Cystatin C as a predictor of mortality in elderly patients with chronic kidney disease

Figures & data

Figure 1. Hazard ratios for death for different markers of kidney function in elderly CKD patients. CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration; BIS: Berlin Initiative Study; FAS: full age spectrum.

Table 1. Baseline characteristics of our patients.

Number of patients	58
Males/females	29/29
Age (years)	73.0 ± 4.8
BMI (kg/m^2)	28.3 ± 5.2
Serum creatinine (mg/dl)	1.62 ± 0.5
Serum cystatin C (mg/l)	1.79 ± 0.5
Measured GFR through ^51CrEDTA clearance (ml/min/1.73 m^2)	53.3 ± 17.4;
	range: 30–86
Estimated GFR through CKD-EPI creatinine equation (ml/min/1.73 m^2)	40.1 ± 14.0
Estimated GFR through BIS2 equation (ml/min/1.73 m^2)	38.9 ± 10.7
Estimated GFR through FAS creatinine equation (ml/min/1.73 m^2)	43.8 ± 13.8
Estimated GFR through FAS cystatin C equation (ml/min/1.73 m^2)	40.1 ± 11.7

Certain results are presented as mean ± SD and range.

Table 2. Baseline characteristics of patients who died and those who survived.

Patients	Died	Survived
Number of patients	47	11
Males/females	24/23	5/6
Age (years)	73.5 ± 4.9	70.7 ± 2.9
BMI (kg/m^2)	28.4 ± 5.4	27.8 ± 4.2
Serum creatinine (mg/dl)	1.71 ± 0.5	1.24 ± 0.2
Serum cystatin C (mg/l)	1.88 ± 0.6	1.41 ± 0.2
Measured GFR through ^51CrEDTA clearance (ml/min/1.73 m^2)	50.7 ± 16.7;	64.7 ± 16.5;
	range: 30–86	range: 38–82
Estimated GFR through CKD-EPI creatinine equation (ml/min/1.73 m^2)	37.3 ± 12.9	52.1 ± 12.6
Estimated GFR through BIS2 equation (ml/min/1.73 m^2)	36.9 ± 10.5	47.6 ± 6.6
Estimated GFR through FAS creatinine equation (ml/min/1.73 m^2)	41.1 ± 13.3	55.3 ± 9.8
Estimated GFR through FAS cystatin C equation (ml/min/1.73 m^2)	38.4 ± 12.1	47.3 ± 5.5

Certain results are presented as mean ± SD and range.

Table 3. Cox regression analysis for risk of death based on different markers of kidney function in elderly CKD patients.

Marker of kidney function	Beta coefficient	HR	95% CI	p Value
^51CrEDTA clearance	0.022	1.022	1.004–1.042	.015
Serum creatinine	0.013	1.013	1.006–1.019	.001
Serum cystatin C	0.707	2.028	1.267–3.241	.003
CKD-EPI creatinine equation	0.047	1.048	1.019–1.076	.001
BIS2 equation	0.053	1.055	1.021–1.088	.001
FAS creatinine equation	0.045	1.046	1.017–1.074	.001
FAS cystatin C equation	0.039	1.039	1.010–1.071	.009

HR: hazard ratio; CI: confidence interval; CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration; BIS: Berlin Initiative Study; FAS: full age spectrum.