Development and validation of a questionnaire to assess health‐related quality‐of‐life in cats with hyperthyroidism

Abstract Background Health‐related quality‐of‐life (HRQoL) assessment tools are becoming increasingly important for the assessment of diseases in veterinary medicine. Objectives To develop a tool to assess the HRQoL of hyperthyroid cats and their owners. Animals Cats with hyperthyroidism (n = 229) and without hyperthyroidism (n = 322). Methods Cross‐sectional study design. A preliminary list of 28 questions relating to the HRQoL of hyperthyroid cats and the influence their cat's disease might have on owners was created. Each question consisted of 2 subquestions: (1) “how often does the item apply”; (2) “how strongly does the item affect HRQoL.” The questionnaire was refined based on statistical analysis, including Mann‐Whitney‐U tests on each item, comparing the results from cats with and without hyperthyroidism. Internal consistency and reliability of the questions were measured by Cronbach's alpha (α). P < .05 was considered significant. Results Overall, 25/28 questions were retained within the final HRQoL tool, which had an excellent internal consistency (α = .92). The tool produced a score between 0 and 382 (lower scores meaning better HRQoL). The median HRQoL score was 87.5 (range, 2‐348) for cats with hyperthyroidism, and 27 (range, 0‐249) for cats without (P < .001), suggesting the HRQoL was poorer in hyperthyroid cats. Conclusions and Clinical Importance This validated HRQoL tool is useful to reliably quantify the influence of hyperthyroidism on the quality‐of‐life of affected cats and their owners. In the future, it could be considered of assistance in the clinical assessment of cats with hyperthyroidism.