Consecutive first-morning urine samples to measure change in the albumin-to-creatinine ratio: a pilot study of a home urine collection protocol

Table 4 Total sample size needed to detect a 10 to 20 % difference between two groups in the geometric mean of the percentage change in ACR under different scenarios

		Minimum detectable difference between groups
Number of urine samples at each time point (baseline and follow-up)	Log-scale standard deviation^a	10 %	15 %	20 %
One sample	0.59	984	414	220
Average of two consecutive samples	0.49	678	286	152
Average of three consecutive samples	0.50	706	298	158

Based on a type I error of 5 % and power of 80 %
^aStandard deviation of the log-transformed percentage change in the albumin-to-creatinine ratio between baseline and 3-month follow-up

ISSN: 2054-3581