Evaluating the Medical Literature

Evaluating the Medical Literature Clista Clanton, MSLS, AHIP January 2009

Haynes, RB. ACPJC Nov/Dec 2006;145(3):A8-9 Start at the top and work your way down.

Computer system Clinical Evidence or PIER (UpToDate) ACP Journal Club, InfoPOEMS, Dynamed Cochrane Library, PubMED Clinical Queries, BMJUpdates, guidelines Original Studies

Original Studies If an original study is your only option…….

IMRAD format ,[object Object],[object Object],[object Object],[object Object]

PP-ICONS ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Flaherty, Robert J. A simple method for evaluating the clinical literature. Fam Prac Mgt, May 2004;47-52. Available online at http://www.aafp.org/fpm/20040500/47asim.html .

Clinical Question ,[object Object],“ Is duct tape an effective treatment for warts in children?” ,[object Object],[object Object]

Search ,[object Object],[object Object],[object Object],[object Object]

Abstract ,[object Object],[object Object]

Problem ( P P-ICONS) ,[object Object],OBJECTIVE: To determine if application of duct tape is as effective as cryotherapy in the treatment of common warts. ,[object Object]

Patient or Population (P P -ICONS) ,[object Object],SETTING: The general pediatric and adolescent clinics at a military medical center. PATIENTS: A total of 61 patients (age range, 3-22 years) ,[object Object]

Intervention (PP- I CONS) ,[object Object],[object Object],The patient’s mother has heard about treating warts with duct tape and wants to know if you would recommend this treatment.

Comparison (PP-I C ONS) ,[object Object],[object Object],INTERVENTION: Patients were randomized using computer-generated codes to receive either cryotherapy (liquid nitrogen applied to each wart for 10 seconds every 2-3 weeks) for a maximum of 6 treatments or duct tape occlusion (applied directly to the wart) for a maximum of 2 months.

Outcome (PP-IC O NS) ,[object Object],[object Object],[object Object],[object Object],MAIN OUTCOME MEASURE: Complete resolution of the wart being studied.

Number (PP-ICO N S) ,[object Object],[object Object],[object Object],[object Object],Krejcie RV, Morgan DW. Determining sample size for research activities. Educational and Psychological Measurements . 1970;30:607-610. 51 patients completed the study

Statistics (PP-ICON S ) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],RRR would be (85 percent – 60 percent/60 percent x 100 = 42 percent I.e. 42 percent more effective than cryotherapy in treating warts

Statistics (PP-ICON S ) ,[object Object],[object Object],ARR for the wart study is the outcome event rate (complete resolution of warts) for duct tape (85 percent) minus the outcome event rate for cryotherapy (60 percent) = 25 percent

Statistics (PP-ICON S ) ,[object Object],[object Object],[object Object],For the wart study, the NNT is 1/25 percent = 1/0.25 = 4 4 patients need to be treated with duct tape for one to benefit more than if treated by cryotherapy ,[object Object],[object Object]

Intention to Treat Analysis ,[object Object],[object Object],[object Object],[object Object],Six patients from cryotherapy group and 4 patients from the duct tape group were lost to follow-up (16% of patients). Worst case scenario: 6 cryotherapy patients had wart resolution and the 4 duct tape patients had residual wart. Wart resolution would then be: duct tape 78% and cryotherapy 68% (95% CI, -17 to 28) – therefore not a statistically significant difference between the two treatments. Christakis DA, Lehmann HP. Is duct tape occlusion therapy as effective as cryotherapy for the treatment of the common wart? Arch Pediatr Adolesc Med, Oct 2002; vol. 156; 975-977.

Best Type of Study for Your Question Type of Question Suggested Best Type of Study Therapy RCT > cohort > case control > case series Diagnosis Prospective, blind comparison to gold standard Etiology / Harm RCT > cohort > case control > case series Prognosis Cohort study > case control > case series Prevention RCT > cohort study > case control > case series Clinical Exam Prospective, blind comparison to gold standard Cost Economic analysis Questions of therapy, etiology and prevention which can best be answered by RCT can also be answered by a meta-analysis or systematic review.

Assignment ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Evaluating the Medical Literature

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (10)

Ähnlich wie Evaluating the Medical Literature

Ähnlich wie Evaluating the Medical Literature (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Evaluating the Medical Literature