Transcultural adaptation and initial validation of Brazilian-Portuguese version of the Basel assessment of adherence to immunosuppressive medications scale (BAASIS) in kidney transplants

Abstract

BackgroundTransplant recipients are expected to adhere to a lifelong immunosuppressant therapeutic regimen. However, nonadherence to treatment is an underestimated problem for which no properly validated measurement tool is available for Portuguese-speaking patients. We aimed to initially validate the Basel Assessment of Adherence to Immunosuppressive Medications Scale (BAASIS®) to accurately estimate immunosuppressant nonadherence in Brazilian transplant patients.MethodsThe BAASIS® (English version) was transculturally adapted and its psychometric properties were assessed. The transcultural adaptation was performed using the Guillemin protocol. Psychometric testing included reliability (intraobserver and interobserver reproducibility, agreement, Kappa coefficient, and the Cronbach’s alpha) and validity (content, criterion, and construct validities).ResultsThe final version of the transculturally adapted BAASIS® was pretested, and no difficulties in understanding its content were found. The intraobserver and interobserver reproducibility variances (0.007 and 0.003, respectively), the Cronbach’s alpha (0.7), Kappa coefficient (0.88) and the agreement (95.2%) suggest accuracy, preciseness and reliability. For construct validity, exploratory factorial analysis demonstrated unidimensionality of the first three questions (r = 0.76, r = 0.80, and r = 0.68). For criterion validity, the adapted BAASIS® was correlated with another self-report instrument, the Measure of Adherence to Treatment, and showed good congruence (r = 0.65).ConclusionsThe BAASIS® has adequate psychometric properties and may be employed in advance to measure adherence to posttransplant immunosuppressant treatments. This instrument will be the first one validated to use in this specific transplant population and in the Portuguese language.

Stress, coping and adherence to immunosuppressive medications in kidney transplantation: a comparative study

“…32,33 Moreover, BAASIS is the only instrument that has been validated for use among Brazilian Portuguese-speaking transplantation patients. 31 In addition, living donor recipients predominated in our sample. Until recently, this donor profile was the most common type of transplantation performed in Brazil.…”

“…We tried to overcome this limitation by applying a sampling design that involved studying the same numbers of adherent and nonadherent subjects, selected from the main study population (BAASIS validation). 31 However, we recognize that this design was underpowered, compared with case-control matched studies. Use of a single self-reporting instrument may have limited the evaluation of immunosuppressive adherence.…”

“…31 Patients were included based on the following criteria: age of at least 18 years, more than one year after transplantation, and willing to participate in the study; which resulted in a convenience sample of the first 100 kidney transplantation patients who were being followed up at our outpatient facility.…”

“…12 As previously mentioned, to evaluate adherence to immunosuppressive drugs, we applied BAASIS, [32][33][34] as validated for use in Portuguese. 31 BAASIS assesses relevant dimensions of immunosuppressive drug use (i.e. adherence to taking the drug, adherence to the times for taking the drug, drug holidays and dose reduction) over a fixed time period consisting of the last four weeks.…”

Multilevel factors are associated with immunosuppressant nonadherence in heart transplant recipients: The international BRIGHT study

“…Any deviation in taking, timing, or dosing was considered nonadherence 34. The instrument's concurrent validity was demonstrated in kidney36 and predictive validity (regarding late acute rejection incidence) in liver Tx recipients 37…”