Construct validity of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) treatment target cut-offs in a BASDAI treat-to-target axial spondyloarthritis cohort: a cross-sectional study.

OBJECTIVE: In axial spondyloarthritis (axSpA), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) are recommended for use in treat-to-target (T2T) strategies. However, BASDAI disease states may be a less suitable T2T instrument than ASDAS, since BASDAI contains non-disease activity related items. The objective of our study was to investigate the construct validity of BASDAI and ASDAS disease states. METHOD: We performed a single-centre cross-sectional study on BASDAI and ASDAS construct validity in long-term BASDAI T2T-treated axSpA patients. Our hypothesis was that BASDAI is less representative of disease activity than ASDAS owing to the focus on pain and fatigue, and missing an objective item, e.g. C-reactive protein (CRP). This was operationalized using several subhypotheses. RESULTS: The study included 242 axSpA patients. BASDAI and ASDAS disease states showed a similar relation to Patient Acceptable Symptom State and T2T protocol adherence. The proportions of patients with high BASDAI and ASDAS disease activity fulfilling Central Sensitization Inventory and fibromyalgia syndrome criteria were similar. The correlation with fatigue was moderate for both BASDAI (Spearman's rho 0.64) and ASDAS (Spearman's rho 0.54) disease states. A high ASDAS was strongly correlated with increased CRP (relative risk 6.02, 95% CI 3.0-12.09), while this correlation was not seen for BASDAI (relative risk 1.13, 95% CI 0.74-1.74). CONCLUSION: Our study showed moderate and comparable construct validity for BASDAI- and ASDAS-based disease activity states, with the expected exception of association with CRP. Therefore, no strong preference can be given for either measure, although the ASDAS seems marginally more valid.

Favourable Tolerability and Drug Survival of Tioguanine Versus Methotrexate After Failure of Conventional Thiopurines in Crohn's Disease.

BACKGROUND AND AIMS: Both methotrexate and tioguanine can be considered as treatment options in patients with Crohn's disease after failure of conventional thiopurines. This study aimed to compare tolerability and drug survival of methotrexate and tioguanine therapy after failure of conventional thiopurines in patients with Crohn's disease. METHODS: We conducted a retrospective, multicentre study, including patients with Crohn's disease initiating monotherapy methotrexate or tioguanine after failure [all causes] of conventional thiopurines. Follow-up duration was 104 weeks or until treatment discontinuation. The primary outcome was cumulative therapy discontinuation incidence due to adverse events. Secondary outcomes included total number of [serious] adverse events, and ongoing monotherapy. RESULTS: In total, 219 patients starting either methotrexate [n = 105] or tioguanine [n = 114] were included. In all 65 [29.7%] patients (methotrexate 43.8% [46/105 people], tioguanine 16.7% [19/114 people], p <0.001) discontinued their treatment due to adverse events during follow-up. Median time until discontinuation due to adverse events was 16 weeks (interquartile range [IQR] 7-38, p = 0.812). Serious adverse events were not significantly different. Patients treated with methotrexate experienced adverse events more often [methotrexate 83%, tioguanine 46%, p <0.001]. Total monotherapy drug survival after 104 weeks was 22% for methotrexate and 46% for tioguanine [p <0.001]. CONCLUSIONS: We observed a higher cumulative discontinuation incidence due to adverse events for methotrexate [44%] compared with tioguanine [17%] in Crohn's disease patients after failure of conventional thiopurines. The total adverse events incidence during methotrexate use was higher, whereas serious adverse events incidence was similar. These favourable results for tioguanine treatment may guide the selection of immunosuppressive therapy after failure of conventional thiopurines.

Increased Discontinuation Rates of Anti-TNF Therapy in Elderly Inflammatory Bowel Disease Patients.

BACKGROUND AND AIMS: There is paucity of data on safety and efficacy of anti-tumour necrosis factor [TNF] in elderly inflammatory bowel disease [IBD] patients. We aimed to compare the long-term treatment failure rates and safety of a first anti-TNF agent in IBD patients between different age groups [<40 years/40-59 years/≥60 years]. METHODS: IBD patients who started a first anti-TNF agent were identified through IBDREAM, a multicentre prospective IBD registry. Competing risk regression was used to study treatment failure, defined as time to drug discontinuation due to adverse events [AEs] or lack of effectiveness, with discontinuation due to remission as a competing risk. RESULTS: A total of 895 IBD patients were included; 546 started anti-TNF at age <40 [61.0%], 268 at age 40-59 [29.9%], and 81 at age ≥60 [9.1%]. Treatment failure rate was higher in the two older groups (subhazard rate [SHR] age ≥60 1.46, SHR age 40-59 1.21; p = 0.03). The SHR in the elderly [>60] was 1.52 for discontinuation due to AEs and 1.11 for lack of effectiveness. Concomitant thiopurine use was associated with a lower treatment failure rate (SHR 0.78, 95% confidence interval [CI] 0.62-0.98, p = 0.031). Serious adverse event [SAE] rate, as well as serious infection rate, were significantly higher in elderly IBD patients [61.2 versus 16.0 and 12.4 per 1000 patient-years, respectively] whereas the malignancy rate was low in all age groups. CONCLUSIONS: Elderly IBD patients starting a first anti-TNF agent showed higher treatment failure rates, but concomitant thiopurine use at baseline was associated with lower failure rates. Elderly IBD patients demonstrated higher rates of SAEs and serious infections.