Biomedical subjects

R A Lew

Publications and source records attributed to R A Lew.

At least 37 records · Page 2Linked to original sources

PubMed1999

Application of statistical graphics to facilitate selection of health status measures for clinical practice and evaluative research.

Relatively little attention has been directed towards the study of the ability of health status measures to demonstrate clinically meaningful change. We examined the use of Tukey's stem and leaf plots and time-path diagrams to assess the sensitivity of a health status measure in showing change. We compared the evaluative characteristics of the physical ability scales of the Sickness Impact Profile (PSIP), and the SF-36 (PSF-36), in 54 consecutive patients undergoing elective primary or revision total hip replacement. To validate time-path diagrams, we used patients' perception of change in physical function (transition question) as an external standard. At baseline there was no clustering at the end of the scales. At 3 months, the distribution of the PSIP showed a clustering at the upper end of the scale and a strong skewness towards lower scores, whereas the PSF-36 showed a wide distribution of the scores. Seven out of 54 patients had perfectly normal scores on the PSIP at 3 months, whereas one patient had a perfect score on the PSF-36 at 3 months. In time-path diagrams the response pattern of the PSIP was similar to that of the PSF-36, with the exception of the patient-fifth with the best initial health status. The overall impression of the time-path diagram for these patients was that of no change. A closer examination revealed that half of these patients had horizontal or downwards sloping lines, indicating a worsening in physical function. However, all these patients perceived themselves as improved. The PSIP has a ceiling effect for patients with relatively good physical health. It was concluded that stem and leaf plots are useful in the assessment of health status measures, for discriminative purposes, to differentiate patients' health cross-sectionally. Time-path diagrams stratified by baseline health status with information on patients' perception or valuation of change provide useful information about the ability of an instrument to detect change over time.

Arthroplasty, Replacement, Hip↗

PubMed1999

Screening for malignant melanoma: A cost-effectiveness analysis.

BACKGROUND: Skin cancer is the most common cancer in the United States. Increasing evidence suggests that screening for malignant melanoma is effective, but its cost-effectiveness has not been determined. OBJECTIVE: We attempted to determine the effectiveness and costs of a visual screen to diagnose malignant melanoma in high-risk persons. METHODS: We developed a decision analysis comparing no skin cancer screen with a single screen by a dermatologist. Clinical outcomes included malignant melanoma, nonmelanoma skin cancer, or no skin cancer. Life expectancy and costs of care were projected on the basis of clinical findings. RESULTS: Skin cancer screening increased average discounted life expectancy from 15.0963 years to 15.0975 years. Based on the prevalence of malignant melanoma, however, this translates into an increased discounted life expectancy of 0.9231 years for each person with diagnosed melanoma. Using a cost of $30 per screen, total skin cancer-related costs for a cohort of 1 million people increased from $826 million with no screen to $861 million with screening, with an increase of 1200 years of life. This results in an incremental cost-effectiveness ratio of $29,170 per year of life saved (YLS) with screening. Sensitivity analysis showed that the cost-effectiveness ratio for screening remained below $50,000/YLS if the prevalence of melanoma in the screened population was at least 0. 0009, the probability that a melanoma detected in screening was localized was at least 94.8%, or the cost of each screen was below $57. CONCLUSION: Skin cancer screening in high-risk patients is likely to be associated with a small increase in discounted life expectancy and is reasonably cost-effective compared with other cancer screening strategies.

Cost-Benefit Analysis↗

PubMed1999

Participant satisfaction and value in American Academy of Dermatology and American Cancer Society skin cancer screening programs in Massachusetts.

