Citations

Open-access or advanced-access scheduling, which opens the clinic calendar to patients without requiring them to schedule far in advance of the visit, is being introduced in primary care for the purpose of improving access. None of the evaluations reported to date have measured differences in actual visits that might be associated with different scheduling systems. The purpose of this study was to compare utilization of visits to primary care providers for patients served by an open-access clinic with utilization patterns of patients served at clinics not using open-access scheduling. We hypothesized that the odds that a continuing patient received more than one primary care visit would be greater in the clinic where open-access scheduling was in use than in comparison clinics. Our study provides mixed support for the hypotheses. After adjustment for case mix, stable chronic patients treated in open-access clinics may sometimes have greater odds of receiving two or more preventive care visits. However, these effects do not occur in all clinics, suggesting that other clinic characteristics may overcome the effects of open-access scheduling.

Abstract Background: The International Staging System for multiple myeloma has increased the importance of accurate measurement of serum albumin. Two common albumin assays, bromcresol green (BCG) and agarose gel protein electrophoresis (PEL), frequently yield discordant results, creating confusion regarding which assay is superior for use in myeloma. Methods: We measured albumin by BCG on a Roche Modular system, by PEL with a Helena SPIFE SPE Vis agarose gel, and by immunonephelometry performed on a Dade Behring BNII nephelometer. BCG and PEL were used to measure albumin in 5777 patient samples, and all 3 methods were used in an additional 252 samples. The clinical impact was assessed on 698 myeloma patient samples. Results: For sera with zero/low monoclonal immunoglobulin protein (M)-spike (0 to <15 g/L), results for both BCG and PEL correlated well to nephelometry, although median PEL results were 8 g/L lower than corresponding BCG measurements. Correlation between PEL and nephelometry or BCG diminished with increasing M-spike, with PEL eventually overestimating albumin compared with both other assays. IgG and IgA M-spikes showed significantly different effects on albumin discordance. For 35% of myeloma patients, discrepancy between BCG and PEL had a potentially clinically significant effect on staging, but no difference in group survival was found. Conclusions: Both BCG and PEL correlate well to nephelometry in sera with zero/low M-spikes. In the presence of larger M-spikes, PEL correlates poorly to nephelometry or BCG, whereas BCG compares well with nephelometry regardless of M-spike. Thus, albumin measurement can be performed reliably in myeloma patient sera by use of inexpensive, automated BCG assays.

Abstract Hyperdiploid multiple myeloma (H-MM) is the most common form of myeloma. In this gene expression profiling study, we show that H-MM is defined by a protein biosynthesis signature that is primarily driven by a gene dosage mechanism as a result of trisomic chromosomes. Within H-MM, four independently validated patient clusters overexpressing nonoverlapping sets of genes that form cognate pathways/networks that have potential biological importance in multiple myeloma were identified. One prominent cluster, cluster 1, is characterized by high expression of cancer testis antigen and proliferation-associated genes. Tumors from these patients were more proliferative than tumors in other clusters (median plasma cell labeling index, 3.8; P < 0.05). Another cluster, cluster 3, is characterized by genes involved in tumor necrosis factor/nuclear factor-κB signaling and antiapoptosis. These patients have better response to bortezomib as compared with patients within other clusters (70% versus 29%; P = 0.02). Furthermore, for a group of patients generally thought to have better prognosis, a cluster of patients with short survival (cluster 1; median survival, 27 months) could be identified. This analysis illustrates the heterogeneity within H-MM and the importance of defining specific cytogenetic prognostic factors. Furthermore, the signatures that defined these clusters may provide a basis for tailoring treatment to individual patients. [Cancer Res 2007;67(7):2982–9]

AbstractWaldenström macroglobulinemia (WM) is a B-cell malignancy characterized by the ability of the B-cell clone to differentiate into plasma cells. Although the clinical syndrome and the pathologic characteristics are well defined, little is known about its biology and controversy still exists regarding its cell of origin. In this gene-expression study, we compared the transcription profiles of WM with those of other malignant B cells including (chronic lymphocytic leukemia [CLL] and multiple myeloma [MM]) as well as normal cells (peripheral-blood B cells and bone marrow plasma cells). We found that WM has a homogenous gene expression regardless of 6q deletion status and clusters with CLL and normal B cells on unsupervised clustering with very similar expression profiles. Only a small gene set has expression profiles unique to WM compared to CLL and MM. The most significantly up-regulated gene is IL6 and the most significantly associated pathway for this set of genes is MAPK signaling. Thus, IL6 and its downstream signaling may be of biologic importance in WM. Further elucidation of the role of IL-6 in WM is warranted as this may offer a potential therapeutic avenue.

Abstract An abnormal serum immunoglobulin free light chain (FLC) ratio at diagnosis may identify risk of progression to myeloma in patients with solitary bone plasmacytoma (SBP). In the cohort of 116 patients, 43 have progressed to myeloma, with a median time to progression of 1.8 years. The FLC ratio was determined in all 116 patients on serum collected at time of diagnosis and was abnormal in 54 patients (47%). An abnormal FLC ratio was associated with a higher risk of progression to myeloma (P = .039). The risk of progression at 5 years was 44% in patients with an abnormal serum FLC ratio at diagnosis compared with 26% in those with a normal FLC ratio. One to 2 years following diagnosis, a persistent serum M protein level of 5 g/L (0.5 g/dL) or higher was an additional risk factor for progression. A risk stratification model was constructed using the 2 variables of FLC ratio and M protein level: patients with a normal FLC ratio at baseline and M protein level less than 5 g/L (0.5 g/dL) at 1 to 2 years following diagnosis (low risk, n = 31); with either risk factor abnormal (intermediate risk, n = 26); and with both an abnormal FLC ratio and M protein level of 5 g/L (0.5 g/dL) or higher (high risk, n = 18). The corresponding progression rates at 5 years were significantly different in the low, intermediate, and high groups: 13%, 26%, and 62%, respectively (P < .001).

