Scientific Publications by FDA Staff

Biopharm Drug Dispos 2015 Dec;36(9):613-21

Kidney function changes with aging in adults: comparison between cross-sectional and longitudinal data analyses in renal function assessment.

Chung SM, Lee DJ, Hand A, Young P, Vaidyanathan J, Sahajwalla C

We evaluated if the renal function decline rates per year with age in adults vary based on two primary statistical analyses: cross-section (CS), using one observation per subject, and, longitudinal (LT), using multiple observations per subject along a time. A total of 16,628 records (3,946 subjects; age ranged from 30 to 92 years) of creatinine clearance and relevant demographic data were used. On an average, 4 samples per subjects were collected up to 2,364 days (mean: 793 days). A simple linear regression and random coefficient models were selected for CS and LT analyses, respectively. The renal function decline rates per year were 1.33 and 0.95 mL/min/year for CS and LT analyses, respectively, and, are slower when the repeated individual measurements are considered. Our study confirms that rates are different based on statistical analyses, and, that a statistically robust longitudinal model with a proper sampling design provides reliable individual as well as population estimates of the renal function decline rates per year with age in adults. In conclusion, our findings indicated that one should be cautious in interpreting the renal function decline rate with aging information because its estimation was highly depended on the statistical analyses. From our analyses, a population LT analysis (e.g., random coefficient model) is recommended if individualization is critical, such as a dose adjustment based on the renal function during a chronic therapy.