1.1 Subjects
The subjects were 161 patients with a confirmed diagnosis of gout in the Department of Rheumatology and Immunology in the First Affiliated Hospital of Shenzhen University (Shenzhen Second People’s Hospital) and the Affiliated Hospital of Guangdong Medical University between October 2015 and December 2016. The diagnostic criteria were based on the 2015 American College of Rheumatology/European League Against Rheumatism Gout Classification Criteria [7]. The eligible patients had basic literacy skills. Pre- and posttreatment quality of life (QOL) assessments were performed after informed consent was obtained.
1.2 Methods
1.2.1 Instrument development The QLICD-GO(V2.0) was developed by combining the widely recognized general module of the Quality of Life Instruments for Chronic Diseases (QLICD-GM) with a specific module for gout. This general module, consisting of 28 items in three domains (physical function, psychological function, and social function), has previously been formulated on the basis of topic discussion, interviews with and investigations in patients with different chronic diseases and medical staff, and multiple discussions, analyses, screening, and revisions by research team members.
With reference to relevant literature and QOL instruments (universal and specific instruments) for patients with gout from China and abroad and in combination with clinical expertise on gout, we proposed a pool of 34 health-related QOL items specifically for patients with gout, covering gout-induced impacts on the physical, psychological, and social functioning of patients, and drug-related side effects. Each potential item for the gout-specific module was analyzed at meetings of the topic panel and core panel. Thirteen items for the specific module were selected and were organized into a patient questionnaire and a medical staff questionnaire. Based on five methods to screen items and the opinions of clinical experts, a 12-item gout-specific module was formed.
The QLICD-GO(V2.0) is divided into four aspects, including physical symptoms and signs (six items), functional limitation to daily life (one item), common drug-related side effects (two items), and unique psychological effects (three items). A five-point Likert scoring method is used, with possible scores between 1 and 5 or between −5 and −1. The higher the score of a positive item, the better the QOL; the greater the absolute value of the score of a negative item, the worse the QOL. For positive items, there is no need to convert, the original score is the item score, for reverse items, it is necessary to "forward transform", that is, subtract the original score from 6 to get the item score.
1.2.2 Data collection Between October 2015 and December 2016, the investigator briefly explained the purpose of the survey and distributed the instrument to the patients, who filled in the instrument independently according to their actual conditions in the Rheumatic immune clinic and rheumatic immune Department of Affiliated Hospital of Guangdong Medical University. Because most patients with gout were outpatients, the subjects fill out the instrument on the day of initial consultation and on the day of subsequent consultation. Inclusion criteria: ①gout was diagnosed according to the 2015 American rheumatology society / European anti rheumatism alliance gout classification standard [8]. ②Primary school and above education level, clear awareness can fill in the questionnaire. ③No mental illness or consciousness disorder. ④No exclusion criteria. Exclusion criteria: ① The patient had joint pain and dysfunction caused by other rheumatic diseases. ② Combined with hypertension, diabetes and other chronic history and cancer history. ③It is associated with heart, liver, lung, kidney and other visceral diseases. ④Illiterate, delirious, mentally ill, critically ill, unwilling to cooperate.
1.2.3 Instrument assessment After conversion of item scores, the raw score (RS) in each aspect was calculated and converted to a standard score (SS) according to the range method to facilitate comparison between items. The SS of a domain was obtained by subtracting the lowest possible score of the domain (Smin) from the RS of the domain, the difference was divided by the range of the RS of the domain, and the result was multiplied by 100. The calculation formula is SS = (RS − Smin) / (Smax − Smin) × 100. 3). The assessment covered the reliability (internal consistency reliability and split-half reliability), validity (content validity, construct validity, and criterion validity), and responsiveness (comparison of pre- and posttreatment mean scores, standardized response mean [SRM]) of the instrument. In this study, we use SF-36 as the calibration standard, because the calibration validity is lack of gold standard, and SF-36 is a widely recognized tool for measuring QOL [9].
1.3 Statistical analysis
SPSS 21.0 statistical software was used for data entry and analysis. The statistical methods included the following two categories: methods for instrument item screening (coefficient of variation, correlation analysis, and factor analysis) and methods for instrument assessment (paired t-test and correlation analysis).
1.4 Patient and Public Involvement
In this experiment, QLICD-GO(V2.0) was developed by combining the common module of chronic diseases with the specific module of gout. The common module of chronic diseases is now mature. We need to develop a specific module of gout. It is divided into issue group and core group, mainly composed of life quality researchers, rheumatology immunologists, epidemiologists, public health scholars, sociologists and other personnel at all levels. The selection of the main items of the topic group, the later development and evaluation of the main scale of the core group, finally formed the specific module of the gout scale.
The scale is patient self-rated. The researcher made a brief introduction to the questionnaire to the respondents. Under the condition of the patients' willingness, the questionnaire was distributed to the patients, and then it was taken back after the patients completed the questionnaire, and carefully checked whether there was any missing item. If there was any missing item, the researcher reminded the respondents to supplement it. If it still could not be filled in, it was treated as the default value and recorded the reason. Since the majority of gout patients are outpatients, in principle, the subjects fill in a questionnaire on the day of inquiry and the day of follow-up.