Severe flare as a predictor of poor outcome in ankylosing spondylitis: a cohort study using questionnaire and routine data linkage.

Objective: To explore severe flare and constant disease pattern (no periods of remission) in AS as predictors of poor outcomes [impaired function, unemployment/early retirement, work impairment, anti-TNF, surgery, frequent general practitioner (GP) visits, depression and anxiety].

Methods: Three hundred and forty-eight AS patients completed questionnaires about their experience with disease flares. Questionnaire data were linked to electronic medical records to examine visits to GPs and hospital admission data. Outcomes were stratified in two ways: self-reported experience of severe flare and constant disease pattern using the flare illustration tool.

Results: The majority of patients (72%, 208/289) experienced flare pre-diagnosis. Severe flares were reported by 58% (202/348) of participants (self-report); of these, 195 responded about earliest flares and 69% (135/195) of severe flare patients experienced flares pre-diagnosis. Patients who self-reported severe flares had worse function, disease activity, work impairment and symptoms of anxiety and depression, were less likely to be employed and had more GP encounters per year compared with those who never reported severe flares. Participants who reported constant unremitting disease on the flare illustration tool had worse disease activity, impaired function and work impairment and were more likely to smoke compared with those with intermittent disease. Analysis showed a relationship between self-report of severe flare and subsequent depression, impaired function, increased disease activity and work limitations.

Conclusion: Severe flare is associated with poor outcomes such as work impairment and impaired function. The onset of severe flare early in the disease course may be a risk factor for later poor outcome and this group could benefit from targeted early aggressive treatment to improve prognosis.