Van de Kerkhof 1996a.

Methods	DESIGN Within‐patient Participant delivery ALLOCATION Random Method of randomisation: not reported Concealment: unclear BLINDING Double‐blind (participant/investigator) WITHDRAWAL/DROPOUT Described
Participants	N: 122 Treatment duration: 8 wks; FU: 12 wks LF: 19 (15.6%) BC: inadequately reported Age: 44.8 (13.69SD) Gender (per cent men): 62.3% Severity: BSA = 5.6% Duration (mths): 233.5 (175.9SD) INCLUSION CRITERIA Stable plaque psoriasis Not localised on the scalp BSA: 5.6% Score ≥ 2 for erythema and desquamation and Score sum > 5 White adults and adolescents EXCLUSION CRITERIA Increased serum calcium or serum phosphate level Recent systemic or topical antipsoriatic treatment Serious disease Known allergy to study medication Recent participation in another clinical trial Expected poor compliance Calcium supplements Drugs influencing calcium metabolism Corticosteroids Barbiturates Phenytoin NSAIDs Pregnancy
Interventions	Tacalcitol 4 mcg/g OD (T) Placebo (vehicle) (P)
Outcomes	Signs: erythema; infiltration; desquamation Total Sign Score (0 to 12) Severity Preference assessment Area of test lesions Investigator Global Assessment (4‐pt: poor to very good) Patient Global Assessment (4‐pt: poor to very good) Assessment of benefit Post‐treatment relapse
Notes	Hermal Kurt Herrmann sponsored the trial. Maximum treatment area: 10% BSA There was SD imputation (TSS).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	The trial reported insufficient details.
Blinding (performance bias and detection bias) All outcomes	Low risk	The trial was double‐blind (participant/investigator).
Randomisation method reported	Unclear risk	The trial did not report this.
Loss to follow up	Low risk	15.6%
Baseline assessments	Low risk	‐
Baseline comparability demonstrated	Unclear risk	The trial did not report this.