Thread by @andreaprinzi

1/ Hey #IDTwitter #LabTwitter @ASCLS @ASMicrobiology , I want to take a moment to break down our new study: Endotracheal Aspirate Culture Variability and Antibiotic Use in Mechanically Ventilated Pediatric Patients ja.ma/31f9Zv8 via @JAMANetworkOpen @JAMANetwork

2/ This work was a multidisciplinary effort, & I am REALLY proud of that! I think this is a great example of the cool work we can do when we put our clinical laboratory and infectious disease minds together to answer questions about diagnostic tests and #stewardship #IDtwitter

3/ Dr. Sarah parker (@HandshakeASP @COpedsID ), Dr. Anna Sick-Samuels (@asicksamuels ) and myself all had a similar question: Do hospitals that use more endotracheal aspirate cultures have more days of therapy in their mechanically ventilated patients?

4 / Endotracheal aspirate cultures (EACs) are often used in pediatrics to assist in assessing cause of fever, diagnosing VAP/VAT, etc...but they are messy specimens. Contaminated w/commensal orgs, VERY hard to differentiate between colonization & infection
asm.org/Articles/2020/…

5/ All components for this process seem to be broken.
* The way we order/collect EACs is broken (collected as surveillance, clinical picture may not fit VAT/VAP when specimen collected, etc. Collecting/using less EACs doesn't seem to impact patient care
pubmed.ncbi.nlm.nih.gov/33827937/

6/ There is a TREMENDOUS amount of variability in how EACs are handled in the lab -- from processing to results reporting. This makes it nearly impossible to study anything involving EACs (including VAP & VAT). pubmed.ncbi.nlm.nih.gov/33298605/

7/ Additionally, reporting organisms from these poor-quality cultures may prompt clinicians to treat, even when it isn't warranted. It's a sticky situation: mechanically ventilated patients are VERY sick, and everyone is probably doing their best, but we have to #saveantibiotics

8 / So given that:
-EACs are usually very junky
-There's lab variability and reporting of EAC results may prompt unnecessary ABX use

We wanted to know:
Is there variability in EAC use across pediatric hospitals in the US, and if so, is ⬆️EAC use associated with ⬆️ABX?

9 / We use the Pediatric Health Information System (PHIS) to gather billing data on mechanically ventilated patients who were admitted between 2016-2019 and had EACs. It took us nearly 2 years to build a data extraction algorithm for this: EACs are hard to capture correctly!

10/ PT Incusion:
- <18 yrs
- >= 1 day of mechanical ventilation (CTC code for mechanical ventilation).
-We did some local validation(s) to determine which codes to use/not to use to ensure we captured the right patients
-Pts without daily coding were excluded (i.e., OR pts)

11 / EAC & Lab stuff
* EACs are billed for differently among labs & may be nonspecific (aerobic culture, "other"). This is a challenge!
* We teamed up with our amazing PHIS team and accessed the "charge description master" - allowed us to identify EACs w/better accuracy

12 /
We defined the rate of EAC use as the total number of EACs billed for on a ventilated day per 1000 total ventilator-days. We identified EACs when the patient had a code for respiratory aerobic culture coinciding with a charge for ventilation on the same calendar day.

13 /
As a team, we went through antibiotics one by one and selected those that would reasonably be used to treat a respiratory infection in these patients. We excluded abx with small n's, or those that were inhaled.

14/ We defined the rate of antibiotic use as an antibiotic day of therapy (DOT) occurring on a ventilated day per 1000 ventilator-days. A DOT was identified when the patient had a billing code for an antibiotic coinciding with a charge for ventilation on the same calendar day.

15/
We also collected patient and hospital demographics like:
Hospital case mix index, age, race/ethnicity, presence of underlying chronic condition(s), cumulative number of ventilator days, geographic location of the hospital, sex, etc.

16/ GET READY FOR SOME BIG NUMBERS!
*31 hospitals met inclusion criteria
*152,132 patients were admitted and received mechanical ventilation on a ventilated day during the study period
*These patients had 79,691 EACs that were collected on a ventilator day.

17/ Unadjusted rate of use for EACS
We broke use down by unit:
1. Overall = 46 per 1000 vent days (IQR, 32-73)
2. ICU group was 100 per 1000 vent days (IQR, 63-137)
3.NICU group= 24 per 1000 vent days (IQR, 11-34)

18/ factors associated with getting an EAC prior to adjustment included:
1. Case mix index (OR, 1.03 [95% CI, 1.02-1.03]; P < .001),
2. non-Hispanic Black race (OR, 1.16 [95% CI, 1.13-1.20]; P < .001)
3. presence of any chronic condition (OR, 2.13 [95% CI, 2.06-2.20]; P < .001)

19/ To try to understand the impact of EAC use on ABX use in ventilated patients, we adjusted for covariates that were associated with receiving an antibiotic. In other words, we tried to account for other reasons why a patient would receive an antibiotic other than EAC results

20 / Adjusted EAC use rates (median):
1. Median, all hospitals=57 per 1000 vent days.
2. The adjusted EAC rates for individual institutions ranged from 20 per 1000 total ventilator-days (95% CI, 13-26) to 119 per 1000 total ventilator-days (95% CI, 80-158)... AKA VARIABILITY!

21 / Patients were more likely to get an EAC test if:
1. Their hospital had a higher case mix index (AOR 1.03)
2. They were in the 1-4 yr age group (AOR 1.31)
3. They were non-Hispanic black patients (1.08)
4. They had more cumulative vent days (2.60)

22 / ANTIBOTICS: Unadjusted median DOT Rates-->
1. All units = 783 per 100 vent days (IQR, 686-875) (all antibiotics)
2. ICU = 1,181 per 1000 vent days (1,062-1,387)
3. NICU=740 per 1000 vent days (IQR, 648-838)

23/ Many variables were significantly associated w/ receiving ABX. Interestingly, Non-Hispanic Black patients had significantly less odds of receiving ABX on a ventilated day than non-Hispanic White patients (AOR, 0.80 [95% CI, 0.77-0.83]). This warrants more investigation.

24/ Correlation of ABX vs EAC
1. All units: R = 0.46; P = .009
2. ICU subgroup: All ABX R = 0.48; P = .001, anti-Staph drugs R = 0.43; P = .015
3.NICU subgroup: All ABX R = 0.5; P = .005, anti-Pseudo ABX R = 0.39; P = .03, anti-Staph ABX R = 0.51, P = .004.

25/ Final analysis:
After adjustment, patients who received EAC testing on a ventilated day had 3 times the odds of receiving an antibiotic than patients with mechanical ventilation who did not receive EAC testing (AOR, 2.87 [95% CI, 2.74-3.01]).

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Proud to have been a member of @CCTSI @CUAnschutz and @COpedsID while doing this work!

Please, share this work with those who are doing similar research, #stewardship, or QI & may be supported by it!
@PIDSociety @IDSAInfo @ASCLS @ASMicrobiology @ASCP_Chicago @ihqse @ABsteward