LAUSR

OBJECTIVE To summarize evidence on the relationship between early treatment (definition based on symptom/disease duration or radiographic damage) and treatment clinical response in patients with SpA. METHODS A systematic literature review was conducted in studies on SpA patients treated with NSAIDs or b/tsDMARDs addressing the impact of symptom/disease duration or presence of radiographic damage on treatment response assessed by any disease activity outcome. For categorical outcomes, relative risk, relative risk ratio (RRR) and number needed to treat were calculated, and for continuous outcomes, differences in differences, to compare groups stratified based on symptom/disease duration or the presence of radiographic damage. RESULTS From the 8769 articles retrieved, 25 were included and 1 added by hand-search, all in axSpA, most of them with low risk of bias. Twenty-one studies compared groups based on symptom duration (n = 6) or disease duration (n = 15) and 7 studies based on absence/presence of radiographic damage (2 studies used two comparisons). When early axSpA was defined by symptom duration (<5 years) in RCTs, early treatment was associated with better outcomes in patients with nr-axSpA (n = 2, ASAS40 RRR 5.24 (95%CI 1.12-24.41) and 1.52 (0.60-3.87)) but not in r-axSpA (n = 1) [ASAS20 0.96 (0.53-1.73)]. When early axSpA was defined based on disease duration or radiographic damage, no differences were found between groups. CONCLUSION Evidence towards better outcomes in early axSpA is very limited and restricted to nr-axSpA and <5 years symptom duration. When early axSpA is defined based on disease duration or radiographic damage, no differences in response to treatment are found.