Background: Modern instant messaging systems facilitate reach-back medical support for Defence Medical Services (DMS) by connecting deployed clinicians to remote specialists. The mobile app Pando (Forward Clinical, UK) has been used for this purpose by the DMS via the ' Ask Advice ' function. We aimed to investigate the usage statistics for this technology in its first 1000 days to better understand its role in the DMS., Methods: An observational study was undertaken using metadata extracted from the prospective database within the application server for clinical queries between June 2019 and February 2022. These data included details regarding number and name of specialties, timings, active users per day and the number of conversations., Results: There were 29 specialties, with 298 specialist users and 553 requests for advice. The highest volume of requests were for trauma and orthopaedics (n=116; 21.0%), ear, nose and throat (n=67; 12.1%) and dermatology (n=50; 9.0%). There was a median of 164 (IQR 82-257) users logged in per day (range 2-697). The number of requests during each day correlated with the number of users on that day (r=0.221 (95% CI 0.159 to 0.281); p<0.001). There were more daily users on weekdays than weekends (215 (IQR 123-277) vs 88 (IQR 58-121), respectively; p<0.001). For the top 10 specialties, the median first response time was 9 (IQR 3-42) min and the median time to resolution was 105 (IQR 21-1086) min., Conclusion: In the first 1000 days of secure app-based reach-back by the DMS there have been over 500 conversations, responded to within minutes by multiple specialists. This represents a maturing reach-back capability that may enhance the force multiplying effect of defence healthcare while minimising the deployed ' medical footprint '. Further discussions should address how this technology can be used to provide appropriately responsive clinical advice within DMS consultant job-planned time., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)