Objective To investigate the incidence and risk of ischaemic heart disease (IHD) and acute myocardial infarction (AMI), including the role of non-steroidal anti-inflammatory drugs (NSAID), in patients with ankylosing spondylitis (AS) compared with population controls.

Methods All patients with newly diagnosed AS (n=3809) from the British Clinical Practice Research Datalink (1987–2012) were matched with up to seven persons without AS by year of birth, gender and practice (n=26 197). Incidence rate ratios (IRR) and HRs for development of IHD and AMI were calculated. Stepwise analyses were performed adjusting for age, gender, comorbidity and drug use, including NSAIDs.

Results At baseline, 4.3% of the patients had IHD and 1.8% had AMI compared with 3.4% and 1.4% of the controls, respectively. After exclusion of pre-existing IHD or AMI, the IRRs were 1.18 (95% CI 0.96 to 1.46) and 0.91 (95% CI 0.65 to 1.27) for IHD and AMI, respectively. Compared with controls, the age-gender adjusted HR for developing IHD was 1.20 (95% CI 0.97 to 1.48), and for AMI 0.91 (95% CI 0.65 to 1.28). In female patients, the risk of developing IHD was increased (HR 1.88, 95% CI 1.22 to 2.90), but after adjustment for all possible risk factors only a non-significant trend was found (HR 1.31, 95% CI 0.83 to 2.08). In particular, NSAID use explained this change (HR IHD adjusted for age-gender-NSAID use 1.57, 95% CI 0.99 to 2.48).

Conclusions Female patients with AS had an increased age-adjusted risk of developing IHD, but after adjustment for NSAID use only a non-significant trend towards increased risk was found.