Increased risk of strokes in patients with chronic low back pain (CLBP): A nationwide population-based cohort study

•No any longitudinal studies about CLBP patients are at risk for stroke were seen.•CLBP was associated with increased risk of stroke in this study.•The association was stronger in younger patients less than 50 years old.•Prospective studies with lifestyle factors are needed to clarify the causal relationship. There have not been any longitudinal studies reported that chronic low back pain (CLBP) patients are at risk for stroke. Thus, in this study, we explored the association between CLBP and strokes. Data (2000∼2010) from the Taiwan National Health Insurance database were analyzed. We matched 10,308 CLBP patients with 20,616 propensity score-matched non-low back pain (NLBP) patients according to age, gender, index year and comorbidities. Covariates of age, gender, comorbidities, and usage of non-steroidal anti-inflammatory drugs (NSAIDs) were adjusted and analyzed. The mean follow-up duration was 8 years. CLBP patients had higher risks of all stroke, hemorrhagic stroke, and ischemic stroke. The adjusted hazard ratios (aHRs) were 2.35 (95 % confidence interval (CI): 2.14–2.57, p < 0.001), 1.55 (95 % CI: 1.16–2.06, p = 0.003), and 2.41 (95 % CI: 2.18–2.66, p < 0.001), respectively. After adjusting and analyzing the NSAIDs used for the varied duration in the CLBP patients, we did not observe any impacts of such NSAIDs used on the association of CLBP with strokes. The association between CLBP and ischemic stroke was most prominent in the patients less than 50 years old with aHR: 3.56 (CI: 2.74∼4.61, p < 0.001). CLBP was associated with increased risk of strokes, especially ischemic stroke, and the association was most prominent in patients less than 50 years old. Further large prospective studies on detailed lifestyle-related factors and qualitative pain assessment are needed to clarify the causal relationship between CLBP and stroke.