Introduction: The kidney is affected by immunoglobulin light chain amyloidosis (AL) in more than 50% of patients who present with the disease, but long-term predictors for and outcomes after renal replacement therapy have not been well described in this patient group

Patients: 145 patients with AL who participated in Mayo Clinic treatment trials and were monitored for at least 11 years. No patient was lost to follow-up

Results: Among patients presenting with renal AL, 42% ultimately received renal replacement therapy compared with 5% of patients who did not have an initial presentation involving the kidney.

Table 1. Monoclonal Protein Studies in 145 Patients With Immunoglobulin Light Chain Amyloidosisa

Patients, No. (%)
Monoclonal ProteinRenal Amyloid at Presentation (n=84)Nonrenal Amyloid at Presentation (n=61)
aP=.02 l more likely to cause renal presentation 
None 7 (8) 2 (3) 
k 6 (7) 12 (20) 
l 71 (85) 47 (77) 
Patients, No. (%)
Monoclonal ProteinRenal Amyloid at Presentation (n=84)Nonrenal Amyloid at Presentation (n=61)
aP=.02 l more likely to cause renal presentation 
None 7 (8) 2 (3) 
k 6 (7) 12 (20) 
l 71 (85) 47 (77) 
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Table 2. Characteristics of All 145 Patients With Immunoglobulin Light Chain Amyloidosis

Amyloid
Renal (n=84)Nonrenal (n=61)P Value
Abbreviations: IQR, interquartile range; NA, not applicable. 
a included in the definition of renal amyloidosis 
Patients with l immunoglobulin light chain amyloid were significantly more likely to have renal involvement and had significantly greater urinary protein loss than patients with κ or no monoclonal light chain amyloid 
Age, median (IQR), y 61 (52–67) 62 (55–68) .47 
Sex, male/female 52/32 40/21 .72 
24-hr urine protein loss, median (IQR), g/d 7.0 (4.4–11.7) 0.3 (0.1–6.4) NAa 
Creatinine, median (IQR), mg/dL 1.1 (0.9–2.2) 1.1 (0.9–1.3) .22 
Cardiac involvement (yes/no) 35/48 48/16 .0001 
Amyloid
Renal (n=84)Nonrenal (n=61)P Value
Abbreviations: IQR, interquartile range; NA, not applicable. 
a included in the definition of renal amyloidosis 
Patients with l immunoglobulin light chain amyloid were significantly more likely to have renal involvement and had significantly greater urinary protein loss than patients with κ or no monoclonal light chain amyloid 
Age, median (IQR), y 61 (52–67) 62 (55–68) .47 
Sex, male/female 52/32 40/21 .72 
24-hr urine protein loss, median (IQR), g/d 7.0 (4.4–11.7) 0.3 (0.1–6.4) NAa 
Creatinine, median (IQR), mg/dL 1.1 (0.9–2.2) 1.1 (0.9–1.3) .22 
Cardiac involvement (yes/no) 35/48 48/16 .0001 
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Table 3 Distribution of Urinary Protein and Creatinine Based on Monoclonal Protein

