Background: Autoimmune conditions are relatively uncommon in patients with Myelodysplastic syndromes (MDS), with only a small proportion of patients affected. Among these autoimmune conditions, rheumatic heart disease (RHD) is the most commonly associated with MDS. Very few cases have been reported in literature that show the impact of RHD on patients diagnosed with MDS. In this study, we aimed to investigate the impact of RHD on the patients with myelodysplastic syndrome who were admitted in hospitals from 2018-2020. Methods: We utilized National Inpatient Sample (NIS) 2018-2020 to identify hospitalizations of patients with Myelodysplastic syndromes with a secondary diagnosis of Rheumatic heart disease. The primary outcomes examined were In-patient mortality and average length of stay, All the patients with MDS were divided into two cohorts based on the presence of rheumatic heart disease. Multivariable regression analyses were conducted, taking into account demographics, hospital-level characteristics, and pertinent comorbidities as adjusting factors. Results: Using the NIS dataset from 2018 to 2020, we identified 222,364 patients admitted with MDS during this period. Among them, 4.57% (10,162 patients) also had a diagnosis of rheumatic heart disease (RHD). The average age of patients with MDS and RHD was 80 years. Among these patients, 50.1% were male and 49.9% were female. The mortality rate among patients admitted with MDS and coexisting RHD was 7.7%. Multivariate regression analysis indicated that the presence of RHD increased the likelihood of mortality with an odds ratio (OR) of 1.2 (95% confidence interval [CI]: 1.0-1.4, p-value <0.05). Additionally, RHD was associated with a higher incidence of arrhythmias (OR: 2.9) and congestive heart failure (OR: 5.0) among MDS patients. The total hospital charges were more in patients with RHD than those without RHD ($80108 vs $82843). However, there was no significant difference in the length of stay (LOS) between patients with MDS alone and those with MDS and RHD. Conclusions: Rheumatic heart disease (RHD) cases in patients with MDS are rare in clinical practice, leading to uncertainty regarding the effects of RHD on admitted MDS patients. Our study sheds light on the influence of RHD on mortality and other outcomes in this patient population. The efficacy of timely RHD treatment in reducing mortality and improving outcomes among hospitalized MDS patients remains to be verified in future investigations.