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A2O1 | Impact of reporting the number treated needlessly on perceived effectiveness and decision to adopt an intervention

Abstract text
Background: Success of evidence-based practice depends on effective communication of clinical trial results. It is suggested that trials should not only provide figures that indicate the positive impact of interventions, but also those that indicate how many would not benefit, the number treated needlessly (NTN).
Objectives: to assess the impact of explicit reporting of NTN on perceived effectiveness and decision to adopt an intervention among professionals and medical students.
Methods: Cross-sectional survey with random allocation to different formats for presenting effect measure (absolute risk reduction (ARR), relative risk reduction (RRR), number needed to treat (NNT), and NTN). The clinical scenario was “use of statins for the primary prevention of cardiovascular disease”. The outcomes were Persuasiveness (measured as a decision to adopt the intervention) and Perception (measured as rating on an 11-point scale of perceived effectiveness). The study included 1472 participants.
Results: The percentage of participants who decided to adopt the intervention was 92.4%, 87.8%, 67.7%, and 26.2% when RRR, NNT, ARR, and NTN were used, respectively. Comparing ARR with NTN, perceived effectiveness was smaller with NTN [Mean Difference (MD) -1.68 (95% Confidence Interval (CI) -2.06 to -1.30)] and Odds Ratio (OR) for decision to adopt the intervention was 0.17 (95% CI 0.12 to 0.23). Comparing RRR with NTN, perceived effectiveness was smaller with NTN [MD -3.88 (95% CI -4.27 to -3.49)] and OR for decision to adopt the intervention was 0.03 (95% CI 0.02 to 0.05). Comparing NNT with NTN, perceived effectiveness was smaller with NTN [MD -3.14 (95% CI -3.58 to-2.70)] and OR for decision to adopt the intervention was 0.05 (95% CI 0.03 to 0.07).
Conclusion: Explicit reporting of the number treated needlessly has a significant impact on perceived effectiveness and decision to adopt an intervention. It is likely to help making a more balanced well-informed decision.
Authors
Nabhan A1
1 Ain Shams University, Egypt
Presenting author and contact person
Presenting author: 
Ashraf Nabhan
Contact person: 
Ashraf Nabhan (Contact this person)
Date and Location
Session: 
Oral session A2O1
Date: 
Thursday 20 October 2011 - 11:15 - 11:35
Location: