The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial Multicenter Study
Study methods, recruitment, sociodemographic findings, and demographic representativeness in the OPPERA study.
This paper describes methods used in the project "Orofacial Pain Prospective Evaluation and Risk Assessment" (OPPERA) and evaluates sociodemographic characteristics associated with temporomandibular disorders (TMD) in the OPPERA case-control study. Representativeness was investigated by comparing sociodemographic profiles of OPPERA participants with population census profiles of counties near study sites and by comparing age and gender associations with TMD in OPPERA and the 2007 to 2009 US National Health Interview Survey. Volunteers aged 18 to 44 years were recruited at 4 US study sites: 3,263 people without TMD were enrolled into the prospective cohort study; 1,633 of them were selected as controls for the baseline case-control study. Cases were 185 volunteers with examiner-classified TMD. Distributions of some demographic characteristics among OPPERA participants differed from census profiles, although there was less difference in socioeconomic profiles. Odds of TMD was associated with greater age in this 18 to 44 year range; females had 3 times the odds of TMD as males; and relative to non-Hispanic-Whites, other racial groups had one-fifth the odds of TMD. Age and gender associations with chronic TMD were strikingly similar to associations observed in the US population. Assessments of representativeness in this demographically diverse group of community volunteers suggest that OPPERA case-control findings have good internal validity. ⋯ Demographic associations with TMD were consistent with population benchmarks and with other studies, suggesting broad applicability of these OPPERA findings. Greater occurrence of TMD in non-Hispanic-Whites than in other racial/ethnic groups and the lack of a socioeconomic gradient contradicts the disparities seen in many other health conditions.
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Randomized Controlled Trial Multicenter Study
Efficacy and safety of buprenorphine transdermal system (BTDS) for chronic moderate to severe low back pain: a randomized, double-blind study.
In this enriched design study, 1,160 opioid-experienced patients with chronic, moderate to severe low back pain entered an open-label run-in period; 660 demonstrated analgesic benefit from and tolerability to buprenorphine transdermal system 20 mcg/hour (BTDS 20) treatment and were randomized to receive either BTDS 20, BTDS 5 mcg/hour (BTDS 5), or the active control (immediate release oxycodone 40-mg/day) during an 84-day double-blind phase. The primary endpoint, "average pain in the last 24 hours" during double-blind weeks 4, 8, and 12, was significantly lower for patients receiving BTDS 20 compared with patients receiving BTDS 5 (P < .001, treatment difference of -.67). A treatment difference of -.75 in favor of oxycodone 40 mg/day versus BTDS 5 (P < .001) indicated the assay sensitivity of the study. Four sensitivity analyses, secondary, and exploratory analyses supported the results of the primary analysis. Incidences of treatment-emergent adverse events were 56% during the open-label period, and 59, 77, and 73% for the BTDS 5, BTDS 20, and oxycodone 40 mg/day treatment groups, respectively, during the double-blind phase. One death considered unrelated to study treatment occurred in a patient receiving BTDS 10 during the run-in period. BTDS 20 treatment was demonstrated to be efficacious and generally well tolerated. ⋯ This article presents results of a pivotal Phase 3 study that assesses a new treatment for the management of chronic low back pain: a transdermal patch containing the opioid buprenorphine (BTDS). In this active controlled, superiority study with an enriched design, BTDS 20 was found to be efficacious and generally well tolerated.