Detection of early age-related macular degeneration using novel functional parameters of the focal cone electroretinogram

The focal cone electroretinogram is a sensitive marker for macular disease, but have we unlocked its full potential? Typically assessment of waveform parameters is subjective and focuses on a small number of locations (e.g. the a-wave). This study evaluated the discriminatory and diagnostic potential of 4 conventional and 15 novel, objectively determined, parameters in patients with early Age-related Macular Degeneration. Focal cone electroretinograms were recorded in 54 participants with early Age-related Macular Degeneration (72.9±8.2 years) and 54 healthy controls (69±7.7 years). Conventional a and b wave amplitudes and implicit times were measured and compared to novel parameters derived from both the 1st and 2nd derivatives and the frequency-domain power spectrum of the electroretinogram.Statistically significant differences between groups were shown for all conventional parameters, the majority of 1st and 2nd derivative parameters and the power spectrum at 25 and 30 Hz. Receiver operating characteristics showed that both conventional and 1st and 2nd derivative implicit times had provided the best diagnostic potential. A regression model showed a small improvement over any individual parameter investigated. The non-conventional parameters enhanced the objective evaluation of the focal electroretinogram, especially when the amplitude was low. Furthermore, the novel parameters described here allow the implicit time of the electroretinogram to be probed at points other than the peaks of the a and b waves. Consequently these novel analysis techniques could prove valuable in future electrophysiological investigation, detection and monitoring of Age-related Macular Degeneration

Buprenorphine Retention in Primary Care

BACKGROUND: This study assesses the rate and predictors of treatment retention for primary care patients with opioid dependence–prescribed buprenorphine, a long-acting partial opioid agonist. METHODS: Observational cohort study of patients prescribed buprenorphine/naloxone and followed for 6 months in the period after the adoption of buprenophine/naloxone by a primary care practice in Rhode Island. Practice policy precluded patient discharges due to continuing drug use. RESULTS: Patients (n=41) had a mean duration of opioid use of 15.7 years and most had a history of heroin use (63.4%). Thirty-nine percent of patients transferred from methadone maintenance. At 24 weeks, 59% remained in treatment. Nearly half of dropouts occurred in the first 30 days. Participants with opiate-positive toxicologies at week 1 were more likely to drop out of the program (P<.01) and had a significantly shorter retention time (P<.01) on average. Among other drug use and drug treatment variables, employment and addiction counseling during treatment were significantly associated with treatment retention (P=.03). CONCLUSION: Retention rates in a real world, primary care–based buprenorphine maintenance practice reflect those reported in clinical trials. Abstinence during the first week of treatment and receipt of counseling were critical to patient retention