Prevalence, severity, and resolution of anemia in patients with infective endocarditis (ANIE study)
N Kader, J Hjulmand, R Hasselbalch, I Lentz, C Moser, E Fosboel, S Ostrowski, R Frikke-Schmidt, K Iversen, A Glenthoej, H Bundgaard, M M Pries-HejeAbstract
Background
Patients with infective endocarditis (IE) and moderate-severe anemia have a 5-fold higher 6-month mortality. The causes of anemia in patients with IE are poorly understood with no specific treatment recommendations in guidelines. This study aimed to describe the prevalence, severity and characteristics of anemia in patients with IE from diagnosis to 9-week follow-up
Methods
This was a prospective, multicentre, observational cohort study conducted in Denmark between March 2021 and October 2022. Patients were eligible if they met modified Duke criteria for IE. Blood samples were collected at baseline, during admission, and weekly after discharge. POET criteria were applied to define time of clinical stability. Blood samples were analysed for hemoglobin (Hb), iron metabolism markers, CRP, red cell turnover markers, and white blood cell count. Anemia was classified according to the World Health gender-specific reference and National Cancer Institute range (mild: Hb <8.1 mmol/L in men, <7.5 mmol/L in women and moderate-severe: Hb <6.2 mmol/L). Univariate logistic regression identified factors associated with anemia 9 weeks after antibiotic therapy completion
Results
In total, 100 patients were included (73% male, 66.8 years (SD±14.4), median baseline Hb was 6.5 mmol/L [IQR 5.9-7.4]. The most common pathogens were Staphylococci (36%, (28% S. aureus)), Streptococci (35%) and Enterococcus faecalis (15%), and others (13%). The mitral valve was the most commonly affected valve (31%). A total of 51 patients (51%) were operated. At diagnosis, 79 of 100 (79%) had anemia (mild: 46%, moderate-severe 37%). At clinical stabilization, anemia was found in 74 of 83 (89%) (mild: 52% and moderate-severe: 37%). At 9 weeks follow-up, 9 (9%) patients had died and 12 (12%) had no follow-up Hb data. In the remaining 79 patients, anemia persisted in 46 (58%) (mild: 40% and moderate-severe: 18% (Figure 1)). In patients who achieved Hb normalization (n=33), the median time to first normal Hb was 63 days (IQR 31–90). Higher risk of anemia at follow-up was seen in patients with pacemaker related IE (RR 1.70, 95% CI 1.31–2.22; p < 0.001), age ≥75 years (RR 1.65, 95% CI 1.21–2.25; p = 0.002), renal failure (RR 1.59, 95% CI 1.19–2.13 p=0.002), and diabetes (RR 1.45, 95% CI 1.05–2.01; p = 0.025). The overall hematological profile throughout the disease was consistent with inflammatory anemia (Figure 2).
Conclusions
Anemia was present in the majority (79-92%) of patients with IE from diagnosis throughout treatment. Nine weeks after completion of antibiotic therapy, mild-moderate anemia persisted in over half the cohort. In patients whose hemoglobin normalized, the median time to resolution was 63 days. Several risk factors associated with persistent anemia at follow-up were identified. Data suggest that anemia is a common and persisting complication to IE and further studies on clinical consequences and treatment are neededAnemia severity in patients with IEIron metabolism in patients with IE