Mass spectrometry-detected MGUS is associated with obesity and other novel modifiable risk factors in a high-risk population

ABSTRACT

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition of multiple myeloma with few known risk factors. The emergence of mass spectrometry (MS) for the detection of MGUS has provided new opportunities to evaluate its risk factors. In total, 2628 individuals at elevated risk for multiple myeloma were enrolled in a screening study and completed an exposure survey (PROMISE trial). Participant samples were screened by MS, and monoclonal proteins (M-proteins) with concentrations of ≥0.2 g/L were categorized as MS-MGUS. Multivariable logistic models evaluated associations between exposures and MS outcomes. Compared with normal weight (body mass index [BMI] of 18.5 to <25 kg/m2), obesity (BMI of ≥30 kg/m2) was associated with MS-MGUS, adjusting for age, sex, Black race, education, and income (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.21-2.47; P = .003). High physical activity (≥73.5 metabolic equivalent of task (MET)-hours per week vs <10.5 MET-hours per week) had a decreased likelihood of MS-MGUS (OR, 0.45, 95% CI, 0.24-0.80; P = .009), whereas heavy smoking and short sleep had increased likelihood of MS-MGUS (>30 pack-years vs never smoker: OR, 2.19; 95% CI, 1.24-3.74; P = .005, and sleep <6 vs ≥6 hours per day: OR, 2.11; 95% CI, 1.26-3.42; P = .003). In the analysis of all MS-detected monoclonal gammopathies, which are inclusive of M-proteins with concentrations of <0.2 g/L, elevated BMI and smoking were associated with all MS-positive cases. Findings suggest MS-detected monoclonal gammopathies are associated with a broader range of modifiable risk factors than what has been previously identified. This trial was registered at www.clinicaltrials.gov as #NCT03689595.

Development of a Multivariable Model to Predict the Need for Bone Marrow Sampling in Persons With Monoclonal Gammopathy of Undetermined Significance : A Cohort Study Nested in a Clinical Trial

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic precursor conditions to multiple myeloma and related disorders. Smoldering multiple myeloma is distinguished from MGUS by 10% or greater bone marrow plasma cells (BMPC) on sampling, has a higher risk for progression, and requires specialist management.

OBJECTIVE

To develop a multivariable prediction model that predicts the probability that a person with presumed MGUS has 10% or greater BMPC (SMM or worse by bone marrow criteria) to inform the decision to obtain a bone marrow sample and compare its performance to the Mayo Clinic risk stratification model.

DESIGN

iStopMM (Iceland Screens, Treats or Prevents Multiple Myeloma), a prospective population-based screening study of MGUS. (ClinicalTrials.gov: NCT03327597).

SETTING

Icelandic population of adults aged 40 years or older.

PATIENTS

1043 persons with IgG, IgA, light-chain, and biclonal MGUS detected by screening and an interpretable bone marrow sample.

MEASUREMENTS

Monoclonal gammopathy of undetermined significance isotype; monoclonal protein concentration; free light-chain ratio; and total IgG, IgM, and IgA concentrations were used as predictors. Bone marrow plasma cells were categorized as 0% to 4%, 5% to 9%, 10% to 14%, or 15% or greater.

RESULTS

The c-statistic for SMM or worse was 0.85 (95% CI, 0.82 to 0.88), and calibration was excellent (intercept, -0.07; slope, 0.95). At a threshold of 10% predicted risk for SMM or worse, sensitivity was 86%, specificity was 67%, positive predictive value was 32%, and negative predictive value was 96%. Compared with the Mayo Clinic model, the net benefit for the decision to refer for sampling was between 0.13 and 0.30 higher over a range of plausible low-risk thresholds.

LIMITATION

The prediction model will require external validation.

CONCLUSION

This accurate prediction model for SMM or worse was developed in a population-based cohort of persons with presumed MGUS and may be used to defer bone marrow sampling and referral to hematology.

PRIMARY FUNDING SOURCE

International Myeloma Foundation and the European Research Council.

Sjögren's disease activity associates with cardiovascular disease and monoclonal gammopathy: a university cohort study of disease activity and comorbidities

BACKGROUND

We used the University of Wisconsin cohort to determine the extent to which the EULAR Sjögren's syndrome disease activity index (ESSDAI) was associated with comorbidities that contribute to mortality.

METHODS

Our University of Wisconsin, Madison cohort had 111 patients with Sjögren's Disease (SjD) by 2016 ACR/EULAR criteria and 194 control patients with sicca. Our study was performed from March 1st, 2020 through April 1st, 2023. We collected data using a standardized collection tool, including components of the Charlson Comorbidity Index (CCI). Stratifying our SjD patients by ESSDAI < 5 and ESSDAI ≥ 5, we assessed differences in comorbidities associated with mortality.

RESULTS

At time of SjD diagnosis, the ESSDAI ≥ 5 group had increased odds of peripheral vascular disease compared to controls (OR 10.17; 95% CI 1.18-87.87). Patients with a current ESSDAI ≥ 5 were more likely to have a myocardial infarction compared to controls (OR 9.87; 95% CI 1.17-83.49). SjD patients had increased prevalence of monoclonal gammopathy compared to controls (9.3% vs 0.5%, p < 0.001). SjD patients with high ESSDAI at diagnosis had greater prevalence of monoclonal gammopathy compared to the SjD patients with a low ESSDAI (16% vs 5%, p = .04). As reported elsewhere, the ESSDAI ≥ 5 group had increased odds of chronic pulmonary disease (OR 4.37; 95% CI 1.59-11.97).

CONCLUSION

We found high ESSDAI scores were associated with worse cardiovascular outcomes, specifically peripheral vascular disease and myocardial infarction. Furthermore, monoclonal gammopathy was more frequent in SjD patients compared to sicca controls, supporting screening for monoclonal gammopathy in the appropriate clinical scenario. Key Points • High ESSDAI scores are associated with worse cardiovascular outcomes, specifically peripheral vascular disease and myocardial infarction. • Monoclonal gammopathy is more frequent in SjD patients than sicca controls, supporting screening for monoclonal gammopathy in the appropriate clinical scenario.

Vitamin D and monoclonal gammopathy of undetermined significance (MGUS) among U.S. Black women

PURPOSE

Risk factors for monoclonal gammopathy of undetermined significance (MGUS), the asymptomatic precursor to multiple myeloma, are largely unknown. We hypothesized that low vitamin D levels might be associated with higher MGUS prevalence in a national cohort of U.S. Black women.

METHODS

We screened archived serum samples (collected 2014-2017) from 3896 randomly selected participants in the Black Women's Health Study ages 50-79 for evidence of MGUS; samples had been assayed for 25-hydroxyvitamin D [25(OH)D] shortly after blood draw. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between 25(OH)D level and MGUS status, adjusting for age, body mass index, and season of blood draw.

RESULTS

We identified 334 MGUS cases (8.6%) in the study population. The adjusted OR comparing women with vitamin D deficiency (25(OH)D < 20 ng/mL) to those with 25(OH)D levels ≥ 30 ng/mL was 1.27 (95% CI: 0.95, 1.72).

CONCLUSION

MGUS was more prevalent among Black women with vitamin D deficiency compared to those with 25(OH)D ≥ 30 ng/mL; however, the association was not statistically significant. Future prospective studies are warranted to clarify the possible association between vitamin D and MGUS.

The Association of Agent Orange Exposure with the progression of monoclonal gammopathy of undetermined significance to multiple myeloma: a population-based study of Vietnam War Era Veterans

Herbicide and pesticide exposure [e.g., agent orange (AO)] is associated with an increased risk of multiple myeloma (MM) due to the contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, it is unclear whether TCDD/AO exposure (AO exposure hereafter) increases the risk of progression of monoclonal gammopathy of undetermined significance (MGUS) to MM. We sought to evaluate the association in a nationwide study of US Veterans. A natural language processing algorithm was used to confirm MGUS and progression to MM. We included Veterans who were diagnosed with MGUS from 10/1/1999 to 12/31/2021 and served during the Vietnam War Era from 1/9/1962 to 5/7/1975. AO exposure was stratified according to three TCDD exposure levels: high (1/9/1962-11/30/1965), medium (12/1/1965-12/31/1970), or low (1/1/1971-5/7/1975). The association between AO exposure and progression was analyzed using multivariable Fine-Gray subdistribution hazard model with death as a competing event. The analytic cohort included 10,847 Veterans with MGUS, of whom 26.3% had AO exposure and 7.4% progressed to MM over a median follow-up of 5.2 years. In multivariable analysis, high exposure was associated with an increased progression rate (multivariable-adjusted hazard ratio 1.48; 95% confidence interval 1.02-2.16), compared to Veterans with no exposure. This information is critical to inform progression risk in patients diagnosed with MGUS and prior AO exposure. It is also applicable to MGUS patients with occupational TCDD exposure from herbicides and pesticides.

