Tosti 1998.

Methods	This was a randomised, double‐blind actively‐controlled study. It was unclear if intention‐to‐treat analysis was conducted.
Participants	Inclusion criteria of the trial Participants were eligible if over 18 years of age, of either sex, with severe subungual hyperkeratosis (> 1 mm for fingernails, > 2.5 mm for toenails). A total of 58 participants were enrolled. (There were 35 men and 23 women; mean age = 51.8 years.) 29 participants received topical calcipotriol ‐ 16 men and 13 women; mean age = 50.7 years ‐ of whom 13 participants (47 nails) had fingernail psoriasis, and 20 participants (109 nails) had toenail psoriasis. The mean duration of nail psoriasis in these participants was 8.3 years. 29 participants (19 men and 10 women; mean age = 53 years) received topical betamethasone dipropionate and salicylic acid, of whom 16 participants (82 nails) had fingernail psoriasis, and 24 participants (161 nails) had toenail psoriasis. The mean duration of nail psoriasis in these participants was 7.1 years. A total of 29 participants had psoriasis of the fingernails, and 44 participants had toenail psoriasis. 2 participants assigned to receive calcipotriol presented exclusion criteria and were not considered in the assessment of efficacy; 12 (4 with calcipotriol and 8 with betamethasone) failed to attend the visit and were considered as dropouts. Exclusion criteria of the trial Onychomycosis Pregnant or breast‐feeding women Known hypersensitivity to the study molecule Receiving vitamin D‐based therapies or other topical or systemic treatments Severe renal or hepatic insufficiency
Interventions	Calcipotriol ointment (50 μg/g) or betamethasone dipropionate (64 mg/g) and salicylic acid (0.03 g/g) ointment, twice daily for at last 3 months. Participants who showed a 50% or more reduction in the baseline hyperkeratotic thickness at least in 1 nail (responders) were offered continuation of treatment for 2 further months. Participants who completed the 5 months of treatment were then followed for 1 month after discontinuation.
Outcomes	Outcomes of the trial Nail thickness (nail plate + hyperkeratotic nail bed) in mm using a calliper Responders (≥ 50% reduction after 3 months, further treatment for 2 months and 1 month follow up) Participant's opinion about acceptability of treatment using a 5‐point scale: 0 = nil, 1 = poor, 2 = fair, 3 = good, 4 = excellent
Notes	The trial was conducted in accordance with the principles of the Declaration of Helsinki.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...randomised study."
Allocation concealment (selection bias)	Unclear risk	Comment: The paper provided insufficient details.
Blinding (performance bias and detection bias) Clinician/ Investigator	Low risk	Quote: "...double blind study."
Blinding (performance bias and detection bias) Participants	Low risk	Quote: "...double blind study."
Blinding (performance bias and detection bias) Outcome assessor	Low risk	Quote: "...double blind study." Comment: The blinded investigator was probably the outcome assessor.
Incomplete outcome data (attrition bias) All outcomes	High risk	2/29 calcipotriol participants presented exclusion criteria, and 12 participants (4 of 29 calcipotriol‐treated participants and 8 of 29 betamethasone + salicylic acid‐treated participants) failed to attend the visits during the trial and were considered as dropouts. Responders (≥ 50% reduction after 3 months, further treatment for 2 months and 1 month follow up); fingernails: 8 (28 nails) calcipotriol, 10 (38 nails) betamethasone; toenails: 7 (51 nails) calcipotriol, 12 (58 nails) betamethasone.
Selective reporting (reporting bias)	Low risk	Comment: All of the outcomes were reported.
Other bias	High risk	Quote: "...partially supported by Prodotti Formenti SRL, Milan, Italy." "The baseline subungual hyperkeratotic thickness of the responder groups was not homogeneous for calcipotriol and betamethasone treatment for fingernails as well as toenails."