BACKGROUND: More than 1 million Americans have attended the American Academy of Dermatology's Melanoma/Skin Cancer Screening Programs since 1985. However, there have been no reports of the participants' perceived value, satisfaction, and benefits of skin cancer screening. OBJECTIVE: We attempted to measure the benefits and subsequent screening practices of persons with presumptive positive screening diagnoses. METHODS: A self-administered questionnaire was sent to participants with positive screening diagnoses in Massachusetts. RESULTS: Of the 643 respondents, 81% rated their satisfaction as high and 84% had similar ratings for the value of the screening. Screenings apparently led to an increase in self-screening (60% before screening compared with 84% after screening). CONCLUSION: Although screening appears to have relatively strong benefits, further studies should be conducted nationally.

Adult↗

PubMed1999

A globin fragment, LVV-hemorphin-7, induces [3H]thymidine incorporation in a neuronal cell line via the AT4 receptor.

The AT4 receptor was characterized initially as a specific binding site for angiotensin IV, a C-terminal fragment of the vasoactive peptide angiotensin II. Recently, we found that LVV-hemorphin-7, a fragment of beta globin, is an abundant peptide in the brain and binds to the AT4 receptor with high affinity and specificity. In the neuroblastoma/glioma hybrid cell line, NG108-15, LVV-hemorphin-7 and angiotensin IV competed for 125I-angiotensin IV binding in a biphasic fashion with IC50 values of 1.2 x 10(-10) and 1.1 x 10(-9) M for the high-affinity site, respectively, and 6.7 x 10(-8) and 1.5 x 10(-8) M for the low-affinity site, respectively. Both peptides were internalized rapidly by the cells. However, LVV-hemorphin-7, but not angiotensin IV, elicited a 1.8-fold increase in DNA synthesis in a dose-dependent manner. Furthermore, co-incubation of the cells with an excess of angiotensin IV (10(-6) M) inhibited LVV-hemorphin-7-stimulated DNA synthesis. Therefore, whereas LVV-hemorphin-7 and angiotensin IV were capable of binding to the AT4 receptor, only LVV-hemorphin-7 elicited [3H]thymidine incorporation in NG108-15 cells. In contrast, angiotensin IV behaved as an antagonist. The current finding suggests that LVV-hemorphin-7 is a functional peptide in the central nervous system and in view of its abundance in neural tissue, compared with angiotensin IV, may be of significant physiological importance.

Angiotensin II↗

PubMed1999

Medical students' knowledge, attitudes, skills, and practices of cancer prevention and detection.

BACKGROUND: Surveys of U.S. physicians show deficiencies in cancer detection and counseling skills. Thus, there is a compelling need to provide skills teaching during medical school for cancers with preventable mortality and for counseling techniques for smoking prevention and cessation. METHODS: In advance of the integration of initiatives for cancer education into the medical school curriculum, the authors conducted a baseline survey of students' knowledge, attitudes, skills, practices, observation, and training (KASPOT) related to cancer education. Eighty-one percent of Boston University School of Medicine students (n = 499) completed surveys. RESULTS: The students reported higher levels of KASPOT for breast and cervical cancers, compared with skin cancer examination or tobacco use cessation or prevention counseling. More than half of third- and fourth-year students reported that too little emphasis was given to cancer control education. CONCLUSIONS: It appears that students' practice and skills for detection of the most common cancer (skin cancer), and for cancers with the greatest mortality (tobacco-related cancers) are deficient. Revisions in medical students' curricula should seek to address these shortcomings.

Clinical Competence↗

PubMed1999

Factors associated with skin cancer prevention practices in a multiethnic population.

A better understanding of factors influencing sun protection practices can improve the design and evaluation of skin cancer prevention programs. These data are from a cross-sectional survey of 756 parents with children in Grades 1 through 3, and 176 recreation program staff members in a multiethnic population in Hawaii. Questionnaires asked about skin cancer prevention practices (sunscreen use, covering up, shade seeking), knowledge, benefits and barriers, policies, and staff norms for prevention. The most important correlates of children's prevention practices were their parents' sun protection habits. Multiple regression models--which included knowledge, beliefs, program policies, and covariates related to sun protection--explained a total of between 38% and 41% of the variance in children's sun safety habits, 22% to 25% of parents' habits, and 24% of recreation staff members' sun safety habits. The models were less successful at predicting the use of hats, shirts, and shade seeking and a composite sun protection habits index. Parents and caregivers' knowledge, beliefs, and behaviors, as well as recreation program policies, are strong predictors of sun protection practices among children in Grades 1 to 3 in a multiethnic sample.

