Age-stratified validation of the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being based on a large cohort of Danish cancer survivors.

OBJECTIVE: Previous research indicate that the FACIT-Sp instrument is susceptible to bias when measuring spiritual well-being in older patients. Our first focus was to evaluate the 2-factor vs the 3-factor model of the FACIT-Sp and our second focus was to explore how these models behave for different age groups. METHODS: We used a large national cohort of Danish cancer patients (N = 3439) which included a significant number of patients aged at least 70 years (N = 1033). Item-test correlations and factor analyses were conducted on complete cases (N = 2820). Additionally, a reliability analysis was performed using Cronbach's alpha and Guttman's lower-bound estimate. RESULTS: Factor analysis revealed a loading pattern for the oldest age group (70+) showing items on peace and meaning loading into a single factor, as originally proposed in the 2-factor model. The loading estimates for the patients younger than 70 matched the 3-factor model. Furthermore, item-test correlations changed as age increased. Based on Cronbach's alpha and Guttman's estimate of 0.83 and 0.89, respectively, total scores proved reliable. Items 4, 8 and 12 are discussed separately concerning their problematic influence on instrument validity in their current formulation. CONCLUSION: Overall, the 3-factor model had a good fit; however, for the eldest patients a 2-factor solution proved even better. Interpretation of FACIT-Sp sub-scale scores of older cancer patients must therefore be done with caution. This article is protected by copyright. All rights reserved.