Summary of findings for the main comparison. Methotrexate compared to placebo for psoriatic arthritis (up to six months).
| Methotrexate compared to placebo for psoriatic arthritis (up to six months) | ||||||
| Patient or population: psoriatic arthritis Setting: rheumatology clinics (outpatient setting) Intervention: methotrexate (oral ≤ 15 mg per week) Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | No. of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with methotrexate | |||||
| Disease response assessed with PsARC (response event indicates improvement) Follow‐up: mean 6 months | 214 per 1000 | 377 per 1000 (244 to 579) | RR 1.76 (1.14 to 2.70) | 221 (1 RCT) | ⊕⊕⊝⊝ LOWa,b | Absolute difference ‐ 16% more responded to treatment with methotrexate (4% more to 28% more); relative change ‐ 76% more responded to treatment with methotrexate (14% more to 170% more) NNTB 6 (5 to 25) When using imputed values, study authors calculated OR 1.77 (95% CI 0.97 to 3.23)c |
| Function assessed with HAQ Scale from 0 to 3 (0 shows no functional impairment) Follow‐up: mean 6 months | Mean HAQ score was 1.0 | Mean difference in HAQ score was 0.3 lower (0.51 lower to 0.09 lower) | ‐ | 221 (1 RCT) | ⊕⊕⊝⊝ LOWa,b | Absolute change ‐ 10% better with methotrexate (3% better to 17% better); relative change ‐ 30% with methotrexate (95% CI 9% to 51% improvement)d |
| Health‐related quality of life ‐ not reported | ‐ | ‐ | ‐ | ‐ | ‐ | Measured in one study but reported as abstract only; data for extraction could not be obtained (personal communication) |
| Disease activity assessed with DAS28‐ESR Scale from: 0 to 10 (0 shows no disease activity) Follow‐up: mean 6 months | Mean DAS28‐ESR was 4.06 | Mean difference in DAS28‐ESR was 0.26 lower (0.65 lower to 0.13 higher) | ‐ | 221 (1 RCT) | ⊕⊕⊝⊝ LOWa,b | Absolute improvement ‐ 3% better with methotrexate (7% better to 1% worse); relative improvement ‐ 6% better with methotrexate (16% better to 3% worse)d |
| Radiographic progression ‐ not measured | ‐ | ‐ | ‐ | ‐ | ‐ | Not measured in any study |
| Serious adverse events (SAEs) assessed by number of events Follow‐up: mean 6 months | 26 per 1000 | 7 per 1000 (1 to 59) | RR 0.26 (0.03 to 2.26) | 293 (3 RCTs) | ⊕⊕⊝⊝ LOWa,b | Absolute difference ‐ 2% fewer events with methotrexate (5% fewer to 1% more); relative difference ‐ 74% fewer (97% fewer to 116% more) |
| Withdrawals due to adverse events (WAEs) assessed by number of events Follow‐up: mean 6 months | 46 per 1000 | 61 per 1000 (23 to 158) | RR 1.32 (0.51 to 3.42) | 293 (3 RCTs) | ⊕⊕⊝⊝ LOWa,b | Absolute difference ‐ 1% more events with methotrexate (4% fewer to 6% more); relative difference ‐ 32% more events with methotrexate (49% fewer to 242% more) |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; DAS28‐ESR: disease activity score (28 joints) with erythrocyte sedimentation rate; HAQ: Health Assessment Questionnaire for Rheumatoid Arthritis; NNTB: number needed to treat for an additional beneficial outcome; NNTH: number needed to treat for an additional harmful outcome; OR: odds ratio; PsARC: Psoriatic Arthritis Response Criteria; RCT: randomised controlled trial; RR: risk ratio; SAEs: serious adverse events; WAEs: withdrawals due to adverse events. | ||||||
| GRADE Working Group grades of evidence. High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. | ||||||
aDowngraded due to risk of bias: judged as unclear or high risk in at least one study.
bDowngraded due to imprecision: low numbers of events with confidence intervals including potentially clinically meaningless benefits.
cStudy authors did not report summary data from the ITT population. We assumed that missing participants had no response, and we calculated the ITT analysis using the number randomised.
dRelative changes calculated as absolute change (mean difference) divided by mean at baseline in the placebo group (values were 1.0 on 0 to 3 HAQ; 4.06 on 0 to 10 DAS28‐ESR).