Drug Resistance in Pneumonia (DRIP) Score

DRIP predicts likelihood of antibiotic resistance in patients with bacterial pneumonia.

Refer to the text below the score for more information on the risk factors, limitations, the original and validation studies.


DRIP predicts risk for community-acquired pneumonia due to drug-resistant pathogens, especially in patients with exposure to the healthcare system, who are known to be at risk for DRPs, particularly methicillin-resistant Staph aureus (MRSA) and Pseudomonas aeruginosa.


  • Scores <4 were associated with lower risk of drug-resistant pneumonia. Consider treating without extended-spectrum antibiotics.

  • Scores ≥4 were associated with higher risk of drug-resistant pneumonia. Extended-spectrum antibiotics likely necessary.


Major Risk Factors

1Antibiotic use within 60 days
2Long term care resident Not including assisted living or group home facilities
3Tube feeding NG, nasojejunal, or PEG
4Prior drug-resistant pneumonia diagnosis within 1 year

Minor Risk Factors

5Hospitalization within 60 days
6Chronic pulmonary disease
7Poor functional status Karnofsky Performance Status <70 or non-ambulatory status
8H2 blocker or PPI within 14 days
9Active wound care at time of admission
10MRSA colonization within 1 year
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DRIP explained

The Drug Resistance in Pneumonia Score predicts risk for community-acquired pneumonia due to drug-resistant pathogens, especially in patients with exposure to the healthcare system, who are known to be at risk for DRPs, particularly methicillin-resistant Staph aureus (MRSA) and Pseudomonas aeruginosa.

DRIP is to be used for assessing patients with COP with a bacterial cause, in determining whether broad-spectrum antibiotics should be used. This is to both guide effective pneumonia treatment and to avoid increasing antibiotic resistance.

The score is composed of 4 major risk factors (scoring 2 points each if present) and 6 minor risk factors (scoring 1 point each if present).

DRIP Score Major Risk Factors:

  • Antibiotic use within 60 days;
  • Long term care resident (Not including assisted living or group home facilities);
  • Tube feeding (NG, nasojejunal, or PEG);
  • Prior drug-resistant pneumonia diagnosis within 1 year.

DRIP Score Minor Risk Factors

  • Hospitalization within 60 days;
  • Chronic pulmonary disease;
  • Poor functional status (Karnofsky Performance Status
  • H2 blocker or PPI within 14 days;
  • Active wound care at time of admission;
  • MRSA colonization within 1 year.

Interpretation

  • Scores <4 were associated with lower risk of drug-resistant pneumonia. Consider treating without extended-spectrum antibiotics.
  • Scores ≥4 were associated with higher risk of drug-resistant pneumonia. Extended-spectrum antibiotics likely necessary for these patients.

It was also found to be more specific and more accurate, not only than HCAP but further eight other predictive models, including the Shorr score.

 

DRIP Score versus HCAP

DRIP score was shown to be more predictive than the healthcare-associated pneumonia (HCAP) criteria for drug-resistant pathogens. At a cutoff of ≥4 points, the DRIP score optimally differentiates high and low risk for drug-resistant pneumonia, supporting the utility of the score in guiding antibiotic treatment choices.

HCAP diagnosis has been eliminated by the Infection Disease Societies of America (IDSA) given its poor sensitivity and specificity for drug resistant organisms. See comparison between HCAP criteria for DRPs and DRIP score:

Performance criteria HCAP DRIP Score
Sensitivity 0.79 (95% CI, 0.67 to 0.88) 0.82 (95% CI, 0.67 to 0.88)
Specificity 0.65 (95% CI, 0.56 to 0.73) 0.81 (95% CI, 0.73 to 0.87)
Positive predictive value (PPV) 0.53 (95% CI, 0.42 to 0.63) 0.68 (95% CI, 0.56 to 0.78)
Negative predictive value (NPV) 0.86 (95% CI, 0.77 to 0.92) 0.90 (95% CI, 0.81 to 0.93)
Overall accuracy 69.5% (95% CI, 62.5 to 75.7%) 81.5% (95% CI, 74.2 to 85.6%)

Unnecessary extended-spectrum antibiotics were recommended 46% less frequently by applying the DRIP score (25/200, 12.5%) than by use of HCAP criteria (47/200, 23.5%) (P = 0.004).

 

Limitations

DRIP Score false negatives may occur in: methicillin-resistant Staphylococcus aureus or P aeruginosa infection; severe chronic obstructive pulmonary disease (requiring oxygen and steroids); intravenous drug use; patients with psychiatric conditions or who are homeless.

DRIP Score false positives may occur in infections with: S pneumoniae and methicillin-susceptible Staphylococcus aureus.

Additional studies are necessary to confirm this new clinical decision criteria across different patient groups, and to possibly refine the rule to enhance its specificity and reduce unnecessary use of antibiotics.

 

About the original study

DRIP Score was initially derived and validated by Webb et al. in 2016 as a clinical prediction tool to aid antibiotic decision making in patients with bacterial pneumonia, who may be at risk of antibiotic resistance.

During derivation, a cohort of 200 microbiologically confirmed pneumonia cases was investigated and multiple risk factors for DRPs were evaluated via logistic regression. The score was then validated in a prospective, observational cohort of a further 200 microbiologically confirmed cases of pneumonia at four US centers.

In the original study, the DRIP score was found to be more sensitive (82% vs 79%) and more specific (81% vs 65%) than HCAP criteria. It decreased use of unnecessary extended-spectrum antibiotics by 46% as compared to HCAP criteria.

 

About the validation study

The original study authors conducted a further validation study in 2019, which focused on evaluating a broader set of risk factors than the HCAP definition on 2169 patients.

It reaffirmed that antibiotic use and hospitalization 60 days prior are major contributors to drug resistance, but did not find a strong association between severity of illness and drug resistance.

The validation study concluded that the DRIP score decreased the use of unnecessary extended-spectrum antibiotics by 38% as compared with HCAP criteria.

Whilst the rate of DRPs was 2.8%, one third of patients received broad-spectrum antibiotics, so there is suggestion that such criteria can be further improved to contribute to an even greater reduction in unnecessary antibiotic administration.

 

References

Original reference

Webb BJ, Dascomb K, Stenehjem E, Vikram HR, Agrwal N, Sakata K, Williams K, Bockorny B, Bagavathy K, Mirza S, Metersky M, Dean NC. Derivation and Multicenter Validation of the Drug Resistance in Pneumonia Clinical Prediction Score. Antimicrob Agents Chemother. 2016; 60(5):2652-63.

Validation

Webb BJ, Sorensen J, Mecham I, Buckel W, Ooi L, Jephson A, Dean NC. Antibiotic Use and Outcomes After Implementation of the Drug Resistance in Pneumonia Score in ED Patients With Community-Onset Pneumonia. Chest. 2019; 156(5):843-851.

Other references

Farkas A, Sassine J, Mathew JP, Stavropoulos C, Stern R, Mckinley G. Outcomes associated with the use of a revised risk assessment strategy to predict antibiotic resistance in community-onset pneumonia: a stewardship perspective. J Antimicrob Chemother. 2018; 73(9):2555-2558. doi: 10.1093/jac/dky202. PMID: 29897465.


Specialty: Pulmonology

System: Respiratory

Objective: Risk Stratification

Type: Score

No. Of Items: 10

Year Of Study: 2016

Abbreviation: DRIP

Article By: Denise Nedea

Published On: April 25, 2024

Last Checked: April 25, 2024

Next Review: April 25, 2029