Validation of the modified transplant symptom occurrence and symptom distress scale and exploring symptom burden in Brazilian kidney transplant recipients

Kidney transplant recipients (KTR) may experience burdensome symptoms, including tremor, nausea, and bruises, sometimes caused by immunosuppressive medication, which can negatively influence health-related quality of life. The 59-item Revised Modified Transplant Symptom Occurrence and Symptom Distress scale (MTSOSD-59R) captures patients' symptom experience but has not been validated in Brazil. We evaluated the Brazilian Portuguese MTSOSD-59R regarding content validity (expert panel), internal structure (factor analysis), and associations with other variables (known-groups approach). Symptom occurrence and distress by sex and age were assessed using ridit analyses. 485 KTR (42.2% women; 50.2 ± 12.8 years) were included at median 7.4 [3.2-13.0] years post-transplantation. The expert-rated scale-content validity index was 0.49. Construct validity and known-group associations were confirmed. The most occurring symptoms were anxiety [ridit score: 0.697], tiredness [0.653], and difficulty seeing well [0.652]. The most distressing symptoms were menstrual problems [0.635], difficulty seeing well [0.606], and genital warts [0.595]. Female/younger KTR tended to report more (distress from) psychological/aesthetic symptoms; male/older KTR tended to report more (distress from) physical symptoms. The MTSOSD-59R showed validity for internal structure and relationships to other variables, but insufficient expert-rated content validity for immunosuppression-specific side effects, suggesting it may better reflect general symptom burden in this population.