Background: Little is known about the decline of kidney function in patients with normal kidney function at baseline. Our objectives were to (i) identify predictors of incident chronic kidney disease (CKD) and (ii) to estimate rate of decline in kidney function.
Methods: The study used a retrospective cohort of adult patients in a hypertension registry in an inner-city health care delivery system in Denver, Colorado. The primary outcome was development of incident CKD, and the secondary outcome was rate of change of estimated glomerular filtration rate (eGFR) over time.
Results: After a mean follow-up of 45 months, 429 (4.1%) of 10 420 patients with hypertension developed CKD. In multivariate models, factors that independently predicted incident CKD were baseline age [odds ratio (OR) 1.13 per 10 years, 95% confidence interval (CI), 1.03-1.24], baseline eGFR (OR 0.69 per 10 units, 95% CI 0.65-0.73), diabetes (OR 3.66, 95% CI 2.97-4.51) and vascular disease (OR 1.67, 95% CI 1.32-2.10). We found no independent association between age, gender or race/ethnicity and eGFR slope. In patients who did not have diabetes or vascular disease, eGFR declined at 1.5 mL/min/1.73 m(2) per year. Diabetes at baseline was associated with an additional decline of 1.38 mL/min/1.73 m(2).
Conclusions: Diabetes was the strongest predictor of both incident CKD as well as eGFR slope. Rates of incident CKD or in decline of kidney function did not differ by race or ethnicity in this cohort.