Development and psychometric validation of a new health-related quality of life instrument for infertility patients (Infertility-QoL)

Abstract

Abstract Background Infertility and its treatment have negative impacts on a couple’s marital relationship, sexual life, psychological state and interpersonal relationships, causing personal distress. Identifying socio-contextual factors and experience of infertile couples can help establish a foundation for tailored interventions that support patient-centered health care. The aim of this study was to develop a de novo HRQoL instrument for male and female infertility patients in China, and evaluate its psychometric properties based on classical test theory (CTT) and item response theory (IRT). Methods The psychometric properties validation study consisted of two phases. First, we conducted a cross-sectional study in five reproductive medicine centers. Offline, one-on-one, and face-to-face surveys were conducted with patients experiencing infertility at each reproductive medicine center. Regarding the test-retest reliability assessment, the online Infertility-QoL was administered 2 weeks after the baseline to a random group of patients with stable disease condition. In the second phase, in order to measure the responsiveness, the patients were invited to complete an online Infertility-QoL after two months. Infertility patients were recruited from a national multicenter survey in China. Participants completed a series of HRQoL instruments, including the Infertility-QoL, FertiQoL, and WHO-5. The survey also involved the socio-demographic information and clinical characteristics of the respondents. CTT and IRT were used to assess psychometric performance of the Infertility-QoL. Results A total of 1343 infertility patients were invited to participate in the study, a valid sample of 1172 (87.3%) participants, and female patients account for 76.5%. Furthermore, 71 and 167 patients finished follow up survey after two weeks and two months, respectively. The Cronbach’s α (0.800 ~ 0.950) and McDonald’s ω (0.798 ~ 0.951) were excellent (> 0.70). The subgroup of the follow-up study ( n = 71) showed an excellent stability ( ICC : 0.788; 95% CI: 0.678, 0.863) of overall Infertility-QoL scores after two weeks. Known-groups validity was demonstrated that the gender, whether to have a child, previous treatment history, embryo transplantation cycles and self-rated mental health were significantly associated with Infertility-QoL total scores ( p < 0.05), and has a moderate (Cohen’s d = 0.24) to large effect size (Cohen’s d = 1.34) among the different groups. Criterion validity was demonstrated between the Infertility-QoL and FertiQoL total scores was strong ( r = 0.706, p < 0.01), and ICC was 0.822 (95% CI: 0.801, 0.842). Factor analysis identified six dimensions, and Infertility-QoL showed moderate or small responsiveness after 2 months of treatment. IRT indicated that most items had well-functioning response categories but there were minor problems with item disordered thresholds. Conclusion The Infertility-QoL instrument primarily validated in female infertility patients, with preliminary evidence for male patients, and demonstrated acceptable psychometric performance, suggesting that it can be considered a valid and reliable instrument to measure HRQoL for patients with infertility in Chinese clinical practice.