Monoclonal gammopathy of unknown significance in kidney transplanted patients: novel insights into long-term outcomes

BACKGROUND

Because of increased access to kidney transplantation in elderly subjects, the prevalence of monoclonal gammopathies of unknown significance (MGUS) in kidney transplantation (KT) is growing. However, little is known about the consequences of MGUS on long-term outcomes.

METHODS

We identified 70 recipients with MGUS present at transplantation (KTMG) and 114 patients with MGUS occurring after KT (DNMG), among 3059 patients who underwent a KT in two French kidney transplantation centers. We compared outcomes of KTMG with those of matched controls.

RESULTS

Baseline characteristics were similar except for an older age in KTMG compared with the DNMG group (62 vs 57 years, P = .03). Transient MGUS occurred more frequently in DNMG patients (45% vs 24%, P = .007). When compared with matched controls without MGUS, KTMG patients showed higher frequency and earlier post-transplant solid cancers (15% vs 5%, P = .04) and a trend for more bacterial infections (63% vs 48%, P = .08), without difference regarding patient and graft survival, rejection episodes or hematological complications. KTMG patients with an abnormal kappa/lambda ratio and/or severe hypogammaglobulinemia at the time of KT experienced shorter overall survival.

CONCLUSIONS

MGUS detection at the time of KT is neither associated with a higher occurrence of graft rejection, nor adversely affects graft or overall survival. MGUS should not contraindicate KT. However, MGUS at the time of KT may be associated with higher risk of early neoplastic and infectious complications and warrants prolonged surveillance. Measurement of serum free light chain should be performed before transplant to refine the risk evaluation of KTMG patients and propose personalized follow-up and immunosuppression.

Gaucher disease prevalence in 600 patients affected by monoclonal gammopathy of undetermined significance

BACKGROUND

Gaucher disease (GD) is a rare autosomal recessive inherited disorder caused by the lysosomal enzyme acid β-glucosidase deficiency. Many patients experience a critical delay in the diagnosis of up to 8-10 years due to its rarity and variability in signs and symptoms, with the consultation of several specialists.

PATIENTS AND METHODS

This prospective observational study analyzed the prevalence of GD in 600 patients with monoclonal gammopathy of uncertain significance (MGUS) from January 2018 until February 2022.

RESULTS

The mean age of participants was 66 years, with a mean monoclonal component of 0.58 g/dL. In 433 MGUS patients with available data, anemia (hemoglobin level < 10 g/dL) was present in 31 patients (7%), and thrombocytopenia (platelet count <100.000/mm3 ) in 24 (5.5%). Of 600 MGUS patients tested for acid β-glucosidase enzyme activity, 7 patients (1.2%) had activity below 2.5 nmol/h/mL. In comparison, GBA gene analysis was executed in 110 patients. It revealed 4 patients (0.7%) affected by GD (3 patients with compound heterozygous mutation and 1 with homozygous mutation), with a prevalence of 1 every 150 MGUS patients. Furthermore, 12 out of the remaining 106 evaluated patients (11%) were carriers of a single heterozygous mutation while having regular enzyme activity.

CONCLUSIONS

The clinical heterogeneity of GD and frequent lack of awareness among physicians often lead to diagnostic delays and severe clinical manifestations. The role of MGUS in the presence of at least one clinical sign, such as low platelet count, organomegaly, bone pain, or bleeding tendency, could aid in initiating GD screening with DBS, thus reducing the period between symptom onset and the diagnosis of this rare disease.

Post-Transplant Monoclonal Gammopathy of Renal Significance: A Case Report

The term monoclonal gammopathy of renal significance has been used to classify the presence of a monoclonal gammopathy or lymphoproliferative disorders that do not meet hematological criteria for myeloma but instead cause kidney damage. Mostly, post-transplant monoclonal gammopathy of renal significance occurs due to recurrent disease. In contrast, the incidence of de novo post-transplant monoclonal gammopathy of renal significance has not been established, as it is considered a rare disease, presenting a unique challenge in terms of diagnosis, management, and potential impact on graft survival. Here, we report a case of de novo monoclonal gammopathy of renal significance diagnosed after kidney transplantation and its complexity due to a concomitant chronic active antibody-mediated rejection.

Disease associations with monoclonal gammopathy of undetermined significance can only be evaluated using screened cohorts: results from the population-based iStopMM study

Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic precursor condition that precedes multiple myeloma and related disorders but has also been associated with other medical conditions. Since systematic screening is not recommended, MGUS is typically diagnosed due to underlying diseases and most cases are not diagnosed. Most previous studies on MGUS disease associations have been based on clinical cohorts, possibly resulting in selection bias. Here we estimate this selection bias by comparing clinically diagnosed and screened individuals with MGUS with regards to demographics, laboratory features, and comorbidities. A total of 75,422 participants in the Iceland Screens, Treats, or Prevents Multiple Myeloma (iStopMM) study were screened for MGUS by serum protein electrophoresis, immunofixation and free light chain assay (clinicaltrials gov. Identifier: NCT03327597). We identified 3,352 individuals with MGUS, whereof 240 had previously been clinically diagnosed (clinical MGUS), and crosslinked our data with large, nationwide registries for information on comorbidities. Those with clinical MGUS were more likely to have at least one comorbidity (odds ratio=2.24; 95% confidence interval: 1.30-4.19), and on average had more comorbidities than the screened MGUS group (3.23 vs. 2.36, mean difference 0.68; 95% confidence interval: 0.46-0.90). They were also more likely to have rheumatological disease, neurological disease, chronic kidney disease, liver disease, heart failure, or endocrine disorders. These findings indicate that individuals with clinical MGUS have more comorbidities than the general MGUS population and that previous studies have been affected by significant selection bias. Our findings highlight the importance of screening data when studying biological and epidemiological implications of MGUS.

Nutritional Status Indices and Monoclonal Gammopathy of Undetermined Significance Risk in the Elderly Population: Findings from the National Health and Nutrition Examination Survey

OBJECTIVE

Although several studies have found dietary intake is related to multiple myeloma (MM) and its precursor status risks, the role of one's nutritional status has been ignored and its role in plasma cell neoplasm development is still unclear. This study aimed to explore the relationship between various clinical indices of nutritional status and the risk of monoclonal gammopathy of undetermined significance (MGUS) in the population.

METHODS

We selected 9520 participants from the NHANES III and NHANES 1999-2004 studies. Controlling nutritional status index (CONUT), prognostic nutritional index (PNI), geriatric nutritional risk index (GNRI) and body mass index (BMI) were calculated as indices of nutritional status of the participants. Associations between nutritional indices and MGUS were investigated using multiple logistic regression, subgroup analysis, and an RCS model.

RESULTS

In our study, 266 participants had MGUS, with a prevalence of 2.79%. This study found that CONUT and PNI identified populations with poor nutritional status and had a significant positive correlation with the risk of MGUS. In multivariate logistic regression, compared with the lower CONUT score (<3) group, the OR for the group with higher scores (≥3) was 1.805 (95%CI: 1.271, 2.564). Compared with the lowest quartile group, the highest quartile PNI score group had an OR of 0.509 (95%CI: 0.290, 0.896). GNRI had no significant correlation with the risk of MGUS, with an OR of 0.737 (95%CI: 0.443, 1.227).

CONCLUSION

This study found that older adults with CONUT and PNI scores indicating poorer nutrition had a higher risk of MGUS.

It is worth the weight: obesity and the transition from monoclonal gammopathy of undetermined significance to multiple myeloma

The overweight/obesity epidemic is a serious public health concern that affects >40% of adults globally and increases the risk of numerous chronic diseases, such as type 2 diabetes, heart disease, and various cancers. Multiple myeloma (MM) is a lymphohematopoietic cancer caused by the uncontrolled clonal expansion of plasma cells. Recent studies have shown that obesity is a risk factor not only for MM but also monoclonal gammopathy of undetermined significance (MGUS), a precursor disease state of MM. Furthermore, obesity may promote the transition from MGUS to MM. Thus, in this review, we summarize the epidemiological evidence regarding the role of obesity in MM and MGUS, discuss the biologic mechanisms that drive these disease processes, and detail the obesity-targeted pharmacologic and lifestyle interventions that may reduce the risk of progression from MGUS to MM.

[Monoclonal gammopathy of uncertain significance]

Monoclonal gammopathy of uncertain significance is a premalignant plasma cell neoplasm with a high prevalence in the population over 50 years of age and an annual risk of progression of 1%. Multiple recent studies have led to advances in understanding both the pathogenesis of these disorders and their risk of progression to other diseases. Patients require lifelong follow-up, and a multidisciplinary and risk-adapted approach is essential. In recent years, an increasing number of entities associated with a paraprotein, known as clinically significant monoclonal gammopathies, have been recognized.

