Introduction: Number needed to treat (NNT) is a clinically useful "yardstick" used to gauge the efficacy of therapeutic interventions. The objective of this project was to develop and pilot a series of pictograms and assess their impact on pharmacist understanding of the NNT.
Methods: Three decision aids containing NNT pictograms were developed following a preliminary literature review and three focus groups with current Australian-registered pharmacists and pharmacist interns. Pharmacists then tested the pictograms in a research pilot in clinical encounters until (1) ≥ 3 sessions had occurred or (2) a two-week period had elapsed from commencement. Knowledge assessment was administered both pre- and post-pilot. Transcription and inductive thematic analysis were applied to focus group data. Descriptive statistics, Wilcoxon signed rank, and McNemar's tests were used to analyse the pilot data.
Results: Six core themes regarding NNT decision aid development were identified with >80% consensus across three focus groups (N = 11). Comparison of the pre-post measures (n = 10) showed an increase in median scores after use of NNT decision aids, correlating to a moderate Cohen classified effect size (d = 0.54). Wilcoxon matched pairs test demonstrated a statistically insignificant influence of NNT pictograms on the knowledge assessment survey (P > .05).
Conclusions: While the NNT is not a new concept, its incorporation as part of pictograms for health practitioner enrichment is novel. This pilot study suggests that utilizing decision aids with NNT pictograms as counselling adjuncts appears promising in the realm of enhancing pharmacists' understanding of the NNT.
Keywords: Decision aids; Evidence-based medicine (EBM); Number needed to treat; Pharmacist interventions; Pictograms; Risk communication.
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