PubMed Health⌕ Search

Biomedical subjects

John T Farrar

Publications and source records attributed to John T Farrar.

At least 19 recordsLinked to original sources
PubMed2006

Economic evaluation of oral treatments for neuropathic pain.

UNLABELLED: The effectiveness of amitriptyline, carbamazepine, gabapentin, and tramadol for the treatment of neuropathic pain has been demonstrated, but it is unknown which one is the most cost-effective. We designed a cost-utility analysis of a hypothetical cohort with neuropathic pain of postherpetic or diabetic origin. The perspective of the economic evaluation was that of a third-party payor. For effectiveness and safety estimates, we performed a systematic review of the literature. For direct cost estimates, we used average wholesale prices, and the American Medicare and Clinical Laboratory Fee Schedules. For utilities of health states, we used the Health Utilities Index. We modeled 1 month of therapy. For comparisons among treatments, we estimated incremental cost per utility gained. To allow for uncertainty from variations in drug effectiveness, safety, and amount of medication needed, we conducted a probabilistic Monte Carlo simulation. Amitriptyline was the cheapest strategy, followed by carbamazepine, and both were equally beneficial. Gabapentin was the most expensive as well as the least beneficial. A multivariable probabilistic simulation produced similar results to the base-case scenario. In summary, amitriptyline and carbamazepine are more cost-effective than tramadol and gabapentin and should be considered as first-line treatment for neuropathic pain in patients free of renal or cardiovascular disease. PERSPECTIVE: Prescription practices should be based on the best available evidence, which includes the evaluation of the medication's cost-effectiveness. This does not mean that the cheapest or the most expensive, but rather the most cost-effective medication should be chosen-the one whose benefits are worth the harms and costs. We report a cost-effectiveness evaluation of treatments for neuropathic pain.

Administration, Oral↗
PubMed2006

Use of the cumulative proportion of responders analysis graph to present pain data over a range of cut-off points: making clinical trial data more understandable.

In randomized controlled trials, no single definition of response is ideal for all purposes. We propose a method to present in a simple fashion the likelihood of response over a full range of response levels, which will facilitate a better understanding of clinical trial data. We present the technique called the cumulative proportion of responders analysis (CPRA) and its application to four pain clinical trial data sets as examples. The CPRA can be used to present the proportion of responders over the entire range of possible cut-off points as a graph. This allows the reader to compare treatment groups at any responder level that is valid for their patient population. Whether as a primary or secondary approach to a clinical trial of pain therapy, the display of data in a CPRA format may be useful in the understanding of results and applicability to patient care.

Analgesics↗
PubMed2006

Women suffer more short and long-term pain than men after major thoracotomy.

OBJECTIVES: Prolonged activation of pain centers is a proposed cause of chronic pain syndromes. Women are at particular risk for chronic pain as they tend to more readily detect pain and to attenuate it less than men. We set out to determine whether sex affected pain and recovery after major surgery by analyzing data originally collected to determine the effect of the timing of epidural analgesia on long-term outcome after thoracotomy. METHODS: Patients presenting for lobectomy, segmentectomy, or bilobectomy, but not pneumonectomy or chest wall resection, were enrolled. Pain, physical activity, and the extent that pain interfered with activities after surgery were prospectively assessed with standard questionnaires (Brief Pain Inventory and physical component score of SF-36) on postoperative days 1 to 5, and at postoperative weeks 4, 8, 12, 24, 36, and 48 by a blinded research assistant. Perioperative care was standardized and included patient-controlled thoracic epidural analgesia until thoracostomy tube removal. RESULTS: Fifty eight men and 62 women were enrolled. Women reported more pain than men throughout the entire study period, and they had a higher rate of nonsteroidal anti-inflammatory drug use, but not opioid use. This increased pain was not explained by incision type, surgeon, tumor type, or tumor stage. Older patients reported less pain after discharge than younger patients. Postoperative physical activity levels were significantly less than those reported preoperatively, but did not differ by sex. DISCUSSION: Women have a distinctly different pain experience than men after thoracic surgery and probably require novel and/or multimodal analgesic regimens to improve their comfort.

