12 research outputs found
"Flogging dead horses": evaluating when have clinical trials achieved sufficiency and stability? A case study in cardiac rehabilitation
<p>Abstract</p> <p>Background</p> <p>Most systematic reviews conclude that another clinical trial is needed. Measures of sufficiency and stability may indicate whether this is true.</p> <p>Objectives: To show how evidence accumulated on centre-based versus home-based cardiac rehabilitation, including estimates of sufficiency and stability</p> <p>Methods</p> <p>Systematic reviews of clinical trials of home versus centre-based cardiac rehabilitation were used to develop a cumulative meta-analysis over time. We calculated the standardised mean difference (SMD) in effect, confidence intervals and indicators of sufficiency and stability. Sufficiency refers to whether the meta-analytic database adequately demonstrates that an intervention works - is statistically superior to another. It does this by assessing the number of studies with null results that would be required to make the meta-analytic effect non-statistically significant. Stability refers to whether the direction and size of the effect is stable as new studies are added to the meta-analysis.</p> <p>Results</p> <p>The standardised mean effect difference reduced over fourteen comparisons from a non-significant difference favouring home-based cardiac rehabilitation to a very small difference favouring hospital (SMD -0.10, 95% CI -0.32 to 0.13). This difference did not reach the sufficiency threshold (failsafe ratio 0.039 < 1) but did achieve the criteria for stability (cumulative slope 0.003 < 0.005).</p> <p>Conclusions</p> <p>The evidence points to a relatively small effect difference which was stable but not sufficient in terms of the suggested thresholds. Sufficiency should arguably be based on substantive significance and decided by patients. Research on patient preferences should be the priority. Sufficiency and stability measures are useful tools that need to be tested in further case studies.</p
Recommended from our members
Nutrition and public health economic evaluations under the lenses of post normal science
The emerging scientific field of public health economics, considering health-related behaviours such as physical activity and smoking, is establishing itself as an important component in assessing the impact of policy interventions on preventing disease. Epidemiological evidence points to links between diet, lifestyle and non-communicable diseases (NCDs). Policy decisions aimed at preventing or reducing the burden of NCDs need credible, reliable and evidence-based scientific information. In this context, facts are uncertain and values are contested, while decisions are often urgent and the stakes are high, a typical setting for post-normal science (PNS). Therefore, this work applies quality tools developed in the context of PNS to models used in nutrition and public health economics, using as a guide the seven-point checklist of sensitivity auditing. This analysis has identified scope for improvement in a number of areas, such as the definition of the modelling exercise scope, the justification of the choice of family of models adopted, comprehensively framing the issue by including the perspective of relevant stakeholders and the exertion of more care in justifying assumptions. Addressing these dimensions may even result in refraining from producing a quantitative assessment when the circumstances do not hold. This would conflict with the common imperative to quantify in regulatory policies - often requested by policy guidelines - and with the dynamics of the policy cycle. For this reason, we discuss the implied trade-offs, contradictions and way forward with an eye to achieving progress in the practice