Peter W. Callas

Determinants of return-to-work among low back pain patients

&NA; This prospective study identifies physical, behavioral, and psychosocial correlates of subsequent employment status in a sample of low back pain patients. The sample of 150 subjects was drawn from 2 populations of persons with chronic low back pain: 87 individuals who were receiving care at a university low back pain clinic, and 63 individuals who had applied for (but not yet received) Social Security compensation on the basis of low back pain. All subjects had worked at least 3 months prior to their latest unemployment period and were currently out of work. Initial assessment included a medical history, physical examination, biomechanical testing, psychiatric interview, and MMPI testing. All subjects were followed up 6 months later to determine whether they had returned to work. Cross‐sectional group comparisons at the time of initial assessment showed that, after controlling for the effects of age, the two samples differed on several physical and biomechanical measures, the Social Security group reflecting a more chronic picture. Group differences on physical variables were found, but most significant differences disappeared when adjusted for length of time out‐of‐work. Longitudinal analyses showed that few objective physical or biomechanical measures were associated with return‐to‐work at 6 months, while a number of psychosocial variables were significant predictors of 6‐month work status. The data suggest that exclusive reliance on the physical examination to determine level of disability, without consideration of psychosocial conditions, and without adjusting for the confounding effects of age and length of time out‐of‐work, is not empirically justified. Logistic regression analysis was used to ascertain the relative contribution of each predictor to outcome and to illustrate the hypothetical effects of changes in the levels of selected risk factors on the likelihood of return‐to‐work. Implications for interventions with low back pain patients are discussed and future research directions suggested.

Both Smoking Reduction With Nicotine Replacement Therapy and Motivational Advice Increase Future Cessation Among Smokers Unmotivated to Quit.

Smokers not currently interested in quitting (N = 616) were randomized to receive telephone-based (a) reduction counseling plus nicotine replacement therapy (NRT) plus brief advice to quit, (b) motivational advice plus brief advice, or (c) no treatment. More smokers in the reduction (43%) and motivational (51%) conditions made a 24-hr quit attempt over 6 months than smokers in the no-treatment condition (16%; p < or = .01), but the 2 active conditions did not differ (p > or = .05). Similarly, 18%, 23%, and 4% of each condition were abstinent (7-day point prevalence) at 6 months (p < or = .01). Results indicate smoking reduction using NRT does not undermine cessation but rather increases the likelihood of quitting to a degree similar to motivational advice.

Heritability of plasma concentrations of clotting factors and measures of a prethrombotic state in a protein C-deficient family

Summary.  Background: Earlier studies found strong support for a genetic basis for regulation of coagulation factor levels and measures of a prethrombotic state (d‐dimer, prothrombin fragment 1.2). Objectives: Estimation of how much of the variation in the levels of coagulation factors and measures of a prethrombotic state, including measures of protein C activation and inactivation, could be attributed to heritability and household effect. Patients and methods: Blood samples were collected from 330 members of a large kindred of French‐Canadian origin with type I protein C deficiency. Heritability and common household effect were estimated for plasma concentrations of prothrombin, factor (F)V, factor VIII, factor (F)IX, fibrinogen, von Willebrand factor (VWF), antithrombin, protein C, protein S, protein Z, protein Z‐dependent protease inhibitor (ZPI), fibrinopeptide A (FPA), protein C activation peptide (PCP), activated protein C–protein C inhibitor complex (APC–PCI), activated protein C–α1‐antitrypsin complex (APC–α1AT), prothrombin fragment 1.2 (F1.2) and d‐dimer, using the variance component method in sequential oligo‐genic linkage analysis routines (SOLAR). Results: The highest heritability was found for measures of thrombin activity (PCP and FPA). High estimates were also found for prothrombin, FV, FIX, protein C, protein Z, ZPI, APC–PCI and APC–α1AT. An important influence of shared household effect on phenotypic variation was found for VWF, antithrombin, protein S and F1.2. Conclusions: We found strong evidence for the heritability of single coagulation factors and measures of a prethrombotic state. Hemostatic markers with statistically significant heritability constitute potential targets for the identification of novel genes involved in the control of quantitative trait loci.

