Discussion
To our knowledge this is the first study that evaluated implementation outcomes of a mHealth intervention which effectively increased adherence to triage Pap among HPV-positive women in a Latin American country. Our post-intervention study showed high acceptability among women. All dimensions related to appropriateness also reported a high level of agreement: most women mentioned that the intervention was useful, positively valued the content, and found the number of messages and their timing were adequate. In addition, the comprehension of the SMS message content was high, and most women perceived the SMS message as a tool that influenced them to go to the health center to get their results. Findings showed high acceptability, appropriateness, and comprehension of the SMS message among HPV-positive women with no significant differences by triage adherence after receiving the SMS messages. These results are important as lack of comprehension of the SMS, as well as its low acceptability by the target population have been indicated in the literature as a main obstacle for effectiveness of mHealth strategies. These findings provide a comprehensive understanding of the effectiveness reported in ATICA trial [High acceptability of an mHealth intervention is key to understanding its success [Legitimacy of the sender is key to engagement with SMS-based interventions [Low comprehension of the content of the message could be a potential barrier to the effectiveness of an SMS-based intervention [Privacy and confidentiality issues, such as disclosing a result to a third-person in shared cellphones, are paramount for SMS-based health intervention [Several studies have shown the effectiveness of SMS-based strategies as reminders to increase adherence to medical visits [Our results showed high acceptability, appropriateness, and comprehension of the SMS message with no significant differences by triage Pap adherence at day 60 after receiving the SMS messages. These results indicate that the implementation of the intervention did not encounter barriers associated with the characteristics of the SMS message itself, suggesting the existence of other barriers to triage adherence. In fact, around 20% of women who went to the health center after receiving the SMS did not know the HPV result in the first attempt due to institutional barriers. Several studies showed that main barriers to follow up among women with positive screening results were related to institutional barriers, such as delays in result delivery or not receiving results, lack of appointments, or lack of human resources to take the samples [Like all studies, there are some limitations to this analysis that must be taken into account. Due to COVID-19 pandemic the field work was interrupted, and it was not possible to contact all HPV positive women. However, sociodemographic characteristics of responding and non-responding women were similar. In addition, a low proportion of women were interviewed by phone between September and October 2020 with potential recall bias. It is also possible that courtesy bias could have resulted in an over-estimation of the acceptability of the SMS strategy.