The efficiency of the EmERGE platform for medically stable people living with HIV in Portugal

**Background:** The EmERGE (Evaluating mHealth technology in HIV to improve Empowerment and healthcare utilization: Research and Innovation to Generate Evidence for Personalized Care) Project developed a mobile health (mHealth) platform, the EmERGE Pathway of Care, implemented in HIV clinics across five European countries. This study aimed to calculate the cost-effectiveness of the Pathway for medically stable people living with HIV (PLHIV) at Hospital Capuchos, Centro Hospitalar Universitário de Lisboa Central (HC-CHLC) in Portugal. The app allows patients to securely access test results, clinical reviews, medication information, and communicate with caregivers, potentially reducing unnecessary clinic visits while maintaining clinical stability.

**Methods:** This before-and-after study collected data on healthcare service use, costs, and outcomes for 586 EmERGE participants one year before and one year after implementation of the Pathway (November 1, 2016, to October 30, 2019). Participants were clinically stable on antiretroviral therapy (ART) for at least one year, with undetectable viral load (<50 copies/mL) and no recent opportunistic infections. A microcosting exercise was performed to calculate unit costs for outpatient visits, laboratory tests, radiology investigations, and pharmacy services (including antiretroviral drugs, ARVs). Mean number of services used per patient-year (MPPY) was calculated using Poisson confidence intervals. Annual costs per patient-year (ACPPY) were derived by multiplying MPPY by unit costs. Primary outcomes were CD4 count and viral load; secondary outcomes included PAM-13 (patient activation measure) and PROQOL-HIV (quality of life). Linear mixed models were used to analyze changes over time.

**Key Results:** The study enrolled 586 participants (87% male, mean age 42.0 years, 95% CI: 39.2–44.8). Outpatient clinic visits decreased by 35% from 3.1 MPPY (95% CI: 3.0–3.3) to 2.0 MPPY (95% CI: 1.9–2.1). Laboratory tests increased by 3% from 246.9 MPPY (95% CI: 244.9–247.5) to 253.1 MPPY (95% CI: 251.9–254.5). Radiology investigations decreased by 39% from 2.8 MPPY (95% CI: 2.6–2.9) to 1.7 MPPY (95% CI: 1.6–1.8). Annual costs per patient-year for outpatient visits decreased by 35% from €301 (95% CI: €288–€316) to €193 (95% CI: €182–€204). Laboratory costs increased by 1% from €741 (95% CI: €735–€743) to €759 (95% CI: €756–€764). Radiology costs decreased by 38% from €50 (95% CI: €47–€52) to €31 (95% CI: €29–€32). Overall annual cost for HIV outpatient services (excluding ARVs) decreased by 5% from €2,093 (95% CI: €2,071–€2,112) to €1,984 (95% CI: €1,968–€2,001). Including ARVs (annual cost €9,976, 83% of total), total annual costs decreased by 1% from €12,069 (95% CI: €12,047–€12,088) to €11,960 (95% CI: €11,944–€11,977). Primary outcomes remained stable: median baseline CD4 count was 723 cells/mm³ (IQR: 506–944), and viral load was undetectable in most participants. PAM-13 and PROQOL-HIV scores did not change substantially between periods.

**Clinical Implications:** The EmERGE Pathway produced cost savings after implementation, primarily driven by a 35% reduction in outpatient visits, without compromising clinical outcomes or patient-reported measures. Antiretroviral drugs were the main cost driver, accounting for 83% of total annual costs, and were more expensive in Portugal (€9,976 per patient-year) compared to other EmERGE sites (range €4,717–€8,837). Extending the Pathway to all PLHIV could generate additional savings that could be redirected to address other healthcare needs. The study highlights the potential of mHealth to safely reduce healthcare utilization and costs for stable chronic disease populations, though longer follow-up and broader implementation studies are needed.