Valves of the deep venous system: an overlooked risk factor

Deep venous valves are frequent sites of deep venous thrombosis initiation. However, the possible contribution of the valvular sinus endothelium has received little attention in studies of thrombosis risk. We hypothesized that the endothelium of valve sinus differs from that of vein lumen with up-regulation of anticoagulant and down-regulation of procoagulant activities in response to the local environment. In pursuit of this hypothesis, we quantified endothelial protein C receptor (EPCR), thrombomodulin (TM), and von Willebrand factor (VWF) by immunofluorescence in great saphenous veins harvested at cardiac bypass surgery. We found significantly increased expression of EPCR and TM in the valvular sinus endothelium as opposed to the vein lumenal endothelium, and the opposite pattern with VWF (paired t test for TM and EPCR, each P < .001; for VWF, P = .01). These data support our hypothesis and suggest that variation in valvular sinus thromboresistance may be an important factor in venous thrombogenesis.

Circulating levels of TNF-α are associated with impaired glucose tolerance, increased insulin resistance, and ethnicity: the Insulin Resistance Atherosclerosis Study.

OBJECTIVE Although several epidemiological studies have investigated associations between TNF-α and insulin resistance, results have been inconsistent. We studied the relationship between TNF-α and glucose tolerance status as part of the Insulin Resistance Atherosclerosis Study. RESEARCH DESIGN AND METHODS Serum concentrations of TNF-α were measured in 1558 individuals in a triethnic population across a spectrum of glucose tolerance. Insulin sensitivity and insulin secretion were assessed by a frequently sampled iv glucose tolerance test (FSIGT). RESULTS Compared with those with normal glucose tolerance, circulating levels of TNF-α were elevated in individuals with impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2D) after adjusting for age, gender, ethnicity, clinic site, and body mass index (3.3, 3.5, and 3.7 pg/ml in subjects with normal glucose tolerance, IGT, and T2D, respectively; P<0.05). Age-, sex-, and body mass index-adjusted levels of TNF-α differed by ethnicity, with Hispanics having the highest levels and African-Americans having the lowest (4.1, 3.6, and 3.0 pg/ml in Hispanics, non-Hispanic whites, and African-Americans, respectively; P<0.05). TNF-α was correlated with waist circumference, high-density lipoprotein, triglycerides, plasminogen activator inhibitor-1 and insulin sensitivity index (SI) (r=0.22, -0.30, 0.35, 0.31, and -0.25; P<0.0001); however, correlations varied by ethnicity. After adjusting for demographics and adiposity, individuals characterized by increased insulin resistance (lower SI), had higher levels of TNF-α than subjects characterized by high insulin sensitivity (3.8 and 3.3 pg/ml in subjects with an SI below/above the median at baseline; P<0.0001). No differences were found for acute insulin response. CONCLUSIONS We confirm that TNF-α is associated with IGT and T2D in a large, multiethnic population, independent of measures of adiposity. Adjusted values of TNF-α, as well as relationships between TNF-α and variables related to T2D, varied by ethnicity. Increased TNF-α levels were predominantly associated with insulin resistance but not with primary defects in β-cell function.

