Prognostic factors in multiple myeloma.

All patients with multiple myeloma seen over a 9-year period at Tygerberg Hospital were studied retrospectively. Presentation data of 144 patients, as well as individual laboratory results were included in the survival analysis. Cox's proportional hazard model (a non-parametric multivariate regression method) was used to predict survival and divide patients into prognostic groups. The relationship between pairs of variables at the time of diagnosis was investigated. The survival of groups of patients was compared using the generalized Wilcoxon and Savage tests. The association of the following factors with prognosis were again substantiated: haemoglobin; serum creatinine, urea and albumin; percentage of plasma cells in the bone marrow aspirate and trephine biopsy specimen; and the number of lytic lesions on skeletal radiography. The following factors were not substantiated: serum uric acid, light-chain proteinuria, age at presentation of the disease and IgG rather than the IgA class. In addition, a higher serum monoclonal peak size at presentation of the disease, and a more rapid fall in the abnormal serum monoclonal peak within the first 40 days after commencing treatment were associated with a significantly longer survival.