-level increases in practice use of CMPs over time. Expanded health information technology functions may aid practices in retaining CMPs. Low provider reimbursement by Medicaid programs, however, may contribute to disinvestment in CMPs by physician organizations.

CONTEXT

Exnovation is the process of removal of innovations that are not effective in improving organizational performance, are too disruptive to routine operations, or do not fit well with the existing organizational strategy, incentives, structure, and/or culture. Exnovation may contribute to the low overall adoption of care management processes (CMPs) by US physician organizations over time.

METHODS

Three national surveys of US physician organizations, which included common questions about organizational characteristics, use of CMPs, and health information technology (HIT) capabilities for practices of all sizes, and Truven Health Insurance Coverage Estimates were integrated to assess organizational and market influences on the exnovation of CMPs in a longitudinal cohort of 1,048 physician organizations. CMPs included 5 strategies for each of 4 chronic conditions (diabetes, asthma, congestive heart failure, and depression): registry use, nurse care management, patient reminders for preventive and care management services to prevent exacerbations of chronic illness, use of nonphysician clinicians to provide patient education, and quality of care feedback to physicians.

FINDINGS

Over one-third (34.1%) of physician organizations exnovated CMPs on net. Quality of care data feedback to physicians and patient reminders for recommended preventive and chronic care were discontinued by over one-third of exnovators, while nurse care management and registries were largely retained. Greater proportions of baseline Medicaid practice revenue (incidence rate ratio [IRR] = 1.44, p < 0.001) and increasing proportions of revenue from Medicaid (IRR = 1.02, p < 0.05) were associated with greater CMP exnovation by physician organizations on net. Practices with greater expansion of HIT functionality exnovated fewer CMPs (IRR = 0.91, p < 0.001) compared to practices with less expansion of HIT functionality.

CONCLUSIONS

Exnovation of CMPs is an important reason why the population-level adoption of CMPs by physician organizations has remained low. Expanded HIT functions and changes to Medicaid reimbursement and incentives may aid the retention of CMPs by physician organizations.

Ensuring Quality in the NICU: Translating Research Into Appropriate Clinical Care

Since the Institute of Medicine's landmark report To Err Is Human, extensive efforts to improve patient safety have been undertaken. However, wide-scale improvement has been limited, sporadic, and inconsistent. Implementation of evidence-based interventions remains a challenge, resulting in unwarranted variations in care. Three main categories of problems in healthcare delivery are defined as overuse, underuse, and misuse of medical services, resulting in inappropriate care, inefficiencies, and poor quality. Although broad acknowledgement that these categories of quality problems exist, there are limited standards for measuring their overall impact. This article aims to discuss the important role of implementation science in advancing evidence-based practice, using neonatal therapeutic hypothermia for the treatment of hypoxic-ischemic encephalopathy as an exemplar for examining appropriateness of care.

Tailored interventions to address determinants of practice

BACKGROUND

Tailored intervention strategies are frequently recommended among approaches to the implementation of improvement in health professional performance. Attempts to change the behaviour of health professionals may be impeded by a variety of different barriers, obstacles, or factors (which we collectively refer to as determinants of practice). Change may be more likely if implementation strategies are specifically chosen to address these determinants.

OBJECTIVES

To determine whether tailored intervention strategies are effective in improving professional practice and healthcare outcomes. We compared interventions tailored to address the identified determinants of practice with either no intervention or interventions not tailored to the determinants.

SEARCH METHODS

We conducted searches of The Cochrane Library, MEDLINE, EMBASE, PubMed, CINAHL, and the British Nursing Index to May 2014. We conducted a final search in December 2014 (in MEDLINE only) for more recently published trials. We conducted searches of the metaRegister of Controlled Trials (mRCT) in March 2013. We also handsearched two journals.

SELECTION CRITERIA

Cluster-randomised controlled trials (RCTs) of interventions tailored to address prospectively identified determinants of practice, which reported objectively measured professional practice or healthcare outcomes, and where at least one group received an intervention designed to address prospectively identified determinants of practice.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality and extracted data. We undertook qualitative and quantitative analyses, the quantitative analysis including two elements: we carried out 1) meta-regression analyses to compare interventions tailored to address identified determinants with either no interventions or an intervention(s) not tailored to the determinants, and 2) heterogeneity analyses to investigate sources of differences in the effectiveness of interventions. These included the effects of: risk of bias, use of a theory when developing the intervention, whether adjustment was made for local factors, and number of domains addressed with the determinants identified.

MAIN RESULTS

We added nine studies to this review to bring the total number of included studies to 32 comparing an intervention tailored to address identified determinants of practice to no intervention or an intervention(s) not tailored to the determinants. The outcome was implementation of recommended practice, e.g. clinical practice guideline recommendations. Fifteen studies provided enough data to be included in the quantitative analysis. The pooled odds ratio was 1.56 (95% confidence interval (CI) 1.27 to 1.93, P value < 0.001). The 17 studies not included in the meta-analysis had findings showing variable effectiveness consistent with the findings of the meta-regression.

AUTHORS' CONCLUSIONS

Despite the increase in the number of new studies identified, our overall finding is similar to that of the previous review. Tailored implementation can be effective, but the effect is variable and tends to be small to moderate. The number of studies remains small and more research is needed, including trials comparing tailored interventions to no or other interventions, but also studies to develop and investigate the components of tailoring (identification of the most important determinants, selecting interventions to address the determinants). Currently available studies have used different methods to identify determinants of practice and different approaches to selecting interventions to address the determinants. It is not yet clear how best to tailor interventions and therefore not clear what the effect of an optimally tailored intervention would be.