First validation study of the living with long term conditions scale (LwLTCs) among English-speaking population living with Parkinson's disease.

Introduction: Parkinson's disease is the second most prevalent neurodegenerative disease, affecting 10 million people worldwide. Health and social care professionals need to have personalised tools to evaluate the process of living with Parkinson's disease and consequently, plan individualised and targeted interventions. Recently, the English version of the Living with Long term conditions (LwLTCs) scale has been developed filling an important gap related to person-centred tools to evaluate the process of living with long term conditions among English-speaking population. However, no validation studies for testing its psychometric properties have been conducted.

Aim: To analyse the psychometric properties of the LwLTCs scale in a wide English-speaking population living with Parkinson's disease.

Methods: Validation study, with an observational and cross-sectional design. The sample was composed of individuals living with Parkinson's disease from non-NHS services in the community. Psychometric properties including feasibility and acceptability, internal consistency, reproducibility, and construct, internal and known-groups validity were tested.

Results: A total sample of 241 people living with Parkinson's disease were included. 6 individuals did not complete 1 or 2 items on the scale. Ordinal alpha was 0.89 for the total scale. The intraclass correlation coefficient for the total scale was 0.88. The LwLTCs scale is strongly correlated with scales measuring satisfaction with life (r=0.67), quality of life (r=0.54), and moderately correlated with social support (r=0.45). Statistically significant difference just for therapy and co-morbidity, yet no for gender, employment situation, or lifestyle changes.

Conclusions: The LwLTCs scale is a valid scale to evaluate how the person is living with Parkinson's disease. Future validation studies to prove the repeatability of the total scale and particularly, domains 3-Self-management, and 4-Integration and internal consistency will be needed. Developing further studies on the English version of the LwLTC in people with other long term conditions is also proposed.