Cost of Illness due to Back Pain in Older People:: Healthcare utilization, modifiable prognostic factors, and the measurement properties of self-reported productivity loss using the iMTA Productivity Cost Questionnaire

Introduction: Back pain imposes substantial individual and societal costs, and with an aging population and an increasing number of older people with back pain, these costs are likely to increase in the years to come. To improve the use of scarce healthcare resources and reduce the economic burden on our healthcare systems, it is vital to map healthcare utilization and related costs and identify modifiable prognostic factors of the high costs related to healthcare utilization. No such studies have been conducted among a sample of exclusively older people, although the prevalence of seeking healthcare for back pain increases with age. Furthermore, to promote comprehensive healthcare economic evaluations, there is a need for valid generic instruments for measuring productivity costs. Productivity costs often reflect a large part of total costs related to health and healthcare interventions. Aims: The primary aim of this thesis was to develop new knowledge on the cost of illness due to back pain among older people, to describe healthcare utilization and estimate associated costs among older people seeking primary care due to back pain (Paper I) and to identify modifiable prognostic factors of high costs related to healthcare utilization (Paper II). A secondary aim was to evaluate the measurement properties of the iMTA Productivity Cost Questionnaire (iPCQ) (Papers III and IV). Methods: Papers I and II were conducted using a cohort study design with one-year of followup. Data from the Back Complaints in the Elders (BACE) consortium in Norway (BACE-N) and the Netherlands (BACE-D) were used. BACE-N included 452 people aged ≥ 55 years seeking Norwegian primary care with a new episode of back pain, and BACE-D included 675 people aged > 55 years seeking Dutch primary care with a new episode of back pain. In Paper I, healthcare utilization and related costs were described for the whole BACE-N sample as well as for patients with different risk profiles according to the STarT Back Screening Tool (SBST). In Paper II, ...