Participants and procedure
Participants in this study were hospitalized patients recruited from the oncology setting in the general hospitals by cluster sampling method. Eligibility criteria included 1) diagnosed with cancer by pathology or cytology; 2) age of 18 years or older; 3) aware of their disease diagnosis; 4) provision of written informed consent. Exclusion criteria was 1) serious illness or cognitive impairment (such as dementia or delusions) or too weak to participate in the survey independently; 2) patients with language communication barriers or lack of capacity to cooperate the interview; 3) family caregivers required confidentiality of their diagnosis to the patients; This study was reviewed and approved by the Human Ethics Committee of Dalian Medical University. After a description of all procedures of the study was provided, patients signed a written informed consent before participate in the interview.
This cross-sectional investigation was conducted in two general hospitals (the Second Affiliated Hospital of Dalian Medical University and the Zhongshan Affiliated Hospital of Dalian University) from January to December 2015 in Dalian, a typical Northeast coastal city of China, the gross domestic product (GDP) ranked 26th in China in 2018, a medium level of the country. Patients were recruited consecutively in the oncology setting and we conducted our interview only if he/she had been undergoing the medical treatment for at least three days. Three interviewers received a seven-day training included general interview skills and good acknowledge of the whole instruments before the survey. All the patients were interviewed face-to-face. Interview lasts 40–50 minutes. As for cancer relevant information, such as type of cancer, stage at diagnosis, medical treatment, and metastatic status were withdrawn from the patients’ medical records.
Measures
Suicidal ideation: We used the Chinese version of the Yale Evaluation of Suicidality scale to evaluate suicidal ideation. The YES scale is a 16-item structured questionnaire assesses suicidal thoughts and actions, history of suicide attempts and feelings/attitudes on suicide[39]. Higher score indicates higher risk of suicidality. The YES has been validated among bereaved population as well as advanced cancer patients[13, 23]. The first 4 items were used as a screening measure in our study, Cronbach'sα = 0.93. Patients were asked following questions to assess SI (Since diagnosis of the disease, in light of your current circumstances, how strong would you say your wish to live has been? 1) strong, 2) moderate, 3) weak, 4) have none. How strong has your wish to die been? 1) strong, 2) moderate, 3) weak, 4) have none. Which of the following best describes your feelings about living versus dying? 1) No, 2) possibly, 3) Yes. Have you ever had thoughts of killing yourself? 1) Living outweighs dying, 2) About equal, 3) Dying outweighs living.) Those patients who endorsed the responses to questions Q1 through Q4 were 1, 4, 1, 1, identified as having no SI, If not, categorized into positive SI.
Independent variables and covariates
Physical symptoms were measured with one-item from the McGill Quality of Life Questionnaire (MQOL)[40]. Participants were asked whether have these symptoms over the previous two days with a response of yes and no. 14 items were included: pain, shortness of breath, insomnia, weakness, fatigue, nausea, lack of appetite, constipation, diarrhea, edema, cough, vomiting, fever and bloated.
Health self-efficacy: We measured health self-efficacy by using the Chinese version of the Strategies Used by People to Promote Health (SUPPH)[41]. This scale is a 29-item validated scale including three dimensions. Each item is rated on a five-point scale ranging from “little confidence” (1) to “ quite a lot of confidence” (5). All the items were summed into a score. Higher score indicates a higher sense of health self-efficacy. To evaluate the relative risk of SI, the scores were categorized into high (≥ 50) and low groups (< 50) by the median. The Cronbach'sαof the current data was 0.96.
Depression: Clinician diagnosis of depression was evaluated by the 17-item version of the Hamilton Depression Rating Scale (HDRS-17)[42], which assess the severity of depression symptoms over the past week. It contains 17 items to detect depressive disorder and identify severity classification by semi-structured interview. A higher total score indicates a greater severity of depression. Severity classifications were defined as follows: 0–7 for no depression, 8–16 for mild depression, 17–23 for moderate depression, and ≥ 24 for severe depression. According to the proposal of Zimmerman et al[43], the cut-off value of HDRS was 8 for identifying depressive disorder. Reliability was good in the present study (Cronbach’sα = 0.84; Split reliability = 0.79).
Other variables: Socio-demographic characteristics included sex, age, marital status, education, residence, employment status, household-income, smoking habit and drinking habit. Clinical related variables included site of cancer, stage at diagnosis, medical treatment, time since diagnosis and metastasis status.
Statistical analysis
Descriptive analyses, chi-square were used to compare the differences in socio-demographics and clinical associations between those who with and without suicidal ideation. Multivariate regression was used to test the regression models and the interaction effects of physical symptoms and health self-efficacy. Six different models were tested in this study. Model 1 tested the relationship between physical symptoms and SI after adjusted for socio-demographic and clinical variables. Model 2 tested physical symptoms, health self-efficacy and SI, adjusted for socio-demographic plus clinical variables. Model 3 tested physical symptoms, health self-efficacy and SI, additionally adjusted for diagnosed depression. As for the regression models of the interaction effects, Model 1 adjusted for the socio-demographic variable and all the other physical symptoms. Model 2 additionally adjusted for clinical variables. Model 3 additionally adjusted for diagnosed depression.
All statistical analyses were performed by SPSS version 21.0 for Windows (IBM, Chicago, USA). The reported CIs were calculated at the 95% and statistical significance was set at .05 level and all tests were two-sided.