Cardiology · Medical Literature
Bidirectional Automated Texting for Cardiovascular Health Among People Living With HIV: Observational Cohort Analysis of a Stepped-Wedge Cluster Randomized Controlled Trial.
Abstract
Feasible and potentially scalable strategies are needed to address the growing cardiovascular disease (CVD) risk among people living with HIV. Bidirectional automated texting (BAT) programs that remind and encourage adherence to evidence-based CVD-reducing interventions represent a potentially scalable strategy, but data on their feasibility are lacking. The goal of the study was to determine whether participant sociodemographic factors and technological constraints influenced engagement with a BAT CVD prevention program by people living with HIV. We conducted an observational cohort analysis embedded within a stepped-wedge cluster randomized trial. The BAT program was designed to address the "Million Hearts" ABCS (aspirin therapy, blood pressure control, cholesterol management, and smoking cessation) of cardiovascular health. The parent study was a stepped-wedge randomized trial that rolled out in 3 wedges across 8 practice sites that provided care to people living with HIV. Participants received and could engage with the text messages weekly using their own phones during the study period. We used a zero-inflated negative binomial model to identify factors associated with participants sending text messages during the study. Of the 471 participants, 94% owned a smartphone capable of text messaging, and 70% reported monthly incomes less than US $1500. Overall, 60.3% (n=284) engaged with the BAT program at least once. Regarding texting behavior, participants aged ≥65 years were more likely to send a text than those aged <50 years (P=.047), although age did not influence the number of texts sent. White participants showed lower texting intensity than Black participants (incidence rate ratio 0.69; P=.04). Overall, 60.3% (n=284) of the participants in the study engaged with BAT at least once. The BAT intervention for ABCS appears to be a feasible intervention for people living with HIV. Only a few factors were associated with sending a text or with the number of text messages sent.
Clinical relevance
Among people living with HIV enrolled in a CVD prevention program targeting the Million Hearts ABCS framework, do sociodemographic factors and technological constraints influence engagement with a bidirectional automated text messaging (BAT) intervention? __SNAPSHOT__ {"studyDesign":"Observational cohort analysis embedded within a stepped-wedge cluster randomized controlled trial (parent trial)","setting":"8 HIV practice sites in the United States (specific institutions not reported); trial rolled out in 3 wedges","sampleSize":"n=471 (single arm; observational analysis of BAT program participants)","population":"People living with HIV (PLWH) ages 40–75 with a 10-year baseline ASCVD risk ≥5%; 70% reported monthly incomes <US$1,500; 94% owned a smartphone capable of text messaging","intervention":"Bidirectional automated text messaging (BAT) program delivered weekly to participants' own phones, targeting the ABCS domains: aspirin therapy, blood pressure control, cholesterol management, and smoking cessation","comparator":"Not applicable (single-arm observational feasibility analysis; no concurrent control group for the BAT engagement outcome)","primaryOutcome":"Factors associated with BAT program engagement, operationalized as whether participants sent at least one text message and the number of text messages sent during the study period, analyzed using a zero-inflated negative binomial model","followUp":"Duration of text message exposure tied to the stepped-wedge roll-out period; exact follow-up duration per participant not reported in the available abstract","fundingSource":"Not reported in the available abstract; the parent trial (Translating the ABCSs into HIV Care SW-CRCT) was associated with a multi-site academic network; specific funder not confirmed from available sources"}
Key findings
Of 471 participants, 94% owned a smartphone capable of text messaging and 70% reported monthly incomes below US$1,500, establishing that the target population possessed substantial technological access despite low income. Overall, 60.3% (n=284) engaged with the BAT program at least once. In zero-inflated negative binomial modeling, participants aged ≥65 years were significantly more likely to send at least one text compared with those aged <50 years (P=.047), though age did not significantly influence the total number of texts sent. White participants demonstrated lower texting intensity relative to Black participants (incidence rate ratio [IRR] 0.69; P=.04), indicating a meaningful racial difference in engagement volume. The study authors concluded that only a few factors were associated with sending a text or with the number of messages sent. Absolute engagement rates for other sociodemographic subgroups (sex, income, education, insurance status), confidence intervals for the age finding, NNT, and adverse event data were not reported in the available abstract.
Practice implications
This observational feasibility analysis demonstrates that a BAT CVD prevention program targeting the ABCS framework was technically accessible to the majority of a low-income PLWH cohort, with nearly two-thirds engaging at least once. The study established that sociodemographic factors—particularly race and older age—were associated with some differences in engagement patterns, though the authors characterize the number of significant predictors as few, suggesting the intervention was broadly accessible across subgroups. However, the study did NOT establish whether BAT engagement improved ABCS adherence, reduced ASCVD risk, or influenced clinical outcomes in this specific sub-analysis; those questions were addressed separately in the parent SW-CRCT. The parent trial found a statistically significant reduction in 10-year ASCVD risk (−0.47; 95% CI −0.93 to −0.01) when analyzed by actual intervention start dates, but this effect was driven by a multicomponent intervention (including patient coaching and clinician-level strategies), not BAT alone. Critically, the current study cannot isolate the contribution of BAT to any clinical outcome. The population—PLWH aged 40–75 with baseline ASCVD risk ≥5% at US HIV practice sites—may not generalize to PLWH at lower cardiovascular risk, younger PLWH, or those in resource-limited international settings. The finding that White participants had lower texting intensity than Black participants is hypothesis-generating and warrants confirmation with adjustment for potential confounders (e.g., access plans, data costs, health literacy). Note: only the abstract was available for this review; complete covariate-adjusted model outputs, sensitivity analyses, and full sociodemographic tables were not accessible. __LIMITATIONS__ Observational sub-analysis design embedded within an RCT: no randomization to BAT vs. no-BAT for the engagement outcome, precluding causal inference about what drives engagement,Modest sample size (n=471) for multivariable zero-inflated modeling with multiple sociodemographic predictors, raising concerns about statistical power for detecting smaller subgroup differences,Engagement defined solely as text-message sending behavior; quality, content, or clinical meaningfulness of responses was not reported,Duration of individual BAT exposure per participant not clearly reported, introducing heterogeneity in the outcome measure across the three stepped wedges,Selection bias: participants enrolled in the parent RCT may over-represent PLWH who are already engaged in HIV care, limiting generalizability to harder-to-reach or unengaged populations,The COVID-19 pandemic affected trial implementation, potentially altering texting behavior (increased remote engagement) and complicating interpretation of the engagement patterns observed,Absence of clinical outcome data in this analysis; cannot determine whether BAT engagement translated to ABCS goal attainment or ASCVD risk reduction at the individual level,Racial and age differences in texting behavior were reported without full covariate adjustment transparency in the abstract; confounders such as differential text plan access, health literacy, and disease severity were not addressed,Funding source not reported, limiting assessment of potential conflicts of interest,Generalizability restricted to PLWH aged 40–75 with elevated ASCVD risk in US-based HIV practice settings; results may not apply to younger patients, lower-risk populations, or non-US health systems __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ In a low-income cohort of PLWH at elevated cardiovascular risk, nearly two-thirds (60.3%) engaged with a weekly bidirectional automated texting CVD prevention program at least once, with high smartphone ownership (94%) suggesting technological feasibility in this population. Only a few sociodemographic factors—older age (≥65 years) and non-White race—were independently associated with engagement patterns, implying broad cross-group reach. Clinicians and program designers can use these data to support the case for BAT as a feasible digital adjunct in HIV cardiovascular care, but confirmation of clinical efficacy attributable to BAT specifically, and longer-term engagement data, are needed before broader implementation.