Clinical Outcomes of Parenteral Methylene Blue as Adjunct Therapy in Hospitalized COVID-19 Patients: A Retrospective Cohort Study

Abstract

Background: During the pandemic, methylene blue emerged as a repurposed drug for the treatment of COVID-19. The objective was to evaluate clinical outcomes of parenteral methylene blue use in hospitalized COVID-19 patients. Methodology: A retrospective cohort study was conducted at COVID-19 hospitals in Rajkot, during 2022-2023. “Exposed” cohort (who received standard care plus parenteral methylene blue), “Unexposed” cohort (with standard care) were matched for age, gender, and HRCT scores. Primary outcomes included length of hospital stay and recovery rate. Secondary outcomes assessed changes in serial laboratory parameters. Data were analyzed using appropriate statistical tests using Jamovi Version 2.6.45. Results: A total of 19 exposed and 34 unexposed patients were analyzed. The exposed cohort had significantly longer hospital stays (median 9 vs. 5 days; p<0.01) and higher mortality (21.1% vs. 2.9%; p=0.09). Baseline hemoglobin (11.30 vs 13.80 g/dL at baseline, p=0.017) was significantly lower in the exposed cohort and showed an initial rise followed by a decline, unlike the stable trend in the unexposed group. D-dimer levels (430.00 vs 220.00 ng/mL at baseline, p=0.02) remained significantly higher in exposed cohort. CRP declined similarly whereas IL-6, ferritin, and creatinine showed differing trends. Conclusions: Longer hospital stays and higher mortality was observed in exposed cohort than unexposed.