Mortality in the US Populations With Monoclonal Gammopathy of Undetermined Significance

This cohort study analyzes a nationally representative sample with a screening test for monoclonal gammopathy of undetermined significance (MGUS) to evaluate overall survival of populations with MGUS compared with those without MGUS among the general population in the US.

Risk and Severity of COVID-19 Infection in Monoclonal Gammopathy of Undetermined Significance: A 3-Year Propensity Matched Cohort Study

INTRODUCTION

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant disorder causing monoclonal plasma cell proliferation in bone marrow. This population is at risk of developing multiple myeloma (MM) and severe viral infections; risk factors of severe COVID-19 infection. Using TriNetX, a global platform providing data of 120 million patients, we aimed to quantify the risk and severity of COVID-19 in MGUS patients.

PATIENTS AND METHODS

A retrospective cohort analysis was performed using the TriNetX Global Collaborative Network. From January 20, 2020, to January 20, 2023, we identified a cohort of 58,859 MGUS patients and compared to non-MGUS patients, determined by relevant diagnosis/LOINC test codes. After 1:1 propensity score-matching, we identified COVID-19 cases to quantify risk and identify patients who had been hospitalized, ventilated/intubated, and deceased to quantify severity. Measures of association and Kaplan-Meier analysis were conducted.

RESULTS

After propensity-score matching, there were 58,668 patients in both cohorts. MGUS patients were found to be at a reduced risk of contracting COVID-19 (RR 0.88, 95% CI 0.85-0.91). MGUS patients with COVID-19 showed higher mortality risk and decreased survival time compared to the general population (HR 1.14, 95% CI 1.01-1.27). MGUS patients with COVID-19 who were hospitalized exhibited significantly decreased survival time (log-rank test, P = 0.04).

CONCLUSION

As COVID-19 remains a looming health concern, especially amongst vulnerable populations, our analysis emphasizes the need for adequate vaccination and treatment regimens as well as an understanding of the severity of infection in MGUS patients and justification for precautionary measures.

Multimorbidity in patients with monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS), a precursor to multiple myeloma, is present in over 5% of adults aged 70 and older, a population with a high prevalence of multimorbidity. MGUS is often diagnosed incidentally when patients seek care for unrelated conditions. Our study sought to examine patterns of multimorbidity among MGUS patients, as overall health may impact patient care and the prioritization of MGUS surveillance. We examined patterns of comorbidities in 429 patients diagnosed with MGUS (2007-2015) and 1287 matched controls. Twenty-seven conditions were defined at diagnosis/index date using algorithms developed by the Centers for Medicare and Medicaid Chronic Conditions Warehouse. Patterns of common comorbidities were identified individually, in dyads and triads, and compared between MGUS cases and controls. We conducted a latent class analysis to identify comorbidity patterns among cases only. We also examined comorbidity patterns among a subset of 32 MGUS cases who progressed to cancer during the study period. The most common comorbidities among both MGUS cases and controls included hypertension and hyperlipidemia. Anemia (cases: 43%; controls: 16%) and chronic kidney disease (CKD; cases: 36%; controls: 18%), and dyads and triads containing those conditions, were more common among cases. Latent class analysis identified three classes of comorbidity among MGUS cases: hypertension-hyperlipidemia plus anemia and CKD (31%); low comorbidity burden (17%); and hypertension-hyperlipidemia alone (52%). The higher prevalence among cases of anemia and CKD, which may be involved in the pathogenesis of, or surveillance for, MGUS, warrants additional investigation.

Monoclonal gammopathy of increasing significance: time to screen?

Monoclonal gammopathy (MG) is a frequently detected clonal B-cell or plasma-cell disorder. Importantly, every multiple myeloma (MM) case is preceded by MG. Although clinical algorithms now allow earlier treatment of patients with biomarkers of malignancy before MM-induced tissue damage (CRAB) occurs, most patients are still diagnosed late. It is important to revisit how MG should be managed in clinical practice and whether screening is required. As the prevalence of MG and other medical co-morbidities both rise with increasing age, the degree of contribution of MG to disease states other than malignant progression is often unclear. This can lead to monitoring lapses and under recognition of the organ dysfunction that can occur with monoclonal gammopathy of clinical significance (MGCS). Therefore, models of progression to MM and/or MGCS require further refinement. While MG is currently detected incidentally, a case for screening has been made with ongoing studies in this area. Screening has the potential benefit of earlier detection and prevention of both MGCS and delayed MM presentations, but important drawbacks include the psychosocial impact on individuals and resource burden on healthcare services. MG terminology should transition alongside our increasing understanding of the condition and genomic characterization that have already begun to revise the MG nomenclature. The biology of MG has been poorly understood and is often inferred from the biology of MM, which is unhelpful. We review the literature and case for MG screening in this paper. In particular, we highlight areas that require focus to establish screening for MG.

Monoclonal Gammopathy of Undetermined Significance in Patients With Transthyretin Amyloidosis (ATTR): Analysis Using the iStopMM Criteria

INTRODUCTION

To identify the prevalence of monoclonal gammopathy of undetermined significance (MGUS) in patients with transthyretin amyloid (ATTR). We used the iStopMM study revised reference ranges for serum free light-chain (sFLC) corrected for eGFR to identify ATTR patients with light-chain MGUS (LC-MGUS). Characteristics and frequencies of the ATTR cohort with underlying MGUS was compared to a cohort of MGUS patients without ATTR.

PATIENTS AND METHODS

A retrospective analysis of ATTR and MGUS patients evaluated at our center between January 2014 to December 2021. A total of 149, predominantly male (87.5%) ATTR patients with a median age of 82 were included. This cohort was compared to 228 MGUS patients.

RESULTS

Of the 149 ATTR patients, 27 (18.1%) had coexisting MGUS. Among ATTR patients with MGUS, 12/27 (44%) had LC-MGUS based on sFLC abnormalities assessed using the iStopMM reference ranges. Of the MGUS only cohort, 44/228 (19.3%) met criteria for LC-MGUS. Utilizing the iStopMM reference ranges, 6 ATTR patients did not meet criteria for abnormal sFLCs, uncovering a 20% false-positive rate.

CONCLUSION

We noted higher rates of MGUS, particularly LC-MGUS, among ATTR patients when compared to our MGUS only cohort. The high prevalence remained after utilizing the iStopMM sFLC corrected for eGFR reference ranges. Additionally, 6 ATTR patients with renal-dysfunction would have met MGUS criteria if not evaluated using the iStopMM revised measures. These findings emphasize careful interpretation of sFLC abnormalities and encourage providers to keep ATTR on the differential when work-up uncovers sFLC aberrations.

Identifying monoclonal gammopathy of undetermined significance from electronic health records

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) precedes multiple myeloma (MM). Use of electronic health records may facilitate large-scale epidemiologic research to elucidate risk factors for the progression of MGUS to MM or other lymphoid malignancies.

AIMS

We evaluated the accuracy of an electronic health records-based approach for identifying clinically diagnosed MGUS cases for inclusion in studies of patient outcomes/ progression risk.

METHODS AND RESULTS

Data were retrieved from Kaiser Permanente Southern California's comprehensive electronic health records, which contain documentation of all outpatient and inpatient visits, laboratory tests, diagnosis codes and a cancer registry. We ascertained potential MGUS cases diagnosed between 2008 and 2014 using the presence of an MGUS ICD-9 diagnosis code (273.1). We initially excluded those diagnosed with MM within 6 months after MGUS diagnosis, then subsequently those with any lymphoid malignancy diagnosis from 2007 to 2014. We reviewed medical charts for 100 randomly selected potential cases for evidence of a physician diagnosis of MGUS, which served as our gold standard for case confirmation. To assess sensitivity, we also investigated the presence of the ICD-9 code in the records of 40 randomly selected and chart review-confirmed MGUS cases among patients with a laboratory report of elevated circulating monoclonal (M-) protein (a key test for MGUS diagnosis) and no subsequent lymphoid malignancy (as described above). The positive predictive value (PPV) for the ICD-9 code was 98%. All MGUS cases confirmed by chart review also had confirmatory laboratory test results. Of the confirmed cases first identified via M-protein test results, 88% also had the ICD-9 diagnosis code.

CONCLUSION

The diagnosis code-based approach has excellent PPV and likely high sensitivity for detecting clinically diagnosed MGUS. The generalizability of this approach outside an integrated healthcare system warrants further evaluation.

