Content validity of the Familial Chylomicronemia Syndrome Symptoms and Impacts Scale (FCS-SIS) for severe hypertriglyceridemia (sHTG).

OBJECTIVE

Severe hypertriglyceridemia (sHTG) and familial chylomicronemia syndrome (FCS) are metabolic conditions associated with an increased risk of adverse health outcomes. The FCS Symptoms and Impacts Scale (FCS-SIS) was developed to assess the symptoms and impacts of FCS. This study assessed the content validity of the 4 FCS-SIS symptom items in adults with sHTG.

METHODS

Two iterative rounds of qualitative interviews were conducted with adults (aged ≥ 18 years) who had clinician-confirmed sHTG (triglycerides ≥ 500 mg/dL) and recently experienced ≥ 2 symptoms of sHTG. Participants described their initial experiences and symptoms of sHTG during concept elicitation. Cognitive debriefing of the 4 FCS-SIS symptom items assessed relevance, interpretability, answerability, and meaningful change.

RESULTS

Among 20 participants, the most frequently reported, most bothersome, and most important-to-treat sHTG symptoms were difficulty thinking (n = 20), physical fatigue (n = 20), diarrhea (n = 19), and abdominal pain (n = 18), which the 4 FCS-SIS symptom items assess. Participants reported these items to be easy to understand (n = 20) and, for most items, reported that a 1- to 2-point improvement would be meaningful.

CONCLUSION

FCS-SIS symptom items are content-valid items for the assessment of sHTG symptoms in adults with sHTG.