This study, as in abstract OP0017, utilizes the National Data Bank for Rheumatic Diseases to do a prospective investigation using COX regression models and generalized estimating equations (GEE) to determine whether a relationship exists between polymorphonuclear cells (PMN) and mortality in patients with rheumatoid arthritis (RA).

Data from a total of 21,581 clinic visits and 18,850 white cell count (WBC) tests from 1500 RA patients were examined. Total PMN counts predicted mortality (p<0.05) with mean values in quartiles of 3.5, 4.9, 6.2, and 9.0. Hazard ratios (HR) for mortality compared with Q1 over the course of the disease were Q2 1.5 (1.1, 1.9), Q3 1.9 (1.4, 2.5) and Q4 2.8 (2.2, 3.7). PMN remained a significant predictor of mortality even when analysis included RF, ESR, age, sex, disease duration, HAQ, and prednisone use. GEE analysis showed that the use of prednisone was the strongest predictor of PMN.

These results indicate that total PMN is as effective a predictor of mortality in RA patients as RF throughout the duration of the disease. PMN is most influenced by corticosteroid use.

Editorial Comment: This is an interesting study made possible by accessing the extensive data in the National Data Bank for Rheumatic Diseases. Although not a clinically useful finding, the increased mortality seen with elevated PMNs appears to be real. Unfortunately, the study does not provide a mechanism for this association. A likely possibility is that increased PMN number is a surrogate for elevated levels of cytokines such as TNF or IL-1.

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