Monoclonal Gammopathies in a Fracture Liaison Service

Monoclonal gammopathies are a spectrum of disorders characterized by the overproduction of plasma B-cells and immunoglobulin. Monoclonal gammopathy of uncertain significance (MGUS), a pre-malignant form of multiple myeloma, is defined by relatively low bone marrow concentration of clonal plasma cells and asymptomatic clinical presentation. New evidence, however, points to an association of MGUS with osteoporosis, microarchitectural bone deficiency, and fractures, and it has been suggested that it be renamed "Monoclonal Gammopathy of Skeletal Significance." The prevalence of MGUS in the general geriatric population is estimated to be 3-8%, while the prevalence in geriatric vertebral fracture patients is 15%, and the prevalence in all fracture patients within the Rhode Island Fracture Liaison Service is 10%. Therefore, MGUS and other monoclonal gammopathies should be suspected in all patients diagnosed with osteoporosis or an osteoporotic fracture, and patients diagnosed with monoclonal gammopathies should be evaluated for osteoporosis and fracture risk and treated appropriately.

Prevalence of monoclonal gammopathy of undetermined significance in Black South African men

BACKGROUND

Both multiple myeloma and its precursor, monoclonal gammopathy of undetermined significance (MGUS), occur twice as often within Black compared to White populations, suggesting that racial disparities lie within the development of MGUS. Nonetheless, MGUS has been studied mainly in White cohorts; the study that first described the natural history of MGUS was conducted in 97.3% White Olmsted County, Minnesota.

METHODS

We determined the prevalence of MGUS among 386 Black South African (SA) men >30 years at Chris Hani Baragwanath Hospital in Johannesburg. We conducted serum protein electrophoresis and free light chain quantification to define MGUS by the same criteria as the Olmsted County studies. We also investigated the association between MGUS and various clinical factors, including HIV infection and smoking.

RESULTS

We found the prevalence of MGUS to be 8.03% (95%CI 5.32-10.74), nearly 1.6-fold higher than in the White Olmsted County male population. In a univariable logistic regression model, MGUS was associated with HIV status (Odds Ratio, OR 2.39, 95%CI 0.95-5.49), but in an adjusted model that included body mass index and cigarette use, the association was not statistically significant. Those who were current (vs. never) cigarette smokers were more likely to have MGUS in both univariable (OR 5.60, 95%CI 2.16-17.42) and multivariable models (OR 4.49, 95%CI 1.63-14.56).

CONCLUSIONS

The prevalence of MGUS in Black SA men is substantially higher than in White populations and may be associated with HIV status and cigarette use.

IMPACT

Racial disparities in MGUS exist and may be associated with potentially modifiable risk factors.

Prevalence of monoclonal gammopathies and clinical outcomes in a high-risk US population screened by mass spectrometry: a multicentre cohort study

BACKGROUND

Prevalence estimates for monoclonal gammopathy of undetermined significance (MGUS) are based on predominantly White study populations screened by serum protein electrophoresis supplemented with immunofixation electrophoresis. A prevalence of 3% is reported for MGUS in the general population of European ancestry aged 50 years or older. MGUS prevalence is two times higher in individuals of African descent or with a family history of conditions related to multiple myeloma. We aimed to evaluate the prevalence and clinical implications of monoclonal gammopathies in a high-risk US population screened by quantitative mass spectrometry.

METHODS

We used quantitative matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry and EXENT-iQ software to screen for and quantify monoclonal gammopathies in serum from 7622 individuals who consented to the PROMISE screening study between Feb 26, 2019, and Nov 4, 2021, and the Mass General Brigham Biobank (MGBB) between July 28, 2010, and July 1, 2021. M-protein concentrations at the monoclonal gammopathy of indeterminate potential (MGIP) level were confirmed by liquid chromatography mass spectrometry testing. 6305 (83%; 2211 from PROMISE, 4094 from MGBB) of 7622 participants in the cohorts were at high risk for developing a monoclonal gammopathy on the basis of Black race or a family history of haematological malignancies and fell within the eligible high-risk age range (30 years or older for PROMISE cohort and 18 years or older for MGBB cohort); those over 18 years were also eligible if they had two or more family members with a blood cancer (PROMISE cohort). Participants with a plasma cell malignancy diagnosed before screening were excluded. Longitudinal clinical data were available for MGBB participants with a median follow-up time from serum sample screening of 4·5 years (IQR 2·4-6·7). The PROMISE study is registered with ClinicalTrials.gov, NCT03689595.

FINDINGS

The median age at time of screening was 56·0 years (IQR 46·8-64·1). 5013 (66%) of 7622 participants were female, 2570 (34%) male, and 39 (<1%) unknown. 2439 (32%) self-identified as Black, 4986 (65%) as White, 119 (2%) as other, and 78 (1%) unknown. Using serum protein electrophoresis with immunofixation electrophoresis, the MGUS prevalence was 6% (101 of 1714) in high-risk individuals aged 50 years or older. Using mass spectrometry, we observed a total prevalence of monoclonal gammopathies of 43% (1788 of 4207) in this group. We termed monoclonal gammopathies below the clinical immunofixation electrophoresis detection level (<0·2 g/L) MGIPs, to differentiate them from those with higher concentrations, termed mass-spectrometry MGUS, which had a 13% (592 of 4207) prevalence by mass spectrometry in high-risk individuals aged 50 years or older. MGIP was predominantly of immunoglobulin M isotype, and its prevalence increased with age (19% [488 of 2564] for individuals aged <50 years, 29% [1464 of 5058] for those aged ≥50 years, and 37% [347 of 946] for those aged ≥70 years). Mass-spectrometry MGUS prevalence increased with age (5% [127 of 2564] for individuals aged <50 years, 13% [678 of 5058] for those aged ≥50 years, and 18% [173 of 946] for those aged ≥70 years) and was higher in men (314 [12%] of 2570) compared with women (485 [10%] 5013; p=0·0002), whereas MGIP prevalence did not differ significantly by gender. In those aged 50 years or older, the prevalence of mass spectrometry was significantly higher in Black participants (224 [17%] of 1356) compared with the controls (p=0·0012) but not in those with family history (368 [13%] of 2851) compared with the controls (p=0·1008). Screen-detected monoclonal gammopathies correlated with increased all-cause mortality in MGBB participants (hazard ratio 1·55, 95% CI 1·16-2·08; p=0·0035). All monoclonal gammopathies were associated with an increased likelihood of comorbidities, including myocardial infarction (odds ratio 1·60, 95% CI 1·26-2·02; p=0·00016 for MGIP-high and 1·39, 1·07-1·80; p=0·015 for mass-spectrometry MGUS).

INTERPRETATION

We detected a high prevalence of monoclonal gammopathies, including age-associated MGIP, and made more precise estimates of mass-spectrometry MGUS compared with conventional gel-based methods. The use of mass spectrometry also highlighted the potential hidden clinical significance of MGIP. Our study suggests the association of monoclonal gammopathies with a variety of clinical phenotypes and decreased overall survival.

FUNDING

Stand Up To Cancer Dream Team, the Multiple Myeloma Research Foundation, and National Institutes of Health.

Body mass index associated with monoclonal gammopathy of undetermined significance (MGUS) progression in Olmsted County, Minnesota

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant clonal disorder that progresses to multiple myeloma (MM), or other plasma-cell or lymphoid disorders at a rate of 1%/year. We evaluate the contribution of body mass index (BMI) to MGUS progression beyond established clinical factors in a population-based study. We identified 594 MGUS through a population-based screening study in Olmsted County, Minnesota, between 1995 and 2003. Follow-up time was calculated from the date of MGUS to last follow-up, death, or progression to MM/another plasma-cell/lymphoid disorder. BMI (kg/m2 < 25/≥25) was measured close to screening date. We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of BMI ≥ 25 versus BMI < 25 with MGUS progression and also evaluated the corresponding c-statistic and 95% CI to describe discrimination of the model for MGUS progression. Median follow-up was 10.5 years (range:0-25), while 465 patients died and 57 progressed and developed MM (N = 39), AL amyloidosis (N = 8), lymphoma (N = 5), or Waldenstrom-macroglobulinemia (N = 5). In univariate analyses, BMI ≥ 25 (HR = 2.14,CI:1.05-4.36, P = 0.04), non-IgG (HR = 2.84, CI:1.68-4.80, P = 0.0001), high monoclonal (M) protein (HR = 2.57, CI:1.50-4.42, P = 0.001), and abnormal free light chain ratio (FLCr) (HR = 3.39, CI:1.98-5.82, P < 0.0001) were associated with increased risk of MGUS progression, and were independently associated in a multivariable model (c-statistic = 0.75, CI:0.68-0.82). The BMI association was stronger among females (HR = 3.55, CI:1.06-11.9, P = 0.04) vs. males (HR = 1.39, CI:0.57-3.36, P = 0.47), although the interaction between BMI and sex was not significant (P = 0.15). In conclusion, high BMI is a prognostic factor for MGUS progression, independent of isotype, M protein, and FLCr. This association may be stronger among females.

