Long-Term Health Outcomes Of People With Reduced Kidney Function In The Uk: A Modelling Study Using Population Health Data

BackgroundPeople with reduced kidney function have increased cardiovascular disease (CVD) risk. We present a policy model that simulates individuals' long-term health outcomes and costs to inform strategies to reduce risks of kidney and CVDs in this population.Methods and findingsWe used a United Kingdom primary healthcare database, the Clinical Practice Research Datalink (CPRD), linked with secondary healthcare and mortality data, to derive an open 2005-2013 cohort of adults (>= 18 years of age) with reduced kidney function (>= 2 measures of estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m(2) >= 90 days apart). Data on individuals' sociodemographic and clinical characteristics at entry and outcomes (first occurrences of stroke, myocardial infarction (MI), and hospitalisation for heart failure; annual kidney disease stages; and cardiovascular and nonvascular deaths) during follow-up were extracted. The cohort was used to estimate risk equations for outcomes and develop a chronic kidney disease-cardiovascular disease (CKD-CVD) health outcomes model, a Markov state transition model simulating individuals' long-term outcomes, healthcare costs, and quality of life based on their characteristics at entry. Model-simulated cumulative risks of outcomes were compared with respective observed risks using a split-sample approach. To illustrate model value, we assess the benefits of partial (i.e., at 2013 levels) and optimal (i.e., fully compliant with clinical guidelines in 2019) use of cardioprotective medications. The cohort included 1.1 million individuals with reduced kidney function (median follow-up 4.8 years, 45% men, 19% with CVD, and 74% with only mildly decreased eGFR of 60-89 mL/min/1.73 m(2) at entry). Age, kidney function status, and CVD events were the key determinants of subsequent morbidity and mortality. The model-simulated cumulative disease risks corresponded well to observed risks in participant categories by eGFR level. Without the use of cardioprotective medications, for 60- to 69-year-old individuals with mildly decreased eGFR (60-89 mL/min/1.73 m(2)), the model projected a further 22.1 (95% confidence interval [CI] 21.8-22.3) years of life if without previous CVD and 18.6 (18.2-18.9) years if with CVD. Cardioprotective medication use at 2013 levels (29%-44% of indicated individuals without CVD; 64%-76% of those with CVD) was projected to increase their life expectancy by 0.19 (0.14-0.23) and 0.90 (0.50-1.21) years, respectively. At optimal cardioprotective medication use, the projected health gains in these individuals increased by further 0.33 (0.25-0.40) and 0.37 (0.20-0.50) years, respectively. Limitations include risk factor measurements from the UK routine primary care database and limited albuminuria measurements.ConclusionsThe CKD-CVD policy model is a novel resource for projecting long-term health outcomes and assessing treatment strategies in people with reduced kidney function. The model indicates clear survival benefits with cardioprotective treatments in this population and scope for further benefits if use of these treatments is optimised.Author summaryWhy was this study done?Chronic kidney disease (CKD) is highly prevalent, and even mildly reduced kidney function increases cardiovascular and kidney disease risks and mortality.In people with CKD, reducing cardiovascular risk with widely available effective cardioprotective treatments (i.e., statins, hypertensives, and antiplatelets) is a key target.Lifetime policy models are needed to project long-term health outcomes and costs and prioritise treatment strategies.What did the researchers do and find?We used a large UK population healthcare database to identify a large open cohort (2005-2013) of 1.1 million individuals with reduced kidney function.We developed a policy model that projects the decline of kidney function, cardiovascular disease (CVD), mortality, healthcare costs, and quality of life using an individual's characteristics.The model achieved good risk discrimination and accurately predicted risks of cardiovascular events in patient categories by kidney function impairment (estimated glomerular filtration rate [eGFR] 60-89; 45-59; 30-44; 15-29; and <15 mL/min/1.73 m2 not on renal replacement therapy [RRT]) and by 10 geographic regions in England.To illustrate model use in this population, we assessed survival benefits with partial (0.06-1.25 extra years per person across patient categories) and optimal (0.10-0.55 extra years per person across patient categories) use of cardioprotective treatments.What do these findings mean?The model can be used to project long-term health outcomes in people with reduced kidney function and assess value of a range of treatment strategies. Further efforts to improve the use of cardioprotective medication are likely to improve life expectancy in this population.