Table 1.

Patient demographics

VariableAll Patients (n=872)cFLC Quartile 1 (<49.4 mg/L)cFLC Quartile 2 (49.4–68.8 mg/L)cFLC Quartile 3 (68.9–100.7 mg/L)cFLC Quartile 4 (>100.7 mg/L)P Value
Age, yr66 (55–74)64 (54–71)65.7 (54–74.75)66 (56–74)68 (56–76.45)0.14
Men61.7%n=119 (54.6%)n=137 (62.8%)n=132 (60.6%)n=150 (68.8%)<0.001
Primary renal disease
 Diabetes15.4%n=17 (7.8%)n=35 (16.1%)n=48 (22%)n=42 (19.3%)<0.001
 ADPKD7.0%n=8 (3.7%)n=18 (8.3%)n=13 (6%)n=10 (4.6%)
 Vascular22.5%n=57 (26.1%)n=67 (30.7%)n=60 (27.5%)n=59 (27.1%)
 GN19.4%n=12 (5.5%)n=9 (4.1%)n=10 (4.6%)n=6 (2.8%)
 Pyelonephrtitis8.0%n=18 (8.3%)n=15 (6.9%)n=18 (8.3%)n=15 (6.9%)
 Other14.0%n=58 (26.6%)n=49 (22.5%)n=39 (17.9%)n=61 (28%)
 Unknown13.7%n=48 (22%)n=25 (11.5%)n=30 (13.8%)n=25 (11.5%)
CVD
 Yesn=75 (34.4%)n=97 (44.5%)n=95 (43.6%)n=101 (46.3%)n=75 (34.4%)<0.001
Diabetes
 Yesn=51 (23.4%)n=62 (28.4%)n=88 (40.4%)n=79 (36.2%)n=51 (23.4%)<0.001
Smoking history
 Nevern=77 (35.3%)n=73 (33.5%)n=74 (33.9%)n=59 (27.1%)n=77 (35.3%)<0.001
 Formern=122 (56%)n=119 (54.6%)n=112 (51.4%)n=121 (55.5%)n=122 (56%)
 Currentn=19 (8.7%)n=26 (11.9%)n=31 (14.2%)n=35 (16.1%)n=19 (8.7%)
Systolic BP (mmHg)134 (122–150)131 (121.5–145.5)132 (120.75–144)138 (123–152)136 (122–152)0.09
Diastolic BP (mmHg)75 (66–82)78 (68.5–83)76 (68–80)72 (62–81)74 (66–82)0.04
eGFR (ml/min per 1.73 m2)30 (21–41)42.94 (33.48–49.08)33.22 (25.72–42.36)25.8 (19.54–35.08)19.99 (15.43–27.51)<0.001
ΔeGFR (ml/min per 1.73 m2 per yr)−1.16 (−2.77–0.19)−0.07 (−1.78–1.8)−0.99 (−2.29–0.2)−1.63 (−2.85 to −0.04)−1.9 (−3.75 to −0.56)<0.001
Phosphate (mg/dl)3.50 (2.73–4.03)3.28 (2.94–3.72)3.47 (3.07–3.96)3.62 (3.10–4.15)3.75 (3.25–4.34)<0.001
Corrected calcium (mg/dl)9.10 (8.82–9.42)9.18 (8.86–9.46)9.14 (8.90–9.42)9.06 (8.74–9.38)9.02 (8.74–9.34)0.05
Parathyroid hormone (mg/L)63 (37–112)43 (24–68)54 (34–90.5)74 (44.25–121.75)97 (51–166)<0.001
Urea (mg/dl)37.8 (28.3–51.8)28.2 (22.9–35.2)35.6 (28–45.4)44.5 (32.6–56.5)48.9 (38.2–66.3)<0.001
Sodium (mmol/L)141 (139–143)141 (140–143)141 (139–142)141 (139–142)141 (139–143)0.08
Potassium (mmol/L)4.8 (4.4–5.2)4.7 (4.3–5.07)4.8 (4.4–5.2)4.8 (4.4–5.3)5 (4.5–5.4)<0.001
Total random cholesterol (mg/dl)166 (139–189)174 (155–201)170 (147–193)159 (135–184)155 (128–182)<0.001
Hemoglobin (g/L)124 (114–136)130 (118.25–139.75)126 (117–137)123 (113–133.75)118 (109–128)<0.001
Albumin (g/L)43 (40–45)44 (42–46)43 (41–45)43 (40–45)42 (39–43.75)<0.001
PCr (mg/mmol)25.4 (12.3–69.2)20 (10–37.5)30 (10–70)40 (20–107.5)80 (30–167)0.01
ESR (mm/h)22 (11–40)13 (8–27)19 (11–35)24 (14–39)33 (18–54)<0.001
κFLC (mg/L)37.4 (25.6–52.6)21.05 (17.33–23.64)31.41 (28.13–34.47)45.17 (40.17–49.42)69.45 (58.48–83.19)<0.001
λFLC (mg/L)32.1 (23.3–45.8)19.23 (15.91–22.19)27.31 (24.28–30.44)38.2 (33.71–41.91)62.13 (52.25–77.24)<0.001
κ\λFLC ratio1.12 (0.95–1.32)1.08 (0.94–1.22)1.13 (0.97–1.37)1.15 (1.02–1.37)1.12 (0.9–1.35)<0.001
cFLC (mg/L)68.9 (49.4–100.9)41.45 (33.97–45.5)58.97 (53.8–64.38)81.95 (75.21–90.1)128.15 (113.35–157.09)<0.001
  • Forty-four patients were not included in the progression analysis, because they had already reached the end point of GFR<9 ml/min per 1.73m2 at recruitment into the study; six patients did not have ΔGFR/RRT status recorded. Values for continuous variables are presented as medians (interquartile ranges). Where protein-to-creatinine ratio (PCr) data were not available, PCr was estimated from 24-h proteinuria on the basis of the assumption that a PCr of 100 mg/mmol is approximately 1 g per 24-h proteinuria. GN includes vasculitis. ADPKD, adult dominant polycystic kidney disease; CVD, cardiovascular disease (defined as angina pectoris, myocardial infarction, percutaneous or surgical coronary revascularization, stroke, or peripheral vascular disease); ESR, erythrocyte sedimentation rate; FLC, free light chain; cFLC, combined free light chain.