Can cost utility evaluations inform decision making about interventions for low back pain?

Background contextLow back pain (LBP) is associated with high health-care utilization and lost productivity. Numerous interventions are routinely used, although few are supported by strong evidence. Cost utility analyses (CUAs) may be helpful to inform decision makers.PurposeTo conduct a systematic review of CUAs of interventions for LBP.Study designSystematic review.MethodsA search strategy combining medical subject headings and free text related to LBP and health economic evaluations was executed in MEDLINE. Cost utility analyses combined with randomized controlled trials for LBP were included. Studies that were published before 1998, non-English, decision analyses, and duplicate reports were excluded. Search results were evaluated by two reviewers, who extracted data independently related to clinical study design, economic study design, direct cost components, utility results, cost results, and CUA results.ResultsThe search produced 319 citations, and of these 15 met eligibility criteria. Most were from the United Kingdom (n=8), published in the past 3 years (n=12), studied chronic LBP or radiculopathy (n=13), and had a follow-up >12 months (n=13). Combined, there were 33 study groups who received a mean 2.1 interventions, most commonly education (n=17), exercise therapy (n=13), spinal manipulation therapy (n=7), surgery (n=7), and usual care from a general practitioner (n=7). Mean baseline utility was 0.57, improving to 0.67 at follow-up; the mean difference in utility improvement between study groups was 0.04. Based on available data and converted to US dollars, the cost per quality-adjusted life year ranged from $304 to $579,527, with a median of $13,015.ConclusionsFew CUAs were identified for LBP, and there was heterogeneity in the interventions compared, direct cost components measured, indirect costs, other methods, and results. Reporting quality was mixed. Currently published CUAs do not provide sufficient information to assist decision makers. Future CUAs should attempt to measure all known direct cost components relevant to LBP, estimate indirect costs such as lost productivity, have a follow-up period sufficient to capture meaningful changes, and clearly report methods and results to facilitate interpretation and comparison.     

The neural substrates of impaired prosodic detection in schizophrenia and its sensorial antecedents

OBJECTIVE: Individuals with schizophrenia show severe deficits in their ability to decode emotions based upon vocal inflection (affective prosody). This study examined neural substrates of prosodic dysfunction in schizophrenia with voxelwise analysis of diffusion tensor magnetic resonance imaging (MRI). METHOD: Affective prosodic performance was assessed in 19 patients with schizophrenia and 19 comparison subjects with the Voice Emotion Identification Task (VOICEID), along with measures of basic pitch perception and executive processing (Wisconsin Card Sorting Test). Diffusion tensor MRI fractional anisotropy valves were used for voxelwise correlation analyses. In a follow-up experiment, performance on a nonaffective prosodic perception task was assessed in an additional cohort of 24 patients and 17 comparison subjects. RESULTS: Patients showed significant deficits in VOICEID and Distorted Tunes Task performance. Impaired VOICEID performance correlated significantly with lower fractional anisotropy values within primary and secondary auditory pathways, orbitofrontal cortex, corpus callosum, and peri-amygdala white matter. Impaired Distorted Tunes Task performance also correlated with lower fractional anisotropy in auditory and amygdalar pathways but not prefrontal cortex. Wisconsin Card Sorting Test performance in schizophrenia correlated primarily with prefrontal fractional anisotropy. In the follow-up study, significant deficits were observed as well in nonaffective prosodic performance, along with significant intercorrelations among sensory, affective prosodic, and nonaffective measures. CONCLUSIONS: Schizophrenia is associated with both structural and functional disturbances at the level of primary auditory cortex. Such deficits contribute significantly to patients' inability to decode both emotional and semantic aspects of speech, highlighting the importance of sensorial abnormalities in social communicatory dysfunction in schizophrenia.     

Distinct neurophysiological mechanisms mediate mixing costs and switch costs

Using event-related potentials (ERPs), we investigated the neural response associated with preparing to switch from one task to another. We used a cued task-switching paradigm in which the interval between the cue and the imperative stimulus was varied. The difference between response time (RT) to trials on which the task switched and trials on which the task repeated (switch cost) decreased as the interval between cue and target (CTI) was increased, demonstrating that subjects used the CTI to prepare for the forthcoming task. However, the RT on repeated-task trials in blocks during which the task could switch (mixed-task blocks) were never as short as RTs during single-task blocks (mixing cost). This replicates previous research. The ERPs in response to the cue were compared across three conditions: single-task trials, switch trials, and repeat trials. ERP topographic differences were found between single-task trials and mixed-task (switch and repeat) trials at approximately 160 and approximately 310 msec after the cue, indicative of changes in the underlying neural generator configuration as a basis for the mixing cost. In contrast, there were no topographic differences evident between switch and repeat trials during the CTI. Rather, the response of statistically indistinguishable generator configurations was stronger at approximately 310 msec on switch than on repeat trials. By separating differences in ERP topography from differences in response strength, these results suggest that a reappraisal of previous research is appropriate.     

