Table 2.
Association of Demographic, and Laboratory Characteristics with Cystatin C Tertiles and Creatinine Groups
| Cystatin C Tertiles* |
Creatinine Groups† |
|||||||
|---|---|---|---|---|---|---|---|---|
| Mean (SD)‡ | Tertile 1 <0.88mg/L (N=80) |
Tertile 2 88-1.05mg/L (N=85) |
Tertile 3 ≥1.06 mg/L (N=85) |
P-value | Group1 (N=102) |
Group2 (N=89) |
Group3 (N=59) |
P-value |
| Age (years) | 41.6 (4.8) | 40.8 (5.5) | 43.0 (5.0) | 0.02 | 41.7 (5.6) | 41.0 (5.0) | 43.1 (4.4) | 0.07 |
| % Female | 44 | 22 | 26 | 0.006 | 24 | 28 | 46 | 0.01 |
| Race(%): | ||||||||
| African American | 43 | 31 | 22 | 0.1 | 27 | 30 | 41 | 0.03 |
| White | 41 | 55 | 61 | 52 | 55 | 51 | ||
| Hispanic | 10 | 8 | 13 | 18 | 8 | 2 | ||
| Other | 6 | 6 | 4 | 3 | 7 | 7 | ||
| BMI (kg/m2) | 26.8 (6.8) | 27.1 (4.8) | 25.5 (4.1) | 0.2 | 26.3 (5.1) | 26.7 (5.8) | 26.5 (5.3) | 0.7 |
| Creatinine (mg/dl) | 0.68 (0.17) | 0.76 (0.18) | 0.85 (0.27) | 0.006 | 0.60 (0.12) | 0.80 (0.12) | 1.00 (0.23) | <0.0001 |
| Cystatin C (mg/L) | 0.80 (0.07) | 0.97 (0.05) | 1.30 (0.26) | <0.0001 | 0.97 (0.19) | 0.99 (0.20) | 1.18 (0.36) | <0.0001 |
| eGFRcreat(ml/min/1.73m2) | 131 (37) | 122 (46) | 108 (49) | <0.0001 | 155 (49) | 105 (12) | 81 (15) | <0.0001 |
| eGFRcys (ml/min/1.73m2) | 101 (11) | 80 (5) | 58 (10) | <0.0001 | 83 (18) | 81 (19) | 69 (20) | <0.0001 |
| HCVAntibody (%) | 20.6 | 36.4 | 56.6 | <0.0001 | 39.0 | 29.6 | 50.9 | 0.04 |
| ALT (IU/L) | 37 (30) | 40 (33) | 53 (47) | 0.001 | 45 (42) | 42 (36) | 44 (34) | 0.4 |
| CD4 cell count (cells/mm3) | 522 (262) | 434 (228) | 373 (303) | 0.0002 | 446 (272) | 489 (299) | 367 (208) | 0.05 |
| Log10 viral load (copies/ml) | 2.48 (0.45) | 2.74 (0.75) | 3.25 (1.21) | <0.0001 | 2.85 (0.95) | 2.80 (0.89) | 2.81 (0.94) | 1.0 |
| % undetectable viral load | 84 | 66 | 52 | 0.0001 | 68 | 69 | 66 | 1.0 |
| IDU ever (%) | 17.5 | 24.7 | 51.8 | <0.0001 | 30 | 25 | 44 | 0.04 |
| Fat Free Mass (kg) | 56.5 (11.3) | 59.5 (10.5) | 56.7 (10.3) | 0.1 | 58.1 (10.5) | 58.9 (11.3) | 54.6 (9.9) | 0.9 |
| Fat Free Mass Percent | 74.9 (11.0) | 75.4 (10.7) | 75.5 (10.3) | 1.0 | 75.3 (10.5) | 76.6 (11.0) | 73.1 (10.2) | 0.1 |
| Years HIV Positive | 9.0 (4.8) | 8.7 (4.1) | 10.0 (4.3) | 0.1 | 9.0 (4.4) | 8.9 (4.6) | 10.3 (4.3) | 0.2 |
| Systolic Blood Pressure | 116 (14) | 119 (15) | 118 (18) | 0.7 | 118 (14) | 117 (15) | 118 (19) | 0.8 |
| Diastolic Blood Pressure | 75 (10) | 76 (8) | 76 (12) | 0.7 | 74 (8) | 76 (11) | 77 (13) | 0.5 |
| Albumin | 4.08 (0.31) | 3.96 (0.36) | 3.80 (0.49) | 0.0001 | 3.93 (0.44) | 3.94 (0.36) | 3.96 (0.45) | 0.9 |
| Hemoglobin | 13.9 (1.6) | 14.1 (1.8) | 13.9 (1.8) | 0.6 | 14.0 (1.7) | 14.1 (1.7) | 13.7 (1.9) | 0. 5 |
| % on Tenofovir | 10.0 | 14.1 | 15.3 | 0.6 | 9 | 13 | 20 | 0.1 |
| % on Indinavir | 12.5 | 7.1 | 10.6 | 0.5 | 9 | 13 | 7 | 0.4 |
| CRP§ | 2.23 (2.56) | 1.98 (1.80) | 3.23 (3.83) | 0.4 | 2.46 (2.27) | 2.06 (2.60) | 2.70 (3.44) | 0.3 |
Abbreviations used in this table: standard deviation (SD), body mass index (BMI), estimated glomerular filtration rate based on the Modification of Diet in Renal Disease estimating equation (eGFRcreat), estimated GFR based on the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin estimating equation (eGFRcys), hepatitis C virus (HCV), hepatitis B surface antigen (HBSAg), alanine aminotransferase (ALT), injection drug use (IDU), human immunodeficiency virus (HIV), C-reactive protein (CRP).
To convert to SI units: for creatinine mg/dl to µmol/L, multiply value by 88.4; for albumin g/dL to g/L multiply value by 10; for hemoglobin g/dL to g/L, multiply value by 10.
Normal range for cystatin C is considered to be <1.00. Cystatin C was normally distributed with a mean (SD) of 1.03 (0.26) mg/L and range 0.62–2.42 mg/L.
Creatinine groups were created using sex specific cut-offs of standardized creatinine: Group 1 had creatinine ≤ 0.53 if female and ≤ 0.73 if male; Group 2 had creatinine > 0.53 and <0.7 if female, and >0.73 and <0.93 if male; Group 3 had creatinine ≥ 0.7 if female and ≥ 0.93 if male. These groups are not tertiles but come as close to tertiles as possible given the resolution and spread of the data.
Values represent mean (SD) unless otherwise indicated.
Of those in cystatin tertile 1, 2, and 3, the number of participants with available CRP was 28, 40, and 25 respectively. Of those in creatinine groups 1, 2, and 3, the number of participants with available CRP was 36, 32,and 25 respectively.