Background: Multinational clinical trials commonly include different language versions of patient-reported outcomes (PRO) instruments without considering the question of their cross-cultural validity. The inclusion of a PRO instrument, the Adult AIDS Clinical Trial Group Symptom Distress Module (SDM), in an multinational clinical trial in HIV-1 antiretroviral-naive patients offered an opportunity to explore the methods to assess cross-cultural validity of PRO instruments in the context of clinical trials.
Purpose: To assess the cross-cultural validity of the SDM across seven cultural groups in the setting of a multinational HIV clinical trial.
Methods: Twenty-five language versions of the SDM were included in a Phase IIb/III trial comparing maraviroc with efavirenz (each in combination with zidovudine/ lamivudine) conducted in 12 countries to assess symptoms perceived by HIV-1-infected antiretroviral-naive patients. Differential item functioning (DIF) detection and the STATIS method were combined in a pragmatic approach to assess the cross-cultural validity of the SDM using pre-antiretroviral treatment data from 759 patients.
Results: Statistically significant DIF between cultural groups was observed for four items: fatigue; fevers; anxiety; and headache. However, examination of these items by linguists did not lead to meaningful explanations for the statistical differences. With the STATIS approach, the Bantu and European Germanic groups were the furthest from the Occidental English group.
Limitations: The assessment of cross-cultural validity had to be performed on some very small samples and on data aggregated by cultural groups, which suggests the need for a cautious interpretation of the results.
Conclusions: Given the heterogeneity of cultures considered, the absence of meaningful explanations for statistically significant differences between cultural groups supports the cross-cultural validity of the SDM versions included in this trial. Thus, this study demonstrated that it is feasible to conduct assessment of crosscultural validity of PRO instruments using data collected in the setting of multinational clinical trials.