Background Little is known about how patient factors may effect the impact of biologics on various quality of life measures used in psoriatic arthritis (PsA).
Objectives The objective of this study was to perform a systematic review and meta-regression analysis to explore the clinical factors that modify the effects of biologics on quality of life in PsA patients.
Methods A systematic literature review was performed in Medline, EMBASE, and Cochrane Central and clinicaltrials.gov. Randomized controlled trials (RCTs) assessing biologics in adults with PsA were eligible. Outcomes of interest included the Health Assessment Questionnaire-Disability Index (HAQ-DI) and the SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS). Clinical factors evaluated for effect on biologic treatment response were age, gender, ethnicity, PsA duration, psoriasis duration, swollen and tender joint counts, steroid baseline use, methotrexate baseline use, prior anti-TNF use, Disease Activity Score (DAS) and study year.
Clinical factors were considered potential effect modifiers (PEM) of quality of life in PsA if they graphically demonstrated associations via forest and l'Abbé plots. PEM were further investigated through meta-regression analyses where covariate effects were assumed to be similar for all treatments.
Results Ten placebo-controlled RCTs were identified as eligible for analysis (10 reporting on SF-36 PCS, 9 reporting on SF-36 MCS, and 9 reporting on HAQ-DI). Treatments assessed in these trials included adalimumab, etanercept, infliximab, ustekinumab, abatacept, certolizumab pegol, golimumab and secukinumab.
Age was found to be a PEM for HAQ-DI at 12 weeks. When this covariate was examined in meta-regression, trials with higher mean age at baseline tended to have higher HAQ-DI scores. Age and psoriasis duration were PEM for HAQ-DI at 24 weeks. In meta-regression, trials with higher mean age at baseline and shorter PsA duration tended to have higher HAQ-DI scores.
Age was identified as a PEM for SF-36 PCS at 12 weeks, but this was not significant in the meta-regression. Psoriasis duration, PsA duration, baseline DAS, and study year were PEM for SF-36 PCS at 24 weeks. Meta-regression analysis of these covariates supported them as effect modifiers, showing trials with shorter psoriasis duration, shorter PsA duration, and more recent study year tended to have lower SF-36 PCS scores. DAS was not found to be related to SF-36 PCS scores.
Age and white race were identified as PEM of SF-36 MCS at 12 weeks, but these were not significant in meta-regression. Age was identified as a PEM for SF-36 MCS at 24 weeks. When this was considered in meta-regression, trials with higher mean age at baseline tended to have lower SF-36 MCS scores.
Conclusions These analyses identified key clinical factors such as age and disease duration, which modify the effects of biologics on quality of life. Accounting for these clinical factors in future real world clinical or pharmacoepidemiologic studies may be important to ensure the best evidence is used for biologic coverage and treatment decision-making.
Disclosure of Interest J. Palmer Employee of: Novartis Pharmaceuticals Corporation, S. Kanter Consultant for: Novartis Pharmaceuticals Corporation, E. Druyts Consultant for: Novartis Pharmaceuticals Corporation, Y. Tsang Employee of: Novartis Pharmaceuticals Corporation, V. Herrera Employee of: Novartis Pharmaceuticals Corporation