Analgesics↗
PubMed2006

What postoperative outcomes matter to pediatric patients?

Children are often excluded from making decisions related to their medical treatment, and parents' proxy reports are often used. This approach fails to consider that parents and children may differ in their perception of the child's health. In this study, we assessed children's decision-making processes related to postoperative pain management. Forty-five children who underwent an anterior cruciate ligament repair or Nuss procedure for pectus excavatum repair were studied. A standard gamble technique was used to assess children's perceptions of the utility of a hypothetical treatment that would provide them with perfect pain control, with respect to different rates of risk for vomiting during the postoperative period. The maximum risk of vomiting that the overall study population was willing to accept to decrease the pain level to zero was 32% +/- 24%. Girls were willing to take a significantly higher risk (41% +/- 24%) compared to boys (25% +/- 22%) (P = 0.02). Children who actually experienced vomiting before they were questioned were willing to take a higher risk (46% +/- 26%) compared to those who did not (23% +/- 17%) (P = 0.035). Children can express opinions about preferred postoperative outcomes and provide useful input about their care. Girls, more than boys, seem to perceive vomiting as less important than improved pain control in the postoperative period.

Adolescent↗
PubMed2005

Risk of serious upper gastrointestinal toxicity with over-the-counter nonaspirin nonsteroidal anti-inflammatory drugs.

BACKGROUND & AIMS: Use of prescription nonaspirin nonsteroidal anti-inflammatory drugs (NANSAIDs) increases the risk of serious upper gastrointestinal toxicity. Less is known about over-the-counter (OTC) NANSAIDs, which are typically used at lower doses and for shorter durations. This study assessed the risk of toxicity with OTC NANSAIDs. METHODS: A total of 359 case subjects hospitalized for upper gastrointestinal bleeding, perforation, or benign gastric outlet obstruction were recruited from 28 hospitals. A total of 1889 control subjects were recruited by random digit dialing from the same region. Data on medication use were collected via structured telephone interview. RESULTS: Use of OTC NANSAIDs on > or = 4 days during the most recent week had an adjusted odds ratio (OR) of 1.83 (95% confidence interval [CI], 1.14-2.95). Use of high-dose OTC NANSAIDs during the index week had an adjusted OR of 5.21 (95% CI, 2.32-11.69). In contrast, use of OTC NANSAIDs <4 times during the index week (adjusted OR, 0.67; 95% CI, 0.43-1.06) and use of very low doses of prescription or OTC NANSAIDs during the index week (adjusted OR, 0.74; 95% CI, 0.49-1.12) were not significantly associated with an increased risk of serious gastrointestinal toxicity. We did not observe a significant difference between the risk of toxicity with OTC naproxen versus OTC ibuprofen (adjusted OR, 0.84; 95% CI, 0.26-2.70). CONCLUSIONS: Use of OTC NANSAIDs at recommended doses has a relatively good safety profile compared with prescription NANSAIDs. However, use of high-dose OTC NANSAIDs (comparable to a prescription dose) is associated with serious gastrointestinal toxicity.

Adult↗
PubMed2005

The effect of group aerobic exercise and t'ai chi on functional outcomes and quality of life for persons living with acquired immunodeficiency syndrome.