Asian↗

PubMed1999

The Falmouth Safe Skin Project: evaluation of a community program to promote sun protection in youth.

A multidimensional community-based skin cancer prevention program was conducted in Falmouth, Massachusetts, combining community activism with publicity campaigns and behavioral interventions to improve sun protection knowledge; attitudes; and practices in parents, caregivers, and children. The program was associated with improvements in target outcomes, based on two telephone surveys of random samples of parents (n = 401, 404). After program implementation, fewer parents reported sunburning of their children, particularly among children 6 years old or younger (18.6% in 1994 vs. 3.2% in 1997), and more parents reported children using sunscreen, particularly continuous use at the beach (from 47.4% to 69.9% in younger children). Hat and shirt use did not increase. Improvements also were seen in parent role modeling of sun protection practices, parents' self-efficacy in protecting children from the sun, and sun protection knowledge. While these findings must be interpreted cautiously, they do suggest that this project was effective in promoting sun protection.

Adolescent↗

PubMed1999

Factors affecting lumbar spinal fusion.

There is little information on the effect of nonsurgical factors or postoperative anemia on achieving spinal fusion. In a prospective cohort study of 184 consecutive lumbar spinal fusions, we obtained data on socioeconomic, clinical, radiologic, and traditional surgical factors and analyzed associations between these factors and fusion status at 6 months post surgery. The overall fusion rate was 74%. Among the surgical factors, use of pedicle screw fixation (p = 0.005) predicted fusion success; postoperative anemia (hematocrit < 30%; p = 0.003) and a history of smoking (p = 0.050) predicted fusion failure. However, when the surgical factors were analyzed together with clinical and socioeconomic factors, back pain greater than or equal to leg pain (p < 0.001) and patients working at the initial visit (p = 0.001) predicted fusion success; shoulder pain at the initial visit (p < 0.001) and a family history of back surgery (p = 0.006) predicted fusion failure. These factors were stronger predictors of fusion status than were traditional surgical factors.

Adolescent↗

PubMed1998

Prevalence and predictors of long-term work disability due to carpal tunnel syndrome.

The objective of this study was to describe patterns and predictors of work absence in the prospective, community-based Maine Carpal Tunnel Study. Three hundred fifteen patients with carpal tunnel syndrome (CTS) were recruited from physicians' offices throughout Maine. The patients completed questionnaires at entry and after 6, 18, and 30 months. The questionnaires included scales measuring symptom severity, functional status, general and mental health status, exposure to physical stressors, work status, and other indicators. The analyses examined univariate and multivariate correlates of work absence. The mean age was 43, 72% of subjects were female, 71% underwent carpal tunnel release, and 45% were receiving Workers' Compensation. Fifty-two percent worked in managerial or technical occupations, 15% in service occupations, and 13% in heavy labor or machine operation. Forty-five percent of patients changed jobs or were absent from work (aside from postoperative recovery) during the 30-month follow-up. In multivariate logistic regression models, correlates of work absence at 18 months included worse functional status of the hand at study entry and at 6-month follow-up, involvement of an attorney at the time of enrollment (P < 0.002 for each), and work absence at 6 months (P = 0.03). Worse upper extremity functional status and having a contested Workers' Compensation claim are critical predictors of work absence and should be principal targets of interventions to reduce work disability in CTS.

Absenteeism↗

PubMed1998

Factors associated with smoking among children and adolescents in Connecticut.