Patients With Multiple Myeloma or Monoclonal Gammopathy of Undetermined Significance

BACKGROUND

Multiple myeloma (MM) is a malignant plasma-cell disease that arises on the basis of a so-called monoclonal gammopathy of undetermined significance (MGUS). The median age at disease onset is over 70. In Germany, there are approximately eight new cases per 100 000 inhabitants per year, or about 6000 new patients nationwide each year.

METHODS

To prepare this clinical practice guideline, a systematic literature review was carried out in medical databases (MEDLINE, CENTRAL), guideline databases (GIN), and the search portal of the German Institute for Quality and Efficiency in Health Care (IQWiG). The recommendations to be issued were based on two international guidelines, 40 dossier evaluations and systematic reviews, 10 randomized controlled trials, and 37 observational studies and finalized in a structured consensus process.

RESULTS

Because of its prognostic relevance, the use of the International Staging System (ISS) is recommended to stage MM and related plasma-cell neoplasms. When symptomatic MM is diagnosed, it is recommended to determine the extent of skeletal involvement by whole-body computed tomography. The indications for treatment shall be determined on the basis of the SLiMCRAB criteria; in all patients with MM it is recommended to include the biological (rather than chronological) age in the decisionmaking process. In suitable patients, it is recommended that initial treatment includes high-dose therapy, followed by main - tenance treatment. Even without high-dose treatment, a median progression-free survival of more than three years can be achieved with combination therapies. For the treatment of relapse, combinations of three drugs are more effective than doublet regimens with a median progression-free survival ranging from 10 to 45 months, depending on the study and prior therapy. Following anti-myeloma therapy, it is recommended to promptly offer physical exercise adapted to individual abilities to all patients who have the potential for rehabilitation, so that their quality of life can be sustained and improved.

CONCLUSION

This new clinical practice guideline addresses, in particular, the modalities of care that can be offered in addition to systemic antineoplastic therapy. In view of the significant recent advances in the treatment of myeloma, affected patients' quality of life now largely depends on optimized interdisciplinary care.

[Monoclonal gammopathies]

Monoclonal gammopathies range from benign conditions to severe malignancies. A summary is given in this review. Overall, the prevalence is high; monoclonal gammopathies (MGUS) occur in > 3% of persons above 50 years of age. Approximately 400 new cases of multiple myeloma and 80 new cases of amyloid light-chain (AL) amyloidosis are diagnosed yearly in Denmark. MGUS is most often asymptomatic, but M-protein associated syndromes exist and should be considered when finding M-protein. Serum free light kappa and lambda chain analysis, CT, PET/CT and whole-body MRI have revolutionised diagnostics and monitoring of monoclonal gammopathies. New treatment modalities have improved outcome in multiple myeloma and AL amyloidosis.

A nationwide study of patients with monoclonal gammopathy of undetermined significance with a 10-year follow-up in South Korea

In clinical practice, most patients with monoclonal gammopathy of undetermined significance (MGUS) undergo long-term follow-up without disease progression. There is insufficient real-world data about how closely and whether anything other than disease progression should be monitored. Herein, we performed a nationwide study of 470 patients with MGUS with a 10-year follow-up to determine the patterns of disease progression and other comorbidities. During the follow-up period, 158 of 470 patients with MGUS (33.62%) progressed to symptomatic monoclonal gammopathies. Most of these were multiple myeloma (134/470 patients, 28.51%), and those diagnosed within 2 years after diagnosis of MGUS was high. Approximately 30-50% of patients with MGUS had hypertension, diabetes, hyperlipidemia, and osteoarthritis at the time of diagnosis, and these comorbidities were newly developed during the follow-up period in approximately 50% of the remaining patients with MGUS. Approximately 20-40% of patients with MGUS have acute or chronic kidney failure, thyroid disorders, disc disorders, peripheral neuropathy, myocardial infarction, stroke, and heart failure during the follow-up period. Altogether, when MGUS is diagnosed, close follow-up of the possibility of progression to multiple myeloma is required, especially within 2 years after diagnosis; simultaneously, various comorbidities should be considered and monitored during the follow-up of patients with MGUS. Continuous research is needed to establish appropriate follow-up guidelines.

Iceland screens, treats, or prevents multiple myeloma (iStopMM): a population-based screening study for monoclonal gammopathy of undetermined significance and randomized controlled trial of follow-up strategies

Monoclonal gammopathy of undetermined significance (MGUS) precedes multiple myeloma (MM). Population-based screening for MGUS could identify candidates for early treatment in MM. Here we describe the Iceland Screens, Treats, or Prevents Multiple Myeloma study (iStopMM), the first population-based screening study for MGUS including a randomized trial of follow-up strategies. Icelandic residents born before 1976 were offered participation. Blood samples are collected alongside blood sampling in the Icelandic healthcare system. Participants with MGUS are randomized to three study arms. Arm 1 is not contacted, arm 2 follows current guidelines, and arm 3 follows a more intensive strategy. Participants who progress are offered early treatment. Samples are collected longitudinally from arms 2 and 3 for the study biobank. All participants repeatedly answer questionnaires on various exposures and outcomes including quality of life and psychiatric health. National registries on health are cross-linked to all participants. Of the 148,704 individuals in the target population, 80 759 (54.3%) provided informed consent for participation. With a very high participation rate, the data from the iStopMM study will answer important questions on MGUS, including potentials harms and benefits of screening. The study can lead to a paradigm shift in MM therapy towards screening and early therapy.

Health impact of monoclonal gammopathy of undetermined significance (MGUS) and monoclonal B-cell lymphocytosis (MBL): findings from a UK population-based cohort

OBJECTIVE

To examine mortality and morbidity patterns before and after premalignancy diagnosis in individuals with monoclonal gammopathy of undetermined significance (MGUS) and monoclonal B-cell lymphocytosis (MBL) and compare their secondary healthcare activity to that of the general population.

DESIGN

Population-based patient cohort, within which each patient is matched at diagnosis to 10 age-matched and sex-matched individuals from the general population. Both cohorts are linked to nationwide information on deaths, cancer registrations and Hospital Episode Statistics.

SETTING

The UK's Haematological Malignancy Research Network, which has a catchment population of around 4 million served by 14 hospitals and a central diagnostic laboratory.

PARTICIPANTS

All patients newly diagnosed during 2009-2015 with MGUS (n=2193) or MBL (n=561) and their age and sex-matched comparators (n=27 538).

MAIN OUTCOME MEASURES

Mortality and hospital inpatient and outpatient activity in the 5 years before and 3 years after diagnosis.

RESULTS

Individuals with MGUS experienced excess morbidity in the 5 years before diagnosis and excess mortality and morbidity in the 3 years after diagnosis. Increased rate ratios (RRs) were evident for nearly all clinical specialties, the largest, both before and after diagnosis, being for nephrology (before RR=4.29, 95% CI 3.90 to 4.71; after RR=13.8, 95% CI 12.8 to 15.0) and rheumatology (before RR=3.40, 95% CI 3.18 to 3.63; after RR=5.44, 95% CI 5.08 to 5.83). Strong effects were also evident for endocrinology, neurology, dermatology and respiratory medicine. Conversely, only marginal increases in mortality and morbidity were evident for MBL.

CONCLUSIONS

MGUS and MBL are generally considered to be relatively benign, since most individuals with monoclonal immunoglobulins never develop a B-cell malignancy or any other monoclonal protein-related organ/tissue-related disorder. Nonetheless, our findings offer strong support for the view that in some individuals, monoclonal gammopathy has the potential to cause systemic disease resulting in wide-ranging organ/tissue damage and excess mortality.

Screening for M-proteinemia consisting of monoclonal gammopathy of undetermined significance and multiple myeloma for 30 years among atomic bomb survivors in Hiroshima

Monoclonal gammopathy (M-proteinemia) is a premalignant plasma cell disorder. The prevalence of M-proteinemia increases with age and is affected by genetic or environmental factors. Atomic bomb (A-bomb) survivors in Hiroshima are in an age range when they are susceptible to M-proteinemia. The prevalence and incidence of M-proteinemia in Hiroshima A-bomb survivors were investigated for 30 years (1989-2018) to examine the influence of radiation exposure. The overall prevalence of M-proteinemia among 38,602 A-bomb survivors was 2.4%. M-proteinemia prevalence at age 70 years and monoclonal gammopathy of undetermined significance (MGUS) incidence were not associated with radiation exposure category. Males had a 2.30-fold higher prevalence and a 2.08-fold higher incidence than females. The risk of incidence for MGUS was 4.32-fold higher in persons aged < 10 years at the time of the A-bombing and 2.56-fold higher in those aged 10-19 years compared with those aged over 30 years. IgG type M-proteinemia was common and the IgM type developed 5-8 years later than other immunoglobulin types. Exposure to radiation was not clearly associated with the prevalence of M-proteinemia or incidence of MGUS in Hiroshima A-bomb survivors. However, males and those aged < 20 years at A-bombing had higher susceptibility to MGUS.

