Characteristics and outcome of a first acute myocardial infarction in patients with ankylosing spondylitis

Objectives To study clinical characteristics, mortality, and secondary prevention, after a first incident acute myocardial infarction (AMI) in patients with ankylosing spondylitis (AS) compared with the general population. Methods In total, 292 subjects with AS and a first AMI between Jan 2006 and Dec 2014 were identified using the Swedish national patient register. Each subject was matched with up to 5 general population comparators per AS-patient (n = 1276). Follow-up started at the date of admission for AMI and extended until death or 365 days of follow-up. Cox regression was used to assess mortality in two time intervals: days 0-30 and days 31-365. For a subgroup with available data, clinical presentation at admission, course, treatment for AMI, and secondary prevention were compared. Results During the 365-day follow-up, 56/292 (19%) AS patients and 184/1276 (14%) comparators died. There were no difference in mortality due to cardiovascular-related causes, although the overall mortality day 31-365 was increased among patients with AS compared with comparators (HR [95% CI] = 2.0 [1.3;3.0]). At admission, AS patients had a higher prevalence of cardiovascular comorbidities compared with comparators. At discharge, patients with AS were less often prescribed lipid-lowering drugs and non-aspirin antiplatelet therapy. Conclusions Patients with AS tend to have a higher comorbidity burden at admission for first AMI. The mortality after a first AMI due to cardiovascular-related causes does not seem to be elevated, despite an increased overall mortality during days 31-365 among patients with AS compared with the general population.