Abstract
BACKGROUND: High blood pressure(BP) is a modifiable risk factor for premature mortality, adverse cardiovascular outcomes and kidney diseases in individuals with type 2 diabetes(T2D). We studied the age-specific associations between BP and incident cardiovascular disease(CVD), chronic kidney disease(CKD), kidney failure, and all-cause death among individuals with T2D. METHODS: We included individuals with T2D who underwent structured diabetes assessment between 2000 and 2022 in Hong Kong Special Administrative Region, People's Republic of China. Participants were stratified by baseline age(18-44 years, 45-59 years, 60-74 years, and 75 years or older). Cox proportional hazard model was used to estimate hazard ratios for the risk of incident CVD, CKD, kidney failure and all-cause death associated with systolic blood pressure(SBP) and diastolic blood pressure(DBP) categories, referenced to SBP 120-129 mmHg and DBP 70-79 mmHg within each age stratum. Non-linear association between SBP/ DBP and clinical outcomes was modelled using restricted cubic splines(RCS). RESULTS: We included 429,740 individuals with T2D (mean age 61.9 years, 52.7% men, 75.3% pre-existing hypertension). SBP above 120-129 mmHg and DBP above 70-79 mmHg were associated with a proportional increase in risks for CVD, CKD, kidney failure and death across ages adjusted for demographics, diabetes duration, BMI, smoking status, HbA1c, lipids, albuminuria, history of CVD, CKD and use of BP-lowering medications. The strength of the risk associations was greatest in youngest age group and declined with increasing age. Among individual components of CVD, risks conferred by an incremental increase in SBP or DBP were high for hemorrhagic stroke. A 10 mmHg or 1-SD increase in SBP / DBP conferred a 1.2 to 1.5-fold increase in hazards for hemorrhagic stroke among individuals aged 18-44 years (p-interaction < 0.001). RCS indicated variable linear and nonlinear associations between SBP/DBP and CVD, kidney disease, or death across age categories. CONCLUSIONS: We observed heterogeneity in the relationship between BP and various clinical outcomes across ages in a diabetes population. Risk associations were strongest among young individuals, emphasising the importance of BP management in this population.