[Renal involvement in amyloidosis. Clinical outcomes, evolution and survival].

BACKGROUND

Systemic amyloidosis is a disease resulting from extracellular deposition of fibrillar protein in various organs. Main systemic amyloidosis are: primary (AL) and Secondary (AA). The kidney is usually involved, conferring and adverse prognosis. In the last decade there has been a change in the aetiology of AA amyloidosis.

OBJECTIVES

To analyse the incidence of AL and AA amyloidosis in our current population as well as the aetiology of AA amyloidosis. To describe clinical outcomes, renal involvement and survival.

PATIENTS AND METHODS

We performed a descriptive analysis of all cases of amyloidosis diagnosed from 1992 to 2004 in our hospital. Diagnosis was assessed on histological criteria: positivity Congo Red stain. Clinical data, renal involvement, dialysis treatment and survival were analysed.

RESULTS

76 cases, 44 women, mean age 70.7 +/- 12. Types: 55 AA (72%), 21 AL (28%) systemic amyloidosis. AA aetiology was: 66% rheumatic disorders, 28% infectious disease, 6% others. Incidence for AL was 4.6 and for AA 12.2 cases/million. Renal involvement was present in 75% at diagnosis (69% Creatinine clearance < 60 ml/min, 37% urinary protein > 3 g/24 hours). 21 cases (28%) progressed to renal disease stage V in the 8.1 +/- 9.8 months follow up period, and 14 cases started dialysis treatment (10 HD, 4 CAPD). In 7 cases (33%) dialysis was not indicated due to their poor clinical condition, short life expectancy and bad quality of life. Mean global survival at diagnosis was 55% and 40% at 12 and 24 months (AL 58% and 19%; AA 55% and 44%). Mean survival from the start of dialysis was 30% and 5% at 12 and 24 months.

CONCLUSIONS

Although amyloidosis has a low incidence in our population, the kidney is usually involved. Rheumatological disorders are the principal aetiology of AA amyloidosis. Long term survival is poor, specially for AL.