To assess whether emergency physicians prescribe morphine differently for patients with or without sickle cell disease (SCD). Given the difficulty of comparing strictly homogeneous patients in real clinical settings, we used a standardised clinical vignette to ensure that all clinical information was identical except for SCD status and sex.

International, randomised controlled, vignette-based study conducted online. The four vignette versions differed only in patient sex and SCD status, with all other clinical information fully standardised. Vignettes were validated by an expert panel and randomly allocated using a computer-generated sequence.

Emergency physicians practising in France, the UK, Belgium and Switzerland were invited to complete an online survey between 17 February and 17 March 2025.

A total of 1060 physicians responded, of whom 953 (90%) met eligibility criteria and were included in the analysis. Respondents were practising emergency department (ED) physicians without exclusion based on seniority or training level.

The primary outcome was the proportion of simulated patients for whom morphine was prescribed. Secondary outcomes included the number and type of analgesics prescribed and the proportion of cases meeting predefined criteria for maximal level of care (urgent triage category, lactate sampling, CT imaging and morphine administration).

Morphine was prescribed in 444 of 492 (90%) SCD vignettes and 389 of 461 (84%) non-SCD vignettes (absolute difference: 6% (95% CI 1% to 10%)). Morphine monotherapy was used in 41% of SCD cases and combined analgesia in 50%. No significant differences were observed according to patient sex or physician characteristics. Maximal level of care was recommended in 22% of SCD cases.

In this randomised vignette study, emergency physicians prescribed morphine more frequently for simulated patients with SCD than for those without SCD, despite identical clinical presentations. These findings contrast with real-world reports of inadequate analgesia in SCD and suggest that the absence of perceptual cues—such as skin colour or names—may reduce implicit bias in opioid prescribing.

NCT06835335. IRB CHU Nîmes No 25.02.01.