Original Article
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©2014 Baishideng Publishing Group Co. , Limited. All rights reserved.
World J Nephrol. Feb 6, 2014; 3(1): 6-15
Published online Feb 6, 2014. doi: 10.5527/wjn.v3.i1.6
Table 1 Clinical characteristics at renal biopsy n (%)
Total n = 45Age (yr) (range) 58.3 ± 13.3 (28-84) Sex (men) 32 (71.1) Diabetes type 2 38 (84.4) Diabetes duration (yr) (range) 9.6 ± 7.8 (0-35) BMI (kg/m2 ) (range) 29.3 ± 5.3 (27.8-47.8) Obesity BMI > 30 kg/m2 18 (40.9) Hypertension (yes) 42 (93.3) Smoker, active or past (yes) 34 (75.6) Dyslipidemic (yes) 33 (73.3) Ischemic heart disease (yes) 7 (15.6) CVA (yes) 6 (13.3) Peripheral arterial disease (yes) 8 (17.8) Any CVD 16 (35.6) Hematuria (yes) 18 (41.9) Serum albumin (g/dL) (range) 3.4 ± 0.7 (2-5) HbA1c% (range) 6.5 ± 1.4 (4.1-9.3) Total cholesterol (mg/dL) 177.9 ± 58.7 Previous nephrology care (yr) (range) 1.21 ± 2.4 (0-12) RAASI treatment 40 (88.9) Statin treatment 33 (73.3) Antiplatelet drug treatment 21 (46.7)
Table 2 Renal parameters and evolution n (%)
Previous renal data (n = 39) Renal biopsy (n = 45) End of follow-up (n = 24) Time prior to biopsy (mo) (range) 7.3 ± 5.2 (1.1-24.1) Follow-up period (yr) (range) 3.4 ± 2.9 (0.2-11.8) Renal biopsy indication RPKI 8 (17.8) Nephrotic proteinuria 28 (62.2) CKD 9 (20) Serum creatinine (mg/dL) (range) 1.6 ± 0.8 2.3 ± 1.5 2.3 ± 1.8 (0.8-4.5) (0.8-6) (0.7-9.1) eGFR (mL/min per 1.73 m2 ) (range) 51.4 ± 20.9 39.1 ± 22.5 40.8 ± 25 (14.7-97.6) (8.1-101.2) (5.1-107.1) 1 eGFR categoryG5 < 15 7 (15.6) 24 (53.3) G4 15-30 8 (17.8) 6 (13.3) G3b 30-45 15 (33.3) 5 (11.1) G3a 45-60 7 (15.6) 7 (15.6) G2 60-90 7 (15.6) 1 (2.2) G1 > 90 1 (2.2) 2 (4.4) > 25% drop in eGFR prior to biopsy 13 (33.3) 2 Proteinuria (range)3.7 ± 3.4 4.5 ± 2.7 (0-12.9) (1-8.9) 3 Proteinuria categoryA1 < 150 3 (8.8) 0 A2 150-500 2 (5.9) 4 (8.9) A3 > 500 29 (85.3) 41 (91.1) RRT 2 5 21 (46.7) 4 CKD progression7 (15.6) eGFR improvement > 25% 4 (8.9) Exitus 5 (11.1)
Table 3 Clinical and histopathological findings according to glomerular classification of diabetic nephropathy n (%)
I-IIa-IIb (n = 18) III (n = 23) IV (n = 4) Age (yr) 59.9 ± 12.2 58.1 ± 14.1 52.3 ± 15.4 Years of diabetes 9.1 ± 7.4 9.3 ± 6.3 15.1 ± 18 BMI (kg/m2 ) 29 ± 4.9 30.1 ± 6 26.8 ± 2.4 Serum creatinine (mg/dL) 2 ± 1.2 2.2 ± 1.4 4.4 ± 1.9 eGFR (mL/min per 1.73 m2 ) 42.3 ± 21.9 40.4 ± 22.9 17.6 ± 12.3 HbA1c (%) 6.7 ± 1.4 6.3 ± 1.3 6.7 ± 2 Proteinuria (g/d) 3.1 ± 2.6 5.2 ± 4 4.7 ± 5.6 Serum albumin (g/dL) 3.6 ± 0.7 3.3 ± 0.7 2.9 ± 0.7 Serum cholesterol (mg/dL) 165.4 ± 71.6 191.5 ± 34.6 213 ± 0 Hypertension 16 (88.9) 22 (95.7) 4 (100) Diabetic retinopathy 7 (38.9) 9 (39.1) 2 (50) CVD 7 (38.9) 6 (26.1) 3 (75) RPKI 0 6 (33.3) 7 (30.4) Patients with renal events 9 (50) 15 (65.2) 4 (100) RRT 6 (33.3) 11 (47.8) 4 (100) 1 Years from biopsy to renal event4.2 ± 1.2 3.4 ± 1.4 0.4 ± 0.4 % of global glomerulosclerosis 18.1 ± 12.8 18.4 ± 15.1 77.3 ± 16.9 Interstitial fibrosis 0 1 (5.6) 0 0 and tubular atrophy 1 10 (55.6) 13 (56.5) 0 2 5 (27.8) 9 (39.1) 1 (25) 3 2 (11.1) 1 (4.3) 3 (75) Interstitial inflammation 0 3 (16.7) 0 0 1 14 (77.8) 22 (95.7) 4 (100) 2 1 (5.6) 1 (4.3) 0 Arteriolar hyalinosis 0 1 (5.6) 1 (4.3) 1 (25) 1 3 (16.7) 2 (8.7) 0 2 14 (77.8) 20 (87) 3 (75) Large vessel arteriosclerosis (yes) 17 (94.4) 19 (86.4) 4 (100)
