Demographics, Pain Characteristics and Diagnostic Classification Profile of Chronic Non-Cancer Pain Patients Attending a Canadian University-Affiliated Community Pain Clinic.

introductionLittle information exists regarding the characteristics of patients with chronic non-cancer pain (CNCP) attending Canadian pain clinics. The study describes the demographics, pain characteristics and the diagnostic classification profile of such patients attending a university-affiliated community-based pain clinic in the Greater Toronto Area.

methodsRetrospective descriptive study based on 644 unique consecutive CNCP patients assessed between January 2016 and December 2017.

resultsThe female/male ratio was 1.6:1; 80% were younger than 65 years; 43% held some form of employment (full-time, part-time or self employment); median pain duration was 3 years; car accidents and medical conditions accounted for 28 and 27% of pain onset, respectively; 34% had four or more distinct areas of pain; and low back pain (LBP) was the most prevalent site (66%), but was the sole site of pain in less than a third of these patients. Age was positively associated with LBP prevalence. Self-reported health service utilization (visits to the emergency room, pain physician or psychologist) increased with patient psychopathology. Cannabis was used by 15% of the cohort and opioids by 34.5%, with only one in six opioid users exceeding 90 mg of morphine equivalent dose per day. Comparison of our data to three previously published studies from other Canadian pain clinics demonstrated both similarities and substantial differences between the populations.

conclusionOur study highlights regional differences between CNCP population phenotypes. Recognition of biomedical, psychological and socio-environmental factors affecting pain should be considered for patient stratification and rational approaches to treatment, as "one size treatment does not fit all".