International psychometric validation of the Living with Chronic Illness Scale in Spanish-speaking patients with chronic obstructive pulmonary disease

Psychometric properties of the living with long term conditions scale in an English-speaking population living with long term conditions in the UK

OBJECTIVE

To present the psychometric properties of the living with long-term condition (LwLTCs) scale in an English-speaking population of people with different LTCs.

DESIGN

An observational and cross-sectional study, with retest was conducted. Psychometric properties including feasibility, internal consistency, confirmatory factor analysis, reproducibility and content validity were tested.

SETTING

The study took place across the UK via primary care surgeries and voluntary organisations, between December 2021 and June 2022.

PARTICIPANTS

The study included 577 patients living with different LTCs, as chronic obstructive pulmonary disease, arthritis, chronic heart failure, Parkinson's disease, chronic kidney disease and type 2 diabetes mellitus. Inclusion criteria included: (a) having been diagnosed with one or more of the conditions; (b) being able to read, understand and answer written questionnaires; (c) being fluent in English and (d) being able to provide written informed consent. Patients were involved in the design and pilot study of the scale.

RESULTS

A total sample of 577 people with an age range of 37-97 years (98±9.65) were recruited. Internal consistency of the total 26-item LwLTCs scale score was excellent (ordinal alpha=0.90) but confirmatory factor analysis showed better fit indices (Normed Fit Index=0.96; standardised root mean square residual=0.051; Goodness of Fit Index=0.98) for a 20-item LwLTCs scale.

CONCLUSIONS

A shorter version of the LwLTCs scale, with just 20 items and with excellent psychometric properties, is recommended. Having a short scale is key when considering the implementation of the scale in clinical practice to develop person-centred pathways and more comprehensive care plans.

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_s=0.67), quality of life (r_s=0.54), and moderately correlated with social support (r_s=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.

Living with Chronic Illness Scale: International validation through the classic test theory and Rasch analysis among Spanish-speaking populations with long-term conditions

BACKGROUND

The Living with Chronic Illness (LW-CI) Scale is a comprehensive patient-reported outcome measure that evaluates the complex process of living with long-term conditions.

OBJECTIVE

This study aimed to analyse the psychometric properties of the LW-CI scale according to the classic test theory and the Rasch model among individuals living with different long-term conditions.

DESIGN

This was an observational, international and cross-sectional study.

METHODS

A total of 2753 people from six Spanish-speaking countries living with type 2 diabetes mellitus, chronic obstructive pulmonary disease, chronic heart failure, Parkinson's disease, hypertension and osteoarthritis were included. The acceptability, internal consistency and validity of the LW-CI scale were analysed using the classical test theory, and fit to the model, unidimensionality, person separation index, item local independency and differential item functioning were analysed using the Rasch model.

RESULTS

Cronbach's α for the LW-CI scale was .91, and correlation values for all domains of the LW-CI scale ranged from .62 to .68, except for Domain 1, which showed correlation coefficients less than .30. The LW-CI domains showed a good fit to the Rasch model, with unidimensionality, item local independency and moderate reliability providing scores in a true interval scale. Except for two items, the LW-CI scale was free from bias by long-term condition type.

DISCUSSION

After some adjustments, the LW-CI scale is a reliable and valid measure showing a good fit to the Rasch model and is ready for use in research and clinical practice. Future implementation studies are suggested.

PATIENT AND PUBLIC CONTRIBUTION

Patient and public involvement was conducted before this validation study - in the pilot study phase.