RESUMEN
BACKGROUND: Recruitment of participants for studies focusing on couples facing illness is a challenging task and participation decline may be associated with nonrandom factors creating bias. This study examines whether patient and relationship characteristics are associated with partner participation in research. METHOD: Patients invited to participate in a cross-sectional study on adaptation and quality of life after renal transplantation were asked to forward information about an add-on study to their partners. RESULTS: A total of 456 participating patients had a partner; 293 of the partners showed interest in the study and 206 actually completed the questionnaire. Backward logistic regression analyses revealed that demographic, illness, and personal characteristics of the patient were not associated with partner interest in the study nor actual partner participation. However, partners who indicated interest in the study showed more active engagement toward the patients (as reported by the patients). Furthermore, patients of partners who actually completed the questionnaire reported less negative affect and higher relationship satisfaction than patients whose partner did not participate in the study. DISCUSSION: It is encouraging that of the large number of variables tested, only 2 were associated with the participation of partners. Nevertheless, well-functioning couples appear to be overrepresented in our study, calling for specific effort to include marital distressed couples in research focusing on dyadic adaptation to illness.