[THE DOUBLE-BLIND TECHNIC. METHOD, APPLICATION AND POSSIBLE ERRORS].

The purpose of this study was to examine independent evaluators' (IEs) blindness to treatment condition during a Multicenter Comparative Treatment Study of Panic Disorder. IEs were 15 doctoral- and masters-level clinicians in psychology, social work, and medicine. They conducted three post-treatment assessments with each patient. Immediately after each assessment interview, IEs completed a form indicating which of the five possible treatments they believed the patient had received and any specific information that provided IEs with information about a patient's treatment condition. These forms were completed for 170 patients. Analyses were conducted to determine the accuracy of guesses about treatment condition by IEs during post-treatment assessments, the relationship between accuracy of IE guessing and actual treatment assignment, the relationship between accurate guessing and outcome ratings, and contributors to the breaking of the blind. A significant relationship was found between IE guesses and actual treatment at all three assessment points, across individual IEs, treatment sites, and IE professional affiliations. IEs were no more accurate in their guessing about patients taking medication than those receiving behavior therapy. Patients and project staff inadvertently provided information to IEs that enhanced the rates of accurate guessing. Implications of these findings on interpretation of the treatment study are discussed, and recommendations are made for improving blindness procedures.

Double-Blind Method↗

PubMed2004

Successful treatment with a nicotine lozenge of smokers with prior failure in pharmacological therapy.

AIMS: To assess the influence of unsuccessful past quit attempts using pharmacological treatment on smoking cessation when using a new nicotine lozenge. DESIGN: A double-blind, randomized, placebo-controlled trial. SETTING: Fifteen sites in the United Kingdom and the United States. PARTICIPANTS: A total of 1818 smokers seeking smoking cessation treatment; 1145 had had previous pharmacological treatment for smoking cessation. INTERVENTION: Lozenge, 2 mg or 4 mg (or matched placebo); a higher dose was assigned to smokers who smoked their first cigarette of the day within 30 minutes, a sign of dependence. Smokers received minimal instruction and counseling. MEASUREMENT: Outcome was 28-day, CO-verified continuous abstinence at 6 weeks. Past use of medications was ascertained by self-report. FINDINGS: Lozenge was efficacious among smokers with prior pharmacotherapy as well as among those without such history. The effect of lozenge (versus placebo) was significantly greater among those with previous treatment experience, because previous treatment was associated with significantly poorer outcome on placebo, and active lozenge treatment corrected this imbalance. Lozenge efficacy was similar whether smokers had previously tried patch or acute forms of nicotine replacement therapy (gum, inhaler and spray), and also similar for past use of Zyban (bupriopion). CONCLUSIONS: Smokers with a history of past failure of pharmacological treatment have lower success rates without pharmacological treatment, but equally good outcomes with active lozenge treatment. Smokers who previously tried pharmacological treatments but resumed smoking should be encouraged to try quitting again with the new nicotine lozenge.

Double-Blind Method↗

PubMed2003

Incidence of resistance in a double-blind study comparing lopinavir/ritonavir plus stavudine and lamivudine to nelfinavir plus stavudine and lamivudine.

Study M98-863 was a double-blind, randomized, phase 3 study that compared lopinavir/ritonavir with nelfinavir, each coadministered with stavudine and lamivudine, in 653 antiretroviral therapy-naive human immunodeficiency virus (HIV) type 1-infected subjects. The incidence of HIV drug resistance was analyzed using baseline and rebound virus isolates from subjects with plasma HIV RNA >400 copies/mL from weeks 24 to 108 of therapy. No evidence of genotypic or phenotypic resistance to lopinavir/ritonavir, defined as any active site or primary mutation in HIV protease, was detected in virus isolates from 51 lopinavir/ritonavir-treated subjects with available genotypes. Primary mutations related to nelfinavir resistance (D30N and/or L90M) were observed in 43 (45%) of 96 nelfinavir-treated subjects. Resistance to lamivudine and stavudine was also significantly higher in nelfinavir-treated versus lopinavir/ritonavir-treated subjects. These differences suggest substantially different genetic and pharmacological barriers to resistance for these 2 protease inhibitors and may have implications for strategies for initiating antiretroviral therapy.

Double-Blind Method↗