Lifetime Pesticide Use and Monoclonal Gammopathy of Undetermined Significance in a Prospective Cohort of Male Farmers

BACKGROUND

Farmers have a higher incidence of multiple myeloma, and there is suggestive evidence of an elevated prevalence of its precursor, monoclonal gammopathy of undetermined significance (MGUS), relative to the general population. Pesticide exposures are suspected to play a role; however, the biologic plausibility for associations with multiple myeloma remains unclear.

OBJECTIVES

Our objectives were to examine the prevalence of MGUS and evaluate associations with a wide range of pesticides in a large sample of farmers.

METHODS

We obtained sera and assessed MGUS among 1,638 male farmers ≥ 50  years of age in the Agricultural Health Study (AHS), a prospective cohort in Iowa and North Carolina. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed to estimate associations with MGUS for recent use (within the 12 months before phlebotomy) and cumulative intensity-weighted lifetime days of use of specific pesticides.

RESULTS

The age-standardized MGUS prevalence was significantly elevated among AHS farmers (7.7%) compared with demographically similar men in the National Health and Nutrition Examination Survey (2.8%) or Olmsted County, Minnesota (3.8%; p < 0.001 ). Recent use of permethrin was associated with MGUS [recent use vs. no recent use, OR = 1.82 (95% CI: 1.06, 3.13)], especially among those who had also used it in the past [recent and past use vs. never use, OR = 2.49 (95% CI: 1.32, 4.69)]. High intensity-weighted lifetime use of the organochlorine insecticides aldrin and dieldrin was associated with MGUS relative to those who never used either of these pesticides [OR = 2.42 (95% CI: 1.29, 4.54); p trend = 0.006 ]. We also observed a positive association with high lifetime use of petroleum oil/distillates as an herbicide, as well as an inverse association with fonofos use.

DISCUSSION

This is the largest investigation of MGUS in farmers and the first to identify an association with MGUS for permethrin, a pyrethroid insecticide previously associated with multiple myeloma. Given the continued widespread use of permethrin in various residential and commercial settings, our findings may have important implications for exposed individuals in the general population. https://doi.org/10.1289/EHP6960.

[Monoclonal gammopathy of uncertain significance (MGUS) and ionizing radiation]

The term monoclonal gammopathy refers to a clinical condition characterized by the presence in serum and/or urine of clonal immunoglobulins, i.e. homogeneous immunoglobulins, structurally identical both as a heavy chain and as a light chain, produced by a B cell clone (1). The prevalence of MGUS is low in young subjects (less than 2% of patients with MGUS are less than 40 years of age, while in the population aged over 50 years it is relatively high (3.2%) and increases considerably with age. Although historically considered to be a benign condition, patients with MGUS are at risk to develop multiple myeloma over time. Therefore, MGUS may be framed as a preneoplastic stage of the plasma cell that precedes the possible development of a multiple myeloma. In a limited percentage of cases, it can be considered the asymptomatic pre-malignant stage preceding multiple myeloma (MM) on a probabilistic basis. Few studies have assessed the prevalence of MGUS in people occupationally exposed to pesticides. Several other studies on atomic bomb survivors in Hiroshima and Nagasaki have revealed a possible association with exposure to ionizing radiation (IR). Routine laboratory tests performed on the subjects exposed to the risk factors studied appear to be indicated for workers from the age of 50 years. The finding of a GMUS in the absence of further laboratory alterations is the most frequent finding and does not require further action, if it is not to plan include blood chemistry tests at least every two years. In this situation, no restrictions appear to be justified on the work activity involving the risk of exposure to IR or pesticides. In case of concurrent presence of alterations that may be indicative or suggestive of an increased risk of evolution in a neoplastic way a close periodicity - every 3-6 months - of haematological checks is recommended. In such cases, it appears justified to move away from activities involving exposure to ionizing radiation for a period of time which should be evaluated on the basis of the evolution of the picture and the progress of laboratory tests during the monitoring period.

Use of trabecular bone score for risk stratification of patients with monoclonal gammopathy of undetermined significance

Monoclonal gammopathy of undetermined significance (MGUS) is a common finding in clinical practice. The risk for developing MGUS increases with aging in parallel with age-associated increases in fracture risk. Although there is good evidence that patients with MGUS suffer from increased fracture risk, no standardized guidelines exist for the evaluation and/or management of skeletal health in patients with MGUS. Trabecular bone score (TBS), a texture index derived from lumbar spine (LS) dual-energy x-ray absorptiometry (DXA) images, provides information about trabecular microarchitecture independent of bone mineral density (BMD). We retrospectively identified 155 adult patients diagnosed with MGUS between 2005 and 2018. This group was matched 1:1 to a control group for sex, age and BMI. TBS was performed retrospectively, and values categorized as low (≤1.23), intermediate (1.23-1.31) or normal (>1.31). Patients had a mean ± SD age of 69.6 ± 10.0. BMD was performed within a median of 28 months (IQR 1-78) of MGUS diagnosis. Cases had a non-statistically significant higher rate of fractures compared to control subjects (27 vs. 17, respectively, p = 0.1). Patients with MGUS had a significantly lower TBS (1.31 ± 0.13 vs. 1.34 ± 0.12, respectively, p < 0.05) and lower LS BMD (1.215 ± 0.223 vs. 1.275 ± 0.247, p < 0.05) compared to controls. Although fractures occurred more commonly in those control subjects with significantly lower TBS values, this was not the case in subjects with MGUS (TBS 1.299 vs. 1.313 in cases with vs. without fractures p = 0.313). Similarly, there was no difference in T-scores in cases with or without fractures (-1.33 vs. -1.37, respectively, p = 0.56). Despite patients with MGUS having a significantly increased fracture risk compared to age-, sex- and BMI-matched control subjects, neither assessment of BMD nor TBS, obtained within two years of MGUS diagnosis, were able to accurately risk stratify MGUS patients. Unlike control subjects, patients with MGUS tend to fracture despite normal BMD and intermediate or normal TBS values, suggesting that deterioration of cortical rather than trabecular skeletal components may be more important for the increased fracture risk seen in MGUS.

The First Case of TEMPI Syndrome in Japan

TEMPI syndrome, a disease entity comprising telangiectasia, erythrocytosis with high erythropoietin, monoclonal gammopathy, perinephric fluid collection, and intrapulmonary shunting, was first described by Sykes et al. in 2011. To our knowledge, only 15 cases have been reported worldwide, none of which were in Japan. We herein report a 47-year-old man who had intractable ascites for 2 and a half years and was referred to our department for a peritoneovenous shunt. In addition to ascites, he had telangiectasia, high erythropoietin, monoclonal gammopathy, and perinephric fluid collection. Thus, this is the first case of TEMPI syndrome in Japan.

Association between non-malignant monoclonal gammopathy and adverse outcomes in chronic kidney disease: A cohort study

BACKGROUND

In studies including the general population, the presence of non-malignant monoclonal gammopathy (MG) can be causally associated with kidney damage and shorter survival. We assessed whether the presence of an MG is associated with a higher risk of kidney failure or death in individuals with chronic kidney disease (CKD).

