Protein Energy Malnutrition and in-Hospital Outcomes of Patients with Waldenström Macroglobulinemia

Introduction: Waldenström macroglobulinemia (WM) or lymphoplasmacytic lymphoma is a lymphoproliferative disorder characterized by IgM paraproteinemia and clinical features of fever, weight loss, night sweats, anemia, hyperviscosity symptoms, and gastrointestinal dysfunction. While the association between WM and protein-losing enteropathies has previously been described, the impact of protein energy malnutrition (PEM) on patient outcomes remains unknown. In this study, we assessed the effect of PEM on mortality and other outcomes in patients with WM. Methods: We conducted a retrospective analysis of patients admitted with WM in the National Inpatient Sample database from 2016 to 2020. To determine our study sample, we used the tenth revision of the International Classification of Diseases (ICD-10) to identify patients with WM (C.88.0). Our exposure variable was PEM (defined based on the ICD code E44.0). In-hospital outcomes assessed were in-hospital mortality (determined based on final disposition at discharge), sepsis, septic shock, thromboembolic events (deep vein thrombosis [DVT] and acute pulmonary embolism [PE]), and the need for renal replacement therapy. The student's t-test was used to evaluate differences in continuous variables and Pearson's chi-square or Fisher's exact tests were used to assess differences in categorical variables. Multivariate logistic regression was used to assess the association between PEM and the outcomes of interest, adjusting for age, sex, race, smoking, alcohol, Charlson index, type of insurance, total charges, and length of hospital stay. Results: Of the6,766 patients with WM included in this study, 84.4% were white, 59.4% were female and the mean age was 75.2 (SD 10.3). Most participants had a median household income in the third quartile of the national average (33.6%). Comorbid PEM was reported among 888 (13.1%) patients with WM. Patients with PEM had higher rates of in-hospital mortality (9.0% vs 3.7%, P-value <0.001), sepsis (23.5% vs 13.7%, P-value <0.001), septic shock (7.9% vs 3.1%, P-value <0.001), acute renal failure (33.4% vs 23.2%, P-value <0.001), and need for hemodialysis (5.9% vs 3.4%, P-value <0.001), compared to patients without PEM. PEM was associated with in-hospital mortality (adjusted odds ratio (aOR) 1.92, 95% CI: 1.39-2.67, P-value <0.001), sepsis (aOR 1.37, 95% CI: 1.10 - 1.70, P-value, 0.004) and acute renal failure (aOR 1.26, 95% CI: 1.06 - 1.50, P-value, 0.01). The results of the association of PEM with septic shock, DVT, and PE were not statistically significant. Conclusions: A considerable proportion of patients with WM in our study had comorbid PEM.Findings suggest that among patients with WM, PEM may contribute to an increased risk of adverse health-related outcomes and mortality. Therefore, considerations for screening, early detection, and management of PEM should be incorporated into the clinical care of patients admitted with WM. In addition, our results show that the association of PEM and outcomes of septic shock, need for renal replacement, and thromboembolic events were inconclusive. Thus, further studies to elucidate these findings in a longitudinal cohort are needed.