INTRODUCTION: The age of smoking initiation has dropped over the past four decades. Since behaviors and attitudes adopted in late childhood or early adolescence predict future smoking, it is important to understand the smoking and other risk-taking behaviors and attitudes of children aged 12 and younger. The goal of the analyses presented here was to describe behavioral and attitudinal factors associated with smoking among elementary school (grades 4-6), middle school (grade 7-8), and high school (grades 9-12) students in Connecticut. METHODS: We have used data from 8 years (1988-1996) of an anonymous, self-administered health risk appraisal survey given to children and adolescents in self-selected public and private schools. We compared the proportion of smokers and nonsmokers who reported various behaviors and attitudes and compared them with the chi-square test. RESULTS: Fifteen percent (n = 4,884) of the total population (n = 31, 861) were current smokers. At all grade levels, current smokers were more likely than nonsmokers to engage in risk-taking behaviors, and to report more stress and depression. Indicators of risk-taking and stress were also associated with the intent to smoke among children in grades 4-6. CONCLUSIONS: Smoking occurs within the context of other risk-taking behavior and psychological distress, among both children and older adolescents. Our data provide support for the idea of early identification and targeting of children at high risk of smoking in elementary school, possibly as early as grade four.

Adolescent↗

PubMed1998

A placebo controlled crossover trial of subcutaneous salmon calcitonin in the treatment of patients with fibromyalgia.

The objective of this study was to evaluate the relative efficacy and tolerability of subcutaneously (s.c.) administered salmon calcitonin (sCT) in the treatment of patients with fibromyalgia. Eleven patients who fulfilled the American College of Rheumatology classification criteria for fibromyalgia were studied in a double-blind, crossover trial in which they alternatively received salmon calcitonin (100 IU s.c.) and isotonic saline (1 cc s.c.) for four weeks, with a four weeks wash-out period between the treatments. None of the 11 outcomes measures (seven analog scales, dolorimetry score, and three SIP scores) showed a significant improvement with sCT. The principal side effect observed with sCT was nausea in ten patients and erythema in four patients. These data suggest that sCT given at a dose of 100 IU daily for one month is not effective in the treatment of fibromyalgia.

Adult↗

PubMed1998

Comparative responsiveness of generic versus disease-specific and weighted versus unweighted health status measures in carpal tunnel syndrome.

OBJECTIVES: The authors evaluated the relative responsiveness to change of generic versus disease-specific and unweighted versus weighted health status measures in carpal tunnel syndrome (CTS). METHODS: Data were obtained from 196 subjects followed in a prospective community-based cohort study in Maine who underwent carpal tunnel release (The Maine Carpal Tunnel Syndrome Study). Patients were evaluated before and 6 months after surgery. The disease-specific, unweighted severity score was derived from the validated Carpal Tunnel Syndrome Assessment Questionnaire. Patients were asked to rate the importance of each symptom included in the severity score. Each severity question was weighted by its importance, creating a disease-specific weighted score. Generic instruments were the SF-36, SF-12, and a Quality of Life Rating Scale. Sensitivity to change was calculated with the standardized response mean (SRM, mean change/standard deviation of change) as well as the effect size (ES, mean change/standard deviation of baseline values). The ability of the instruments to distinguish clinically important differences was assessed by correlating the changes in scores with global ratings on satisfaction and perceived improvement as external criteria. RESULTS: The disease-specific weighted score (SRM: 1.56, ES: 1.99) was more responsive than the unweighted score (SRM: 1.36, ES: 1.57). The Quality of Life Rating Scale, SF-36, and SF-12 subscales were less sensitive to change, with standardized response means and effect sizes that ranged from -0.23 to 0.88. The ability to distinguish clinically important differences was higher for the two disease-specific scales. The coefficients of correlation with the external criteria ranged from 0.50 to 0.56 for the unweighted score and 0.56 to 0.62 for the weighted score and were significantly stronger than the correlations between external measures and the most responsive subscale of the SF-36 (Bodily Pain subscale, r = 0.36). The SF-12 health survey performed as well as the SF-36 in term of responsiveness and ability to distinguish clinically important change. CONCLUSIONS: Disease-specific measures were superior to generic measures in capturing clinical change after carpal tunnel release, and a weighted score was slightly more responsive than the unweighted score. The SF-12 showed comparable psychometric properties compared with the longer 36-item Short-Form Survey.

