CAT on Therapy

1. Critical Appraisal
Treatment
Emmanuel D. Margate, Jr.

2. CASE SCENARIO
• 43/M
• Consult done with gastroenterologist due to abdominal pain
• Triple Contrast Enhanced CT was requested
• Found out to have increased creatinine at 3.36mg/dL with eGFR of
21ml/min
• Referred to a nephrologist and was then admitted as a Case of CKD
4 from Tubulointerstitial Nephropathy

3. Directness
• P : Patients undergoing Contrast Enhanced CT Scan
• I : Short Term High Dose Atorvastatin Therapy
• O : Prevention of Contrast-Induced Nephropathy
• M : Randomized controlled trial
Clinical Question:
Is short term high dose treatment of atorvastatin effective in
the prevention of contrast-induced nephropathy in patients
undergoing computed tomography with contrast in a
randomized controlled trial?

7. Relevance: Is the objective of the article
comparing therapeutic interventions similar to your
clinical dilemma?
STUDY CLINICAL QUESTION
Population Patients undergoing Angiography Patients undergoing Contrast Enhanced
CT
Intervention Atorvastatin 80mg Atorvastatin 80mg
Outcome Prevention of Contrast-Induced
Nephropathy
Prevention of Contrast-Induced
Nephropathy

8. Relevance: Is the objective of the article
comparing therapeutic interventions similar to your
clinical dilemma
• Objective of the article: To evaluate the
effectiveness of 80mg atorvastatin in the
prevention of contrast-induced nephropathy
in patients undergoing Angiography
• Clinical Question: Is short term high dose
treatment of atorvastatin effective in the
prevention of contrast-induced nephropathy
in patients undergoing computed tomography
with contrast?

9. Validity: Was the assignment of patients to
treatment randomized?

10. Validity: Was the Allocation concealed?
• No discussion about allocation concealment

11. Validity : Were patients, their clinicians,
and study personnel ”blind” to treatment?

12. Validity : Were the groups similar at the
start of the trial?

13. Validity : Were the patients analyzed in the groups to
which they were randomized? (intent–to-treat analysis)

14. Validity: Aside from the experimental
intervention, were the groups treated equally?
• No co-interventions mentioned

15. OVERALL, IS THE STUDY VALID?
• All validity guidelines were met

16. • Absolute Risk in Control (Rc) = 11/110 = 0.1
• Absolute Risk in Tx (Rt) = 3/110 = 0.027
• Absolute Risk Reduction (Rc-Rt) = 0.073
• Relative Risk (Rt/Rc) = 0.27
• Relative Risk Reduction (Rc-Rt/Rc) = 0.73
• NNT (1/ARR) = 13.69

17. WHAT ARE THE RESULTS?
• Decision (a= 0.05)
• Atorvastatin 80mg vs Placebo
• P value – 0.01
• p < a, indicates strong evidence against the null hypothesis, so null
hypothesis can be rejected. Therefore, a high dose of Atorvastatin
significantly reduces risk of CIN 24 hours after contrast medium
injection.

18. Can the results be applied to my patient?
INCLUSION CRITERIA (At LEAST 1) EXCLUSION CRITERIA
• Diabetes (fasting blood sugar > 126 mg/dL, random
blood sugar > 200 mg/dL, and glucose tolerance
test 200 mg/dL)
• Chronic renal failure (creatinine > 1.5 mg/dL or 15
< glomerular filtration rate [GFR] < 60
mls/min/1.73m2)
• Recent treatment with 80 mg of statin (not low-
dose atorvastatin) need for emergency
angiography
• Contraindications to statin prescription
• Previous contrast-media administration during the
preceding 10 days
• Chronic dialysis treatment
• Informed refusal of consent

19. Were all clinically important outcomes
considered?

20. RESOLUTION OF THE PROBLEM IN THE
SCENARIO
• Standard hydration and N-acetylcysteine and atorvastatin (80 mg)
reduced the incidence of CIN, and this regimen was more effective
than was the regimen of hydration and N-acetylcysteine (without
atorvastatin) in decreasing CIN. Accordingly, it is reasonable to
prescribe atorvastatin before angiography in high-risk patients.

21. Thank you!