Table 3.

GEE Results: Effects of Regional Patient and Dialysis Facility Composition on Percent of Dialysis Facilities Offering Peritoneal Dialysis Service, 1995–2003

N = 2,448 HRR-years	β	(95% CI)	P	χ2	P
ESRD patient composition				36.42	<0.0001
Incidence (per 10,000 pop)	−0.90	(−2.07, 0.28)	0.1
Race / ethnicity (ref: White)
% African American	−0.26	(−0.39, −0.13)	0.0001
% Asian	−0.26	(−0.57, 0.05)	0.1
% Other race	−0.62	(−1.05, −0.20)	0.004
% Hispanic ethnicity	−0.16	(−0.39, 0.07)	0.2
% Non-elderly	−0.14	(−0.55, 0.28)	0.5
% Employed	−0.49	(−1.18, 0.19)	0.2
Dialysis facility composition				15.09	0.01
% For-profit owned	−0.002	(−0.06, 0.05)	0.9
% Chain-affiliated	−0.04	(−0.07, 0.004)	0.08
% Freestanding	0.02	(−0.05, 0.08)	0.6
% Urban location	0.11	(0.05, 0.17)	0.0006
% Ownership change	−0.02	(−0.05, 0.02)	0.4
Other regional characteristics				22.53	<0.0001
Per capita income	0.76	(0.26, 1.27)	0.003
Healthcare provider density	2.82	(−1.47, 7.12)	0.2
Dialysis market competition	−15.96	(−25.23, −6.69)	0.0007

Notes:

1. Covariates in the multivariate model are lagged by one year of the dependent variable.
2. The statistical model also controlled for year indicators (not shown).
3. ESRD incidence is modeled because PD may be more appropriate for early dialysis patients or those with residual renal function. However, modeling ESRD prevalence (in lieu of incidence) on PD supply yielded similar results.
4. To test groups of variables (e.g., patient composition, facility composition), we conducted Wald tests. Results of the Chi-square statistics and p-values are reported here.