Study: Patients with chronic widespread pain had a greater mortality risk

Nancy E. Lane, MD

Clinicians have often wondered how best to categorize chronic widespread pain. While some have considered chronic widespread pain as the result of other diseases, such as generalized osteoarthritis, vasculopathy of sickle cell disease or a central nervous system-originating entity, such as fibromyalgia, chronic widespread pain has not been considered a risk factor for mortality until this report by Macfarlane and colleagues.

To determine if chronic widespread pain was associated with excess mortality, they performed two studies. The first study used the British BioBank — a cohort of 500,000 British individuals aged 40 years to 69 years — in which subjects were asked if they had pain all over their body for 3 months or more. They then performed a meta-analysis with other published report to obtain a more objective estimate of widespread risk of excessive mortality in patients with chronic pain. Interestingly, they found individuals with chronic widespread pain had an excess of mortality of about 2.5-times that of individuals without chronic widespread pain and the causes of death were cancer, respiratory, cardiovascular and other reasons. There are confounders known to be associated with both chronic widespread pain and death. When the confounders, including low levels of physical activity, smoking, high BMI and smoking were reduced, the meta-analysis showed individuals with widespread chronic pain had a significant all-cause mortality of about 1.59, which was significant because the confidence intervals did not cross 1.

Results of this study can make health care providers think that instituting an exercise routine, regular cancer screening, smoking cessation program and weight loss program may help these patients’ overall health and longevity, as the estimate for reduced mortality may be as high as 35% and should have priority in the routine care of these individuals. However, I am inclined to think a little more deeply about this observation and suggest that more biologic hypotheses be tested, such as a microvascular deficiency that prevent tissues from receiving oxygen which result in widespread pain. Investigators at Harvard have reported red blood cells coated with C4 do not move through capillaries normally and this can cause tissue ischemia at the capillary level. While patients with systemic lupus erythematosus complain of fatigue, other patients may describe this as widespread pain.

Clearly, this study by Macfarlane suggests we have more to think about and we should immediately begin to work to modify the lifestyle factors of patients with chronic widespread pain to those of patients without the chronic widespread pain, which may reduce mortality by 35%. We should consider biologic mechanisms that explain this pain.

Reference:

Ghiran IC, et al. Arthritis Rheum. 2011;doi:10.1002/art.30143.