Hospital discharge database optimization in Guillain-Barré syndrome surveillance.

INTRODUCTION: Precise causes and risk factors for Guillain-Barré syndrome (GBS) remain incompletely understood, and monitoring its incidence remains important in public health. Active surveillance is not sustainable, but hospital discharge databases (HDDs) may be suitable for passive surveillance. METHODS: We optimized Tennessee's HDD of all ICD-9 codes of 357.0, from 2000 to 2010. Discharges for persons with a GBS diagnosis in a previous hospitalization in the database were excluded. HDD results were compared with the CDC's active surveillance program during the H1N1 vaccination program of 2009-2010. RESULTS: Of 2,659 records of Tennessee residents initially identified, 1077 (40%) had prior diagnoses of GBS. Adjusted annual rates ranged from 1.24 to 1.57 per 100,000 population. The sensitivity of the optimized HDD was 0.81 with a positive predictive value of 0.45. CONCLUSIONS: Optimization of a HDD through exclusion of nonacute cases results in an acceptable and practical database for passive surveillance of GBS.

Muscle ultrasound quantifies the rate of reduction of muscle thickness in amyotrophic lateral sclerosis.

Sensitive biomarkers are lacking in amyotrophic lateral sclerosis (ALS). Muscle ultrasound (MUS) can quantify muscle thickness and echointensity (EI). We evaluated the rate of muscle atrophy in ALS using MUS. Ten patients had serial unilateral MUS examination of biceps, wrist flexors, and tibialis anterior over 6 months. The rates of change of muscle thickness and EI were determined. Muscle thickness declined at a mean rate of -0.663 mm/month (P = 0.0014), greatest in biceps. Muscle thickness correlated moderately with ALSFRS-R, grip dynamometry, and body weight. There was no change in EI. MUS can quantify the rate of reduction in muscle thickness in ALS patients. The lack of strong correlation between muscle thickness and standard ALS measures may reflect limited sensitivity in these conventional measures. The rate of change of muscle thickness merits further study as a potential biomarker in ALS, particularly when considering biceps brachii as a candidate.

A systematic review of validated methods for identifying Bell's palsy using administrative or claims data.

PURPOSE: To identify and assess billing, procedural, or diagnosis code, or pharmacy claims-based algorithms used to identify Bell's palsy in administrative and claims databases. METHODS: We searched the MEDLINE database via PubMed from 1991 to September 2012 using controlled vocabulary and key terms related to Bell's palsy. We also searched the reference lists of included studies. Two investigators independently assessed the full text of studies against pre-determined inclusion criteria. Two reviewers independently extracted data regarding participant and algorithm characteristics and assessed a study's methodologic rigor. RESULTS: One study identified Bell's palsy using an algorithm that included ICD-9 code 351.x and H-ICDA code 350.x, and two other studies analyzed a dataset for ICD-9 code 351.0. The positive predictive values of these studies were 0.81 and 0.88, based on case adjudication of ICD-9 matches. Two further studies calculated incidence rates without validation of their methods, also including ICD-9 code 351.0. No study reported the sensitivity of algorithms to identify Bell's palsy. CONCLUSIONS: Few publications used rigorous methods to identify a validated algorithm that could identify cases of Bell's palsy from an administrative database. The best evidence from two different datasets in the literature addressed in this review used ICD-9 code 351.0 or a collection of ICD-9 codes 351.x for facial nerve disorders including Bell's palsy, along with other ICD-9 and H-ICDA codes for facial weakness. Each study had acceptable PPV, suggesting that ICD-9 based-algorithms have some utility in detecting Bell's palsy cases.

A systematic review of validated methods to capture several rare conditions using administrative or claims data.

PURPOSE: To identify and assess billing, procedural, or diagnosis code, or pharmacy claim-based algorithms used to identify the following health outcomes in administrative and claims databases: acute disseminated encephalomyelitis (ADEM), optic neuritis, tics, and Henoch Schönlein purpura (HSP). METHODS: We searched the MEDLINE database from 1991 to September 2012 using controlled vocabulary and key terms related to the conditions. We also searched the reference lists of included studies. Two investigators independently assessed the full text of studies against pre-determined inclusion criteria and extracted case validation data from those studies meeting inclusion criteria. RESULTS: Two eligible studies addressed ADEM, two addressed optic neuritis, and four studies addressed tics. Only one study addressed HSP. Among these, one study of ADEM reported a positive predictive value of 66%, however the identification algorithm contained a combination of International Classification of Diseases (ICD) codes and other identification methods and the performance of the ICD-9 codes alone was not reported. No other studies reported validation data. CONCLUSIONS: The lack of data on the validity of algorithms to identify these conditions may hamper our ability to determine incidence patterns with respect to infection and vaccination exposures. Further epidemiologic research to define validated methods of identifying cases could improve surveillance using large linked healthcare databases.

Estrogen replacement in ovariectomized rats affects strategy selection in the Morris water maze.

While estrogen enhances performance on some tasks of learning and memory, it has impairing or no effects on others. It has been proposed that estrogen differentially affects performance on various tasks of learning and memory by influencing the strategy used to solve a task. The goal of the present study was to determine if estrogen would influence strategy selection in the Morris water maze. Long-Evans rats were ovariectomized and implanted with Silastic capsules containing 25% estradiol diluted in cholesterol or 100% cholesterol. Rats were trained in a water maze task in which multiple strategies were available for use to locate a hidden escape platform that was moved to a new location for each set of four daily trials. During 10 days of acquisition trials, a visible floating landmark was always located in a static position relative to the hidden escape platform. Additionally, fixed extramaze cues visible to the animals surrounded the maze. Following acquisition, 2 days of probe trials were conducted in which the static landmark was removed. Estrogen replacement in ovariectomized rats resulted in impaired performance across 10 days of acquisition. Additionally, while removal of the visible landmark during the probe trials had no effect on the performance of the females receiving estrogen, it significantly disrupted performance of females receiving cholesterol treatment. These results indicate that estrogen replacement in ovariectomized rats biases an animal against using a landmark or static cue to aid in the location of a hidden escape platform in the water maze.