OBJECTIVE: This study aimed to assess the usefulness of two interventions in a group rehabilitation medicine setting to determine strategies and exercise guidelines for long-term care of the HIV/AIDS population with human immunodeficiency virus (HIV) and/or acquired immunodeficiency syndrome (AIDS). DESIGN: This was a randomized clinical trial investigating the effects of tai chi (TC) and aerobic exercise (EX) on functional outcomes and quality of life (QOL) in patients with AIDS. SETTING: Two outpatient infectious disease clinics in a mid-atlantic state were the setting. SUBJECTS AND INTERVENTION: Thirty-eight (38) subjects with advanced HIV (AIDS) were randomized to one of three groups: TC, EX, or control. Experimental groups exercised twice weekly for 8 weeks. OUTCOME MEASURES: The primary outcomes included QOL as measured by the Medical Outcomes Short Form (MOS-HIV) and Spirituality Well-Being Scale (SWB). Functional measures included the functional reach (FR) for balance, sit and reach (SR) for flexibility, and sit-up (SU) test for endurance. The physical performance test (PPT) was used to determine overall function, and the Profile of Mood States (POMS) was used to evaluate psychologic changes. To consider the patients' explanations for these measurements, qualitative data were collected from subjects' journals, focus groups, and nonparticipant observation. RESULTS: Thirty-eight (38) subjects were included in data analysis: 13 in the TC group, 13 in the EX group, and 12 in the control group. Results of analysis of covariance showed significant changes in the exercise groups in overall functional measures (p < 0.001). The MOS-HIV showed a significant difference on the subscale of overall health (p = 0.04). The POMS showed significant main effect for time in confusion-bewilderment (p = 0.000) and tension-anxiety (p = 0.005). Three dominant themes emerged from the qualitative data, including: positive physical changes, enhanced psychologic coping, and improved social interactions. CONCLUSIONS: This study shows that TC and EX improve physiologic parameters, functional outcomes, and QOL. Group intervention provides a socialization context for management of chronic HIV disease. This study supports the need for more research investigating the effect of other types of group exercise for this population. This study sets the stage for a larger randomized controlled trial to examine the potential short- and long-term effects of group exercise that may prove beneficial in the management of advanced HIV disease. Further research is warranted to evaluate additional exercise interventions that are accessible, safe, and cost-effective for the HIV population.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Cerebral blood flow effects of pain and acupuncture: a preliminary single-photon emission computed tomography imaging study.

BACKGROUND: The purpose of this study was to investigate the cerebral blood flow changes associated with the analgesic effect of acupuncture in patients with chronic pain. METHODS: Seven patients presenting with a chronic pain syndrome and 5 healthy controls were included. All single-photon emission computed tomography (SPECT) scans were acquired with a uniform protocol. The patient group was injected with the radioisotope hexamethyl propyleneamine oxime (HMPAO) while experiencing their usual level of pain. A baseline scan was acquired approximately 20 minutes after administration of the HMPAO. The patient then underwent acupuncture therapy with needles placed in points specifically selected to relieve pain. When the pain improved, as determined by a 10-digit score for pain assessment, the patient was reinjected with HMPAO and imaged 20 minutes later for the acupuncture scan. The reference group also had a baseline and acupuncture scan, although the acupuncture itself was performed using a standardized set of needle points. RESULTS: The reference group participants were found to have significant increases in the thalamic and prefrontal cortex activity on the acupuncture scan compared to the baseline. The baseline scans of the pain patients showed significant asymmetric uptake in the thalami compared to controls. This asymmetry reversed or normalized after the acupuncture therapy. Significant correlations were observed between the change of activity in the prefrontal cortex and ipsilateral sensorimotor area. CONCLUSION: The results from these cases show that HMPAO-SPECT is capable of detecting changes in cerebral blood flow associated with pain and that acupuncture analgesia is associated with changes in the activity of the frontal lobes, brain stem, and thalami.

Acupuncture Analgesia↗
PubMed2004

Quality of care indicators for gout management.

OBJECTIVE: Despite the significant health impact of gout, there is no consensus on management standards. To guide physician practice, we sought to develop quality of care indicators for gout management. METHODS: A systematic literature review of gout therapy was performed using the Medline database. Two abstractors independently reviewed each of the articles for relevance and satisfaction of minimal inclusion criteria. Based on the review of the literature, 11 preliminary quality indicators were developed and then reviewed and refined by an initial feasibility panel of community and academic rheumatologists. A twelfth indicator was added at the request of the first panel. Using a modification of the RAND/University of California at Los Angeles appropriateness method (bridging teleconference and white-board Internet technology were added), a second expert panel rated each of the proposed indicators for validity using a 9-point scale, in which ratings of 1-3, 4-6, and 7-9 were considered "invalid," "indeterminate," and "highly valid," respectively. Indicators were considered valid if the median panel rating was > or =7 and there was no evidence of panel disagreement (defined to occur when 2 of 6 panelists provided a validity rating of 1-3 and 2 panelists provided a validity rating of 7-9). RESULTS: Ten of the 12 draft indicators were rated to be valid by our second expert panel. Validated indicators pertained to 1) the use of urate-lowering medications in chronic gout, 2) the use of antiinflammatory drugs, and 3) counseling on lifestyle modifications. CONCLUSION: Using a combination of evidence and expert opinion, 10 indicators for quality of gout care were developed. These indicators represent an important initial step in quality improvement initiatives for gout care.