Abstract To assess fractures in monoclonal gammopathy of undetermined significance (MGUS), the precursor of multiple myeloma, we followed 488 Olmsted County, MN, residents with MGUS in a retrospective cohort study. There was a 2.7-fold increase in the risk of axial fractures but no increase in limb fractures. The pathophysiologic basis for the increased axial fractures should be determined. Introduction: Multiple myeloma is often preceded by monoclonal gammopathy of undetermined significance (MGUS). Fractures are common in myeloma as a result of lytic bone lesions, generalized bone loss, and elevated bone turnover from excessive cytokine production. Whether fractures are also increased in MGUS is unknown. Materials and Methods: In a population-based retrospective cohort study, 488 Olmsted County, MN, residents with MGUS first diagnosed in 1960–1994 (52% men; mean age, 71.4 ± 12.8 years) were followed for 3901 person-years; follow-up was censored at progression to myeloma. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models. Results and Conclusions: Altogether, 200 patients experienced 385 fractures. Compared with expected rates in the community, statistically significant increases were seen for fractures at most axial sites, for example, vertebrae (SIR, 6.3; 95% CI, 5.2–7.5). There was a slight increase in hip (SIR, 1.6; 95% CI, 1.2–2.2) but not distal forearm fractures (SIR, 0.8; 95% CI, 0.4–1.5). The relative risk (SIR) of any axial fracture was 2.7 (95% CI, 2.3–3.1) compared with only 1.1 (95% CI, 0.9–1.4) for all limb fractures combined. In a multivariate analysis, the independent predictors of any subsequent fracture were age (hazard ratio [HR] per 10-year increase, 1.4; 95% CI, 1.2–1.6) and corticosteroid use (HR, 1.8; 95% CI, 1.2–2.6); greater weight at diagnosis (HR per 10 kg, 0.8; 95% CI, 0.8–0.9), and IgG monoclonal protein (HR, 0.7; 95% CI, 0.5–0.97) were protective. Baseline monoclonal protein level, a determinant of myeloma progression, did not predict fracture risk. Thus, the risk of axial, but not peripheral, fractures is increased among MGUS patients even before progression to myeloma. The pathophysiologic basis for this should be determined because elevated bone turnover, for example, might be treatable.

Abstract Pathologic fractures, especially of the axial skeleton, are extremely common in patients with multiple myeloma and cluster around the time of diagnosis. Osteoporotic fractures seem to be less of a problem in these patients. Introduction: It is generally believed that fractures are common in patients with multiple myeloma as a result of lytic bone lesions, generalized bone loss, and/or elevated bone turnover from excessive cytokine production, but the actual risk of pathologic versus osteoporotic fractures has not been quantified. Materials and Methods: In a population-based retrospective cohort study, 165 Olmsted County, MN, residents with myeloma diagnosed from 1945 to 2001 (55% men; mean age, 70.7 ± 11.1 years) were followed for 537 person-years. The relative risk of fractures was assessed by standardized incidence ratios (SIRs), and risk factors were evaluated in proportional hazards models. Results: Altogether, 134 patients experienced 463 fractures. In the year before diagnosis, 16 times more fractures were observed than expected, mostly pathologic fractures of the vertebrae and ribs. Subsequently, there was a 9-fold increase in fracture risk. However, 69% of these fractures were pathologic, and another 11% were found incidentally on myeloma monitoring. With the latter two groups excluded, subsequent fracture risk was elevated 3-fold, with a 2-fold increase in the risk of an osteoporotic fracture. In multivariate analyses, the predictors of overall fracture risk were oral corticosteroid use and elevated serum calcium levels, whereas pathologic fractures were additionally predicted by use of chemotherapy. Conclusion: There is a dramatic increase in fractures around the time of diagnosis of myeloma, most of which are pathologic fractures. The most important predictor of overall fracture risk is oral corticosteroid use.

Antibodies are generally thought to be a class of proteins that function without the use of cofactors. However, it is not widely appreciated that antibodies are believed to be the major carrier protein in human circulation for the important riboflavin cofactor that is involved in a host of biological phenomena. A further link between riboflavin and antibodies was discovered 30 years ago when a bright-yellow antibody, IgG GAR , was purified from a patient with multiple myeloma who had turned yellow during the course of her disease. It was subsequently shown that the yellow color of this antibody was due to riboflavin binding. However, it was not known how and where riboflavin was bound to this antibody. We now report the crystal structure of this historically important IgG GAR Fab at 3.0-Å resolution. The riboflavin is located in the antigen-combining site with its isoalloxazine ring stacked between the parallel aromatic moieties of TyrH33, PheH58, and TyrH100A. Together with additional hydrogen bonds, these interactions reveal the structural basis for high-affinity riboflavin binding. The ligand specificity of IgG GAR is compared with another riboflavin-binding antibody, IgG DOT , which was purified from a second patient with multiple myeloma. The crystal structure of IgG GAR provides a starting point for attempts to understand the physiological relevance and chemical functions of cofactor-containing antibodies.