Study Finds One-Third of Patients Report Coexisting Chronic Pain Conditions

A study in Canada of nearly 4,000 patients with chronic pain found that one-third reported coexisting chronic pain conditions, but no specific patterns of co-occurrence of pain comorbidity were identified.

The study was conducted to add more to the body of knowledge about what is known about chronic pain (CP), which is experienced by up to 20% of the population. CP is defined as pain persisting for longer than normal or expected (about 3 to 6 months) or is associated with a progressive nonmalignant disease. It is its own disease entity and not a symptom of underlying diseases.

The study, published in the Journal of Pain Research, sought to:

• Determine the prevalence of coexisting chronic pain conditions
• Identify the most frequent coexisting pain conditions in patients attending multidisciplinary pain clinics
• Characterize patterns of co-occurrence
• Examine relationships among patients’ biopsychosocial characteristics and number of coexisting CP conditions
• Determine the impact of coexisting CP conditions on treatment response.

The presence of coexisting pain conditions was significantly associated with lower quality of life, longer pain duration, older age, and being female. Contrary to study hypotheses, the presence of coexisting CP diagnoses did not seem to have a clinically significant impact on treatment responses.

Results showed that sex, age, pain duration, and physical health-related quality of life might be associated with number of pain comorbidities. Results suggested that different risk factors exist for having one versus coexisting pain conditions. However, the occurrence of coexisting pain conditions does not seem to follow a specific type or pattern, even if specific vulnerabilities exist.

Results showed that the mean number of pain diagnoses across classes was 1.45. These results are similar to those found in some population studies.

The most prevalent pain diagnostic class was chronic musculoskeletal pain (37.9%), followed by chronic neuropathic pain (32.2%), chronic primary pain (25.4%), and chronic postsurgical and posttraumatic pain (20.5%). The most prevalent specific diagnostic categories were peripheral neuropathic pain (26.9%) and chronic musculoskeletal pain from structural osteoarticular changes (21.6%). Chronic musculoskeletal pain, chronic cancer pain, chronic primary pain, and chronic headache and orofacial pain had the highest average number of pain diagnoses for patients with at least one diagnosis in these categories. Chronic cancer pain (76.5%), chronic headache and orofacial pain (63.7%), and chronic visceral pain (63.6%) had more than half of patients with a coexisting pain diagnosis from other pain categories.

The number of pain classes was statistically significantly associated with pain intensity, interference, and quality of life after controlling for age and sex. Longer pain duration was associated with increased number of pain conditions.

Results of the present study did not find a significant interaction between time and number of pain classes in predicting pain and related outcomes, which suggests that the presence of coexisting pain conditions would not impact on treatment responses.

Reference

Pagé MG, Fortier M, Ware MA, et al. As if one pain problem was not enough: prevalence and patterns of coexisting chronic pain conditions and their impact on treatment outcomes. J Pain Res. 2018;(11):237-254. doi.org/10.2147/JPR.S149262 Published January 26, 2018. Accessed February 2, 2018.