Growing implementation scientists: NHLBI's K12 programs in heart, lung, blood, and sleep research

Implementation science seeks to accelerate the adoption, integration, and scale-up of evidence-based interventions (EBIs) to improve health and reduce disparities. As the field expanded, demand for trained implementation scientists rapidly outpaced workforce capacity. To address this need, the National Heart, Lung, and Blood Institute (NHLBI) launched the institutional Research Career Development Programs in T4 Implementation Research (K12) Next Generation of Implementation Science (iNexIS) in 2016. The program aimed to expand the national pool of rigorous implementation researchers prepared to conduct late-stage translation (T4) studies focused on heart, lung, blood, and sleep (HLBS) conditions. This report presents early outcomes from the inaugural K12 implementation science cohort to assess preliminary workforce growth and productivity.

A retrospective cohort analysis was conducted using NIH RePORTER, Query/View/ Report (QVR), and Research Performance Progress Reports (RPPRs) for all awards funded through RFA-HL-17-016. Data extracted (through September 2025) included institutional characteristics, scholar demographics, training duration, grant applications and awards, and peer-reviewed publication output. Productivity measures encompassed: (1) Career Development Awards (CDAs), (2) Research Project Grants (RPGs) and equivalents, and (3) Loan Repayment Program (LRP) applications/awards. Descriptive statistics were used to characterize scholar output, time to first CDA or RPG, and cumulative citation metrics.

Ten institutions were funded, supporting 75 scholars across diverse disciplines, primarily pulmonary/critical care medicine (16%), internal medicine (15%), and pediatrics (13%). Most scholars were women (58%); 42% held PhDs and 32% held MDs. Of 215 grant submissions, 95 awards were made to 54 scholars (44% success rate overall; 36% excluding LRPs). Scholars achieved 32 RPGs (24% success rate across RPG submissions) and 27 CDAs. Median time to CDA was 31 months, and to RPG was 43 months-shorter than typical NIH-wide timelines. Scholars collectively generated an estimated 393 publications with a median Relative Citation Ratio of 1.64, reflecting strong research influence. Post-training positions span academic health centers, VA medical centers, community health organizations, research institutes, and industry settings across 17 states.

Early findings suggest that NHLBI's iNexIS K12 program effectively expanded the implementation science workforce, accelerated progression to independent funding, and fostered high research productivity. While long-term impact will require follow-up at beyond 10-years post-program, current metrics indicate strong return on investment. Continued support for structured implementation science training programs remains critical to meet growing workforce demands and advance late-stage translational research.