METHODS AND FINDINGS

Data were used from 3 prospective cohorts of individuals with CKD (not on dialysis or with a kidney transplant): (1) Renal Impairment in Secondary Care (RIISC, Queen Elizabeth Hospital and Heartlands Hospital, Birmingham, UK, N = 878), (2) Salford Kidney Study (SKS, Salford Royal Hospital, Salford, UK, N = 861), and (3) Renal Risk in Derby (RRID, Derby, UK, N = 1,739). Participants were excluded if they had multiple myeloma or any other B cell lymphoproliferative disorder with end-organ damage. Median age was 71.0 years, 50.6% were male, median estimated glomerular filtration rate was 42.3 ml/min/1.73 m2, and median urine albumin-to-creatinine ratio was 3.4 mg/mmol. All non-malignant MG was identified in the baseline serum of participants of RIISC. Further, light chain MG (LC-MG) was identified and studied in participants of RIISC, SKS, and RRID. Participants were followed up for kidney failure (defined as the initiation of dialysis or kidney transplantation) and death. Associations with the risk of kidney failure were estimated by competing-risks regression (handling death as a competing risk), and associations with death were estimated by Cox proportional hazards regression. In total, 102 (11.6%) of the 878 RIISC participants had an MG. During a median follow-up time of 74.0 months, there were 327 kidney failure events and 202 deaths. The presence of MG was not associated with risk of kidney failure (univariable subhazard ratio [SHR] 0.97 [95% CI 0.68 to 1.38], P = 0.85; multivariable SHR 1.16 [95% CI 0.80 to 1.69], P = 0.43), and although there was a higher risk of death in univariable analysis (hazard ratio [HR] 2.13 [95% CI 1.49 to 3.02], P < 0.001), this was not significant in multivariable analysis (HR 1.37 [95% CI 0.93 to 2.00], P = 0.11). Fifty-five (1.6%) of the 3,478 participants from all 3 studies had LC-MG. During a median follow-up time of 62.5 months, 564 of the 3,478 participants progressed to kidney failure, and 803 died. LC-MG was not associated with risk of kidney failure (univariable SHR 1.07 [95% CI 0.58 to 1.96], P = 0.82; multivariable SHR 1.42 [95% CI 0.78 to 2.57], P = 0.26). There was a higher risk of death in those with LC-MG in the univariable model (HR 2.51 [95% CI 1.59 to 3.96], P < 0.001), but not in the multivariable model (HR 1.49 [95% CI 0.93 to 2.39], P = 0.10). An important limitation of this work was that only LC-MG, rather than any MG, could be identified in participants from SKS and RRID.

CONCLUSIONS

The prevalence of MG was higher in this CKD cohort than that reported in the general population. However, the presence of an MG was not independently associated with a significantly higher risk of kidney failure or, unlike in the general population, risk of death.

Gamma gap thresholds and HIV, hepatitis C, and monoclonal gammopathy

BACKGROUND

An elevated gamma gap (>4 g/dL), the difference between serum total protein and albumin, can trigger testing for chronic infections or monoclonal gammopathy, despite a lack of evidence supporting this clinical threshold.

METHODS

Using the National Health and Nutrition Examination Survey (NHANES) 1999-2014, gamma gap was derived in three subpopulations based on availability of testing for human immunodeficiency virus (HIV; N = 25,680), hepatitis C (HCV; N = 45,134), and monoclonal gammopathy of unknown significance (MGUS; N = 6,118). Disease status was confirmed by HIV antibody and Western blot, HCV RNA test, or electrophoresis with immunofixation. Sensitivity, specificity, and likelihood ratios were calculated for different gamma gap thresholds. Area under the curve (AUC) was used to assess performance and cubic splines were used to characterize the relationship between the gamma gap and each disease.

RESULTS

Mean gamma gaps of participants with HIV, HCV, or MGUS ranged from 3.4-3.8 g/dL. The AUC was 0.80 (95%CI: 0.75,0.85) for HIV, 0.74 (0.72,0.76) for HCV, and 0.64 (0.60,0.69) for MGUS. An elevated gamma gap of over 4 g/dL corresponded to sensitivities of 39.3%, 19.0%, and 15.4% and specificities of 98.4%, 97.8%, and 95.4% for HIV, HCV, and MGUS, respectively. A higher prevalence of all three diseases was observed at both low and high gamma gaps.

DISCUSSION

An elevated gamma gap of 4 g/dL is insensitive for HIV, HCV, or MGUS, but has a high specificity for HIV and HCV, suggesting that the absence of an elevated gamma gap does not rule out HIV, HCV, or MGUS. Conversely, an elevated gap may justify further testing for HIV and HCV, but does not justify electrophoresis in the absence of additional clinical information.

Identifying monoclonal gammopathy of undetermined significance in electronic health data

PURPOSE

Monoclonal gammopathy of undetermined significance (MGUS) is a prevalent yet largely asymptomatic precursor to multiple myeloma. Patients with MGUS must undergo regular surveillance and testing, with few known predictors of progression. We developed an algorithm to identify MGUS patients in electronic health data to facilitate large-scale, population-based studies of this premalignant condition.

METHODS

We developed a four-step algorithm using electronic health record and health claims data from men and women aged 50 years or older receiving care from a large, multispecialty medical group between 2007 and 2015. The case definition required patients to have at least two MGUS ICD-9 diagnosis codes within 12 months, at least one serum and/or urine protein electrophoresis and one immunofixation test, and at least one in-office hematology/oncology visit. Medical charts for selected cases were abstracted then adjudicated independently by two physicians. We assessed algorithm validity by positive predictive value (PPV).

RESULTS

We identified 833 people with at least two MGUS diagnosis codes; 429 (52%) met all four algorithm criteria. We randomly selected 252 charts for review, including 206 from patients meeting all four algorithm criteria. The PPV for the 206 algorithm-identified charts was 76% (95% CI, 70%-82%). Among the 49 cases deemed to be false positives (24%), 33 were judged to have multiple myeloma or another lymphoproliferative condition, such as lymphoma.

CONCLUSIONS

We developed a simple algorithm that identified MGUS cases in electronic health data with reasonable accuracy. Inclusion of additional steps to eliminate cases with malignant disease may improve algorithm performance.

[Monoclonal gammopathy of uncertain significance (MGUS) and occupational risk factors: criteria to carry out the health surveillance]

Monoclonal gammopathy of uncertain significance (MGUS) identifies a clinically asymptomatic and laboratory-based situation characterized by a modest monoclonal component (MC). In a limited percentage of cases, on a probabilistic basis, the asymptomatic genepremalignant stage could lead to multiple myeloma (MM). Materials and Methods. Based on literature data and available Guidelines on the subject, the diagnostic criteria and a methodological path are here suggested to the Occupational Physician to formulate a judgment of suitability for the task with exposure risk to RI or pesticides. Results. Some studies have evaluated the prevalence of MGUS in subjects exposed professionally to pesticides. Numerous other studies conducted on the survivors of the atomic bombing of Hiroshima and Nagasaki have highlighted a possible association with exposure to ionizing radiation (IR). The guidelines relating to the diagnosis and management of MGUS cases (with respect to the potential evolution in MM allow) to draw important operational indications for the competent/authorized physician. Conclusions. The routinely use of laboratory tests for subjects exposed to the studied risk factors is generally indicated starting from the worker's 50 years of age. The finding of a MGUS in the absence of further laboratory alterations represents the situation most frequently and does not require further measures, other than those of foreseeing even blood controls at least every two years. In this situation, there are no justified restrictions on work activities with exposure risks to IR or pesticides. If alterations suggestive for an increased risk of evolution in a neoplastic way could be identified, a close periodicity - every 3-6 months - of haematological checks is recommended. In these cases, it appears justified an abstention from activities involving exposure to ionizing radiation for a period of time that will be evaluated based on the evolution of the framework and by the progress of laboratory tests in the monitored period.

Impact of prior diagnosis of monoclonal gammopathy on outcomes in newly diagnosed multiple myeloma

Multiple myeloma (MM) is consistently preceded by monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma (SMM), or solitary plasmacytoma (SPC). There is a lack of data regarding impact of these pre-existing monoclonal gammopathies (MGs) on MM outcomes. Patients with prior diagnosis of MGUS, SMM, or PC from 1973 to 2015 (cases) were identified from our institution's database and compared to those without a known MG (controls). The primary outcome of interest was overall survival (OS). Multivariate analysis was performed to ascertain factors impacting all-cause mortality. We identified 774 patients with a prior diagnosis of MGUS, SMM or SPC (cases) and a control population (1:2) matched for the year of diagnosis (n = 1548). After a median follow-up of 81 months, the cases showed a longer median OS than the controls (71 months vs. 56 months). The improved OS was limited to those with a known prior diagnosis of SMM (80 months) and SPC (95 months), compared to MGUS (60 months). Multivariable analysis revealed that MM patients with known prior MG had less overall mortality than those without, and this was limited to prior SMM/SPC group (HR 0.68, 95% CI: 0.50-0.93), as compared to the MGUS group (HR 0.83, 95% CI: 0.66-1.05).

Monoclonal Gammopathy of Undetermined Significance (MGUS)Monoclonal Gammopathy of Undetermined Significance (MGUS)

BACKGROUND

Monoclonal gammopathy of undetermined significance (MGUS) is one of the most prevalent premalignant conditions associated with a risk of malignant transformation to multiple myeloma (MM) or other forms of lymphoproliferative disorders with risk of progression of approximately 1% per year. IgG and IgA MGUS are precursor conditions of multiple myeloma (MM), whereas light-chain MGUS is a precursor condition of light chain MM. IgM MGUS is a precursor condition of Waldenström macroglobulinemia (MW) or other lymphoproliferative diseases.

