Development of the Cold Agglutinin Disease Symptoms and Impact Questionnaire (CAD‐SIQ)

Abstract Objectives Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia. This study aimed to identify disease‐related symptoms and impacts important to patients with CAD, and to develop a novel CAD‐specific patient‐reported outcome measure. Methods Adults with CAD were randomly selected from a United States patient panel to participate in concept elicitation (CE) interviews to identify important symptoms and impacts or cognitive debriefing (CD) interviews to assess the comprehension and relevance of the draft item set. Results Overall, 37 adults were included (mean [range] age 67.2 [35–87] years). In CE interviews ( n = 16), the most frequently reported CAD‐related symptoms were reactions to cold environments and fatigue (both 93.8%). CAD had negative impacts on enjoyable activities (81.3%) and daily activities (75.0%). Following CE, standard survey methodological principles were used to develop a draft item pool of 14 concepts. Items were refined through three iterative rounds of CD interviews ( n = 21), yielding 11 final items: fatigue; cold sensitivity; dyspnea; wearing extra clothing; limited physical, social, and enjoyable activities; difficulty with usual activities; mood; frustration; and anxiety/stress. Conclusions The novel 11‐item CAD‐Symptoms and Impact Questionnaire provides a measure of the symptoms and impacts of CAD that are important to patients.