Pulmonary embolism (PE) is a common contributor to inpatient disease burden in the US with an annual incidence of 69 per 100,000 patients [
Clinical findings at the time of diagnosis of acute PE can help in prognostic assessment of patients [
It is unclear whether clinicians are frequently utilizing risk prediction models such as PESI in a community hospital setting. We wanted to find if there was a difference in the length of hospital stay in patients at low, moderate, and high risks as classified by the PESI score. Furthermore, we wanted to determine the number of low risk patients with acute PE who were discharged early from the hospital.
This is a retrospective study of patients with acute PE who were admitted to St. Joseph Mercy Oakland Hospital, Pontiac, Michigan, from January 2005 to August 2010. Patients with PE were identified by computer listings of ICD-9 diagnosis codes (415.11, 415.19). The study population included all the adult patients ≥ 18 years of age. Patients who died during the index admission were excluded from the study.
The PESI score, a well-validated prognostic tool, was utilized to risk-stratify patients with PE into low, moderate, and high risk groups (Supplemental Table 1 in Supplementary Material available online at
The main outcome variable was length of hospital stay in days. As a dichotomous variable, we further determined if any of the low risk patients left the hospital early (≤3 days).
Baseline differences between patients at low, moderate, or high risk for PE (PESI score) were compared by use of Analysis of Variance (ANOVA) for continuous variables and cross tabulation for categorical variables. ANOVA testing was also used to determine if there was a statistically significant difference between the three PESI risk groups (low, moderate, and high) in regard to their respective length of hospital stay. The data fulfilled the most important assumption for ANOVA testing in that the observations were independent. The data further fulfilled most of the other assumptions; the groups were homogenous in terms of their variances. The distributions of the groups approached normality. There were some outliers in the low and high risk groups but these were taken care of by winsorizing. IBM SPSS version 22 was used to run all the analyses.
After applying the inclusion and exclusion criteria, our study group comprised 315 patients, with females comprising 55% of the sample. The mean age of the study group was 63 ± 17 years and the mean length of hospital stay was
Baseline characteristics of total study population as well as risk stratified by PESI.
Variables | Total |
Low risk PE |
Moderate risk PE |
High |
---|---|---|---|---|
Age (yrs ± SD) | 63 ± 17 | 55 ± 16 | 72 ± 11 | 73 ± 14 |
Male (%) | 44 | 40 | 43.2 | 56.3 |
Medical history | ||||
Heart failure (%) | 20.3 | 4.3 | 31 | 45 |
Cancer (%) | 23 | 6 | 33 | 52 |
CLD (%) | 19 | 10 | 22 | 35 |
Hospital characteristics (%) | ||||
Tachypnea (RR > 30) | 4.4 | 0 | 1 | 18 |
Tachycardia (HR > 100) | 13 | 7.4 | 11 | 30 |
Hypotension (SBP < 100) | 7.3 | 1.2 | 6.2 | 22.5 |
Hypothermia (temp. < 96 F) | 2.5 | 0 | 1.2 | 10 |
Encephalopathy | 2 | 0 | 0 | 8.5 |
Hypoxia (Ox sat < 90%) | 6.3 | 0.6 | 2.5 | 24 |
Early discharge (≤3 days) (%) | 7.6 | 9.2 | 8.6 | 3 |
Hospital stay (days ± SD) | 7.3 ± 3 | 7.1 ± 3 | 6.8 ± 2.9 | 8.1 ± 3 |
Reason for hospital stay (%) | ||||
Anticoagulant bridging | 85.6 | 82 | 89 | 90 |
Other | 14.4 | 18 | 11 | 10 |
CLD: chronic lung disease; HR: heart rate; Ox sat: oxygen saturation; SD: standard deviation.
The differences in demographic characteristics between the risk groups can be found in Table
Comparing the length of hospital stay (days) of low, moderate, and high risk PE groups.
By using one-way ANOVA analysis testing, we found that there was a statistically significant difference between the mean lengths of hospital stay in our 3 different pulmonary embolism risk groups stratified by the PESI score with
From among the total study group, 7.6% of patients were discharged early (≤3 days). 15/163 (9%) of the low risk (Figure
Proportion of low risk PE patients discharged from the hospital early (≤3 days). Pie chart representing all low risk PE patients with a proportion (blue) that shows early discharge (≤3 days). PE: pulmonary embolism.
The most common presenting symptom in the total study group was dyspnea (43%). Among the risk groups, chest pain was the most common presenting symptom in the low risk PE patients (40%) but dyspnea remained the common presenting symptom in moderate risk (50.6%) and high risk (50.7%) PE patients. The least common presenting symptom in the study group was syncope (6%) but when present it was most commonly seen in high risk (13%) followed by moderate risk (5%) and low risk (3.7%) patients (Table
Presenting symptoms of the study population and in different PESI risk groups.
Presenting symptom | Total | Low risk | Moderate risk | High risk |
---|---|---|---|---|
Dyspnea (%) | 43.50 | 36.80 | 50.60 | 50.70 |
Chest pain (%) | 32.10 | 40.50 | 26 | 20 |
Leg swelling (%) | 7.30 | 8.60 | 8.60 | 3 |
Syncope (%) | 6 | 3.70 | 5 | 13 |
Other (%) | 11.10 | 10.40 | 9.90 | 14 |
In this retrospective observational study, we found that the average length of hospital stay for patients who presented with an acute PE was 7 days which was similar to previous reports [
More and more evidence is emerging where an early discharge from the hospital and/or outpatient treatment of selective low risk PE patients may be safe [
Our study shows that there is potential for a large patient population that present to the hospital with an acute PE to be discharged early. 50% of patients who presented to our community hospital were found to be at low risk which is similar to previous studies [
Our study should be interpreted in light of the limitations of a retrospective observational study. First, this was a single center study and we had a fairly small patient population (sample size) making the generalizability of the results across other centers be less certain. Secondly, the diagnosis of acute PE was made through chart review and was not confirmed with results from any diagnostic testing which could have led to misdiagnosis. We could not report information regarding several variables (BNP, D-dimer, and troponin) that we collected because of missing data in the majority of the study population. Furthermore, we did not collect data regarding the type of anticoagulation the patients received, which could have helped provide further information of their length of hospital stay. Finally, we did not look at mortality and other outcome data at follow-up for the risk groups. Future work should include investigating the outcomes of patients with PE who are discharged early as compared to having a prolonged hospital stay.
In our retrospective study of patients with acute PE, we found no meaningful difference in the length of hospital stay between different risk group categories after risk-stratifying with PESI score. Half of the patients admitted to our community based teaching hospital with acute PE were at low risk but a very small number, that is, 9%, of low risk patients were discharged from the hospital early (within 3 days of admission). This might imply that clinicians are not routinely making use of risk stratification tools such as the PESI score to help guide management and disposition of acute PE patients. Identifying such low risk patient population for early hospital discharge has the potential to decrease hospital stay and be cost effective.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Ali Shafiq, M.D., received support from the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award no. T32HL110837.