Epidemiology of chronic non- malignant pain in Spain Professor Jos Kleijnen, MD, PhD Kleijnen Systematic Reviews Ltd Report authors: Karla Soares Weiser, Ivan Sola, Ed Aromataris, Jesús Tornero, Concepción Pérez, César Margarit, Jos Kleijnen

Background Chronic pain is very common but good data are scarce about the prevalence, incidence, diagnosis, severity, treatment, utilization of health care, and the impact of chronic pain on society, health care systems and the patient. Information about the epidemiology of chronic pain can help health care professionals as well as decision and policy makers decide about health budgets and prioritization, patient segmenting and budget fencing, and therapy budgets, including behavioural therapy and drug budgets.

Objectives To provide information about chronic pain in Spain, by preparing a review of the available published and unpublished data, using the principles of systematic reviews in searching and identifying relevant studies, and summarizing their findings. Given the types of questions to be addressed, we aimed to use the most representative, recent, comprehensive and valid studies, rather than summarizing the results of all studies that were found.

Questions – epidemiology flow What are the population and demographics of Spain? What is the prevalence of chronic pain conditions? What is the incidence of chronic pain conditions? What percentage of chronic pain patients are untreated or inadequately treated? How many chronic pain patients present themselves for treatment? How many chronic pain patients get treated broken down by treatment? What is the compliance of treated chronic pain patients?

Questions – impact What is the disease duration of chronic pain conditions? What are the demographics of pain sufferers? What are the co-morbidities of pain sufferers? How many sufferers have inadequate pain control? What is the impact of chronic pain on: – Quality of life – Activities of daily living – Depression and other mental illness – Isolation, helplessness – Days off work – Incapacity benefits What are the costs of chronic pain from a – Societal perspective? – Health care system perspective? – Patient perspective?

Questions – awareness What are issues/determinants of patients’ awareness of chronic pain? What are issues/determinants of health care professionals’ awareness of chronic pain? What are the main symptoms and complaints with which patients present themselves to health care professionals? What are the frequencies of drug (per WHO class), non-drug, and combined treatments? What are determinants of treatment choice between drug treatment and non-drug treatment? What are determinants of treatment choice within drug treatments? What are determinants of compliance / adherence to drug treatments? What is patients’ satisfaction about drug treatments?

Methods Inclusion criteria: patients with chronic non-malignant moderate and/or severe pain from Spain. We aimed to identify all relevant studies regardless of publication status (published, unpublished, in press, and in progress), or language. We searched the following databases: – MEDLINE (1995 to August 2009) – EMBASE (1995 to August 2009) – CDSR (Cochrane Library issue ) – CENTRAL (Cochrane Library issue ) – DARE (August 2009, CRD website) – HTA (August 2009, CRD website) – Guidelines International Network database (August 2009, GIN website) Furthermore, references in retrieved articles and systematic reviews were checked. Relevant websites were searched for national statistics, insurance data, health surveys and other relevant data.

Prevalence

Demographics of chronic pain patients

Average age of chronic pain patients

Proportion presenting for treatment Fibromyalgia patients Non- fibromyalgia patients

Breakdown per treatment

Types of drugs used

Determinants of compliance / adherence to therapy

Control of pain

Duration of chronic pain

Co-morbidities

Sick leave due to pain

Proportion receiving disability compensations

Conclusions (1) Pain is a common condition that is a major source of suffering and disability in patients worldwide and has a considerable impact on quality of life. This condition has direct social repercussions and also direct work related and economic costs. To our knowledge this is the most comprehensive literature review on epidemiological Spanish data in this field. We have focused on the most representative, recent and valid studies published about chronic pain in Spain, including data from the main collaborative research projects (EPISER, EPIDOR, Miró 2007, PREVADOL). Prevalence of chronic pain in Spain is estimated at 12% (Breivik 06), and data suggest that prevalence increases with increasing age (Miró 07). Those most commonly afflicted by the condition are women between the age of 51 to 57 years, live with their families in an urban setting, and are often also overweight. The duration of chronic non-malignant pain ranges from 6 to 14 years.

Conclusions (2) Chronic pain has an enormous impact on patients. The literature shows that it affects all the areas of patients’ quality of life, with variations depending on type of pain, gender, age, or disease duration. It is important to note that this condition interferes in half of all patients older than 65 years (Miró 05). Although the majority of patients with chronic pain in Spain are treated, a significant percentage appear to be inadequately treated. Often patients perceived that their treatments had no effect (EPIDOR). The paucity of data on satisfaction and/or compliance with treatment is worrying. Some studies have shown that up to 60% of patients are dissatisfied or highly dissatisfied with the treatment received (VIOXX study). Hypertension was the main co-morbidity in patients with chronic pain, followed by other cardiovascular conditions, diabetes and mental health problems in the case of fibromyalgia. There is a need for more accurate data about the main co-morbidities and risk factors to allow physicians to identify the patients that are more prone to suffer from chronic pain.

Conclusions (3) The variability in the collected data reflects an inconsistency in the definition of the condition, and the measurement approach to assess its impact. To have feasible and reliable epidemiological data about chronic pain, researchers should join efforts to define minimum standards to approach the research in this field. Research should also encourage and promote studies designed with a multidisciplinary approach, including different healthcare professionals and specialities responsible for pain management. These studies should be based on common and standardised diagnostic criteria, focusing on the treatments used, the social impact of chronic pain, and its related costs. Only studies with a broad approach will provide healthcare professionals and Spanish society with a clear image of the implications derived from a complex problem such as chronic pain, and will contribute to identify the gaps and neglected needs related to this condition.