Table 3.

Comparison between the conventional Cox proportional hazards models and the structural marginal models for the assessment of the association of time-varying hyperparathyroidism, hypocalcemia, and hyperphosphatemia with allograft dysfunction

Cox proportional hazards model (adjusted)	HR	95% CI	P value
Hyperparathyroidism	2.94	1.82–4.74	<0.001
Hypocalcemia	1.31	0.92–1.87	0.132
Hyperphosphatemia	1.94	1.28–2.92	0.002
Marginal structural model (adjusted)
Hyperparathyroidism	2.74	1.71–4.38	<0.001
Hypocalcemia	1.47	1.04–2.09	0.030
Hyperphosphatemia	1.35	0.87–2.09	0.177

CI, confidence interval; HR, hazard ratio.

The models were adjusted for baseline and time-varying risk factors for allograft dysfunction (baseline confounders: primary kidney disease, sex, recipient age, donor source, year of transplantation, disease vintage, dialysis vintage, dialysis mode, graft sequence, cold ischemia time, body mass index Z score, and delayed graft function [stratified until and after 1 year posttransplant]); time-varying confounders: allograft rejection, spline for systolic blood pressure Z score.