Demographic and Biomedical Characteristics of an Observational Cohort With Chronic Low Back Pain: A Descriptive Analysis

Background: The chronic low back pain (cLBP) literature rarely includes comprehensive characterization of demographic and biomedical factors in a large sample of individuals. The University of Pittsburgh Mechanistic Research Center, entitled, "Low Back Pain: Biological, Biomechanical, Behavioral Phenotypes (LB3P)," is part of the National Institutes of Health's Helping to End Addiction Long-term Initiative. The LB3P conducted a prospective, observational cohort study to identify phenotypes of people with cLBP. Here, we report demographic and biomedical characteristics of a large cohort of individuals with cLBP, stratified by sex and age, collected at the in-person enrollment visit. Methods: The key eligibility criteria were adults with cLBP, English speakers, and identified in the electronic health record of our medical center. Recruitment strategies were through clinical partners who invited their patients to join the study and research registries. Participants completed demographic and biomedical surveys. Descriptive statistics were computed for the sample overall, and for the subgroups (male/female and age < 60/>= 60). Results: N = 1007 individuals (60% female) were enrolled, with an average age of 59 +/- 17 years. Most participants were non-Hispanic (90%), White (75%), and 53% attained college or higher education. 54% were married or had a partner, 43% were employed, 38% retired, 41% had an annual household income < $50 000, 20% had been off work for more than 30 days due to low back pain (LBP), 16% had applied for or received disability, and 6% were on worker's compensation. The majority were obese (average BMI of 31.5 kg/m(2)), 61% had back pain for > 5 years, and pain had been ongoing every or nearly every day in 76% of the sample. The participants reported a high prevalence of osteoarthritis (58%), anxiety (40%), depression (40%), vision impairment (35%), and balance problems/falls (31%). Among the chronic overlapping pain conditions, the most common were migraine or headache (29%), irritable bowel syndrome (16%), and temporomandibular joint dysfunction (12%). Previous low back surgery was reported by 25%. The most frequently reported LBP treatments during the previous month were exercise routine done on their own (58%), physical therapy, occupational therapy, or chiropractic care (33%), mindfulness, meditation, or relaxation (22%), and diet or nutrition counseling (21%). Medication intake during the last month was 43% for nonsteroidal anti-inflammatory drugs, 18% for gabapentin, 13% for opioid, and 10% for antidepressants. Conclusions: Describing comprehensive demographic and biomedical characteristics of individuals with cLBP stratified by sex and age will serve as a reference for clinicians and research planning, particularly with respect to comorbid conditions and utilization of treatment for cLBP. These data will be useful in future efforts to comprehensively phenotype cLBP.