The C-reactive protein Albumin ratio was not consistently associated with cardiovascular and all-cause mortality in two community-based cohorts of 70-year-olds

Figures & data

Table 1. Baseline characteristics of the participants in the included cohorts.

	PIVUS	ULSAM
	(n = 912)	(n = 924)
Age, years, mean (SD)	70.2 (0.15)	71.0 (0.62)
Sex, female, %	50	0
BMI, kg/m^2, %:
<18.5	0.88	0.43
18.5–24.9	32.2	36.8
25–29.9	45.0	51.5
≥30	21.9	11.3
Systolic BP, mm HG (SD)	150 (22.5)	133 (16.0)
LDL-cholesterol, mmol/L (SD)	3.40 (0.87)	3.90 (0.89)
Smoking status, %:
Non-smoker	48.0	80.7
Former smoker	41.2	NA
Current smoker	10.8	19.3
Diabetes, %	11.3	14.3
Physical activity level:
METs/week (SD)	259 (4.84)	NA
sedentary, %		3.14
moderate, %		33.7
regular, %		56.9
athletic, %		6.30
S-Albumin, g/L (SD)	40.3 (2.68)	43.6 (2.60)
S-C-reactive protein, mg/L (SD)	2.07 (2.75)	2.78 (2.79)
Interleukin-6 (IL-6), ng/L (SD)	1.84 (1.56)	NA
Excluded in analysis	66	0

Table 2. The relative risk of cardio-vascular mortality shown as hazard ratios (HRs) for CRP/Albumin ratio (CAR) in the PIVUS cohort (n = 846 observations) and the ULSAM cohort (n = 924 observations).

	PIVUS			ULSAM
	HR	95% CI	p>|z|	HR	95% CI	p>|z|
Model 1	1.19	1.04–1.36	0.0095	1.13	1.04–1.24	0.0064
Model 2	1.19	1.04–1.36	0.0096	1.13	1.03–1.23	0.0079
Model 3	1.18	1.02–1.35	0.0215	1.10	1.01–1.21	0.0301
Model 4	1.18	1.03–1.35	0.0162	1.12	1.03–1.23	0.0104
Model 5	1.17	1.02–1.34	0.0263
Model 6	1.14	0.99–1.31	0.063	1.07	0.98–1.17	0.14

Model 1 crude; Model 2 adjusted for age; Model 3 adjusted for age, sex (PIVUS) and BMI level; Model 4 adjusted for age and physical activity; Model 5 adjusted for age and inflammatory markers (PIVUS); and Model 6 adjusted for BMI level, smoking, systolic blood pressure, LDL-cholesterol, and diabetes.

Table 3. The relative risk of all-cause mortality shown as hazard ratios (HRs) for CRP/Albumin ratio (CAR) in the PIVUS cohort (n = 846 observations) and the ULSAM cohort (n = 924 observations).

	PIVUS			ULSAM
	HR	95% CI	p>|z|	HR	95% CI	p>|z|
Model 1	1.02	0.90–1.16	0.736	1.36	1.16–1.59	0.0001
Model 2	1.02	0.90–1.16	0.737	1.34	1.15–1.57	0.0002
Model 3	1.04	0.91–1.19	0.519	1.33	1.14–1.56	0.0003
Model 4	1.01	0.89–1.15	0.905	1.31	1.12–1.54	0.0007
Model 5	1.01	0.89–1.16	0.829
Model 6	1.01	0.89–1.15	0.919	1.31	1.12–1.54	0.0007

Model 1 crude; Model 2 adjusted for age; Model 3 adjusted for age, sex (PIVUS) and BMI level; Model 4 adjusted for age and physical activity; Model 5 adjusted for age and inflammatory markers (PIVUS); Model 6 adjusted for smoking, BMI level, systolic blood pressure, LDL-cholesterol, and diabetes.

Table 4. Harrell’s C-statistics for CRP-Albumin ratio (CAR) compared to CRP and Albumin alone, respectively, with cardio-vascular mortality as outcome in model adjusting for age and CVD risk factors; hazard ratios comparing Harrell’s C between the different biomarkers.

	CAR	CRP	Albumin	CAR-CRP	CAR-albumin
	Coeff (95% CI)	Coeff (95% CI)	Coeff (95% CI)	HR	HR
CVD-mortality
PIVUS	0.596 (0.540–0.652)	0.594 (0.538–0.651)	0.596 (0.539–0.654)	1.00 (1.00–1.01)	1.00 (0.99–1.01)
Adjusted for CVD-factors
ULSAM
Adjusted for CVD-factors	0.611 (0.573–0.649)	0.613 (0.575–0.650)	0.600 (0.561–0.638)	1.00 (0.99–1.01)	1.01 (1.00–1.02)

CVD-factors: smoking, BMI level, systolic blood pressure, LDL-cholesterol, and diabetes.

Data availability statement

Both the PIVUS and the ULSAM studies are listed in the SND (Swedish National Data Service). Access to data is limited, contact persons are for PIVUS Lars Lind ([email protected]) and for ULSAM Lars Lannfelt ([email protected]).