Critical Appraisal of an Article on Therapy (2)

Formulate Clinical Question

•Patient/ population

• Intervention•Comparison•Outcome (s)

• Women with IBS

• Alosetron• Placebo• Efficacy (relief of

symp) Tolerability (SE)

Users‘ Guides to the Medical Literature

• Are the results valid?• What were the results?• Will the results help me in

caring for my patients?

Are the Results of the Study Valid?

1. Was the assignment of patients to treatment randomized?

Primary guides

Are the Results of the Study Valid?

2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?

• Was follow-up complete?• Were patients analyzed in the

groups to which they were randomized?• Intention-to-treat analysis

Primary guides

Are the Results of the Study Valid?

3. Were patients, their clinicians, and study personnel ‘blind’ to treatment?

Secondary guides

Are the Results of the Study Valid?

4. Were the groups similar at the start of the trial?

Secondary guides

Are the Results of the Study Valid?

5. Aside from the experimental intervention, were the groups treated equally?

• Co-intervention?• Contamination?• Compliance?

Secondary guides

Any questions?

I Are the results of the study valid?

Was the assignment of patients to treatment randomized?

Were all patients who entered the trial properly accounted for and attributed at its conclusion?

Were patients, their clinicians, and study personnel ‘blind’ to treatment?

Were the groups similar at the start of the trial?

Aside from the experimental intervention, were the groups treated equally?

What Were the Results?

• How large was the treatment effect?– Absolute risk reduction (ARR)– Relative risk reduction (RRR)

What Were the Results?

2. How precise was the estimate of the treatment effect?

– Confidence intervals?

The 95% confidence interval (or 95% limits) would include 95% of the results from studies of the same size & design in the same population

What Were the Results?

1. How large was the treatment effect?

2. How precise was the estimate of the treatment effect?

More questions?

Will the Results Help Me in Caring for My Patients?

1. Can the results be applied to my patient care?

– Pts similar for demographics, severity, co-morbidity and other prognostic factors?

– Compelling reason(s) why the results should not be applied?

Will the Results Help Me in Caring for My Patients?

2. Were all clinically important outcomes considered?

– Are substitute endpoints valid?

Will the Results Help Me in Caring for My Patients?

3. Are the likely treatment benefits worth the potential harms and costs?

– ‘Number needed to treat’ (NNT) for different outcomes?• NNT= 1 / ARR

Will the Results Help Me in Caring for My Patients?

3. Are the likely treatment benefits worth the potential harms and costs?

• NNT = 100/ 12 = 8.3• NNT = 100/ 4.7= 21.3• NNT = 100/ 19.2 = 5.2

• NNH = 100/ 27 = 3.7

Will the Results Help Me in Caring for My Patients?

1. Can the results be applied to my patient care?

2. Were all clinically important outcomes considered?

3. Are the likely treatment benefits worth the potential harms and costs?

More questions?

Would You Use Alosetron in Treating Patients With IBS?

Thank you …