The goal of this observational case-control study is to learn about direct healthcare use and costs of functional somatic disorders.

The aim of the proposed study is to investigate the use and costs of direct healthcare for individuals with functional somatic disorders.

Researchers will compare direct healthcare use and costs of individuals with functional somatic disorders and compare them with that of healthy controls and individuals with other severe physical disease, respectively.

Functional somatic disorders (FSD) are common conditions characterized by persistent patterns of physical symptoms that cannot be better explained by other physical or mental conditions. The conditions may cause severe impairment for the patients who are often characterized by impaired physical and mental health, lower social status, and poor labour market association.

In 2005, it was estimated that FSD accounted for 3% of hospitalizations and 10-20% of health care expenses in Denmark, and a newer Danish primary care study has shown patients with FSD to have higher annual health care costs compared with conventionally-defined conditions. In foreign nations, studies in clinical samples have shown increased direct and indirect health care costs of FSD which showed a dose-response relationship with severity of the FSD. One Canadian population-based study found increased health care use and costs in children, adolescents, and young adults with a first health record diagnosis of somatic symptom and related disorders. Even though these previous studies provide valuable knowledge to the field of FSD, their methodology may give rise to bias, i.e. inclusion of highly selected patient samples, the use of various diagnostic criteria for defining FSD, and the establishment of FSD by means of self-report. Evidently, studies investigating the socioeconomic burden in terms of direct health care use and costs of FSD in a randomly obtained population-based sample using solid methodology such as validated symptom criteria and diagnostic interviews for establishing FSD are highly lacking.

The objectives of this proposed study are:

To describe and investigate the healthcare use and healthcare costs for individuals with FSD and compare them with

1. individuals without FSD, and
2. individuals with severe physical disease

Inclusion Criteria:

• None

Exclusion Criteria:

• not born in Denmark
• not being a Danish citizen
• pregnancy.

Data from the DanFunD baseline cohort will be included. For this cohort, a total of 25,368 men and women aged 18-72 years living in the Western part of Greater Copenhagen were randomly obtained from the nationwide Danish registries and invited to participate; 9656 accepted. All of them answered questionnaires about physical symptoms, physical and mental health as well as social components. A stratified sub sample consisting og every tenth participant together with every high score on the symptoms questionnaires were invited to participate in a diagnostic interview performed over telephone by trained family physicians. A total of 2450 were invited and 1590 accepted and participated in the interview.