Background In the United States, patients with HIV face significant barriers to linkage to and retention in care which impede the necessary steps toward achieving the desired clinical outcome of viral suppression. Individual-level interventions, such as patient navigation, are evidence based, effective strategies for improving care engagement. In addition, use of surveillance and clinical data to identify patients who are not fully engaged in care may improve the effectiveness and cost-effectiveness of these programs. Methods and findings We employed a pre-post design to estimate the outcomes and costs, from the program perspective, of 5 state-level demonstration programs funded under the Health Resources and Services Administration’s Special Projects of National Significance Program (HRSA/SPNS) Systems Linkages Initiative that employed existing surveillance and/or clinical data to identify individuals who had never entered HIV care, had fallen out of care, or were at risk of falling out of care and navigation strategies to engage patients in HIV care. Outcomes and costs were measured relative to standard of care during the first year of implementation of the interventions (2013 to 2014). We followed patients to estimate the number and proportion of additional patients linked, reengaged, retained, and virally suppressed by 12 months after enrollment in the interventions. We employed inverse probability weighting to adjust for differences in patient characteristics across programs, missing data, and loss to follow-up. We estimated the additional costs expended during the first year of each intervention and the cost per outcome of each intervention as the additional cost per HIV additional care continuum target achieved (cost per patient linked, reengaged, retained, and virally suppressed) 12 months after enrollment in each intervention. In this study, 3,443 patients were enrolled in Louisiana (LA), Massachusetts (MA), North Carolina (NC), Virginia (VA), and Wisconsin (WI) (147, 151, 2,491, 321, and 333, respectively). Patients were a mean of 40 years old, 75% male, and African American (69%) or Caucasian (22%). At baseline, 24% were newly diagnosed, 2% had never been in HIV care, 45% had fallen out of care, and 29% were at risk of falling out of care. All 5 interventions were associated with increases in the number and proportion of patients with viral suppression [percent increase: LA = 90.9%, 95% confidence interval (CI) = 88.4 to 93.4; MA = 78.1%, 95% CI = 72.4 to 83.8; NC = 47.5%, 95% CI = 45.2 to 49.8; VA = 54.6, 95% CI = 49.4 to 59.9; WI = 58.4, 95% CI = 53.4 to 63.4]. Overall, interventions cost an additional $4,415 (range = $3,746 to $5,619), $2,009 (range = $1,516 to $2,274), $920 (range = $627 to $941), $2,212 (range = $1,789 to $2,683), and $3,700 ($2,734 to $4,101), respectively per additional patient virally suppressed. The results of this study are limited in that we did not have contemporaneous controls for each intervention; thus, we are only able to assess patients against themselves at baseline and not against standard of care during the same time period. Conclusions Patient navigation programs were associated with improvements in engagement of patients in HIV care and viral suppression. Cost per outcome was minimized in states that utilized surveillance data to identify individuals who were out of care and/or those that were able to identify a larger number of patients in need of improvement at baseline. These results have the potential to inform the targeting and design of future navigation-type interventions., Starley Shade and co-workers study outcomes and costs associated with interventions seeking to improve engagement with HIV care in the United States., Author summary Why was this study done? ➢ The Health Resources and Services Administration’s Special Projects of National Significance Program (HRSA/SPNS) funded an initiative that implemented 5 state-level interventions which used existing surveillance and/or clinical data to identify individuals who had never entered HIV care, had fallen out of care, or were at risk of falling out of care and navigation strategies to engage patients in HIV care. ➢ This study estimates the outcomes and incremental costs of these 5 state-level interventions relative to the standard of care provided prior to implementation of the interventions. What did researchers do and find? ➢ We estimated the additional cost of interventions during the first year of implementation (2013 to 2014). Among HIV–infected patients who enrolled in each intervention during the first year of implementation, we estimate how much the number and proportion of patients with viral suppression increased from before to up to 12 months after enrollment in the intervention. Then, we estimated the additional cost per additional patient with viral suppression for each intervention. ➢ We found that these interventions had similar or lower costs than similar previous interventions ($223 to $3,631 per patient), were associated with larger increases in the proportion of patients with viral suppression than similar previous interventions (47.5% to 90.9% increase in proportion of patients with viral suppression), and had similar or lower costs per additional patient with viral suppression compared to similar previous interventions ($920 to $4,415 per additional patient with viral suppression). What do these findings mean? ➢ These results show that using existing data to identify HIV–infected patients who are out of care and patient navigation to link, reengage, or retain patients in care is associated with increased viral suppression and had similar costs per outcome compared to patient navigation alone. These results also showed that use of surveillance data to identify HIV–infected patients who are out of care does not increase costs and may improve the cost per outcome of these interventions. ➢ This study did not include a contemporaneous comparison group. Therefore, we do not know the degree to which patients would have engaged or reengaged in care and achieved viral suppression due to other changes in care that occurred during the first year of implementation of the intervention.