Quality of care of hospitalized infective endocarditis patients: Report from a tertiary medical center
OBJECTIVE
There have been no recent studies describing the management and outcomes of patients with infective endocarditis (IE).
PATIENTS AND METHODS
We conducted a retrospective cohort study of adult patients admitted to a tertiary medical center from 2007 to 2011 with a Duke criteria consistent discharge diagnosis of IE. We examined concordance with guideline recommendations. Outcomes included embolic events, inhospital and 1-year mortality, length of stay (LOS) and cardiac surgery. We used descriptive statistics to describe the cohort and Fisher exact and unpaired t tests to compare native valve endocarditis (NVE) with prosthetic valve endocarditis (PVE).
RESULTS
Of 170 patients, definite IE was present in 135 (79.4%) and possible IE in 35 (20.6%); 74.7% had NVE, and 25.3% had PVE. Mean ± standard deviation age was 60.0 ± 17.9 years. Comparing PVE to NVE, patients with PVE were less likely to have embolic events (14.0% vs. 32.3%; P = 0.03), had shorter LOS (median 12.0 days vs. 14.0 days; P = 0.047), but they did not show a statistically significant difference in inhospital mortality (20.9% vs. 12.6%; P = 0.21). Of 170, patients 27.6% (n = 47) underwent valve surgery. Most patients received timely blood cultures and antibiotics. Guideline-recommended consults were underused, with 86.5%, 54.1%, and 47.1% of patients receiving infectious disease, cardiac surgery, and cardiology consultation, respectively. As the number of consultations increased (from 0 to 3), we observed a nonsignificant trend toward reduction in 6-month readmission and 12-month mortality.
CONCLUSION
IE remains a disease with significant morbidity and mortality. There are gaps in the care of IE patients, most notably underuse of specialty consultation. Journal of Hospital Medicine 2017;12:414-420. © 2017 Society of Hospital Medicine
© 2017 Society of Hospital Medicine
Data Collection
We used billing and clinical databases to collect demographics, comorbidities, antibiotic treatment, 6-month readmission and 1-year mortality. Comorbid conditions were classified into Elixhauser comorbidities using software provided by the Healthcare Costs and Utilization Project of the Agency for Healthcare Research and Quality.9,10
We obtained all other data through electronic health record abstraction. These included microbiology, type of endocarditis (native valve endocarditis [NVE] or prosthetic valve endocarditis [PVE]), echocardiographic location of the vegetation, and complications involving the valve (eg, valve perforation, ruptured chorda, perivalvular abscess, or valvular insufficiency).
Using 2006 AHA/ACC guidelines,11 we identified quality metrics, including the presence of at least 2 sets of blood cultures prior to start of antibiotics and use of transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE). Guidelines recommend using TTE as first-line to detect valvular vegetations and assess IE complications. TEE is recommended if TTE is nondiagnostic and also as first-line to diagnose PVE. We assessed the rate of consultation with ID, cardiology, and cardiac surgery specialties. While these consultations were not explicitly emphasized in the 2006 AHA/ACC guidelines, there is a class I recommendation in 2014 AHA/ACC guidelines5 to manage IE patients with consultation of all these specialties.
We reported the number of patients with intracardiac leads (pacemaker or defibrillator) who had documentation of intracardiac lead removal. Complete removal of intracardiac leads is indicated in IE patients with infection of leads or device (class I) and suggested for IE caused by Staphylococcus aureus or fungi (even without evidence of device or lead infection), and for patients undergoing valve surgery (class IIa).5 We entered abstracted data elements into a RedCap database, hosted by Tufts Clinical and Translational Science Institute.12
Outcomes
Outcomes included embolic events, strokes, need for cardiac surgery, LOS, inhospital mortality, 6-month readmission, and 1-year mortality. We identified embolic events using documentation of clinical or imaging evidence of an embolic event to the cerebral, coronary, peripheral arterial, renal, splenic, or pulmonary vasculature. We used record extraction to identify incidence of valve surgery. Nearly all patients who require surgery at BMC have it done onsite. We compared outcomes among patients who received less than 3 vs. 3 consultations provided by ID, cardiology, and cardiac surgery specialties. We also compared outcomes among patients who received 0, 1, 2, or 3 consultations to look for a trend.
Statistical Analysis
We divided the cohort into patients with NVE and PVE because there are differences in pathophysiology, treatment, and outcomes of these groups. We calculated descriptive statistics, including means/standard deviation (SD) and n (%). We conducted univariable analyses using Fisher exact (categorical), unpaired t tests (Gaussian), or Kruskal-Wallis equality-of-populations rank test (non-Gaussian). Common language effect sizes were also calculated to quantify group differences without respect to sample size.13,14 Analyses were performed using Stata 14.1. (StataCorp LLC, College Station, Texas). The BMC Institutional Review Board approved the protocol.
RESULTS
We identified a total of 317 hospitalizations at BMC meeting criteria for IE. Of these, 147 hospitalizations were readmissions or did not meet the clinical criteria of definite or possible IE. Thus, we included a total of 170 patients in the final analysis. Definite IE was present in 135 (79.4%) and possible IE in 35 (20.6%) patients.
Patient Characteristics
Of 170 patients, 127 (74.7%) had NVE and 43 (25.3%) had PVE. Mean ± SD age was 60.0 ± 17.9 years, 66.5% (n = 113) of patients were male, and 79.4% (n = 135) were white (Table 1). Hypertension and chronic kidney disease were the most common comorbidities. The median Gagne score15 was 4, corresponding to a 1-year mortality risk of 15%. Predisposing factors for IE included previous history of IE (n = 14 or 8.2%), IVD use (n = 23 or 13.5%), and presence of long-term venous catheters (n = 19 or 11.2%). Intracardiac leads were present in 17.1% (n = 29) of patients. Bicuspid aortic valve was reported in 6.5% (n = 11) of patients with NVE. Patients with PVE were older (+11.5 years, 95% confidence interval [CI] 5.5, 17.5) and more likely to have intracardiac leads (44.2% vs. 7.9%; P < 0.001; Table 1).
Microbiology and Antibiotics
Staphylococcus aureus was isolated in 40.0% of patients (methicillin-sensitive: 21.2%, n = 36; methicillin-resistant: 18.8%, n = 32) and vancomycin (88.2%, n = 150) was the most common initial antibiotic used. Nearly half (44.7%, n = 76) of patients received gentamicin as part of their initial antibiotic regimen. Appendix 1 provides information on final blood culture results, prosthetic versus native valve IE, and antimicrobial agents that each patient received. PVE patients were more likely to receive gentamicin as their initial antibiotic regimen than NVE (58.1% vs. 40.2%; P = 0.051; Table 1).
