Ankylosing spondylitis: a risk factor for myocardial infarction?
To ascertain the prevalence of myocardial infarction (MI) in ankylosing spondylitis (AS) relative to that in the general population. A questionnaire was sent to 593 patients with AS, aged between 50 and 75 years and registered at the Jan van Breemen Institute or VU University Medical Centre. A total of 383 (65%) patients with AS returned their questionnaire that covered the primary outcome, (non-fatal) MI. The prevalence of MI was calculated with data from the general population provided by Netherlands Information Network of General Practice databases as reference. The overall prevalence for MI was 4.4% in patients with AS versus 1.2% in the general population, resulting in an age- and gender-adjusted odds ratio of 3.1 (95% CI 1.9 to 5.1) for patients with AS. When non-responders (35%) were considered as non-MI the odds ratio decreased to 1.9 (95% CI 1.2 to 3.2). These observations indicate that the prevalence of MI is increased in patients with AS.