AimsWe aimed to develop and internally validate a real‐world prognostic model for Level 3 hypoglycaemia risk compatible with outpatient care in the United States.Materials and MethodsiNPHORM is a 12‐month, US‐based panel survey. Adults (18‐90 years old) with type 1 diabetes mellitus or insulin‐ and/or secretagogue‐treated type 2 diabetes mellitus were recruited from a nationwide, probability‐based internet panel. Among participants completing 1 follow‐up questionnaire(s), we modelled 1‐year Level 3 hypoglycaemia risk using Andersen and Gill's Cox survival and penalized regression with multiple imputation. Candidate variables were selected for their clinical relevance and ease of capture at point‐of‐care.ResultsIn total, 986 participants [type 1 diabetes mellitus: 17%; men: 49.6%; mean age: 51 (SD: 14.3) years] were analysed. Across follow‐up, 035.1 (95% CI: 32.2‐38.1)% reported ≥1 Level 3 event(s), and the rate was 5.0 (95% CI: 4.1‐6.0) events per person‐year. Our final model showed strong discriminative validity and parsimony (optimism corrected c‐statistic: 0.77). Numerous variables were selected: age; sex; body mass index; marital status; level of education; insurance coverage; race; ethnicity; food insecurity; diabetes type; glycated haemoglobin value; glycated haemoglobin variability; number, type and dose of various medications; number of SH events requiring hospital care (past year and over follow‐up); type and number of comorbidities and complications; number of diabetes‐related health care visits (past year); use of continuous/flash glucose monitoring; and general health status.ConclusionsiNPHORM is the first US‐based primary prognostic study on Level 3 hypoglycaemia. Future model implementation could potentiate risk‐tailored strategies that reduce real‐world event occurrence and overall diabetes burden.