Early onset of hypertension and increased relative risks of chronic kidney disease and mortality: two population-based cohort studies in United Kingdom and Hong Kong.

This study aimed to evaluate the association between hypertension (HT) onset age and later risks of chronic kidney diseases (CKD) and mortality. Adult patients without CKD from 2008 to 2013 were identified using electronic medical records from United Kingdom (UK) and Hong Kong (HK). Patients newly diagnosed with HT and those without were included in the HT and control groups, respectively. All subjects were stratified into six age groups (18-39, 40-49, 50-59, 60-69, 70-79, ≥80). Multivariable Cox proportional hazard regression, adjusted with baseline characteristics and fine stratification weights, was conducted to investigate the association between HT onset and risks of CKD, renal decline, end-stage renal disease (ESRD), and all-cause mortality. Subjects were followed up from baseline until an outcome event, death, or administrative end of the cohort, whichever occurred first. A total of 4,413,551 and 3,132,951 subjects were included in the UK and HK cohorts, respectively. HT was significantly associated with increased risks of outcome, but the hazard ratios (HRs) decreased with increasing onset age. In the UK cohort, the HRs (95% confidence intervals) for subjects aged 18-39 and ≥80 were 3.69 (3.53, 3.86) and 2.01 (1.96, 2.06) for CKD, 3.83 (3.60, 4.07) and 3.17 (2.97, 3.38) for renal decline, 17.26 (14.34, 20.77) and 2.55 (2.12, 3.07) for ESRD, 2.88 (2.66, 3.11) and 1.09 (1.07, 1.12) for mortality. The HK cohort exhibited a similar pattern. Our study concluded that early onset of HT significantly affects renal health later in life, while the contribution decreases with the onset age of HT.