Association Between Autoimmune Diseases and Monoclonal Gammopathy of Undetermined Significance : An Analysis From a Population-Based Screening Study.

BACKGROUND: Monoclonal gammopathy of undetermined significance (MGUS) is a precursor of multiple myeloma (MM) and related conditions. In previous registry-based, retrospective studies, autoimmune diseases have been associated with MGUS. However, these studies were not based on a screened population and are therefore prone to ascertainment bias. OBJECTIVE: To examine whether MGUS is associated with autoimmune diseases. DESIGN: A cross-sectional study within iStopMM (Iceland Screens, Treats, or Prevents MM), a prospective, population-based screening study of MGUS. SETTING: Icelandic population of adults aged 40 years or older. PATIENTS: 75 422 persons screened for MGUS. MEASUREMENTS: Poisson regression for prevalence ratios (PRs) of MGUS among persons with or without an autoimmune disease, adjusted for age and sex. RESULTS: A total of 10 818 participants had an autoimmune disorder, of whom 599 had MGUS (61 with a prior clinical diagnosis and 538 diagnosed at study screening or evaluation). A diagnosis of an autoimmune disease was not associated with MGUS (PR, 1.05 [95% CI, 0.97 to 1.15]). However, autoimmune disease diagnoses were associated with a prior clinical diagnosis of MGUS (PR, 2.11 [CI, 1.64 to 2.70]). LIMITATION: Registry data were used to gather information on autoimmune diseases, and the homogeneity of the Icelandic population may limit the generalizability of these results. CONCLUSION: The study did not find an association between autoimmune disease and MGUS in a systematically screened population. Previous studies not done in systematically screened populations have likely been subject to ascertainment bias. The findings indicate that recommendations to routinely screen patients with autoimmune disease for MGUS may not be warranted. PRIMARY FUNDING SOURCE: The International Myeloma Foundation and the European Research Council.

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.

[Impact of renal dysfunction on early outcomes of coronary artery bypass grafting surgery].

INTRODUCTION: Impaired renal function as seen in chronic kidney disease (CKD) is a known risk factor for coronary artery diseases and has been linked to inferior outcome after myocardial revascularization. Studies on the outcome of coronary bypass grafting (CABG) in CKD-patients are scarce. We aimed to study this subgroup of patients following CABG in a well defined whole-nation cohort, focusing on short term complications and 30 day mortality. MATERIALS AND METHODS: A retrospective study on 2300 consecutive patients that underwent CABG at Landspítali University Hospital 2001-2020. Patients were divided into four groups according to preoperative estimated glomerular filtration rate (GFR), and the groups compared. GFR 45-59 mL/mín/1.73m2, GFR 30-44 mL/mín/1.73m2, GFR <30 mL/mín/1.73m2 and controls with normal GFR (≥60 mL/mín/1.73m2). Clinical information was gathered from medical records and logistic regression used to estimate risk factors of 30-day mortality. RESULTS: Altogether 429 (18.7%) patients had impaired kidney function; these patients being more than six years older, having more cardiac symptoms and a higher mean EuroSCORE II (5.0 vs. 1.9, p<0.001) compared to controls. Furthermore, their left ventricular ejection fraction was also lower, their median hospital stay extended by two days and major short-term complications more common, as was 30 day mortality (24.4% vs. 1.4%, p<0.001). In multivariate analysis advanced age, ejection fraction <30% and GFR <30 mL/min/1.73m2 were independent predictors of higher 30-day mortality (OR=10.4; 95% CI: 3.98-25.46). CONCLUSIONS: Patients with impaired renal function are older and more often have severe coronary artery disease. Early complications and 30-day mortality were much higher in these patients compared to controls and advanced renal failure and the strongest predictor of 30-day mortality.