Scales to Assess Knowledge, Motivation, and Self-Efficacy for HIV PrEP in Colombian MSM: PrEP-COL Study

Objective. We evaluated the construct validity Spanish version of knowledge, stigma, norms, and self-efficacy scales regarding PrEP in MSM. Methods. Sample of 287 MSM. Exploratory confirmatory factor analysis and item response theory were used to validate the constructs. Correlations and confidence interval-based estimation of relevance analyses were conducted to correlate the scales with willingness and intention to use PrEP. Results. Attitude, stigma, and descriptive and subjective norms scales showed good construct validity and were related to intention and willingness to use PrEP. However, the knowledge scale and self-efficacy scales require further refinement. Conclusions. The study provides useful information for assessing information, motivation, and self-efficacy related to PrEP use. Our results could be used to test the scales and the theoretical model in other contexts to confirm their usefulness.

1. Introduction
As MSM continue to be disproportionately affected by HIV, a combination of preventive strategies, including preexposure prophylaxis (PrEP), is urgently needed to curtail the rate of new HIV diagnoses worldwide. PrEP acceptance in MSM has been low despite years of availability and demonstrated efficacy [1, 2]. In the United States only one of five PrEP-eligible MSM is taking PrEP [3, 4]. Latino MSM in North America had lower PrEP knowledge, acceptance, and uptake [5, 6]. In Latin American countries, where MSM account for 40% of the new cases of HIV each year, PrEP awareness was reported around to 58%, and nearly 52% were willing to use daily PrEP [6]. PrEP uptake is a complex behaviour [1, 7], and the use of a theoretical model to identify appropriate targets for interventions is needed if PrEP is to be adopted widely.

One explanatory model for reducing HIV risk behaviours that has potential in MSM populations is the information motivational behavioural (IMB) model [8]. The IMB model posits that individuals will likely initiate and sustain a behaviour if they are well informed and motivated and perceive themselves as having the skills to initiate and maintain the behaviour. The IMB model has been used to develop HIV prevention interventions proven to be effective in decreasing condomless sex [9] and increasing adherence to antiretroviral therapy [10, 11]. Barriers related to PrEP uptake in MSM are also consistent with the IMB model, including lack of knowledge, negative attitudes, lack of self-efficacy, and low motivation due to stigma [12]. Hence, it is a relevant framework for the development of behavioural interventions for populations at risk of HIV infection and in need of PrEP [12–14].

Identification of PrEP knowledge, motivation, and skills in MSM requires either new instruments or the adaptation and validation of existing ones in different populations. In a recent publication, Walsh [14] used the IMB model to develop new measures for these constructs and relate them to PrEP uptake. The scales assessing knowledge, descriptive norms, and subjective norms have high levels of reliability with alphas of Cronbach greater than or equal to 0.90. The attitude, stigma, and self-efficacy scales had good alphas from 0.79 to 0.87. Confirmatory factor analyses supported the correlation of the scales and the item loading in each a priori latent construct, with most of the scales related to the intention to use PrEP, thus supporting the IMB model. Since the scales have been recently developed and only used in MSM populations living in the United States and are not yet available in Spanish, in this paper, we present the assessment of their internal coherence and construct validity in a sample of MSM from Colombia. In this work, we explored if the items of the scales represent one construct and a relationship exists between the scales and the intention to uptake PrEP. If the PrEP scales are valid and the relations are supported, the results could be used to gain an understanding of PrEP uptake in other Spanish-speaking MSM populations and delineate interventions.