Gout↗
PubMed2003

Comparison of logistic regression versus propensity score when the number of events is low and there are multiple confounders.

The aim of this study was to use Monte Carlo simulations to compare logistic regression with propensity scores in terms of bias, precision, empirical coverage probability, empirical power, and robustness when the number of events is low relative to the number of confounders. The authors simulated a cohort study and performed 252,480 trials. In the logistic regression, the bias decreased as the number of events per confounder increased. In the propensity score, the bias decreased as the strength of the association of the exposure with the outcome increased. Propensity scores produced estimates that were less biased, more robust, and more precise than the logistic regression estimates when there were seven or fewer events per confounder. The logistic regression empirical coverage probability increased as the number of events per confounder increased. The propensity score empirical coverage probability decreased after eight or more events per confounder. Overall, the propensity score exhibited more empirical power than logistic regression. Propensity scores are a good alternative to control for imbalances when there are seven or fewer events per confounder; however, empirical power could range from 35% to 60%. Logistic regression is the technique of choice when there are at least eight events per confounder.

Bias↗
PubMed2003

Advances in neuropathic pain: diagnosis, mechanisms, and treatment recommendations.

Chronic neuropathic pain, caused by lesions in the peripheral or central nervous system, comes in many forms. We describe current approaches to the diagnosis and assessment of neuropathic pain and discuss the results of recent research on its pathophysiologic mechanisms. Randomized controlled clinical trials of gabapentin, the 5% lidocaine patch, opioid analgesics, tramadol hydrochloride, and tricyclic antidepressants provide an evidence-based approach to the treatment of neuropathic pain, and specific recommendations are presented for use of these medications. Continued progress in basic and clinical research on the pathophysiologic mechanisms of neuropathic pain may make it possible to predict effective treatments for individual patients by application of a pain mechanism-based approach.

Analgesics↗
PubMed2003

Core outcome domains for chronic pain clinical trials: IMMPACT recommendations.

OBJECTIVE: To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of data, encourage more complete reporting of outcomes, simplify the preparation and review of research proposals and manuscripts, and allow clinicians to make informed decisions regarding the risks and benefits of treatment. METHODS: Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 27 specialists from academia, governmental agencies, and the pharmaceutical industry participated in a consensus meeting and identified core outcome domains that should be considered in clinical trials of treatments for chronic pain. CONCLUSIONS: There was a consensus that chronic pain clinical trials should assess outcomes representing six core domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, (6) participant disposition (e.g. adherence to the treatment regimen and reasons for premature withdrawal from the trial). Although consideration should be given to the assessment of each of these domains, there may be exceptions to the general recommendation to include all of these domains in chronic pain trials. When this occurs, the rationale for not including domains should be provided. It is not the intention of these recommendations that assessment of the core domains should be considered a requirement for approval of product applications by regulatory agencies or that a treatment must demonstrate statistically significant effects for all of the relevant core domains to establish evidence of its efficacy.

Chronic Disease↗
PubMed2003

Side effects of opioids during short-term administration: effect of age, gender, and race.

