Participants and procedures
A cross-sectional study was analyzed in consecutive inpatients with PCa during January 2018 and August 2019. The study took place at the Department of Urology in our Hospital, which is the main provider of cancer services to a geographically defined area of 8.2 million people. The eligibility criteria for patient recruitment were (1) age 18 years or older, (2) being histologically diagnosed with PCa, (3) aware of the cancer diagnosis, (4) able to understand and read Chinese well enough to answer the questionnaires, (5) time since diagnosis ≤ 18 months. Exclusion criteria were the following: (1) patients had a history of psychiatric problems before cancer diagnose, (2) patients had intellectual and/or cognitive impairments, (3) patients had other active cancers.
Consecutive patients from the Urology wards were potentially eligible, unless they demonstrated unwillingness to participate. The patients’ attending physicians discussed eligibility on a case-by-case basis to avoid biased judgment and selection bias (e.g., interacting with patients face to face based on the inclusion and exclusion criteria). All registered patients were all volunteers and anonymous for investigators. After obtaining written consent, patients were asked about socio-demographic characteristics, including ability to read and number of years’ formal schooling. Clinical data was collected from the medical record and a set of self-report questionnaires were distributed to patients at the time of hospitalization. Data was mainly obtained using self-administered questions, so there was a possibility of recall and reporting bias.
Among a total of 667 registered patients, 10 patients refused to participate, and 5 patients had other active cancers. Of 652 eligible patients for this study, 88 were excluded from analysis (> 30% missing data). Finally, we received effective responses from 564 PCa patients with effective response rate 86.5%. Medical Ethics Committee of Shengjing Hospital Affiliated to China Medical University reviewed this study, provided the ethics for the approval of this study, and determined that the study procedures were in accordance with the ethical standards.
Demographic and cancer-related variables
The demographic variables included age, marital status and education. Time since diagnosis, cancer stage, treatment type and metastasis (yes vs. no) were included as the clinical variables. They were mainly collected by medical record and questionnaires.
Depression was measured by the Center for Epidemiologic Studies Depression Scale (CES-D), which is a 20-item measure of the severity of depressive symptoms . Items are ranked on a four-point frequency scale from 0 (never) to 3 (always). Higher scores reflect worse depressive symptoms, and a score ≥16 indicates probable clinical depression . The Chinese version of CES-D was validated for criterion, content, reliability and convergent [34,35]. The advantages of CES-D are that patients could complete these scales in a shorter period of time, which is very important given their diseases and physical/mental states. For the disadvantages, CES-D is a screening and non-diagnostic measure. It should be more cautious throughout the study to state the findings about the prevalence of depression. Cronbach’s alpha for CES-D was 0.794 in this study.
Perceived social support
Perceived social support was measured by the Multidimensional Scale of Perceived Social Support (MSPSS) , which is 12-item measure of the sources of perceived social support, rated on a seven-point scale from 1 (very strongly disagree) to 7 (very strongly agree). It provides a summary score (12 to 84), as well as three subscales for perceived support from family, friends, and significant others. The MSPSS was validated and commonly used in Chinese cancer patients [20,21,26]. In this study, the Cronbach’s alpha was 0.942, 0.923, 0.896, and 0.931 respectively for MSPSS, family, friends, and significant others subscales.
For hope, we correlated this with “hope” and this was measured by the Adult Hope Scale (AHS) which included eight items and four filler items rated on 4-point scales (1 = strongly disagree, 4 = strongly agree) . The AHS contains four Agency and four Pathways items, and a high score denotes a higher level of pathways and agency. The hope level is the sum of the agency and pathways items. The AHS and its Chinese version have been used in cancer patients with acceptable validity and reliability [20,21]. The Cronbach’s alpha was 0.742, 0.772, and 0.849 respectively for the pathway, agency and AHS.
The 14-items version of Resilience Scale (RS-14), a short version of the original RS (i.e. RS-25), was used to assess resilience . RS-14 consists of 14 items rated on a 7-point scale, ranging from 1 (strongly disagree) to 7 (strongly agree). The total score ranges from 14 to 98 scores, with higher scores indicating higher resilience. The Chinese version of RS-14 had a good validity and reliability among cancer patients [20,21,38]. In this study, the Cronbach’s alpha was 0.959 for RS-14.
The Statistical Package for the Social Sciences (SPSS, version 13.0) was used to perform the statistical analyses, with two-tailed probability value of < 0.05 considered to be statistically significant. The distributions of CES-D in categorical variables were calculated using independent sample t-test and one way analysis of variance (ANOVA). When one-way ANOVA was found to be significant, least-significant-difference (LSD) was done to perform multiple comparisons. Pearson’s correlation was used to examine correlations among psychosocial variables. Hierarchical regression analysis was used to explore the effects of perceived social support, hope and resilience on depression with adjustment for demographics and clinical variables related to depression in univariate analysis (p < 0.05). There were two models (Model 1 and Model 2) in Step 2. Total score of MSPSS was added in Model 1, and three subscales of MSPSS (others, friend and family) were added in Model 2. Due to the high correlations among the MSPSS subscales, these variables were adjusted in the stepwise regression in Step 2 (Model 2).We provided data including R2, adjusted R2 (Adj.R2), R2-changes, F, standardized regression coefficient (β) and p value for each step in the regression model. Asymptotic and resampling strategies were used to examine the mediating roles (a*b product) of hope and resilience on the association between perceived social support and depression . In these equations, perceived social support was modeled as the independent variable, CES-D score as the dependent variable, hope and resilience as the mediators. The auxiliary routine estimate was based on 5000 bootstrap samples. Then, the bias-corrected and accelerated 95% confidence interval (BCa95% CI) for each a*b product was investigated, and a BCa95% CI not including 0 indicated a significant mediating role. All study variables were centralized before analysis to account for differences in scale scores. Moreover, tolerance (> 0.10) and variance inflation factor (< 10) were used to check for multicollinearity.