Associations between modest reductions in kidney function and adverse outcomes in young adults: retrospective, population based cohort study

Abstract

Objective To study age specific associations of modest reductions in estimated glomerular filtration rate (eGFR) with adverse outcomes. Design Retrospective, population based cohort study. Setting Linked healthcare administrative datasets in Ontario, Canada. Participants Adult residents (18-65 years) with at least one outpatient eGFR value (categorized in 10 unit increments from 50 mL/min/1.73m 2 to >120 mL/min/1.73m 2 ), with no history of kidney disease. Main outcome measures eGFRs and hazard ratios of composite adverse outcome (all cause mortality, any cardiovascular event, and kidney failure) stratified by age (18-39 years, 40-49 years, and 50-65 years), and relative to age specific eGFR referents (100-110 mL/min/1.73m 2 ) for ages 18-39 years, 90-100 for 40-49 years, 80-90 for 50-65 years). Results From 1 January 2008 to 31 March 2021, among 8 703 871 adults (mean age 41.3 (standard deviation 13.6) years; mean index eGFR 104.2 mL/min/1.73m 2 (standard deviation 16.1); median follow-up 9.2 years (interquartile range 5.7-11.4)), modestly reduced eGFR measurements specific to age were recorded in 18.0% of those aged 18-39, 18.8% in those aged 40-49, and 17.0% in those aged 50-65. In comparison with age specific referents, adverse outcomes were consistently higher by hazard ratio and incidence for ages 18-39 compared with older groups across all eGFR categories. For modest reductions (eGFR 70-80 mL/min/1.73m 2 ), the hazard ratio for ages 18-39 years was 1.42 (95% confidence interval 1.35 to 1.49), 4.39 per 1000 person years; for ages 40-49 years was 1.13 (1.10 to 1.16), 9.61 per 1000 person years; and for ages 50-65 years was 1.08 (1.07 to 1.09), 23.4 per 1000 person years. Results persisted for each individual outcome and in many sensitivity analyses. Conclusions Modest eGFR reductions were consistently associated with higher rates of adverse outcomes. Higher relative hazards were most prominent and occurred as early as eGFR <80 mL/min/1.73m 2 in younger adults, compared with older groups. These findings suggest a role for more frequent monitoring of kidney function in younger adults to identify individuals at risk to prevent chronic kidney disease and its complications.

Adults are just big kids: pediatric considerations for adult critical care nephrology

“…A recent study in young adults with mild GFR impairment have a higher risk for CKD, cardiovascular disease, and death [73 ▪ ]. Despite these risks, many studies have reported that children with AKI are not routinely followed long-term [74].…”

Estimated glomerular filtration rate and risk of all‐cause mortality

“…First, Hussain et al 2 investigated age‐specific associations of eGFR with adverse outcomes. By setting age‐specific eGFR reference as a control, the adjusted HR (95% CI) of modest reduction in eGFRs for composite adverse outcome (all‐cause mortality, any cardiovascular event, and kidney failure) in subjects aged 18–39, 40–49, and 50–65 were 1.42 (1.35–1.49), 1.13 (1.10–1.16), and 1.08 (1.07–1.09), respectively.…”