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.

The first wave of COVID-19 and concurrent social restrictions were not associated with a negative impact on mental health and psychiatric well-being

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic and efforts to contain it have substantially affected the daily lives of most of the world's population.

OBJECTIVE

We describe the impact of the first COVID-19 wave and associated social restrictions on the mental health of a large adult population.

METHODS

We performed a cohort study nested in a prospective randomized clinical trial, comparing responses during the first COVID-19 wave to previous responses. We calculated the odds ratio (OR) of the population moving up one severity category on validated instruments used to measure stress (PSS-10), anxiety (GAD-7), depression (PHQ-9), and Satisfaction With Life Scale (SWLS). Responses were linked to inpatient and outpatient ICD-10 codes from registries. Models were adjusted for age, sex, comorbidities, and pre-existing diagnoses of mental illness.

RESULTS

Of 63,848 invited participants, 42,253 (66%) responded. The median age was 60 (inter-quartile range 53-68) and 19,032 (45%) were male. Responses during the first wave of COVID-19 did not suggest increased stress (OR 0.97; 95% confidence interval [CI], 0.93-1.01; p = 0.28) or anxiety (OR 1.01; 95% CI, 0.96 to 1.05; p = 0.61), but were associated with decreased depression (OR 0.89; 95% CI, 0.85-0.93, p < 0.0001) and increased satisfaction with life (OR 1.12; 95% CI, 1.08-1.16, p < 0.0001). A secondary analysis of repeated measures data showed similar results.

CONCLUSIONS

Social restrictions were sufficient to contain the pandemic but did not negatively impact validated measures of mental illness or psychiatric well-being. However, responses to individual questions showed signs of fear and stress. This may represent a normal, rather than pathological, population response to a stressful situation.