Efficacy of Oral Methotrexate in the treatment of Plaque Psoriasis in a local population

Abstract

Background:  Plaque psoriasis constitutes around 90% of psoriasis prevalent in the world. It’s medically introduced as well demarcated erythematous plaques with coarse silvery scales predominantly involving extensor surfaces of the knees, elbows, sacrum, scalp, nails and sites of injury. Methotrexate has been widely used to treat psoriasis and associated arthritis, it is mainly used to treat plaque psoriasis in patients not responding to topical therapy. Systemic therapy is required for patients who don’t respond to topical or where there is extensive disease. These include photochemotherapy, ciclosporin, biological agents.2,9 Various studies show methotrexate as an efficient drug to treat plaque psoriasis by reducing inflammation, and reducing cell proliferation by exerting its immunosuppressant effect.

Objective: To determine the safety and efficacy of methotrexate in treating plaque psoriasis.

Materials and Methods: The interventional descriptive single-arm pre and post-study was conducted in the department of dermatology Fauji Foundation Hospital Rawalpindi from August 2018 to January 2021. This research was approved by the ethical review committee of the hospital. One hundred forty two patients between 15 to 60 years of age suffering from plaque type psoriasis with PASI score of >8 were included in the study after taking the informed consent. Oral methotrexate in a dose of 10 mg/week was given for 8 weeks to patients from dermatology outdoor and Indoor. (PASI 6 or greater).Baseline blood counts,  blood urea nitrogen, serum creatinine, electrolytes,  alkaline phosphatase, alanine aminotransferase and chest Xray to rule out latent tuberculosis. They all got cured through a methotrexate dosage of 10mg that was adjusted between 5 mg to 25 mg based on individual conditions. Outcomes were measured as Psoriasis Area Severity Index PASI and Disease Activity Score DAS 28 for patients having psoriatic arthritis.

Results: Of all the participants 116(81.1%) were female and 26 (18.2%) were male whereas mean age of participants was 41.6 years. The mean pretreatment and post treatment PASI score shows significant drop from baseline (13.01+6.02) to eight weeks post treatment (5.4+3.2)  which is statistically significant (P=<0.05). The change in percentage of PASI from baseline was analyzed by the Wilcoxon signed ranks test after 8 weeks (t=17.29) ie PASI 75 was achieved in more than 50% of participants. There was a marked improvement in the DAS28 score of participants having Psoriatic arthritis. Regarding Psoriatic arthritis, Table 6 shows that 26 out of 29 (96.29%) patients had moderate Psoriatic arthritis with DAS 28 score of  less than 5 while 1(3.7%) patient had mild and 2(7.4%) had severe joint disease of greater than 5.1 DAS 28 score before methotrexate treatment. However majority ie 17/29 (62.9%) achieved complete remission in joint disease after 8 weeks of methotrexate treatment while a small number 2/29 (7.4%) still had DAS 28 score of upto 5.1 or moderate remission while none had high score of DAS28 of greater than 5.1 after 8 weeks. 

Conclusion: The outcome of this study has shown that the effective way to treat plaque psoriasis is through methotrexate which is efficient in treating coexisting psoriatic arthritis which is one of the important commodities associated with plaque psoriasis