Increased risk of ischaemic stroke amongst patients with chronic osteomyelitis: A population-based cohort study in Taiwan

Background and purpose: Inflammatory processes, which kindle endothelial dysfunction and atherosclerosis, may facilitate the development of cardiovascular disease, including ischaemic stroke. Evident stroke risk factors may not be identified in up to 40% of stroke patients, especially in the younger population. Inflammation remains to be established as a stroke risk factor. In this study, it was assessed whether chronic osteomyelitis (COM), an infectious disease with chronic inflammation, increases stroke risk. Methods: A national insurance claim data set of 22 million enrollees in Taiwan was used to identify 18 509 patients with COM and 74 034 randomly selected age- and gender-matched controls for a follow-up period of 11 years starting 1 January 2000 and ending 31 December 2010. Stroke risk was analyzed using the Cox proportional hazards regression model. Results: Comorbidities known to increase stroke risk, including hypertension, diabetes, hyperlipidemia, coronary heart disease and peripheral arterial disease, were more frequently noted in the COM group who had significantly greater stroke risk than the control cohort. Comparing only those without comorbidities, COM carried greater stroke risk than the control group [hazard ratio (HR) = 1.40, 95% confidence interval (CI) 1.22-1.62, P < 0.001]. The younger population carried even greater risk (age < 45, HR = 2.73, 95% CI 1.71-4.35; age > 65, HR = 1.16, 95% CI 1.02-1.31). Conclusions: This is the first report linking COM to an increased risk of developing stroke. Results suggest that COM is a significant stroke risk factor and call for closer attention to this group of patients for more rigorous stroke prevention, especially in the younger age group.