Development of a prediction model for bacteremia in hospitalized adults with cellulitis to aid in the efficient use of blood cultures: a retrospective cohort study

Abstract

BackgroundCellulitis is a common infectious disease. Although blood culture is frequently used in the diagnosis and subsequent treatment of cellulitis, it is a contentious diagnostic test. To help clinicians determine which patients should undergo blood culture for the management of cellulitis, a diagnostic scoring system referred to as the Bacteremia Score of Cellulitis was developed.MethodsUnivariable and multivariable logistic regression analyses were performed as part of a retrospective cohort study of all adults diagnosed with cellulitis in a tertiary teaching hospital in Taiwan in 2013. Patients who underwent blood culture were used to develop a diagnostic prediction model where the main outcome measures were true bacteremia in cellulitis cases. Area under the receiver operating characteristics curve (AUC) was used to demonstrate the predictive power of the model, and bootstrapping was then used to validate the performance.ResultsThree hundred fifty one cases with cellulitis who underwent blood culture were enrolled. The overall prevalence of true bacteremia was 33/351 cases (9.4 %). Multivariable logistic regression analysis showed optimal diagnostic discrimination for the combination of age ≥65 years (odds ratio [OR] = 3.9; 95 % confidence interval (CI), 1.5–10.1), involvement of non-lower extremities (OR = 4.0; 95 % CI, 1.5–10.6), liver cirrhosis (OR = 6.8; 95 % CI, 1.8–25.3), and systemic inflammatory response syndrome (SIRS) (OR = 15.2; 95 % CI, 4.8–48.0). These four independent factors were included in the initial formula, and the AUC for this combination of factors was 0.867 (95 % CI, 0.806–0.928). The rounded formula was 1 × (age ≥65 years) + 1.5 × (involvement of non-lower extremities) + 2 × (liver cirrhosis) + 2.5 × (SIRS). The overall prevalence of true bacteremia (9.4 %) in this study could be lowered to 1.0 % (low risk group, score ≤1.5) or raised to 14.7 % (medium risk group, score 2–3.5) and 41.2 % (high risk group, score ≥4.0), depending on different clinical scores.ConclusionsDetermining the risk of bacteremia in patients with cellulitis will allow a more efficient use of blood cultures in the diagnosis and treatment of this condition. External validation of this preliminary scoring system in future trials is needed to optimize the test.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-1907-2) contains supplementary material, which is available to authorized users.

Factors associated with sepsis development in 606 Spanish adult patients with cellulitis

“…The bacteremia rate in our cohort was 18.3% among the patients with blood culture drawn, a value situated in the high range of those previously reported in cellulitis [4][5][6][7][8][9][10][11][12][13][14][15][16], although rates of 18.7% [8] and 21.3% [9] have been reported in hospitalized patients like ours. Of note is that blood cultures were positive in only 24.4% of patients with sepsis.…”

“…Cellulitis can lead to bacteremia and ultimately trigger sepsis development. The frequency of bacteremia in patients with cellulitis ranges from 2 to 21.3% among patients for whom blood cultures were available, depending on the study, setting and typology of the cases analyzed [4][5][6][7][8][9][10][11][12][13][14][15][16]. Taking into account that most cases of cellulitis are treated in the ambulatory setting and that blood cultures are not obtained in many hospitalized patients with less severe cellulitis, populations in which expectedly bacteremia occurs more infrequently, the overall prevalence of positive blood cultures considering the full spectrum of cellulitis would be even lower.…”

“…However, other studies have shown that older age, male sex, diabetes, infected devices, alcohol abuse, cirrhosis, lymphedema and diverse other comorbidities increase the probability of bacteremia and, therefore, the performance of blood cultures in these patients would be advisable [9][10][11][12][13][14][15][16]18].…”

Diagnostic Stewardship: A Clinical Decision Rule for Blood Cultures in Community-Onset Methicillin-Resistant Staphylococcus aureus (MRSA) Skin and Soft Tissue Infections

“…Abnormal vital signs have been most consistently associated with bacteremia in previous studies examining risk factors in SSTI due to a range of bacterial etiologies [ 7 , 12 , 15 ]. Thus, a derivation sample size of 152 cases and 152 controls was required to achieve 80% power at the 0.05 significance level to detect an odds ratio of two or greater for a risk factor with a prevalence of 25% in controls.…”

Sphingobacterium spiritivorum bacteremia due to cellulitis in an elderly man with chronic obstructive pulmonary disease and congestive heart failure: a case report

“…Lee et al . proposed an initial diagnostic prediction model with four independent predictors for estimating probability of bacteremia in patients with cellulitis: age ≥ 65 years, involvement of non-lower extremities, liver cirrhosis, and systemic inflammatory response syndrome [ 27 ]. In a recent study, van Daalen et al .…”