Introduction: Pain frequently occurs after ischemic and hemorrhagic stroke. Though conditions such as hypertension are associated with both pain and stroke, little is known about the relationship between pain and stroke risk.
Hypothesis: Pain will be associated with increased hemorrhagic rather than ischemic stroke.
Methods: We examined stroke among Veterans in the Musculoskeletal Disorder (MSD) Cohort, which contains 4.1 million Veterans diagnosed with at least one musculoskeletal disorder between 2001 and 2011. All conditions were identified via ICD-9 codes and all comorbidity defined as occurring one year prior to and six months after the date of first MSD diagnosis. Pain was measured by the pain intensity numeric rating scale score on the date of first MSD diagnosis. Logistic regression was used to examine the association between pain and stroke subtype.
Results: Comorbid hemorrhagic (n=9,141; 0.22%) and ischemic (n=19,301; 0.47%) strokes were uncommon in the MSD cohort. The majority of hemorrhagic stroke patients (88%) had their stroke following their first MSD diagnosis, compared with 58% of ischemic stroke patients (p<.0001). After controlling for sociodemographic characteristics, medical comorbidities (including hypertension), and BMI, persons with pain had a higher odds of having a hemorrhagic, rather than an ischemic stroke (odds ratio ∼ 1.35, confidence interval = 1.2, 1.6). When examining odds including persons without stroke (multinomial model), severe pain (versus ‘no pain’) was significantly associated with increased odds of hemorrhagic stroke (versus ‘no stroke’). When comparing ischemic stroke to no stroke, odds ratios at all pain levels revealed significantly higher pain in those patients without comorbid ischemic stroke.
Conclusion: Pain was associated with increased odds of having a hemorrhagic stroke (compared to ischemic). Only severe pain increased the odds of hemorrhagic stroke (compared to ‘no stroke’). Pain was significantly decreased in the ischemic stroke group compared to the group without comorbid stroke. Further work is necessary to understand mediators and moderators between pain, increased hemorrhagic (e.g., NSAID use) and decreased ischemic (e.g., aphasia) stroke risk.