Diagnostic labels and advice for rotator cuff disease influence perceived need for shoulder surgery: an online randomised experiment

Question: What are the effects of diagnostic labels and advice, and interactions between labels and advice, on perceived need for shoulder surgery for rotator cuff disease?

Design: 2×2 factorial online randomised experiment.

Participants: People with shoulder pain.

Intervention: Participants read a scenario describing a patient with rotator cuff disease and were randomised to bursitis label plus guideline-based advice, bursitis label plus treatment recommendation, rotator cuff tear label plus guideline-based advice, and rotator cuff tear label plus treatment recommendation. Guideline-based advice included encouragement to stay active and positive prognostic information. Treatment recommendation stressed that treatment is needed for recovery.

Outcome measures: Perceived need for surgery (primary outcome), imaging, an injection, a second opinion and to see a specialist; and perceived seriousness of the condition, recovery expectations, impact on work performance and need to avoid work.

Results: A total of 2,024 responses (99.8% of 2,028 randomised) were analysed. Labelling as bursitis (versus rotator cuff tear) decreased perceived need for surgery (mean effect -0.5 on a 0-to-10 scale, 98.3% CI -0.7 to -0.2), imaging and to see a specialist, and perceived seriousness of the condition and need to avoid work. Guideline-based advice (versus treatment recommendation) decreased perceived need for surgery (mean effect -1.0, 98.3% CI -1.3 to -0.7), imaging, an injection, a second opinion and to see a specialist, and perceived seriousness of the condition and recovery expectations. There was little to no evidence of an advice label interaction for any outcome.

Conclusion: Labels and advice influenced perceived need for surgery and other secondary outcomes in people with rotator cuff disease, with larger effects for advice. There was evidence of little or no interaction between labels and advice for any outcome, but the additive effect of labels and advice appeared large for some outcomes (eg, perceived need for imaging and perceived seriousness of the condition).

Trial registration: ACTRN12621001370897.