Eliminating Patient Queues for Payment via Asynchronous Mobile Money Integration: Architecture and an Eight-Month Performance Evaluation at a Rwandan Tertiary Hospital (Preprint)

BACKGROUND Patient payment queuing at hospital cashier desks is a persistent operational challenge in resource-limited healthcare settings. In October 2025, the University Teaching Hospital of Butare (CHUB), a public tertiary referral centre in Rwanda, integrated an asynchronous Mobile Money payment module with its OpenClinic GA hospital management information system (HMIS) through the Irembo payment gateway, as an unfunded quality improvement initiative. OBJECTIVE To describe the integration architecture and quantify its impact on patient payment cycle time, channel adoption, and transaction reliability over eight months of routine operation. METHODS The architecture is described from direct analysis of the deployed production source code. Performance was evaluated by retrospective analysis of all closed invoices for prepaid services (laboratory, imaging, pharmacy) from 1 October 2025 to 31 May 2026. Payment cycle time was defined as the interval from bill creation to payment confirmation; transactions exceeding 24 hours were excluded. RESULTS The integration implements a fully asynchronous, non-blocking model with dual trigger pathways (patient-initiated SMS and staff-initiated HMIS form) and a four-step Irembo API workflow. Across 146,203 invoiced episodes, Mobile Money adoption grew from 3.8% to 20.9%. Among 131,037 within-24-hour transactions, median payment cycle time was 5 minutes for Mobile Money versus 72 minutes for cash, a 93.1% reduction. The system processed 44,216 transactions with a 97.9% success rate; all failure causes were identified and resolved. Insurer paper-documentation requirements were the principal structural ceiling on adoption. CONCLUSIONS Asynchronous mobile money integration delivered large, sustained reductions in patient payment waiting time and provides a reproducible reference model for sub-Saharan African hospitals.