. Author manuscript; available in PMC: 2016 Aug 1.

Published in final edited form as: Kidney Int. 2016 Feb;89(2):450–458. doi: 10.1038/ki.2015.288

Table 3.

Independent risk factors for allograft failure within 5 years after the diagnosis of transplant glomerulopathy

Variable	Reference Category	Unit Change	Full Model^a			Final Model^b
Variable	Reference Category	Unit Change	Hazard Ratio	95% Confidence Interval	p- value	Hazard Ratio	95% Confidence Interval	p value
Serum creatinine at biopsy, mg/dl	-	Increase by 1 mg/dl	1.33	1.19–1.47	<0.001	1.35	1.22–1.49	<0.001
Proteinuria at biopsy, grams/day	<1 gram/day	>1 gram/day	1.73	0.94–3.20	0.07	1.62	0.90–2.92	0.10
Acute-tubulointerstitial score, i+t scores	i+t score=0	Increase in score by 1	1.04	0.91–1.19	0.49
Chronic-inflammation score, ci+ct+ti scores	ci+ct+ti score=0	Increase in score by 1	1.12	1.01–1.24	0.03	1.13	1.02–1.25	0.01
Chronic-arteriolar score, ah+cg scores	ah+cg score=1	Increase in score by 1	0.94	0.79–1.12	0.52
Glomerulosclerosis score, gs score	Gs score=0	Increase in score by 1	1.12	0.81–1.55	0.45

^a:

Based on the results of the univariate Cox analyses (Table 2) and principal component analysis (Figure 3), we included six variables in a multivariate Cox proportional hazard regression analyses.

^b:

In order to develop a prognostic index for allograft failure, we developed a final model from the full model. For this purpose, we sequentially removed each variable from the full model and assessed the change in model fit by the Likelihood-ratio test to test the significance of the individual variables controlling for all other variables. We chose a p-value of <0.1 by the Likelihood-ratio test, to assess the change in model fit. Removal of acute-tubulointerstitial score, chronic-arteriolar score or glomerulosclerosis score from the full model did not impact the model (p>0.1), whereas removal of serum creatinine, proteinuria or chronic-inflammation score impacted the model (p<0.1). Hence, we retained serum creatinine, proteinuria, and chronic-inflammation score in the final model. We confirmed the proportionality assumption of the final Cox model by the global test and by visual inspection of the Schoenfeld residual plots. The coefficients (ln[Hazard Ratio]) of serum creatinine (0.29), proteinuria (0.48) and chronic-inflammation (0.12) in the final model constituted the prognostic index represented by the equation: (0.29*serum creatinine)+(0.48*proteinuria)+ (0.12*chronic-inflammation score).