OBJECTIVE: Little is known about risk factors that increase the risk of development of opioid side effects. Our objective was to evaluate the effect of the type of opioid, age, gender, and race on the incidence of side effects from short-term opioid use. METHODS: A secondary analysis of a retrospective cohort study in 35 community-based and tertiary hospitals was done. There were 8855 black or white subjects aged 16 years and older. Patients received meperidine (INN, pethidine), morphine, or fentanyl as part of their treatment. Measurements were made to assess the presence of nausea and vomiting and respiratory depression. RESULTS: Of the patients, 26% had nausea and vomiting and 1.5% had respiratory depression after opioid administration. After adjustment for opioid dose, route of administration, age, gender, and race, meperidine produced less nausea and vomiting (odds ratio [OR] = 0.7; 95% confidence interval [CI], 0.5-0.8) and less respiratory depression (OR = 0.6; 95% CI, 0.2-0.9) than morphine. The risk of respiratory depression increased with age. Compared with patients aged between 16 and 45 years, those aged between 61 and 70 years had 2.8 times the risk of development of respiratory depression (95% CI, 1.2-6.6); those aged between 71 and 80 years had 5.4 times the risk (95% CI, 2.4-11.8); and those aged older than 80 years had 8.7 times the risk (95% CI, 3.8-20.0). Men had less nausea and vomiting than women (OR = 0.5; 95% CI, 0.4-0.6). White subjects had more nausea and vomiting than black subjects (OR = 1.4; 95% CI, 1.1-1.7). CONCLUSIONS: Meperidine produced fewer side effects than morphine during short-term use. The risk of respiratory depression increases substantially after 60 years of age. Women have nausea and vomiting more often than men. The effect of race deserves further investigation.

Adolescent↗
PubMed2003

Clinically important changes in acute pain outcome measures: a validation study.

The purpose of this study was to validate the changes in acute pain measurement scales that are most strongly associated with a patient-determined indicator of clinical importance. Measures of pain intensity and pain relief are commonly used outcomes in therapeutic clinical trials. Recent studies of the properties of acute pain measures have provided data defining the cut-off points that are best associated with clinically important differences. Validation of these findings in another clinical trial data set is important. Data were obtained from the titration phase of a recently conducted randomized controlled clinical trial of oral transmucosal fentanyl citrate (OTFC), which compared OTFC to immediate release morphine sulfate (MSIR) for the treatment of cancer-related acute breakthrough pain. Changes in pain intensity and pain relief were recorded every 15 minutes for 60 minutes and global medication performance recorded at the end of each study pain episode. At any titration step, if the patient felt that the first dose of the study medication did not provide adequate relief within 30 minutes, an additional rescue medication could be taken. To find the level of each pain scale best associated with this measure of the adequacy of pain relief, the calculated sensitivity, specificity, and accuracy for different cut-off points of the measured pain scales were compared to whether or not the patient needed rescue medication. The overall ability of the pain measures to discriminate episodes for which a rescue was not needed was calculated using area under the receiver operating characteristics (ROC) curves. Data were analyzed from 134 OTFC-naive patients who collected data on 1307 episodes of breakthrough pain. Using the criteria of a balanced sensitivity and specificity, the best cut-off points were determined to be: 33% for the percent pain intensity difference; > or =2 for the raw pain intensity difference on a 0-10 numeric rating scale; > or =2 (i.e., moderate or better) for pain relief; > or =33% for the percent maximum total pain relief; and > or =2 (good or better) for global medication performance. ROC area under the curve ranged from 0.839 to 0.862 for each of the pain measures listed above, calculated at 60 minutes. These data indicate that the pain scale cut-off points that are best associated with a patient-derived measure of a clinically important difference closely approximate those found in an earlier study. ROC analysis provided evidence that the overall pain measures were strongly associated with not requiring an "additional dose of rescue medication." Thus, the cut-off points determined for these pain scales provide a good surrogate measure of a patient-determined clinically important response. This provides support for the usefulness of these values in future clinical trials of pain therapy.

Acute Disease↗
PubMed2003

Optimal matching with a variable number of controls vs. a fixed number of controls for a cohort study. trade-offs.

Matching is used to control for imbalances between groups, but the preferable strategy for matching is not always clear. We sought to compare two algorithms-optimal matching with a fixed number of controls (OMFC), and optimal matching with a variable number of controls (OMVC). We compared the degree of bias reduction and relative precision using Monte Carlo simulations. We systematically changed the magnitude of the matching variable difference, the variance ratios of the matching variable in the exposed and unexposed groups, the sample size, and the number of unexposed subjects available for matching. OMVC always produced larger removal of bias than the OMFC. The mean percentage reduction of bias was 38.3 with the OMFC and 52.6 with OMVC. OMVC increased the variance 6%. OMVC should be employed when researchers have access to a pool of unexposed subjects because it removes more bias with little loss in precision.

Algorithms↗