Twenty-two RCTs were included in the analysis (n=9,917): 20 RCTs (n=9,704) of biologics versus placebo and two RCTs (n=213) of comparators. The quality of the included trials was high: mean Jadad score 4.3 and no trial less than 3.
Probabilities of response: TNF inhibitors generally gave rise to the greatest probability of response. Infliximab (5mg/kg every eight weeks following doses at zero, two and six weeks) produced the greatest probability of response in all PASI response categories. Probabilities of response were 93% (PASI 50), 81% (PASI 75) and 54% (PASI 90). T-cell agents were estimated to have the lowest probability of response compared with all other treatments analysed.
Relative risk: TNF inhibitors were most likely to achieve a response at all PASI response levels. When combined (for PASI 75) the relative risk for systemic non-biologics was 9.24 (95% CI 5.33 to 13.95), for T-cell agents the relative risk was 5.65 (95% CI 3.74 to 7.97) and for TNF inhibitors the the relative risk was 15.57 (95% CI 12.46 to 19.25).
Number needed to treat and sensitivity analyses were reported. Sensitivity analysis identified dosage as an important determinant of outcome whereas quality of study was not.