Neuropathic pain, depression, and cardiovascular disease: a national multicenter study

Individuals with spinal cord injury (SCI) have a more than twofold increased risk of heart disease and stroke compared with able-bodied individuals. The increased risk appears to be in excess of the risk conferred by several well-established risk factors, including diabetes, hypertension, and sex. This raises the question whether other factors, secondary to SCI, are also contributing to the development of cardiovascular disease (CVD). Two potential factors associated with SCI and CVD are pain and depression. Both are frequently reported among individuals with SCI, develop in the acute stages of injury, and are commonly described as severe. Therefore, the primary aim of this study was to examine the relationship between pain (and types of pain) and depression with CVD among individuals with SCI.

A total of 1,493 individuals (referred sample) with chronic SCI participated in a self-report cross-sectional multicenter Canada-wide survey from 2011-2012 (mean age ± standard deviation: 49.6 ± 13.9 years).

After adjustment for age, sex, and injury characteristics, neuropathic pain and depression were significantly and independently associated with CVD (adjusted odds ratio and 95% confidence interval: 2.27 (1.21, 4.60) for neuropathic pain; 4.07 (2.10, 7.87) for depression). In contrast to neuropathic pain, non-neuropathic pain was not significantly associated with CVD (p = 0.13).

In conclusion, these data illustrate important interrelationships between secondary complications following SCI, as well as raise the possibility of neuropathic pain (versus nociceptive pain) as a novel and emerging risk factor for CVD.