AIM

Assessment of the risk of progression of patients with asymptomatic monoclonal gammopathies (MG) is based on various factors, including the serum paraprotein (M protein) concentration, isotype of M protein, serum free light chain ratio, infiltration of bone marrow plasmocytes, reduction of one or two noninvolved immunoglobulin subtype levels (immunoparesis), evolving and non-evolving subtype of MGUS, ratio of normal/abnormal plasma cells in bone marrow identified by multiparametric flow cytometry techniques and number of circulating plasma cells in peripheral blood. Three risk stratification models have been constructed that are useful in daily practice for predicting risk of progression of MGUS into malignant forms of monoclonal gammopathy - MAYO, PETHEMA and CMG model. The goal of all three models is to identify correctly prognostic markers that can divide patients into low-risk MGUS and high-risk MGUS groups.

CONCLUSION

This review provides a look at the definition, pathogenesis, diagnostic algorithm, clinical significance and stratification of MGUS patients, followed by recommendations for patient risk dispensarisation intervals.

Dietary intake is associated with risk of multiple myeloma and its precursor disease

The etiology of monoclonal gammopathy of undetermined significance (MGUS), the precursor state of multiple myeloma (MM), is mostly unknown and no studies have been conducted on the effect of diet on MGUS or progression from MGUS to MM. We aimed to explore the association between common foods and MGUS and progression to MM. Data from the population-based AGES Study (N = 5,764) were utilized. Food frequency questionnaire was used to assess dietary intake during adolescence, midlife, and late life. Serum protein electrophoresis and serum free light-chain assay was performed to identify MGUS (n = 300) and LC-MGUS cases (n = 275). We cross linked our data with the Icelandic Cancer Registry to find cases of MM in the study group. We found that intake of fruit at least three times per week during adolescence was associated with lower risk of MGUS when compared to lower fruit consumption (OR = 0.62, 95% CI 0.41–0.95). We additionally found that intake of fruit at least three times per week during the late life period was associated with decreased risk of progressing from MGUS to MM (HR = 0.34, 95% CI 0.13–0.89) when compared to lower intake. Adolescent intake of fruit may reduce risk of MGUS, whereas fruit intake after MGUS onset may reduce risk of progressing to MM. Our findings suggest that diet might alter the risk of developing MGUS and progression to MM.

What is the significance of monoclonal gammopathy of undetermined significance?

Monoclonal gammopathy of undetermined significance (MGUS) is characterised by the presence of a monoclonal paraprotein in the blood, without the characteristic end organ damage seen in multiple myeloma. MGUS is more common in older age groups and has a risk of progression to myeloma of 1% per year. Population screening is not currently recommended, but retrospective studies have suggested improvements in myeloma outcomes in those under MGUS follow-up; in addition, MGUS has associated complications, including fracture, osteoporosis, renal disease and infection, which can be treated. Given this increasing evidence of disease related directly to MGUS, strategies for early identification might be needed. In this review, we discuss the complications of MGUS and whether MGUS fulfils the criteria needed to implement a screening programme. We also highlight areas where more evidence is needed, including identification of a higher risk population to make screening more practical and economically viable.

Enrichment of B cell receptor signaling and epidermal growth factor receptor pathways in monoclonal gammopathy of undetermined significance: a genome-wide genetic interaction study

BACKGROUND

Recent identification of 10 germline variants predisposing to monoclonal gammopathy of undetermined significance (MGUS) explicates genetic dependency of this asymptomatic precursor condition with multiple myeloma (MM). Yet much of genetic burden as well as functional links remain unexplained. We propose a workflow to expand the search for susceptibility loci with genome-wide interaction and for subsequent identification of genetic clusters and pathways.

METHODS

Polygenic interaction analysis on 243 cases/1285 controls identified 14 paired risk loci belonging to unique chromosomal bands which were then replicated in two independent sets (case only study, 82 individuals; case/control study 236 cases/ 2484 controls). Further investigation on gene-set enrichment, regulatory pathway and genetic network was carried out with stand-alone in silico tools separately for both interaction and genome-wide association study-detected risk loci.

RESULTS

Intronic-PREX1 (20q13.13), a reported locus predisposing to MM was confirmed to have contribution to excess MGUS risk in interaction with SETBP1, a well-established candidate predisposing to myeloid malignancies. Pathway enrichment showed B cell receptor signaling pathway (P < 5.3 × 10- 3) downstream to allograft rejection pathway (P < 5.6 × 10- 4) and autoimmune thyroid disease pathway (P < 9.3 × 10- 4) as well as epidermal growth factor receptor regulation pathway (P < 2.4 × 10- 2) to be differentially regulated. Oncogene ALK and CDH2 were also identified to be moderately interacting with rs10251201 and rs16966921, two previously reported risk loci for MGUS.

CONCLUSIONS

We described novel pathways and variants potentially causal for MGUS. The methodology thus proposed to facilitate our search streamlines risk locus-based interaction, genetic network and pathway enrichment analyses.

Monoclonal gammopathy of undetermined significance as viewed by haematology healthcare professionals

OBJECTIVES

To investigate the words and descriptions used by haematology healthcare professionals (HCPs) to describe monoclonal gammopathy of undetermined significance (MGUS) to their patients.

METHODS

A cross-sectional survey of haematology HCPs attending an annual haematology conference was undertaken. Content analysis was applied to the returned qualitative responses.

RESULTS

In total, 55 people, many of whom were doctors (n = 32; 58.2%), responded. The majority of respondents reported using simple terminology such as "abnormal protein" to describe MGUS to their patients. Some reported using analogies that the patient was more likely to be familiar with, such as comparing a paraprotein to the finding of a mole or lump. Education level, age and cognitive ability were cited as important factors in deciding how and whether information was relayed to patients. Many respondents supported frequent follow-up and the transfer of low-risk MGUS patients to primary care. However, several highlighted a lack of awareness and understanding of MGUS outside of haematology, particularly within primary care. Only 41.8% of respondents reported providing all of their patients with an information leaflet.

CONCLUSIONS

With an ageing population, it is important to consider management strategies for MGUS patients. Our findings will assist those in making these arrangements.

Is long-term particulate matter and nitrogen dioxide air pollution associated with incident monoclonal gammopathy of undetermined significance (MGUS)? An analysis of the Heinz Nixdorf Recall study

BACKGROUND

Exposure to air pollution activates the innate immune system and influences the adaptive immune system in experimental settings. We investigated the association of residential long-term exposure to particulate matter (PM) and NO₂ air pollution with monoclonal gammopathy of undetermined significance (MGUS) as a marker of adaptive immune system activation.

METHODS

We used data from the baseline (2000-2003), 5-year (2006-2008) and 10-year (2011-2015) follow-up examinations of the German Heinz Nixdorf Recall cohort study of 4814 participants (45-75years). Residential exposure to PM size fractions and NO₂ was estimated by land-use regression (ESCAPE-LUR, annual mean 2008/2009) and dispersion chemistry transport models (EURAD-CTM, 3-year mean at baseline). We used logistic regression to estimate the effects of air pollutants on incident MGUS, adjusting for age, sex, education, smoking status, physical activity, and BMI. As a non-linear approach, we looked at quartiles (2-4) of the air pollutants in comparison to quartile 1.

RESULTS

Of the 3949 participants with complete data, 100 developed MGUS during the 10-year follow-up. In the main model, only PM_coarse was associated with incident MGUS (OR per IQR (1.9μg/m³): 1.32, 95% CI 1.04-1.67). We further found positive associations between PM size fractions estimated by ESCAPE-LUR and incident MGUS by quartiles of exposure (OR Q4 vs Q1: PM_2.5 2.03 (1.08-3.80); PM₁₀ 1.97 (1.05-3.67); PM_coarse 1.98 (1.09-3.60)).

CONCLUSIONS

Our results indicate that an association between long-term exposure to PM and MGUS may exist. Further epidemiologic studies are needed to corroborate this possible link.

Monoclonal Gammopathy-Associated Peripheral Neuropathy: Diagnosis and Management

Monoclonal gammopathies comprise a spectrum of clonal plasma cell disorders that include monoclonal gammopathy of undetermined significance, multiple myeloma, and Waldenström macroglobulinemia. In this review, we outline the epidemiology, etiology, classification, diagnosis, and treatment of monoclonal gammopathy-associated peripheral neuropathy. Monoclonal gammopathy of undetermined significance is relatively common in the general population, with a prevalence of 3% to 4% among individuals older than age 50 years. Therefore, the presence of M protein in a patient with neuropathy does not automatically indicate a causal relationship. Monoclonal gammopathy-associated peripheral neuropathy is often a difficult diagnosis with limited treatment options. Studies addressing the optimal approach to diagnosis and management of this entity are limited. In addition to a review of the literature, we present a diagnostic approach to patients with monoclonal gammopathy-associated peripheral neuropathy and discuss available data and options for treatment.