Table 3.

Association of sickle cell trait protein risk score with incident kidney failure in those with and without sickle cell trait in Women's Health Initiative

Covariate Adjustment	With Sickle Cell Trait			Without Sickle Cell Trait			P for Interaction
	Cases/Total	OR (95% CI)	P Value	Cases/Total	OR (95% CI)	P Value
Age	19/592	1.42 (1.27 to 1.59)	<0.001	8/592	1.10 (0.94 to 1.27)	0.24	0.007
Age and baseline eGFR	13/429	1.38 (1.16 to 1.63)	<0.001	8/554	1.06 (0.90 to 1.25)	0.50	0.01
Age, baseline eGFR, smoking, diabetes, and hypertension	13/414	1.32 (1.10 to 1.58)	0.003	7/541	0.94 (0.77 to 1.14)	0.51	0.003

Note that the sample size of the analyses declined with each subsequent model because of missing covariate data. There were 201 individuals (38 with sickle cell trait and 157 without sickle cell trait) who were dropped from the second model because of missing baseline eGFR. An additional 28 individuals (15 with sickle cell trait and 13 without sickle cell trait) were dropped from the third model because of missing data for smoking, diabetes, or hypertension. OR, odds ratio; CI, confidence interval.