DOI: 10.7910/dvn/imco1y
title: COVID-19 contagion concern scale (PRE-COVID-19): Validation in Cuban patients with type 2 diabetes

description: 2.1. Participants and procedure

The participants were patients with DM from nine primary health care areas corresponding to four Cuban provinces belonging to different regions of the country (Pinar del Río, Havana, Ciego de Ávila and Santiago de Cuba), selected by means of non-probabilistic sampling. The inclusion criteria included: 1) having type 2 diabetes mellitus according to the criteria of the World Health Organization 2) being ≥18 years of age 3) being attended in the previously mentioned health areas where their clinical histories were located and 4) being willing to participate in the research study and answer the survey after signing the informed consent form. Patients with severe mental illness or cognitive deficits (dementia, psychosis or mental disabilities) or any other apparent condition that compromised their ability to understand and complete the questionnaire were not included in the study. The sample size was calculated with the Soper software [29], which indicated a number of 200 participants. For this we considered the number of observed variables (6 items), latent variables of the model to be evaluated (concern for COVID-19 contagion), the anticipated effect size (λ = 0.3), the probability (α = 0.05) and the statistical power (1 - β = 0.95).

Finally, 219 people with type 2 DM were surveyed. The application of the survey was carried out between the months of January and April 2021, while the patients attended consultation or in their own homes by the researchers trained for the task and complying with strict COVID-19 prevention protocols. The Cuban panorama in the fight against COVID-19 during the period of data collection was not favorable, as the country was in a phase of resurgence characterized by high numbers of people infected with the virus, much higher compared to the diagnoses at a similar point during the first stage of the disease, in 2020. Although government health measures were strengthened to contain the pandemic, the population's perception of risk was on the rise. During those dates, more than 64,414 positive diagnoses and 384 deaths were reported. 
Participation in the study was voluntary and no financial compensation was provided. All participants signed informed consent and were allowed to withdraw at any time from the study without having to justify their decision. In addition, the data were guaranteed to be confidential and anonymous. The study received approval from the ethics committee of the Universidad Privada del Norte in Peru (registration number: 20213002).

The majority of the participants were women (66.2%) with a mean age of 58.5 years old (SD = 18.2). Thirty-two point nine percent had higher education. Of the total participants, 37.9% were retired and 32% were state workers; while 43.4 had more than 10 years with the disease. The majority (68.9%) had no associated chronic complications and were receiving treatment for diabetes (98.2%). More details of the sociodemographic variables can be seen in Table 1.

Table 1. Characteristics of the participants (n = 219).

Characteristic n (%)
Age 58.5 (18.2)a
Sex
Female 145 (66.2)
Male 74 (33.8)
Level of education
University 72 (32.9)
Pre-university 63 (28.8)
Mid-level technical 39 (17.8)
Secondary 25 (11.4)
Primary 17 (7.8)
No schooling 3 (1.4)
Occupation
Retired/pensioned 83 (37.9)
State employee 70 (32.0)
Self-employed 37 (17.0)
Housewife 17 (7.8)
Student 10 (4.6)
Unemployed 2 (0.9)
Time of evolution of diabetes (years)
Less than 5 52 (23.7)
From 5 to 10 72 (32.9)
More than 10 95 (43.4)
Associated chronic complications b
None 151 (68.9)
Diabetic foot 31 (14.2)
Polyneuropathy 20 (9.1)
Retinopathy 15 (6.8)
Nephropathy 7 (3.2)
Other 2 (0.9)
Treatment of diabetes
Yes 215 (98.2)
No 4 (1.8)
Comorbidities
Yes 141 (64.4)
No 78 (35.6)
Family member or friend infected by COVID-19
Yes 110 (50.2)
No 109 (49.8)
Family member or friend deceased due to COVID-19
No 210 (95.9)
Yes 9 (4.1)
a: mean and standard deviation; b: a patient may have more than one complication.

2.2. Instruments
Scale of Worry for Contagion of COVID-19 (PRE-COVID-19). The scale is comprised of 6 items that assess concern about becoming infected with COVID-19 and its impact on people's daily functioning, specifically on their mood and their ability to perform their daily activities. Each item presented 4 Likert-type response options (from 1 = never or rarely to 4 = almost all the time), with higher scores indicating greater concern about COVID-19 infection.

Generalized Anxiety Disorder Scale-2 (GAD-2) [30]. The GAD-2 consists of 2 items that measure an emotional (feeling nervous) and cognitive (worry) symptom of generalized anxiety in the past 2 weeks. The 2 items have 4 response options using a Likert-type scale (from 0 = not at all to 3 = almost every day), where a higher score indicates a higher level of generalized anxiety.

2.3. Data analysis
Confirmatory Factor Analysis (CFA) was performed using the Diagonally Weighted Least Squares with Mean and Variance corrected (WLSMV) estimator since the items are ordinal in nature. The chi-square test (χ2), the RMSEA index and the SRMR index were used to evaluate the model fit. In the case of the latter two indices, values less than 0.05 indicate good fit, and between 0.05 and 0.08 is considered acceptable. In addition, the CFI and TLI indices were used, where values greater than 0.95 indicate good fit and greater than 0.90 an acceptable fit. To assess validity based on the relationship with other constructs, structural equation modeling (SEM) was employed to assess the latent relationship between concern for being infected with COVID-19 and anxiety. The above fit indices, and their respective cutoff points, were used to assess the adequacy of the model. Cronbach's alpha coefficient and the omega coefficient were used to assess the internal consistency of the scale, where a value greater than 0.70 is adequate.

As for the use of Item Response Theory (IRT), a Graded Response Model (GRM) [35] was employed, specifically an extension of the 2-parameter logistic model (2-PLM) for ordered polytomous items. For each item, two types of parameters were estimated: discrimination (a) and difficulty (b). The a parameter determines the slope at which item responses change as a function of the level in the latent trait and the b parameters determine how much of the latent trait the item requires to be answered in a given way. Since the scale has four response categories, there are three estimates of difficulty, one per threshold. The estimates for these three thresholds indicate the level of the latent variable at which an individual has a 50% chance of scoring at or above a particular response category. Item information curves (IIC) and the test information curve (TIC) were also calculated.

All statistical analyses were performed using the "lavaan" package for the CFA and the "ltm" package for the GRM. In all cases, the RStudio environment was used for R.
description: RStudio, null