Treated versus self-reported prevalence of chronic pain and costs of patients' health services utilization: a population-based study of health administrative databases.

Objectives: To compare treated to self-reported prevalence of chronic pain (CP) and to estimate health services utilization (HSU) costs of patients treated for CP in Alberta, Canada. Methods: Patients treated for CP were identified by the physician billing codes of health services for CP from the practitioner claims database in fiscal year 2021/22. The treated prevalence of CP (number of these patients divided by the population) was compared to the self-reported prevalence of CP previously estimated (doi:10.1371/journal.pone.0272638). Costs of patients' HSU included costs for general practitioner (GP), specialist, inpatient, emergency department, outpatient clinic services, and prescription drugs. Results: The treated prevalence of CP was 6.0% (4.4% among males and 7.8% among females) which was 30% to 41% of the self-reported prevalence. The highest treated prevalence (7.2%) was found in the age group of 18-64 years, followed by age groups of >64 years (7.0%) and <18 years (2.1%). The average cost per patient per year was $5096 ($5878 for males and $4652 for females), of which hospitalizations accounted for 65.0%, outpatient clinic visits 16.4%, ED visits 9.5%, prescription drugs 4.7%, GP visits 3.9%, and specialist visits 0.4%. The total cost of patients with CP for the health system was $1.37 billion (∼7% of total health expenditure), of which males accounted for 41.7% and females for 58.3%. Discussion: Our findings suggest that the economic burden of CP is considerable and that many people with self-reported CP do not use the public healthcare services. This can be multifactorial, including lack of availability and accessibility of publicly funded services, people's lack of awareness of available services, lower utilization due to COVID-19 pandemic, and reliance on self-management, private services, and alternative treatments. Further studies are warranted to inform future policies and health system initiatives aiming to reduce the burden of CP and improve lives of people living with it.