Topical preparations for the treatment of psoriasis in primary care: a systematic review

Context: There is clinical uncertainty about the appropriate use of first-line topical treatments for psoriasis. Objective To assess the relative effectiveness and tolerability of topical treatments for psoriasis in primary care. Data sources: All major medical databases of published literature were searched electronically; references of trial reports and recent reviews were searched; authors and companies were contacted for missing data from published reports. Study selection: (1) Randomised placebo-controlled trials of topical treatments for psoriasis and (2) randomised head-to-head studies of the new vitamin D3 derivative treatments for psoriasis, that reported clinical outcome using a Total Severity Score (TSS), Psoriasis Area Sensitivity Index or Investigator Assessment of Global Improvement. Data extraction: Eligibility and validity were assessed and data extracted independently by two authors. Data synthesis: Clinical outcomes were pooled using a random effect standardised weighted mean difference (SWMD) metric, including 3,380 patients randomised in 41 placebo (vehicle) controlled trials and 4,898 patients randomised in 28 head-to-head studies. There was a significant benefit in favour of active treatments against vehicle, SWMD: -1.06 (95%Cl: -1.26 to -0.86), approximately a 2-point improvement on a 12-point TSS after 6 to 8 weeks of treatment. The only significantly different benefit was for very potent corticosteroids; SWMD: -1.51 (95%Cl: -1.76 to -1.25), approximately a 3-point improvement on a 12-point TSS. Head-to-head studies support these findings, except that calcipotriol was estimated to be more effective than dithranol, coal tar and other vitamin D3 derivatives. Polytherapy, using a potent steroid and calcipotriol, was more effective than calcipotriol alone: SWMD 0.42 (95%Cl: 0.12 to 0.72) approximately a 0.8 point improvement on a 12-point TSS> No important differences in withdrawal or reporting of adverse events were identified. Conclusions Trials of short duration neither adequately inform the management of chronic disease nor describe the sequelae of treatment. The evidence base for long-term care, reflecting the disease pathway, should be improved. Combination therapy with topical vitamin D analogues and steroids, and maintenance therapy following treatment response merit further investigation.