Association between obesity and venous thromboembolism in hospitalized patients with multiple myeloma - perspective from national inpatient sample (NIS) database

Abstract Background: Patients with multiple myeloma (MM) have a high risk of venous thromboembolism (VTE) due to disease and treatment related factors. VTE is associated with worse outcomes in hospitalized cancer patients. Obesity also independently increases thrombotic risk, but its association with VTE in MM patients is not fully understood. We studied the association between obesity and VTE and their trends on clinical outcomes in the MM population. Methods: A retrospective cohort analysis was done on hospitalized MM patients using the National Inpatient Sample (NIS) database from 2016 to 2022. Patients were identified using ICD-10-CM codes. They were stratified into 4 groups: No Obesity/No VTE, Only Obesity, Only VTE, and Obesity+VTE. We analyzed the association between obesity and VTE risk. We also did a comparative analysis involving demographics, comorbidities, in-hospital death, length of stay (LOS), and total charges. Multivariate logistic and linear regression were used to evaluate these trends. A p-value of less than 0.05 was set as significant. Results: Out of 699680 in-hospital MM patients, 582,730 (83.3%) had neither obesity nor VTE, 78,795 (11.3%) had obesity only, 33,125 (4.7%) had VTE only, and 5,030 (0.7%) had both. We observed that obesity was independently associated with a 12% higher odds of VTE in MM patients (adjusted odds ratio [aOR] 1.12; 95% CI, 1.04 to 1.20; p < 0.005). Compared to no obesity/no VTE group, In-hospital mortality was lower in the obesity-only group (aOR 0.65; 95% CI 0.59–0.71; p < 0.001), higher in the VTE-only group (aOR 1.57; 95% CI 1.42–1.73; p < 0.001), and no significant relation was found in the obesity + VTE group (aOR 1.08; 95% CI 0.82–1.42; p = 0.605). LOS was modestly increased in obesity-only group (+0.19 days; 95% CI 0.04–0.33; p < 0.05), significantly prolonged in VTE-only group (+3.03 days; 95% CI 2.71–3.36; p < 0.001), and obesity + VTE group (+2.80 days; 95% CI 2.08–3.52; p < 0.001). Total hospital charges were also higher in all the groups: obesity-only (+$3 188; 95% CI $422–$5 954; p = 0.024), VTE-only (+$43 590; 95% CI $36 760–$50 421; p < 0.001), and obesity + VTE (+$39 559; 95% CI $26 868–$52 250; p < 0.001). Conclusion: Our study concludes that obesity increases the risk of VTE in MM inpatients. VTE, in turn, was associated with poorer in-hospital outcomes, including more deaths, longer stays, and increased charges. Thus, these observations necessitate the need for extensive thromboprophylaxis in MM patients, particularly those who are obese, to minimize the risk of VTE and possibly prevent the adverse outcomes associated with it.