Circuit-based framework for understanding neurotransmitter and risk gene interactions in schizophrenia

Many risk genes interact synergistically to produce schizophrenia and many neurotransmitter interactions have been implicated. We have developed a circuit-based framework for understanding gene and neurotransmitter interactions. NMDAR hypofunction has been implicated in schizophrenia because NMDAR antagonists reproduce symptoms of the disease. One action of antagonists is to reduce the excitation of fast-spiking interneurons, resulting in disinhibition of pyramidal cells. Overactive pyramidal cells, notably those in the hippocampus, can drive a hyperdopaminergic state that produces psychosis. Additional aspects of interneuron function can be understood in this framework, as follows. (i) In animal models, NMDAR antagonists reduce parvalbumin and GAD67, as found in schizophrenia. These changes produce further disinhibition and can be viewed as the aberrant response of a homeostatic system having a faulty activity sensor (the NMDAR). (ii) Disinhibition decreases the power of gamma oscillation and might thereby produce negative and cognitive symptoms. (iii) Nicotine enhances the output of interneurons, and might thereby contribute to its therapeutic effect in schizophrenia.     

Hemispheric asymmetry and callosal integration of visuospatial attention in schizophrenia: a tachistoscopic line bisection study

BACKGROUND: A hallmark of visuospatial neglect syndrome is that patients with lesions to right parietal cortex misbisect horizontal lines far rightward of veridical center. Neurologically normal subjects misbisect lines with a systematic leftward bias (pseudoneglect). Both phenomena, as well as neuroimaging studies, disclose a predominant right-hemisphere control of spatial attention. Numerous studies of patients with schizophrenia have implicated global deficits of either right or left hemisphere function, as well as compromised integrity of the corpus callosum. METHODS: To better understand the functional implications of schizophrenia we utilized a forced-choice tachistoscopic line bisection task to probe the status of right-hemisphere control of spatial attention, and compared left- versus right-hand unimanual responses to index the degree of callosal transfer of visuospatial information in both patient and control groups. RESULTS: In contrast to the significant leftward bisection errors of control subjects, patients exhibit no significant leftward error. Whereas control subjects evince a significant correlation between left- and right-hand bisection errors, patients lack a significant intermanual correlation. CONCLUSIONS: The lack of significant leftward bisection error of patients implies a deficit of right-hemisphere function. The lack of a significant correlation between left- and right-hand bisection errors in patients implies a loss of callosal integrity.     

Health Promotion and the First Amendment: Government Control of the Informational Environment

Government efforts to protect public health often include controlling health information. The government may proscribe messages conveyed by commercial entities (e.g., false or misleading), recommend messages from commercial entities (e.g., warnings and safety instructions), and convey health messages (e.g., health communication campaigns). Through well-developed, albeit evolving, case law, government control of private speech has been constrained to avoid impinging on such values as free expression, truthfulness, and autonomous decision making. No simple legal framework has been developed for the government's own health messages to mediate between the legitimate goals of health protection and these other values. Nevertheless, government recommendations on matters of health raise difficult social and ethical questions and involve important societal trade-offs. Accordingly, this article proposes legal and ethical principles relating to government control of the health information environment.     

Surgical bacterial infections and antimicrobial susceptibility patterns at Lilongwe Central Hospital

A cross sectional study was done between October 1999 and February 2000 to determine antimicrobial susceptibility patterns of consecutive bacterial isolates of 102 clinical samples among surgical in-patients at Lilongwe Central Hospital (LCH), Malawi. Antimicrobial susceptibility was determined using comparative disc diffusion techniques. 83 (81.4%) samples were culture positive for bacterial growth while 19 (18.6%) grew nothing. Of the 93 culture positive specimens, Staphylococcus aureus was the predominant organism 43(51.8%) followed by Proteus species 8(9.6%) and E. coli 7(8.4%). Overall, 98.6% of all isolates tested against ciprofloxacin were susceptible, and against gentamicin and flucloxacin were 84.8% and 66.7% respectively. 59.3% of isolates tested against chloramphenicol were resistant. We recommend a review on the use of chloramphenicol as first-line antimicrobial therapy among surgical in-patients at Lilongwe Central Hospital. We also recommend restricted use of antimicrobials so as to minimise development of drug resistance. Periodic susceptibility studies are necessary to guide judicious use of antibiotics.