Implementation science to expand an mHealth intervention for improving retention in care for women living with HIV and their children

Introduction: The multi-step cascade of care for prevention of mother-to-child HIV transmission (PMTCT) paves the way to potentially eliminating mother-to-child HIV transmission; yet, it also lays the foundation for attrition and disengagement from care, increasing the risk of morbidity and mortality for both mother and child. We recently concluded a randomized controlled trial (RCT) in Kenya where we developed text messages using a behavioral theoretical framework and found that this “texting to improve testing” (TextIT) strategy significantly improved maternal retention in postpartum PMTCT care and rates of infant HIV testing. The goals of this dissertation were to understand “why” and “how” the intervention worked. Methods: We conducted a “parallel cohort RCT” comparison of infant HIV testing rates in RCT non-participants (reference category) versus control, and intervention group participants (chapter 2). We also conducted a cluster-randomized, stepped-wedge trial in western Kenya to determine the real-world effect of TextIT on infant HIV testing within eight weeks after birth (chapter 3), and maternal retention in postpartum HIV care (chapter 4). Results: Chapter 2: Compared to trial-ineligible participants, women in the control group of the TextIT RCT (hazard ratio [HR] 2.82; 95% CI 2.29–3.48) and the trial SMS group (HR 3.48; 95% CI 2.84–4.27) were more likely to have their infants tested for HIV. Chapter 3: A greater proportion of infants in the intervention group received HIV testing compared with the standard care group, but the difference was small, and not statistically significant (relative risk [RR] 1.05; 95% CI 0.98–1.12; p=0.2). Chapter 4: TextIT led to a significant improvement in postpartum retention in PMTCT compared to standard care (RR 1.18; 95% CI 1.01–1.39; p=0.04). Conclusions: The combined results of Chapters 2 and 3 could be interpreted as showing that simply paying more attention to infant HIV testing within PMTCT programs can achieve fairly high rates of testing even without the SMS part of the intervention. The results in Chapter 4 go a step further, showing that the SMS component of the intervention can be a powerful adjunct to a functional health system to bolster maternal retention in early postpartum PMTCT care.