Investigation of the effectiveness of prophylaxis applied against bone complications, thrombosis and infection in multiple myeloma patients

Objective: In comparison to the general population, Multiple Myeloma patients face a 9-fold increased risk of venous thromboembolism (VTE), 7 to 10 times higher risk of bacterial and viral infections, and encounter lytic bone lesions in 60% of cases at diagnosis. This study aims to investigate the effectiveness of anticoagulant, antibacterial, antiviral, antifungal, and bone-preserving agents applied for VTE, infectious, and bone-related complications in patients diagnosed with Multiple Myeloma. Method: Our study is a retrospective cross-sectional analysis. We examined the demographic characteristics (age, gender), VTE risk factors, prophylaxis application and type, occurrence of VTE, infection risk factors, antimicrobial prophylaxis application and type, infectious agent, infection focus, bone prophylaxis application, and the occurrence of pathological fractures in 100 patients monitored for Multiple Myeloma at the Akdeniz University Faculty of Medicine Hospital between January 2014 and December 2022. We retrospectively reviewed and scanned the data from our hospital's MIAMED information system. Findings: In the first 6 months post-treatment, the infection frequency was 50%, and there was a similar infection frequency (54% vs. 43%) between groups receiving and not receiving quinolone prophylaxis. Almost all patients (n=97) received TMP-SMX prophylaxis. The most common infection focus in our study was respiratory tract (66%), and the most common bacterial agent was E. Coli (34%). The fungal infection frequency in the first 6 months was 6%, with a rate of 10% in patients not using prophylaxis compared to 5% in those using prophylaxis. There was no significant difference in infection rates in groups using PI, IMID, or both. The thromboembolism rate in the first 6 months of our study was 13%, and antiplatelets were preferred 4 times more than anticoagulants for thromboprophylaxis. Patients with an Impede score >8 had an 81% rate, while those with a score of 4-7 had a 19% rate. The use of low-dose dexamethasone was universal, and the rates of PI, IMID, and both were over 90%. Epo had a usage rate of only 9%. In 13 patients who experienced VTE, 9 did not receive VTE prophylaxis, 3 received antiplatelets, and 1 received DMAH prophylaxis. Treatment regimens during VTE development were VCd (7 patients) ,VRd (1 patient), Rd (3 patients), bortezomib+doxorubicin+low dose dexametasone (1patient) and bortezomib+low dose dexametasone(1 patient). 2 of 13 patients were using EPO which had chronical renal failure. In this regimen, 4 patients with IMID in the treatment regimen received VTE prophylaxis, while 9 patients with Bortezomib in the treatment regimen did not receive VTE prophylaxis. More care should be taken to ensure that VTE prophylaxis reserved for those receiving non-IMID Multiple Myeloma treatment is not overlooked. 95 percent of patients received bisphosphonates and 4 percent of patients received denosumab as bone-preserving agents. Fractures occurred within the first 3 months in 42% and after 12 months in 40%, with spinal cord (66%) and vertebral (52%) fractures being the most common. The increase in fracture rate after the 3rd month and 12th month is believed to be related to tumor burden and disease progression. A significant portion of the fractures occurred in the first 3 months. A significant number of these patients have spinal cord fractures, and it is important to predict the fracture risk in the follow-up of the patients and apply surgical stabilization (such as kyphoplasty, vertebroplasty) to the bones of selected patients with high fracture risk. Conclusion: Despite prophylaxis, Multiple Myeloma patients have a high risk of infection. Thorough evaluation is crucial for thromboprophylaxis, as overlooking the need may lead to a high risk of thromboembolism. Myeloma-related pathological fractures, especially during the first 3 months of induction therapy, are higher. Patients should be informed, fracture risk should be assessed through scoring, and necessary precautions should be taken. Keywords: Multiple Myeloma, Antimicrobial Prophylaxis, VTE Prophylaxis, Bone-preserving Agent Use