The prognostic value of serum beta 2 microglobulin compared with other presentation features in myelomatosis.

The levels of serum beta 2 microglobulin, blood urea concentration, serum creatinine, haemoglobin and performance status have been measured in 476 patients in the Medical Research Council's 4th trial for myelomatosis. Levels of serum beta 2 microglobulin were also subsequently measured in 208 patients who achieved a stable "plateau" condition. Serum beta 2 microglobulin levels, uncorrected for serum creatinine, were found to be the single most powerful prognostic variable available at presentation. Multivariate analysis showed that only the addition of haemoglobin levels could improve upon this and the improvement, though statistically significant (P = 0.006), appeared to be of much less clinical value. The prognostic value of serum beta 2 microglobulin at plateau appeared to be equally large for a given difference in value, but the variability between patients was much less at that time. Serum beta 2 microglobulin would appear to be a key measurement for assessing the prognosis and response to treatment in patients with myelomatosis.