Background:
Chronic Kidney Disease (CKD) is an important public health issue and is associated with an increased risk of cardiovascular disease. Risk factors for CKD are well established, but most are typically assessed at or near the time of CKD diagnosis. Our hypothesis was that risk factors for CKD are present earlier in the course of the disease. We compared the prevalence of risk factors between CKD cases and controls at time points up to 30 years prior to CKD diagnosis.
Methods:
Participants were drawn from the Framingham Heart Study Offspring cohort. CKD was defined as an estimated glomerular filtration rate of ≤60ml/min/1.73m2. Incident CKD cases occurring at examination cycles 6, 7, and 8 were age- and sex-matched 1:2 to controls. Risk factors including systolic blood pressure (SBP), hypertension, lipids, diabetes, smoking status, body mass index (BMI) and dipstick proteinuria were measured at the time of CKD diagnosis and 10, 20 and 30 years prior. Logistic regression models, adjusted for age, sex, and time period, were constructed to compare risk factor profiles at each time point between cases and controls
Results:
During follow-up, 441 new cases of CKD were identified and these were matched to 882 controls (mean age 69.2 years, 52.4% women). Up to 30 years prior to CKD diagnosis, those who ultimately developed CKD were more likely to have hypertension (OR 1.74, CI 1.21-2.49), be obese (OR 1.74, CI 1.15-2.63) and have higher triglycerides (OR 1.43, CI 1.12-1.84, p=0.005 per 1 standard deviation increase). Each 10mmHg increase in SBP was associated with an OR of 1.22 for future CKD (95% CI 1.10-1.35) Additionally, cases were more likely to have diabetes (OR 2.90, CI 1.59-5.29) and be on antihypertensive therapy (OR 1.65, CI 1.14-2.40, p=0.009) up to 20 years prior to diagnosis. Increasing HDLc was associated with a lower risk of CKD (OR 0.84, CI 0.81-0.97 per 10mg/dl).
Conclusions:
As many as 30 years prior to diagnosis, risk factors for CKD are identifiable. In particular, modifiable risk factors such as obesity, hypertension and dyslipidemia are present early in the course of the disease. These findings demonstrate the importance of early identification of risk factors in patients at risk of CKD through a life-course approach.
Elevated body mass index as a risk factor for chronic kidney disease: current perspectives
