(291) Development and Validation of the CF Stress Questionnaire: A CF-Specific Measure of Perceived Stress

Background: The CF Foundation recommends annual screening for depression and anxiety among people with CF (PwCF) with standardized measures for the general population, the PHQ-9 and GAD-7. Research in other chronic illness groups such as diabetes has demonstrated that illness-specific distress—for example, distress associated with high treatment burden, or feeling powerless in the face of illness—is a stronger predictor of daily functioning than depression alone. Therefore, screening tools that assess anxiety and depressive symptoms may provide an incomplete picture of the daily psychosocial challenges faced by PwCF. To address the need for a measure of illness-specific distress, we aim to develop the CF Stress Questionnaire (CFSQ) as a reliable and valid measure that could improve mental health screening and discussions between PwCF and their care teams.

Methods: We created the CFSQ by adapting an established measure in the diabetes literature, the Diabetes Distress Scale (DDS), to CF. The adapted CFSQ had 4 subscales paralleling the DDS (Emotional, Provider-related, Regimen-related and Interpersonal) as well as 3 derived with input from PwCF in a previous, smaller pilot study (Powerlessness, Functional Impairment and Economic Burden). We first conducted a single-site pilot study with 30 adults with CF. Next, we conducted 25 cognitive interviews with pwCF to assess clarity and comprehensiveness, iteratively revising the measure and securing feedback.

Results: Pilot participants had a mean age of 33.3 years (SD=9.8), and 57% were female. Mean FEV₁ was 70.6 (SD=25.4). Results of the pilot indicate that all but one subscale met the established internal consistency cut-off of > 0.7. The CFSQ and its subscales were moderately to highly significantly correlated with the PHQ9 (0.38) and the GAD7 (0.74). A McNemar chi-squared test was used to compare the relative sensitivity of the CFSQ vs. the PHQ9 and GAD7 using established clinical cutoffs for the PHQ9/ GAD7 and for the DDS. Results of this test were highly statistically significant (p< 0.01) and showed the CFSQ to be more sensitive. Participants in the cognitive interviews reported that the questionnaire items were relevant to their experience with CF. Based on these interviews, we added three new items to the CFSQ, to capture emotional reactions to getting PFT’s, the impact of CF on relationships, and managing CFRD. We also changed the wording of three items to clarify and make items more inclusive, and we eliminated two items that participants found either harshly worded or not relevant.

Conclusions: Preliminary results suggest the CFSQ is a promising measure in terms of its internal consistency, convergent validity with measures of mental health, and sensitivity. Additionally, PwCF have generally found the CFSQ to be reflective of their CF-related experiences. We will build upon these results by conducting a multi-site validation study with 200 adults with CF across 3 geographically diverse CF centers. Future analyses will examine the CFSQ’s factor structure, convergent validity, test-retest reliability and known group differences in order to formally validate this measure for clinical and research use.

Acknowledgements: This work was supported by the CF Foundation (grant number SNELL21A0-I).

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