Antihypertensive medication use is associated with increased organ system involvement and hospitalization in emergency department patients with anaphylaxis.

BACKGROUND: Risk factors for increased anaphylaxis severity are poorly understood. Angiotensin-converting enzyme (ACE) inhibitors have been associated with severe anaphylactic reactions in patients with hymenoptera venom allergy. Studies evaluating the association between beta-blockers and severe anaphylaxis have been conflicting. OBJECTIVE: To evaluate the association between antihypertensive medication use and increased anaphylaxis severity. METHODS: We included emergency department anaphylaxis patients aged 18 years and older. Markers of severe anaphylaxis were defined as (1) syncope, hypotension, or hypoxia; (2) signs and symptoms involving 3 or more organ systems; and (3) hospitalization. Antihypertensive medications evaluated included beta-blockers, ACE inhibitors, calcium channel blockers, angiotensin receptor blockers, and diuretics. Simple and multiple logistic regression analyses were conducted to estimate the association between antihypertensive medication use and markers of increased anaphylaxis severity. RESULTS: Among 302 patients with anaphylaxis, 55 (18%) had syncope, hypoxia, or hypotension, 57 (19%) required hospitalization, and 139 (46%) had 3 or more organ system involvement. After adjusting for age, gender, suspected trigger, and preexisting lung disease, beta-blocker, ACE-inhibitor, diuretic, or antihypertensive medication use in aggregate remained associated with both 3 or more organ system involvement and need for hospital admission. The adjusted associations between antihypertensive medication use in aggregate and 3 or more organ system involvement yielded an odds ratio of 2.8 (95% CI, 1.5-5.2; P=.0008) and with hospitalization an odds ratio of 4.0 (95% CI, 1.9-8.4; P=.0001). CONCLUSIONS: In emergency department anaphylaxis patients, antihypertensive medication use is associated with increased organ system involvement and increased odds of hospital admission, independent of age, gender, suspected trigger, or preexisting lung disease.

Failure of prospective validation and derivation of a refined clinical decision rule for chest radiography in emergency department patients with chest pain and possible acute coronary syndrome.

OBJECTIVES: The authors previously derived a clinical decision rule (CDR) for chest radiography in patients with chest pain and possible acute coronary syndrome (ACS) consisting of the absence of three predictors: history of congestive heart failure, history of smoking, and abnormalities on lung auscultation. The aim of the investigation was to prospectively validate and refine the CDR for chest radiography in an independent patient population. METHODS: Patients over 24 years of age with a primary complaint of chest pain and possible ACS were prospectively enrolled from September 2008 to January 2010 at an academic emergency department (ED) with 73,000 annual patient visits. Physicians completed standardized data collection forms before ordering chest radiographs. Two investigators, blinded to the data collection forms, independently classified chest radiographs as "normal,""abnormal not requiring intervention," or "abnormal requiring intervention" (e.g., heart failure, infiltrates), based on review of the radiology report and medical record. Analyses included descriptive statistics, interrater reliability assessment (kappa), and recursive partitioning. RESULTS: Of 1,159 visits for possible ACS in which chest radiography was obtained, mean (±SD) age was 60.3 (±15.6) years, and 51% were female. Twenty-four percent had a history of acute myocardial infarction, 10% congestive heart failure, and 11% atrial fibrillation. Sixty-nine (6.0%, 95% confidence interval [CI] = 4.7% to 7.5%) patients had a radiographic abnormality requiring intervention. The kappa statistic for chest radiograph classification was 0.93 (95% CI = 0.88 to 0.97). The previously derived prediction rule (no history of congestive heart failure, no history of smoking, and no abnormalities on lung auscultation) was 78.3% sensitive (95% CI = 67.2% to 86.4%) and 45.1% specific (95% CI = 42.2% to 48.1%) and had a positive predictive value of 8.3% (95% CI = 6.4% to 10.7%) and a negative predictive value of 97.0% (95% CI = 95.2% to 98.2%). Due to suboptimal performance, the rule was refined. The refined rule (no shortness of breath, no history of smoking, no abnormalities on lung auscultation, and age < 55 years) was 100.0% sensitive (95% CI = 93.4% to 100.0%) and 11.5% specific (95% CI = 9.6% to 13.5%) and had a positive predictive value of 6.7% (95% CI = 5.3% to 8.4%) and a negative predictive value of 100.0% (95% CI = 96.3% to 100.0%). CONCLUSIONS: Prospective validation of our previously derived CDR for clinically important chest radiographic abnormalities was not successful. Derivation of a refined rule identified all clinically important radiographic abnormalities, but was insufficiently specific. No CDR with adequate sensitivity and specificity could be found.