Symptom factors and their clinical correlates among adults with cystic fibrosis

Despite cystic fibrosis transmembrane conductance (CFTR) modulator therapy that may dramatically alter the course of disease, many people living with cystic fibrosis (PwCF) experience co-occurring symptoms that may be interrelated and may synergistically degrade quality of life. We sought to identify symptom factors, or groups of correlated symptoms, connected by underlying latent variable(s). We then examined demographic and clinical characteristics associated with these groups among PwCF.

Using baseline data from a trial of specialist palliative care in PwCF, we assessed symptoms with the Memorial Symptom Assessment Scale-CF. We used exploratory factor analysis followed by confirmatory factor analysis to identify and validate symptom factors. For each factor (using only the symptoms identified in the factor), we then created a binary variable (Symptom Factor Severity) that identified patients as Low versus High Severity, by mean splitting the sum of each patient's severity symptom scores for that factor. Multivariable logistic regression was used to examine associations between demographic and clinical characteristics with each split Symptom Factor Severity score.

Among 262 participants, median age was 33 years, and 78 % were prescribed a CFTR modulator. We identified three symptom factors: respiratory-energy, mood-gastrointestinal irritability, and pain-gastrointestinal dysmotility. High symptom severity in each factor was associated with specific demographic and clinical characteristics.

CF symptom management strategies have historically focused on single-symptom approaches. Findings from this study may prompt clinicians to consider co-occurring symptoms, and ensure their assessment and management is tailored to the unique experiences of PwCF.