Evaluating chronic venous disease with a new venous severity scoring system

BACKGROUND The Venous Clinical Severity Score (VCSS) has been proposed by the American Venous Forum as an objective means to clinically assess venous disease more completely than with the clinical CEAP classification. However, validation of the VCSS against an objective test is lacking. The purpose of this study was to test the VCSS against abnormalities found on venous ultrasound (US) scans. METHODS As part of a screening project in a large kindred population with protein C deficiency, VCSS and venous US scanning were performed in 210 patients (420 limbs). A single examiner scored the VCSS (0-3) clinically for pain, varicose veins, edema, skin pigmentation, inflammation, induration, ulcer duration and size, and compressive therapy. Another experienced examiner, blinded to the subjects medical history, performed a US examination of the deep and superficial venous system, with a hand-carried US system. The relationship between US and VCSS scores was analyzed by calculating an odds ratio (OR) and its 95% confidence interval (CI). RESULTS Of the 420 limbs screened, VCSS was 0 in 283 limbs, and VCSS was 1 or greater in the following categories: pain, 63 limbs; varicose veins, 70 limbs; edema, 51 limbs; skin pigmentation, 17 limbs; inflammation, 2 limbs; induration, 8 limbs; and compressive therapy, 9 limbs. The highest total score in any limb was 8. A clear association was seen with the VCSS and abnormalities found on US scans. When the score was dichotomized (0 = normal, 1 = any abnormality), it was a strong predictor of US scan abnormalities; limbs with VCSS greater than 0 had a 26-fold greater chance of US scan abnormalities than did limbs with VCSS = 0 (OR, 26.5; 95% CI, 11-64). With ultrasonography as the standard, sensitivity of VCSS compared with US scans was 89.3%, and specificity was 76.1%. Negative predictive value of VCSS = 0 was 97.9%, and positive predictive value for any positive score was 36.5% CONCLUSIONS The results of this study are based on a large kindred population with a higher risk for venous disease than found in the general population. Though the VCSS was devised to quantify the severity of chronic venous disease, this study found it a useful screening tool. The VCSS showed good association with abnormalities on US scans, and when VCSS = 0 there is a high likelihood that the patient does not have venous disease. This simple test may prove valuable in clinical practice.

Comparison of Telecommunication, Community, and Home-Based Tai Chi Exercise Programs on Compliance and Effectiveness in Elders at Risk for Falls

OBJECTIVE To compare the adherence to and effectiveness of Tai Chi exercise program through a live, interactive, telecommunication-based exercise (Tele-ex) with that of a similar program through a community center-based exercise (Comm-ex) and a home video-based exercise (Home-ex) among community-dwelling elders who are at risk for falls. DESIGN Three groups randomized controlled trial with pretests and posttests. SETTING Exercise programs were community-based, and the outcome measures were laboratory-based. PARTICIPANTS Adults (N=64) age 65+ years with positive fall history in the previous year and/or significant fear of falling. INTERVENTION A 24-form, Yang-style Tai Chi for 15 weeks, 3 hours a week. MAIN OUTCOME MEASURES Exercise compliance, number of falls, fear of falling (Activities-specific Balance Confidence [ABC] score), self-perceived health (Medical Outcomes Study 36-Item Short Form Health Survey [SF-36]), Timed Up & Go (TUG), single leg stance (SLS), and body sway during quiet stance (medial-lateral foot center of pressure [ML-COP]). RESULTS Tele-ex and Comm-ex groups demonstrated significantly higher exercise attendance and in-class practice time than the Home-ex group (P<.01) and significant reductions in the mean number of falls and injurious falls (P<.01). There were significant improvements posttraining in SLS, ABC, ML-COP, and Physical Health subscore of the SF-36 (P<.05). Both Tele-ex and Comm-ex groups demonstrated larger improvements than the Home-ex group in TUG, ML-COP, and the Social Function, Mental Health, and Physical Health subscores of the MOS SF-36. CONCLUSION Compared with the Home-ex, the Tele-ex and Comm-ex groups are better in exercise compliance, fall reduction and balance and health improvements. Tele-ex is an effective, affordable, and acceptable choice of exercise for elders.

