Severe asthma predicts poor anaphylaxis outcomes
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NASHVILLE, Tenn. — Patients with asthma who experience anaphylaxis have higher rates of complications, 30-day readmissions and mortality than those without anaphylaxis, according to a presentation at the CHEST Annual Meeting.
These findings indicate the need to obtain an asthma history when managing patients with anaphylaxis, Amir Khalil, MD, an internal medicine resident at Wayne State University and Detroit Medical Center, and colleagues wrote.
“I was taking care of a patient who presented for anaphylaxis and required intubation and mechanical ventilation. While obtaining the history, I saw that he had history of moderate-persistent asthma,” Khalil told Healio.
This prompted Khalil to ask if the patient would have developed such a significant reaction if his asthma were less severe.
“I did some literature review and found that while the relationship between asthma and anaphylaxis is well documented, there is no strong observational data that posits an answer to asthma being a predictor of anaphylaxis severity,” Khalil said.
Khalil and his colleagues then used the National Readmission Database (NRD) to search for index hospitalizations for anaphylaxis with a related diagnosis of asthma of varying severity. Primary outcomes included mortality and 30-day readmissions, with secondary outcomes of multi-organ complications, need for mechanical ventilation and ICU admission.
“My hypothesis was that as asthma severity would increase, the incidence, morbidity and mortality of those anaphylaxis admissions would also increase,” Khalil said.
The researchers found 1,755,467 index hospitalizations (mean age, 58.2 ± 12.4 years; 27.9% female) for asthma including 1,470 patients with a primary diagnosis of anaphylaxis recorded in the NRD between January 2018 and December 2019.
The researchers observed an association between anaphylaxis and higher mortality (OR = 1.22; 95% CI, 1.11-4.9) among all patients with asthma. Malignancy (OR = 2.2; 95% CI, 1.5-3.5) and severe-persistent asthma (OR = 3.2; 95% CI, 2.1-4.4) were predictors of mortality among patients with asthma and anaphylaxis.
Khalil also called this finding related to malignancy unique.
“In utilization of the NRD, we added several baseline conditions to see if there were other predictors of anaphylaxis morbidity and mortality,” he said. “In this, we found that malignancy, which includes solid and liquid cancers, was also a greater predictor of mortality in anaphylaxis-related hospitalizations.”
Compared with patients who only had asthma, those with asthma and anaphylaxis also had higher rates of noninvasive mechanical ventilation (12.4% vs. 9.3%), mechanical ventilation (33% vs. 12.1%), ICU admission (39.2% vs. 13%), pneumonia (30% vs. 9.9%) and pulmonary embolism (10.9% vs. 4.8%; P < .001 for all).
Additionally, the patients with asthma and anaphylaxis had higher rates of all-cause mortality (3% vs. 0.8%) and 30-day readmissions (9.9% vs. 7.1%; P < .001 for both) than the asthma-alone group.
“Severe asthma was found to indeed be a greater predictor of mortality in anaphylaxis hospitalizations. However, this did not track linearly, as I hypothesized, as asthma severity increased, ie, mild and moderate asthma did not seem to have any relationship with morbidity and mortality of anaphylaxis,” Khalil said.
Noting these associations between anaphylaxis and greater rates of asthma complications as well as a threefold increase in odds for in-hospital mortality among patients with severe-persistent asthma and anaphylaxis, the researchers encouraged clinicians to obtain an asthma history from patients presenting with anaphylaxis.
“These findings can be utilized to inform practitioners that severe-persistent asthma was observed to be an independent predictor of morbidity and mortality in anaphylaxis patients,” Khalil said.
“While further studies are required to broaden our understanding of these two related but distinct conditions, practitioners today can reference our study when educating patients with history of atopic conditions on the higher odds of serious illness and mortality when anaphylaxis presents in a patient with severe asthma,” he continued.
Next, the researchers indicated a need to study the relationship between asthma and anaphylaxis.
“Our study recognizes the limitation of using national databases that utilize ICD coding for identification of diagnoses, especially with diagnoses as specific as mild-intermittent asthma versus mild-persistent asthma,” Khalil said.
However, Khalil noted that the sheer power of the study and strong statistical relationship add much credence to its results and beg several questions that warrant further study.
“Firstly, a retrospective observational single or multicenter study with data of individual hospitalizations for anaphylaxis with history of asthma diagnosis confirmed by a pulmonary function test would allow us to dive deeper into a more accurate relationship between asthma severity and anaphylaxis presentation and outcomes,” Khalil said.
“If our results are re-demonstrated, even on a smaller scale, it would prompt even further study,” he continued. “A prospective study with similar design would allow us to ultimately establish a causal relationship between asthma severity and anaphylaxis.”