Serum cystatin C in the aged: relationships with health status.
BACKGROUND
Serum cystatin C (Cys C) is claimed to be superior to serum creatinine (Cr) in estimating glomerular filtration rate, but its utility in assessing renal function in the polymorbid elderly needs to be evaluated.


METHODS
In a cross-sectional, community-based survey performed in Lieto in southwestern Finland, Cys C, Cr, and urinary albumin-creatinine ratio (ACR) were measured in 1,260 subjects aged 64 to 100 years. Associations of demographic characteristics and health status factors with levels of Cys C, Cr, and ACR were assessed by means of linear models.


RESULTS
In men, hypertension, coronary heart disease, urinary infection, rheumatoid arthritis, glucocorticoid treatment, older age, and lower functional status were found to be significant predictors of higher Cys C values, whereas hypertension, coronary heart disease, urinary infection, older age, and increasing body mass index (BMI) significantly predicted higher Cr values. Among women, corresponding factors were hypertension, glucocorticoid treatment, age, functional status, and BMI for Cys C and hypertension, BMI, and age for Cr. Diabetes was significantly associated only with ACR. These factors explained 35% of variation in Cys C values in men and 34.5% in women versus only 14.8% and 11.3% for Cr, respectively.


CONCLUSIONS
Glucocorticoid treatment was recognized as an independent Cys C-increasing factor, presumably nonglomerular. In comparison with Cys C, a considerably greater proportion of total variation in Cr values seems to be explained by extrarenal factors.
Wasén
Elise
E
Institute of Clinical Medicine, General Practice, University of Turku, Turku, Finland. elise.wasen@utu.fi
Isoaho
Raimo
R
Mattila
Kari
K
Vahlberg
Tero
T
Kivelä
Sirkka-Liisa
SL
Irjala
Kerttu
K
D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000453:epidemiology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000453:epidemiology; D015415:Biomarkers; D003327:Coronary Disease / Q000097:blood / Q000453:epidemiology; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005387:Finland / Q000453:epidemiology; D005938:Glucocorticoids / Q000494:pharmacology; D006304:Health Status; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000453:epidemiology; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000453:epidemiology; D011237:Predictive Value of Tests; D012307:Risk Factors; D014552:Urinary Tract Infections / Q000097:blood / Q000453:epidemiology
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D005938:Glucocorticoids; D003404:Creatinine