Diabetes progression and severe hypoglycemia: a nationwide cohort study of 2,475,605 adults with type 2 diabetes mellitus

Lee, Kyu-Na; Kim, Bongseong; Kim, Mee Kyoung; Kim, Sukil

doi:2026.41.5.903

Korean J Intern Med > Volume 41(5); 2026 > Article

ORIGINAL ARTICLE

Korean J Intern Med. 2026;41(5):903-913. doi: https://doi.org/10.3904/kjim.2026.084

Diabetes progression and severe hypoglycemia: a nationwide cohort study of 2,475,605 adults with type 2 diabetes mellitus

Kyu-Na Lee¹, Bongseong Kim², Mee Kyoung Kim³

, and Sukil Kim¹

¹Department of Preventive Medicine and Public Health, College of Medicine, The Catholic University of Korea, Seoul, Korea
²Department of AI-Bio, Graduate School of AI, Soongsil University, Seoul, Korea
³Division of Endocrinology and Metabolism, Department of Internal Medicine, Eunpyeong St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea

Corresponding Author: Mee Kyoung Kim , Tel: +82-2-2030-4435, Fax: +82-2-595-2534, Email: makung@catholic.ac.kr
Sukil Kim , Tel: +82-2-2258-7367, Fax: +82-2-532-6537, Email: sikimmd@catholic.ac.kr

Received: February 20, 2026; Revised: April 22, 2026; Accepted: May 11, 2026.

Abstract

Background/Aims: Severe hypoglycemia (SH) is a major concern in type 2 diabetes mellitus (T2DM). We evaluated whether a composite diabetes progression score could predict incident SH.
Methods: Using the Korean National Health Insurance Service database, we identified 2,475,605 adults with T2DM who underwent health examinations in 2015−2016. Incident SH was defined by ICD−10 codes plus emergency department visit or hospitalization. The progression score (range, 0−6) comprised six indicators: longer diabetes duration, use of ≥ 3 oral glucose-lowering drug classes, insulin use, chronic kidney disease (CKD), cardiovascular disease, and diabetic retinopathy.
Results: During 1 year of follow-up, 1,186 SH events occurred. Each component of diabetes progression was independently insuassociated with SH risk hazard ratios (HRs) from 1.19–3.27, with insulin use and CKD showing the largest effects. SH risk increased stepwise with higher progression scores. Compared with a score of 0, the adjusted HRs (95% confidence intervals) were 3.35 (2.63−4.27), 7.74 (6.15−9.74), 12.61 (9.97−15.95), 22.39 (17.44−28.75) for scores 1, 2, 3, and ≥ 4, respectively.
Conclusions: A concise diabetes progression score strongly stratified short-term SH risk in this nationwide cohort, and may help target proactive prevention and early intervention.

Keywords: Diabetes mellitus, Type 2 ; Hypoglycemia ; Disease progression