Older women with late-onset hypertension are at higher CKD risk than males

Background Females develop hypertension later and are less likely to receive chronic kidney disease (CKD) prevention treatments. The long-term impact of these differences remains unclear. We aimed to investigate sex-based differences in the in CKD outcomes among older adults with hypertension. Methods We conducted a population-based retrospective cohort study of adults aged ≥66 years with new hypertension using linked health data from Ontario, Canada (January 1, 2010, to December 31, 2021). The primary composite outcome was a 40% decline in estimated glomerular filtration rate (eGFR) or kidney failure. We used Cox proportional hazards models to calculate hazard ratios (HRs) and Fine-Gray models accounting for death as a competing risk (subdistribution HRs, sHRs). Results Incident hypertension developed in 121,490 individuals (57.7% female; mean age 73.1; mean eGFR 83.2 ml/min/1.73 m²; median follow-up 6.8 years), 17,343 (14.3%) experienced the composite kidney outcome. The crude incidence rate per 1,000 person-years was higher for females compared to males (22.0 in females vs. 21.1 in males; P<0.001). Females had a higher adjusted risk of the primary outcome, after accounting for death (sHR, 1.10 [95% CI, 1.07-1.14]). Females had a higher crude incidence of eGFR <60 ml/min/1.73 m² than males (66.6 vs. 59.4; P<0.001), and a higher adjusted risk (sHR, 1.15 [95% CI, 1.13-1.18]). For eGFR <45 ml/min/1.73 m², females had a higher crude incidence (19.2 vs. 17.5; P<0.001) and a higher adjusted risk (sHR, 1.13 [95% CI, 1.10-1.17]) compared to males. Conclusion Older females with new onset hypertension were more likely to develop a 40% decline in eGFR or kidney failure compared to older males. This study will inform hypertension management practices in aging populations.