This study is a prospective, mixed-method scale development of oral chemotherapy self-management scale (OCSMS). Figure 1 describes the development of this scale.
Ethical approval
This study was approved by the medical ethics committee of ZheJiang Cancer Hospital, Hangzhou, Zhejiang, China(IRB-2015-208).
Item generation
Literature review and semi-structured interviews were conducted to generate an item pool. A comprehensive literature review was performed to generate a semi-structured interview guide, which was used for in-depth interviews. Purpose sampling was adopted, involving 10 experts (including nurses, doctors and pharmacists) and 9 patients. Data were analysed using Nvivo11 software. A total of seventy-eight items and six domains of oral chemotherapy self-management were generated.
Research seminar
A total of seventy-eight items and six domains were scrutinized during two-round research seminar. Eight experts with a titles of deputy senior or above and bachelor’s degree or above and six experts with master’s degree or above and more than 3 years of relevant work experience were selected in the two-round research. Thirty items and four domains of oral chemotherapy self-management were chosen in the two-round research seminar.
Delphi survey
Two rounds of Delphi consultation were conducted. Eighteen experts (nurses, doctors and pharmacists) from eight provinces, including Shanghai, Beijing, Zhejiang and Hunan, were invited to evaluate the scale format and each item. All experts have a bachelor’s degree and more than 10 years of relevant work experience. They read, evaluated and rated each item based on its clarity, uniqueness and relevance to oral chemotherapy self-management. Items with a coefficient of variation >0.25 and average score < 3.5 were removed[13, 14]. We had removed one item, and had added nine items and one domain of oral chemotherapy self-management by using Delphi method.
Additional information on this study design, data analysis and results of literature review and Delphi survey can be found in previous publications[14, 15].
Pilot testing
Prior to undertaking the psychometric properties of the scale, we recruited 40 participants (20 females) for pilot testing. The mean age of 40 participants from Zhejiang Cancer hospital was 53.05±10.68 years (range 27 - 73 years). The purpose of the pilot testing is to find possible administration problem, such as miss-phrasing, and to determine which items should be modified, added or removed. The researchers explained the purpose of the study, and gave an example before its completion for each participant. After the patients completed the scale, the researchers asked the patients whether they unable to respond. Through the pilot testing, we modified two items without adding or removing any items.
Validity and reliability
To evaluate the psychometric properties of the scale, we recruited 261 participants from Zhejiang Cancer hospital in China between May 1 2018 and January 31 2019. The minimum sample size for factor analysis should be five times the number of items with at least 200 cases[16]. For the test–retest reliability evaluation of the scale, 40 of the participants returned 2–5 weeks later to complete the same survey. Two participants withdrew from the study. The inclusion criteria were as follow: adults (more than 18 years old) with confirmed diagnosis of cancer, using an oral chemotherapy regimen, willing to participate, and able to communicate using Mandarin. The exclusion criterion was inability for self-care.