Evolving Patterns of Infective Endocarditis: Insights from a Tertiary Healthcare Institute in Western India
Authors: Chigullapalli Sridevi , Nalawade Digvijay D , Jadhav Ajitkumar Krishna , Malani Susheel Kumar , Wadhokar Pratik Satyajit , Khan Anish Kumar 
Published: December 2023

Abstract

Context:
Infective endocarditis (IE) is a dynamic disease with high morbidity and mortality despite advancements in diagnostics, antimicrobial therapy, and surgery. India faces a complex situation due to changing factors such as host characteristics, diagnostic techniques, antibiotics, and aggressive surgical approaches. Monitoring local epidemiology is crucial for prompt recognition and treatment. However, studies on IE trends in India are scarce and outdated.

Aims:
To investigate the clinical, microbiological, predisposing conditions, echocardiographic characteristics, and treatment outcomes of IE patients admitted to a Tertiary Care Academic Institute in Western India.

Settings and Design:
This retrospective observational study was done in a 2011-bedded tertiary care referral hospital in Western Maharashtra, between June 2019 and May 2023. The records of all adult patients (age >14 years) admitted during the study period with a definite diagnosis of IE, both native valve endocarditis and prosthetic valve endocarditis according to the modified Duke criteria, were included in the study. Baseline demographic data on age, sex, underlying heart disease, and predisposing conditions for bacteremia (infections, central venous catheters, surgeries, and invasive procedures) were collected.

Subjects and Methods:
The echocardiographic and microbiological findings, complications, treatment, and outcomes were noted. All blood cultures done for the diagnosis of IE were processed using standard methods to identify bacterial and fungal species and antimicrobial susceptibility profiles. For all the patients in this study, blood (5–8 mL per bottle) was collected in adult blood culture bottles using standard precautions and processed by a semiautomated blood culture system (BioMérieux, Marcyl̕ Etoile). Identification of causative organisms was performed by standard microbiological methods. Transthoracic and transesophageal echocardiography were performed to determine the location of vegetation, type of valve infected, and cardiac complications.

Sample Size Calculation:
Considering the Indian prevalence of IE to be 14.5% as observed by Gupta et al.,margin of error as 9%, and 95% of confidence level, the minimum required sample size calculated using WinPepi software (version: 11.65) for conducting the study was 59 patients.

Statistical Analysis:
Data was collected and entered into a database using Microsoft Excel. Data was represented as the frequency with percentage and Chi-square test (two-sample proportionality test) were applied for comparison of categorical variables. Quantitative data was summarized using mean and standard deviation and a two-sample t-test was applied to compare differences. P < 0.05 was considered statistically significant.

Results:
The mean age in the study was 44.1 ± 10.6 years with a female preponderance (male:female – 0.85:1). Rheumatic heart disease (RHD) (44.3%) was the most common underlying heart disease etiology, whereas 33% of patients did not have any cardiac disease. Blood culture was positive in 34.9% of episodes, with the most common organisms being Gram-positive Staphylococci (38%). Medical complications such as congestive heart failure (CHF) and acute kidney injury were seen in 41.2% of patients, followed by cerebrovascular accident and stroke in 20.6%. The majority of patients, 61.9%, had received antibiotics before referral to our center. Thirty-seven (58.7%) patients underwent definitive surgery for IE. The total in-hospital mortality rate was 12 (19.1%). In the univariate analysis, younger patients (<50 years) with CHF, diabetes mellitus, and Staphylococcus culture-positive IE were independent predictors of mortality.

Conclusions:
Over the past four decades, the landscape of IE in India has experienced noteworthy transformations. The disease profile of patients has shifted from predominantly older individuals with RHD to a rising number of younger patients with prosthetic valves or those without identified valvular conditions. Moreover, the yield of blood cultures has declined due to the increased utilization of antibiotics over the last two decades, although Staphylococcus species continue to be the most common organisms detected. Despite significant advancements in medical technology, the mortality rate remains unchanged. Our study provides compelling evidence to advocate for early surgical intervention, which holds the potential for improved outcomes.