Table 1.

Comparison of Characteristics Between Patients Who Did Not Respond to an Invitation to Participate and Those Who Completed an Informed Consent Form^a

COMPARATOR	IC (N = 220)	PNR = 1,601	p VALUE
% Female	78.2%	74.1%	0.19
Mean (SD) age	48.6 (9.7)	47.2 (11.3)	0.06
% White	75.9	78.0	0.21
% Married	61.4	57.7	0.30
Census-based mean (SD) household incomeb	$68,896.00($23,349.00)	$69,714.31($23,544.30)	0.63
Census-based % with at least a college degreeb	27.2	26.8	0.68
Census-based % with commercial health insurancec	65.1	61.1	0.52
Mean (SD) Charlson Comorbidity Index	0.90 (1.20)	0.95 (1.30)	0.55
% Charlson = 0	59.1	58.4	0.85
Median (interquartile range) number of Mellen Center physician or advanced practice nurse/physician's assistant visits in preceding 12 months	9.0 (5.0, 18.0)	6.0 (3.0, 12.0)	0.001d

^aData based on date “Letter of Invitation” was mailed.

^bBased on zip code data from the 2000 US Census.

^cData missing for 46 patients (5 from IC, 41 from PNR).

^dSignificant.

IC, informed consent; PNR, patient nonresponder; SD, standard deviation.