Development and validation of a prognostic model for predicting the risk of allopurinol-induced severe cutaneous adverse reactions: a retrospective new-user cohort study using linked primary care, hospitalisation, and mortality data
Authors' conclusion
We developed and validated a prognostic model for the 100-day risk of an allopurinol-induced severe cutaneous adverse reaction with good predictive performance and clinical utility.
Study context
- Population
- Adults (aged ≥18 years) in England newly prescribed allopurinol, UK Clinical Practice Research Datalink (CPRD), Jan 1, 2001, to March 29, 2021
- Participants
- 173,812 vs 41,610
- Exposure
- Development vs Validation
- Developmentn = 173,812
- Validationn = 41,610
- Outcome
- Prediction of the risk of allopurinol-induced severe cutaneous adverse reactions
- Follow-up
- 100 days
Methodological detailsprognostic model development and validation, multivariable Cox regression and pseudo-values, penalisation, external validation
- Prognostic model development and validation
- Multivariable Cox regression and pseudo-values
- Penalisation
- External validation
Main finding
As reported in the abstract
Model performance, 100-day risk of allopurinol-induced severe cutaneous adverse reactions
| Group | R2D (optimism-adjusted) | Harrell's C (optimism-adjusted) | Calibration slope (95% CI 0.18-1.68) | R2D (95% CI 0.20-0.62) | Harrell's C (95% CI 0.71-0.88) |
|---|---|---|---|---|---|
| Development | 0.50 | 0.82 | |||
| Validation | 0.93 | 0.44 | 0.79 |
R2D (optimism-adjusted)
Development0.50
Validation— not stated in the abstract
Harrell's C (optimism-adjusted)
Development0.82
Validation— not stated in the abstract
Calibration slope (95% CI 0.18-1.68)
Development— not stated in the abstract
Validation0.93
R2D (95% CI 0.20-0.62)
Development— not stated in the abstract
Validation0.44
Harrell's C (95% CI 0.71-0.88)
Development— not stated in the abstract
Validation0.79
Observational data: associations, not effects.
Further findings
Severe cutaneous adverse events · 100 days
Predictors of 100-day risk (aHR)
| aHR (95% CI) | ||
|---|---|---|
| Age | 1.03 (1.01–1.06) | |
| CKD stage 3 | 2.24 (1.20–4.17) | |
| CKD stage 4 | 6.65 (2.90–15.23) | |
| CKD stage 5 | 18.85 (6.32–56.19) | |
| Initial allopurinol dose ≥300 mgCI as printed | 5.99 (3.56–0.08) | |
| South Asian ethnicity | 5.35 (2.37–12.07) | |
| Other Asian ethnicity | 5.63 (1.34–23.61) | |
| 0.050.21520Adjusted hazard ratio (log scale) |
Original publication
Development and validation of a prognostic model for predicting the risk of allopurinol-induced severe cutaneous adverse reactions: a retrospective new-user cohort study using linked primary care, hospitalisation, and mortality data. Lancet Rheumatol. Published 4 September 2025. doi:10.
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