Gaps in the Type 1 Diabetes Mellitus care cascade: a national perspective using South Africa's National Health Laboratory Service (NHLS) database.

Objective: Type 1 diabetes mellitus (T1DM) requires lifelong management, yet access to insulin, specialized care, and education is limited in low- and middle-income countries (LMICs). While cascade-of-care analyses are well documented for type 2 diabetes (T2DM), to our knowledge no population-level estimates of the T1DM care cascade exist from LMICs. We therefore evaluated the T1DM care cascade nationally in South Africa and compared outcomes between youth living with HIV (YLWH) and youth living without HIV (YLWOH).

Research design and methods: We analyzed South Africa's National Health Laboratory Service (NHLS) data for patients <20 years with a first glycated hemoglobin A1c (HbA1c) or plasma glucose [fasting (FPG), random (RPG)] between April 2004 and March 2015. Laboratory-diagnosed T1DM was defined as HbA1c ≥6.5%, FPG ≥7.0 mmol/L, or RPG ≥11.1 mmol/L. Cascade stages over 24 months were remaining in care and achieving glycemic control (HbA1c <7.0%, FPG <8.0 mmol/L, or RPG <10.0 mmol/L).

Results: Of 256,449 youth tested for diabetes, 12.1% met criteria for laboratory-diagnosed T1DM. Among these, 15.9% remained in care and 7.2% achieved glycemic control by 24 months. Retention was similar between YLWH and YLWOH (16.8% vs. 15.8%), but glycemic control was higher among YLWH (72.5% vs. 43.4%).

Conclusions: Four of five South African youth with T1DM lacked consistent care, and fewer than 10% achieved glycemic control within two years. Higher control rates among YLWH suggest lessons from HIV care models may strengthen T1DM services. These findings provide the first national estimates of the T1DM care cascade from sub-Saharan Africa and highlight the urgent need for targeted strategies to improve outcomes.