Table 4 Clinical differences at the time of biopsy between silent and non-silent diabetic nephropathy n (%)
Non-silent DN (n = 20) Silent DN (n = 25) P valueAge (yr) 55.8 ± 12.2 60.3 ± 14.1 Sex (women) 5 (25) 8 (32) BMI (kg/m2 ) 30.9 ± 6.3 28 ± 4.1 T2 DM 17 (85) 21 (84) Duration of diabetes (year) 12.5 ± 5.3 7 ± 8.9 0.005 Follow-up period (year) 3.4 ± 3.5 3.5 ± 2.7 Smoking, active or past 16 (80) 18 (72) Retinopathy 8 (40) 10 (40) CVD 6 (30) 10 (40) HbA1c (%) 7 ± 1.2 6.2 ± 1.5 0.03 Serum creatine at biopsy (mg/dL) 1.8 ± 1 2.7 ± 1.6 0.03 eGFR at biopsy (mL/min per 1.73 m2 ) 47 ± 22.5 32.9 ± 20.8 0.04 Proteinuria (g/d) 3.5 ± 2.6 5 ± 4.3 Hematuria 8 (44.4) 10 (40) RPKI 3 (15) 12 (48) 0.03 CKD progression 3 (15) 10 (50) 0.04 Renal events 8 (40) 20 (80) 0.01 Histopathological class AP III-IV 9 (45) 18 (72) Glomerular sclerosis percentage 18.8 ± 14.3 27.2 ± 26.4 IFTA 0-1 12 (60) 12 (48) IFTA 2 7 (35) 8 (32) IFTA 3 1 (5) 5 (20) Severe arteriolar hyalinosis 15 (75) 22 (88) Large vessel arteriosclerosis 18 (94.7) 22 (88) RAASI treatment 18 (90) 22 (88) Statins treatment 15 (75) 18 (72)
Table 5 Multivariate Cox proportional model of renal end point by the variable silent diabetic nephropathy
Variables in the equation HR 95%CI Lower Upper CVD 3.943 1.649 9.429 HbA1c% 0.724 0.516 1.016 Silent DN 2.137 0.819 5.573
Table 6 Univariate Cox proportional hazard analysis of renal end point, according to clinical variables
HR 95%CI P valueLower Upper Age (yr) 1.00 0.97 1.03 Sex (men) 1.19 0.50 2.85 Diabetes type (2/1) 0.76 0.31 1.91 Diabetes duration (years) 1.01 0.95 1.07 BMI < 30 (yes/no) 2.94 1.09 7.69 0.03 Smoker (yes/no) 0.92 0.34 2.50 Hypertension (yes/no) 1.01 0.13 7.69 CVD (yes/no) 4.56 1.94 10.69 0.000 Retinopathy (yes/no) 1.24 0.56 2.75 Baseline Serum creatinine (mg/dL) 2.18 1.14 4.16 0.02 Baseline eGFR (mL/min per 1.73 m2 ) 0.98 0.95 1.00 1 Baseline proteinuria (g/g)1.12 0.98 1.27 eGFR drop > 25% before biopsy 3.96 1.54 10.18 0.004 Serum creatinine (mg/dL) at biopsy 2.97 1.91 4.61 0.000 eGFR (mL/min per 1.73 m2 ) at biopsy 0.94 0.92 0.97 0.000 RPKI 2.74 1.21 6.24 0.02 2 Proteinuria at biopsy (g/d)1.09 0.97 1.23 Hematuria 1.65 0.72 3.82 Serum albumin (g/dL) 0.75 0.41 1.35 HbA1c % (< 7/≥ 7) 3.37 1.23 9.25 0.02 Total cholesterol (mg/dL) 0.98 0.96 1.01 RAASI treatment (yes/no) 0.59 0.22 1.59 Statin treatment 0.66 0.27 1.62 Silent DN 3.04 1.26 7.3 0.02
Table 7 Univariate Cox proportional hazard analysis of renal end point, according to histological variables
HR 95%CI P valueGlomerular class III/I-IIa-IIb 1.2 0.5 2.9 IV/I-IIa-IIb 5.6 1.6 19.7 0.007 IV/III 4.6 1.4 15.1 0.01 % of global glomerulosclerosis 1.0 1.0 1.0 0.01 IFTA (> 25 ≤ 25%) 1.2 0.5 2.5 Arteriolar hyalinosis Severe/mild 0.7 0.2 2.2 Large vessel arteriosclerosis (yes) 1-2/0 1.2 0.4 4.1
Table 8 Multivariate Cox proportional hazard model of renal end point, adjusted for age and sex
HR 95%CI for HR P valueLower Upper CVD 2.75 1.07 7.11 0.036 RPKI 1.29 0.46 3.64 0.626 eGFR (10 mL/min per 1.73 m2 ) 1.96 1.28 3.00 0.001 HbA1c% (< 7/≥ 7) 2.88 0.98 8.44 0.054