Efficacy of Nicotine Patch in Smokers With a History of Alcoholism

BACKGROUND Smokers with a history of alcohol dependence may have more difficulty quitting, might relapse to alcohol use, and might especially benefit from nicotine replacement therapy for smoking cessation. METHODS One hundred fifteen smokers with a history of alcohol dependence (median of 5 years previously) were randomly assigned to either a 21-mg nicotine patch or placebo in a trial designed to be as similar as possible to a prior study that examined smokers with no history of alcoholism. Both studies were of heavy smokers with similar levels of nicotine dependence; thus, any differences in trials would be due to a history of alcohol problems per se. RESULTS In the current trial, adjusted prolonged smoking abstinence in those with a history of alcohol dependence was higher in the active than the placebo group at end-of-treatment (28% vs. 11%; odds ratio, 3.2; p = 0.04) and at 6-month follow-up (24% vs. 6%; odds ratio, 4.9; p = 0.02). Among subjects not lost to follow-up, none reported drinking problems or increases in craving for alcohol. Smoking abstinence was not lower and the odds ratio for nicotine patch therapy was not greater in smokers with a history of alcohol dependence than in smokers with no such history. CONCLUSIONS Heavy smokers with a history of alcoholism benefit from nicotine patch treatment. A history of alcohol problems after a period of stable sobriety does not appear to influence smoking outcomes or response to nicotine replacement. Although no smokers relapsed to alcohol use, a trial that follows up all subjects is needed to verify this.

The Vermont Diabetes Information System: A Cluster Randomized Trial of a Population Based Decision Support System

BACKGROUNDOptimal care for patients with diabetes is difficult to achieve in clinical practice.OBJECTIVETo evaluate the impact of a registry and decision support system on processes of care, and physiologic control.PARTICIPANTSRandomized trial with clustering at the practice level, involving 7,412 adults with diabetes in 64 primary care practices in the Northeast.INTERVENTIONSProvider decision support (reminders for overdue diabetes tests, alerts regarding abnormal results, and quarterly population reports with peer comparisons) and patient decision support (reminders and alerts).MEASUREMENTS AND MAIN RESULTSProcess and physiologic outcomes were evaluated in all subjects. Functional status was evaluated in a random patient sample via questionnaire. We used multiple logistic regression to quantify the effect, adjusting for clustering and potential confounders. Intervention subjects were significantly more likely to receive guideline-appropriate testing for cholesterol (OR = 1.39; [95%CI 1.07, 1.80] P = 0.012), creatinine (OR = 1.40; [95%CI 1.06, 1.84] P = 0.018), and proteinuria (OR = 1.74; [95%CI 1.13, 1.69] P = 0.012), but not A1C (OR = 1.17; [95% CI 0.80, 1.72] P = 0.43). Rates of control of A1C and LDL cholesterol were similar in the two groups. There were no differences in blood pressure, body mass index, or functional status.CONCLUSIONSA chronic disease registry and decision support system based on easily obtainable laboratory data was feasible and acceptable to patients and providers. This system improved the process of laboratory monitoring in primary care, but not physiologic control.

Improved rural provider access to continuing medical education through interactive videoconferencing.

We sought to describe use patterns and user evaluation of remotely-attended continuing medical education (CME) programs in Vermont and upstate New York. Remote attendees were required to return an evaluation form to receive CME credit. The form included name and date of the program; name, location, and specialty of the respondent; and questions regarding program quality, value, effectiveness, and attendee plans if the program had not been available via telemedicine. From April, 1996, through December, 1998, health care providers from 14 remote sites used the network 927 times to attend 394 CME programs at Fletcher Allen Health Care in Burlington, Vermont. After the start-up period, an average of over three programs per week was attended, with an average of 2.4 remote attendees per program. Seventy-seven percent of remote attendees stated that they would not have attended the program if it had not been available over telemedicine, while the remaining 23% said that they avoided traveling due to videoconferencing. When asked the effectiveness of telemedicine technology for attending, 73% said it was as effective as having the presenter in the room, 23% said it was less effective, and 4% said it was more effective. Major technical problems, such as having the call disconnect during the presentation, decreased over time. There were continuing minor logistical problems common to large group videoconferencing. The telemedicine system has increased availability of CME programs for rural providers in Vermont and upstate New York. Most attendees have found the programs to be worthwhile, and technological advancements have improved the quality of the system.