Chronic pain can increase the risk of ischaemic and haemorrhagic stroke, as underlying comorbidities like hypertension increase stroke risk, according to results of a retrospective analysis presented at the 142nd Annual Meeting of the American Neurological Association (ANA).
“Chronic pain may be an important, modifiable risk factor for ischaemic and haemorrhagic stroke,” stated lead author Jason Sico, MD, MHS, Yale University School of Medicine, New Haven, Connecticut, speaking here at a poster session on October 15.
Patients with chronic pain frequently have comorbid conditions like hypertension and polysubstance use that can increase the risk of stroke. “Despite several potential mechanisms by which pain and its comorbid conditions may increase stroke risk, little is known about whether there is an independent association between chronic pain and stroke risk,” Dr. Sico and colleagues noted.
The study examined the 2001 to 2011 data of 5.4 million veterans in the Musculoskeletal Disorder Cohort (U.S. Department of Veterans Affairs), which was created to support research into pain that afflicts half of all veterans. Exclusion criteria concerning prior stroke and pain scores eliminated nearly 3.4 million subjects. The researchers examined data from the remaining 1,993,623 people.
Three models were used to probe the association between chronic pain and ischaemic and haemorrhagic stroke. Model 1 accounted for chronic pain. Model 2 was model 1 adjusted for age, race/ethnicity, and sex. Model 3 was model 2 adjusted for diabetes, coronary artery disease, alcohol/drug abuse, traumatic brain injury, migraine, and hypertension.
Chronic pain was independently associated with both incident ischaemic stroke and incident haemorrhagic stroke in all 3 models. In the fully adjusted model 3, the odds ratio (OR) for ischaemic and haemorrhagic stroke was 1.27 (95% confidence interval [CI]: 1.22 to 1.33) and 1.31 (95% CI: 1.15 to 1.49). For incident ischaemic stroke, an interaction with hypertension was evident. With hypertension, the OR was 1.43 (95% CI: 1.37 to 1.50). Without hypertension, the OR was 1.17 (95% CI: 1.17 to 1.39). No interactions were evident for incident haemorrhagic stroke.
“After controlling for sociodemographic characteristics and medical comorbidities, chronic pain was associated with higher odds of having an incident stroke,” the researchers concluded.
Study limitations include the predominant white and male nature of the cohort, lack of adjustment for how well hypertension was controlled, and incomplete information concerning non-steroidal drugs.