[Renal manifestations of light chain associated diseases - epidemiology and prognosis].

BACKGROUND

An impaired renal function in light chain associated disorders may be caused by myeloma cast nephropathy (MCN) but also by AL-amyloidosis (AL-A) and monoclonal immundeposition disease (MIDD).

PATIENTS AND METHODS

In a monocentric, retrospective analysis, patients suffering from multiple myeloma (MM) (n = 392) requiring medical therapy, AL-A (n = 53) or MIDD (n = 12) diagnosed between 1996 and 2008 were evaluated for renal insufficiency. The different patient cohorts were compared in terms of their clinical course and outcome.

RESULTS

Renal insufficiency in MM-, AL-A- or MIDD-patients at the time of diagnosis was found in 45,5 % of the patients. MCN, AL-A and MIDD were found in 68, 25 and 6 %, respectively. Dialysis dependency was seen in 17 % of MCN, in 8 % of AL-A and in 50 % of MIDD patients. Signs of hypervolemia were the leading symptoms in MIDD/AL-A. The time between the occurence of first symptoms and diagnosis was as long as 52 weeks in patients with AL-A. Patients with renal involvement showed a reduced median survival of 17 compared with 77 months in patients with a normal renal function. Median survival was only 12 months in AL-A compared to 21 months in MCN. Stabilization of renal function after chemotherapy occurred only in MCN. Multivariate Cox regression analysis showed impaired renal function as independent risk factor (Hazard-Ratio 2,88 [2,06-4,0]. In terms of survival and kidney function, autologous stem cell transplantation (ASCT) was beneficial for patients with renal involvement.

CONCLUSION

Renal insufficiency is an independent risk factor in MM, AL-A and MIDD. Specific therapy, especially ASCT may improve prognosis in patients with renal insufficiency and could stabilize renal function in MCN-patients.