Monoclonal Protein
Testk (n=18)l (n=118)None (n=9)P Value
Abbreviation: IQR, interquartile range. 
Patients with renal amyloid who ultimately received dialysis support had significantly higher serum creatinine and 24-hour urine protein levels at presentation. Absence of cardiac involvement at diagnosis predicted an increased likelihood of dialysis 
All patients (N=145)     
24-hr urine protein loss, median (IQR), g/d 0.73 (0.16–2.37) 3.61 (0.35–7.8) 5.68 (0.3–12.2) .001 
Creatinine, median (IQR), mg/dL 1.1 (0.9–1.3) 1.1 (0.9–1.3) 1.5 (1.2–1.6) NS 
Patients with renal amyloid at presentation (n=84)     
24-hr urine protein loss, median (IQR), g/d 2.93 (1.1–5.0) 7.2 (4.8–11.8) 7.8 (3.8–12.6) .04 
Creatinine, median (IQR), mg/dL 1.0 (0.8–2.6) 1.1 (0.9–2.2) 1.5 (1.1–1.6) NS 
Monoclonal Protein
Testk (n=18)l (n=118)None (n=9)P Value
Abbreviation: IQR, interquartile range. 
Patients with renal amyloid who ultimately received dialysis support had significantly higher serum creatinine and 24-hour urine protein levels at presentation. Absence of cardiac involvement at diagnosis predicted an increased likelihood of dialysis 
All patients (N=145)     
24-hr urine protein loss, median (IQR), g/d 0.73 (0.16–2.37) 3.61 (0.35–7.8) 5.68 (0.3–12.2) .001 
Creatinine, median (IQR), mg/dL 1.1 (0.9–1.3) 1.1 (0.9–1.3) 1.5 (1.2–1.6) NS 
Patients with renal amyloid at presentation (n=84)     
24-hr urine protein loss, median (IQR), g/d 2.93 (1.1–5.0) 7.2 (4.8–11.8) 7.8 (3.8–12.6) .04 
Creatinine, median (IQR), mg/dL 1.0 (0.8–2.6) 1.1 (0.9–2.2) 1.5 (1.1–1.6) NS 
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Table 4 Characteristics of 84 Patients Presenting With Renal Amyloidosis

Dialysis
SubsequentlyNot Required
CharacteristicRequired (n=35)(n=49)P Value
Abbreviation: IQR, interquartile range. 
The median time from diagnosis to dialysis was 29.5 months for those that went into renal failure.). However, the actuarial risk reached 50% at 12 years 
Kaplan-Meier failure curve demonstrating the actuarial time from diagnosis to the start of dialysis therapy N=145 
For 38 patients who received dialysis, median survival from day 1 of dialysis was 10.4 months 
Kaplan-Meier survival of 38 patients from the start of dialysis therapy 
Age, median (IQR), y 60 (52–67) 62 (52–67) .90 
Sex, male/female 21/14 31/18 .76 
24-hr urine protein loss, median (IQR), g/d 7.4 (5.0–14.8) 5.9 (3.7–9.1) .03 
Creatinine, median (IQR), mg/dL 1.4 (0.9–2.8) 1.1 (0.9–1.5) .01 
Cardiac involvement (yes/no) 9/26 26/23 .01 
Dialysis
SubsequentlyNot Required
CharacteristicRequired (n=35)(n=49)P Value
Abbreviation: IQR, interquartile range. 
The median time from diagnosis to dialysis was 29.5 months for those that went into renal failure.). However, the actuarial risk reached 50% at 12 years 
Kaplan-Meier failure curve demonstrating the actuarial time from diagnosis to the start of dialysis therapy N=145 
For 38 patients who received dialysis, median survival from day 1 of dialysis was 10.4 months 
Kaplan-Meier survival of 38 patients from the start of dialysis therapy 
Age, median (IQR), y 60 (52–67) 62 (52–67) .90 
Sex, male/female 21/14 31/18 .76 
24-hr urine protein loss, median (IQR), g/d 7.4 (5.0–14.8) 5.9 (3.7–9.1) .03 
Creatinine, median (IQR), mg/dL 1.4 (0.9–2.8) 1.1 (0.9–1.5) .01 
Cardiac involvement (yes/no) 9/26 26/23 .01 
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Conclusion: In our study, 26% of all patients with AL ultimately received renal replacement therapy compared with 42% of patients who presented with renal AL specifically. The presenting 24-hour urine protein loss and creatinine values predict which patients will require dialysis. Median survival for patients starting dialysis is less than 1 year. Presence of l light chain amyloid predicts an increased likelihood of renal involvement and, when the kidney is affected, increased proteinuria.

Topics:
kidney, primary amyloidosis, treatment outcome, dialysis procedure, hemodialysis, creatinine, urine protein test, monoclonal immunoglobulin, cardiovascular findings, renal replacement therapy

Disclosures: No relevant conflicts of interest to declare.

Author notes

Corresponding author

2008, The American Society of Hematology
2008
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