Incidence and risk factors for chronic kidney disease in individuals with type 1 diabetes: A population-based study in Salford, Manchester.

AIMS: Chronic kidney disease (CKD) is a serious and common complication of type 1 diabetes (T1D). Despite improvements in diabetes management, the prevalence of CKD in people with T1D remains high. However, large-scale, real-world data from the UK are limited. This study aimed to provide contemporary estimates of CKD incidence and its associated risk factors in a population with T1D in Salford, Greater Manchester. METHODS: We conducted a retrospective cohort study using anonymised electronic health records from the Salford Integrated Record Research Database between 2010 and 2023. Adults with T1D were assessed for CKD, defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and/or albuminuria (urine albumin-to-creatinine ratio ≥3 mg/mmol), confirmed by two readings at least 90 days apart. Competing risk regression models (accounting for death as a competing event) were used to identify associations with demographic and clinical risk factors, including age, sex, ethnicity, deprivation, smoking, body mass index (BMI), HbA1c and use of ACE inhibitors or ARBs. RESULTS: Among 1106 adults with T1D, 38.5% developed reduced eGFR, 47.2% had albuminuria, and 23.8% met both criteria for CKD. Older age was strongly associated with reduced eGFR: compared to those aged 18-28 years, the sub-distribution hazard ratio (sHR) was 3.1 (95% CI: 2.0-5.0) for ages 42-54 and 8.6 (95% CI: 5.4-13.9) for ≥55 years. Other significant predictors included missing ethnicity data (sHR 1.5), higher BMI (sHR 1.1 per kg/m2), higher HbA1c (sHR 1.1 per mmol/mol) and not being prescribed an ACE inhibitor or ARB (sHR 1.4). For albuminuria, increased risk was associated with female sex (sHR 1.3), missing ethnicity (sHR 1.4), higher HbA1c (sHR 1.1), current smoking (sHR 1.5), living in the second most deprived quintile (sHR 1.9) and being prescribed ACE inhibitors or ARBs (sHR 2.1). CONCLUSION: This large UK cohort study highlights a high burden of CKD among adults with T1D. Key risk factors included older age, higher BMI, poor glycaemic control, smoking and deprivation. Although ACE inhibitors and ARBs were commonly prescribed, the uptake of newer reno-protective treatments was low. These findings point to a need for earlier detection, targeted interventions and broader implementation of effective therapies to reduce kidney disease burden in this population.