Aim: To explore the pain experience of Thalidomide survivors and propose an effective pain management service, tailored to meet the unique needs of this population.

Background: Approximately 400 thalidomide survivors live in the UK, who are also beneficiaries of the Thalidomide Trust. Such individuals have been mainly born with upper or lower limb problems, but some also experience sight, hearing, or speaking difficulties. Most tend to experience additional problems, acquired after birth, including persistent muscle or joint pain as well as mental health problems. Such conditions may reduce the quality of life of thalidomide survivors, who face significant difficulties in accessing healthcare services or receiving effective treatment. Specialist services such as pain management are not easily available to thalidomide survivors. Providers' lack of understanding or flexibility to treat populations with unique needs, and geographical or financial barriers have been considered as possible reasons.

Methods: This is a cross-sectional observational study. Thalidomide survivors, who are also beneficiaries of the Thalidomide Trust, will be offered a questionnaire booklet to fill, featuring questionnaires aiming to explore their pain experience (0-10 Pain Numerical Rating Scale, Central Aspects of Pain, painDETECT, Widespread Pain Index), mental health (Hospital Anxiety and Depression Scale), beliefs (Pain Catastrophizing, Tampa Scale of Kinesiophobia), quality of life (EQ-5D-5L), disability (Health Assessment Questionnaire), sleep (Athens Insomnia Scale), and medicines use (Pain Medication Attitude Questionnaire). Linear regression modelling will explore the factors that best explain the overall pain experience of Thalidomide Survivors.

Impact: The research will inform how thalidomide survivors might gain access to an evidence-based pain management service designed specifically for them, which will improve their quality of life.

Between 1958 and 1961, Thalidomide was widely prescribed in the UK as a safe, non-addictive sedative and tranquiliser. Despite being marketed as an entirely safe treatment for the discomforts of pregnancy (including morning sickness), Thalidomide caused serious damage to the unborn child when taken during the first trimester. Foetal damage typically included upper and/or lower limb malformation (total limb absence, missing bones, etc), eye, ear and facial damage (damaged ears, narrow ear canals, small or damaged eyes, restricted eye movement and facial palsy), and malformation of internal organs (heart, urinary and alimentary tracts, and reproductive organs). Collectively, such birth defects are referred to as Thalidomide Embryopathy or Thalidomide Syndrome. A charitable trust - the Thalidomide Children's Trust (now the Thalidomide Trust), was established to oversee compensation payments from Distillers to those children affected by Thalidomide in the UK.

Thalidomide survivors experience significantly worse physical and mental health than the general population of the same age, demonstrating a wide range of secondary health problems, in particular chronic musculoskeletal pain, which is the most reported symptom, as well as movement restrictions, and mental disorders. Such health problems impair the ability of these individuals to remain fully independent, and negatively impact on their health-related quality of life as they limit their overall ability to adopt an active lifestyle and engage or access potentially beneficial treatments.

Thalidomide survivors form a unique, underrepresented, and disadvantaged group of people who must overcome a number of additional barriers in order to receive appropriate care. Compared with non-Thalidomide age-matched populations, Thalidomide survivors demonstrate higher prevalence of pain and disability. However, most comparisons have been done with members of the general population. Thalidomide Trust beneficiaries with lived experience of chronic pain might share features with other populations with chronic musculoskeletal pain (e.g., Fibromyalgia, Rheumatoid Arthritis, Chronic Low Back Pain), such as reluctance to take tablets due to their formative experience with medicines, poor experiences from exposure to multiple interventions and surgeries, and difficult experiences with health care professionals who seem not to understand or often dismiss their unique and complex needs. Despite the prevalence of shared features, Thalidomide survivors might also experience unique issues that are not shared with other populations with chronic pain. Whilst effective pain management has become more accessible to some populations with chronic musculoskeletal pain, for Thalidomide survivors, inequity persists. Novel research, investigating the lived experience of pain by Thalidomide survivors, is needed explore potential barriers in pain management of Thalidomide Survivors.

To address this gap in literature the project aims to define the pain experience of beneficiaries. This cross-sectional observational study entails a questionnaire booklet designed to collect numerical and categorical data about the experience of pain by Thalidomide survivors as well as the impact of pain on their lives and overall wellbeing. To ensure that participants adequately represent Thalidomide survivors as a unique population, a purposive sampling strategy will be followed.

Distinct categories of pain have been identified in the general population, such as neuropathic pain, nociplastic pain, or chronic primary pain. The project will quantitatively, via collection of new primary data, explore whether these categories can be also identified in Thalidomide survivors, whether one or more category is more common than others, and whether there is a unique 'Thalidomide pain' category. A combination of different sets of criteria developed by the International Association for the Study of Pain (IASP) and patient reported outcome measures, namely Central Aspects of Pain (CAP) and painDETECT, will be used for categorising.

All beneficiaries of the Thalidomide Trust can potentially be recruited (n≈400). However, past pain-related research exploring combinations of biopsychosocial variables and pain intensity 2 has shown that with estimated variation of 40% (R2=0.40) and an estimated number of independent variables (5 to 7) to be included in regression analyses, 120 individuals are considered sufficient to power the study and explain 38-49% of the variance in the regression model. Calculations are based on the estimated squared multiple correlation-coefficient (R2) [10].

Regression analyses will explore whether certain factors, potentially identified also as barriers in the qualitative aspect of the WP, are associated with the experience of pain.

Inclusion Criteria:

• Be beneficiaries of the Thalidomide Trust
• Be able to communicate in English or via using the British Sign Language as all interview questions and questionnaires are designed in the English language

Exclusion Criteria:

• Inability to give informed consent due to cognitive impairment or otherwise - (capacity levels are already established under General Practitioner (GP) care)
• Inability to understand key aspects of the study due to cognitive impairment or otherwise
• Giving history of critical or terminal co-morbidities such as cancer

Thalidomide survivors experience significantly worse physical and mental health than the general population of the same age, demonstrating a wide range of secondary health problems, in particular chronic musculoskeletal pain, which is the most reported symptom, as well as movement restrictions, and mental disorders. Such health problems impair the ability of these individuals to remain fully independent, and negatively impact on their health-related quality of life as they limit their overall ability to adopt an active lifestyle and engage or access potentially beneficial treatments. Thalidomide survivors form a unique, under-represented, and disadvantaged group of people who must overcome a number of additional barriers in order to receive appropriate care.

Agreement is already in place for anonymised raw data of all study outcomes to be shared with the Thalidomide Trust. Agreement is already in place for anonymised raw dat of the painDETECT questionnaire to be shared with IQVIA, who is the provider of the tool.

For the Thalidomide Trust, after analysis is completed. For IQVIA, as soon as recruitment ends and data input is complete.

A separate data sharing agreement will need to be signed, as per the policies of the University of Nottingham, with each party wishing to access the data of this study.