Results, principles and pitfalls in the management of renal AA-amyloidosis; a 10-21 year followup of 16 patients with rheumatic disease treated with alkylating cytostatics.

OBJECTIVE

To assess renal functional outcome at 10-21 years in 16 consecutive patients with rheumatic disease, treated with alkylating agents for secondary renal AA-amyloidosis, and to review management principles developed during 21 years.

METHODS

Renal function was assessed by S-creatinine and the albumin/creatinine clearance ratio, and arthritic activity by joint score and C-reactive protein (CRP). In the event of signs of renal deterioration, cyclophosphamide, or since 1975 chlorambucil, was given until stable remission of the arthritis was obtained.

RESULTS

Of the 7 cases of precipitous uremia that occurred, 4 were not treated with cytostatics at the patients' local hospitals. By 1992, median survival of renal function was 11 years (range 4-21). At 10 years 12 (75%) still had kidneys with preserved function, and at that stage accounted for 22 instances of renal deterioration treated with alkylating agents for periods of 6-45 months (median 13). Renal function was improved in 18 of these instances, and deterioration arrested in 3, the general trend being stabilized or moderately increased S-creatinine and successively declining proteinuria. Prompt institution of corticosteroid treatment is regarded as indispensable at increase of CRP/S-AA due to infection or surgery.

CONCLUSIONS

Our results indicate that the survival of renal function may be substantially prolonged (compared to no treatment) when cyclophosphamide, or preferably chlorambucil, is appropriately administered at signs of kidney deterioration due to active arthritis, and lifelong, continuous monitoring maintained.