Estimating the cost and epidemiology of mild to severe chronic pain associated with osteoarthritis in England: a retrospective analysis of linked primary and secondary care data

Abstract

Objective Osteoarthritis (OA) affects 10% of adults in the UK. Despite over one-third of people with OA experiencing chronic pain, few studies have examined the population-level impact of chronic pain associated with OA. We compared resource-use and epidemiological outcomes in patients with mild, moderate and severe chronic OA-associated pain and matched controls without known OA.Design Retrospective, longitudinal, observational cohort study (July 2008 to June 2019).Setting Electronic records extracted from Clinical Practice Research Datalink GOLD primary care linked to Hospital Episode Statistics (HES).Participants Patients (cases; n=23 016) aged ≥18 years with chronic OA-associated pain. Controls (n=23 016) without OA or chronic pain matched on age, sex, comorbidity burden, general practitioner practice and available HES data.Interventions None.Primary and secondary outcome measures Total healthcare resource use (HCRU), direct healthcare costs in 0–12, 12–24 and 24–36 months postindex. Secondary outcomes included incidence and prevalence of chronic OA-associated pain and pharmacological management.Results HCRU was consistently greater in cases versus controls for all resource categories during preindex and postindex periods. Across follow-up periods, resource use was greatest in patients with severe pain. In the first 12 months postindexing, mean total costs incurred by cases were four times higher versus matched controls (£256 vs £62); costs were approximately twice as high in cases vs controls for months 12–24 (£166 vs £86) and 24–36 (£150 vs £81; all p<0.0001). The incidence of new cases of chronic pain associated with OA was 2.64 per 1000 person-years; the prevalence was 1.4%.Conclusions This study highlights the real-world cost of chronic pain associated with OA in cases versus matched controls. We included patients with mild, moderate and severe pain associated with OA, and showed HCRU in discrete 1-year time frames. The true economic burden of pain associated with OA is likely to be considerably higher when indirect costs are considered.