Adult↗

PubMed1998

Outcomes of children treated for Lyme disease.

OBJECTIVE: To study the outcome of Lyme disease (LD) in children identified in a total population survey of an endemic island. METHODS: We conducted a population-based retrospective cohort study off the coast of Massachusetts. Twenty-five children who met the Centers for Disease Control case definition for prior LD were compared with 26 children without LD from the same community. All children with LD received antibiotics during the acute phase of their disease. All 51 children were invited for a clinical evaluation, including 12-lead electrocardiogram (EKG), and measurement of antibodies to Borrelia burgdorferi by antibody-capture ELISA and Western blot. RESULTS: At a mean of 3.2 years from the initial manifestation of LD, children with prior LD did not have a higher prevalence of musculoskeletal or neurological symptoms, examination abnormalities, abnormal EKG, or behavioral difficulties, compared to children with no history of LD. CONCLUSION: Children who receive appropriate antimicrobial therapy for LD appear to have no demonstrable longterm morbidity.

Administration, Oral↗

PubMed1997

Thiol activation of endopeptidase EC 3.4.24.15. A novel mechanism for the regulation of catalytic activity.

Endopeptidase EC 3.4.24.15 (EP24.15) is a thermolysin-like metalloendopeptidase involved in the regulated metabolism of a number of neuropeptides. Unlike other thermolysin-like peptidases EP24.15 displays a unique thiol activation, a mechanism that is not clearly understood. In this study we show that both recombinant and tissue-derived EP24.15 are activated up to 8-fold by low concentrations (0.1 mM) of dithiothreitol. Additionally, under non-reducing conditions, recombinant and native EP24.15 forms multimers that can be returned to the monomeric form by reduction. We have also shown that competitive inhibitor binding occurs only to the monomeric form, which indicates that catalytic site access is restricted in the multimeric forms. Through systematic site-directed mutagenesis we have identified that cysteine residues 246, 253, and possibly 248 are involved in the formation of these multimers. Furthermore, both a double mutant (C246S/C253S) and a triple mutant (C246S/C248S/C253S) are fully active in the absence of reducing agents, as measured by both inhibitor binding and hydrolysis. The formation and disruption of disulfide bonds involving these cysteine residues may be a mechanism by which EP24.15 activity is regulated through changes in intra- and extracellular redox potential.

Amino Acid Sequence↗

PubMed1997

Lumbar laminectomy alone or with instrumented or noninstrumented arthrodesis in degenerative lumbar spinal stenosis. Patient selection, costs, and surgical outcomes.

DESIGN: A prospective, multicenter observational study. OBJECTIVES: 1) Identify correlates of the decision to perform arthrodesis in patients undergoing laminectomy for lumbar spinal stenosis. 2) Compare symptoms, walking capacity, and satisfaction 6 and 24 months after laminectomy alone and laminectomy with noninstrumented and with instrumented arthrodesis. BACKGROUND DATA: Few prospective studies have compared outcomes of laminectomy alone or laminectomy with noninstrumented or with instrumented arthrodesis in patients with degenerative lumbar spinal stenosis. There is uncertainty regarding the optimal use of arthrodesis and instrumentation. METHODS: Two hundred seventy--two patients undergoing--surgery for degenerative lumbar stenosis by eight surgeons at four centers were included in the study cohort. Of these, 37 had noninstrumented and 41 had instrumented arthrodesis. Logistic regression identified factors associated with arthrodesis. The principal outcomes-health status, walking capacity, back and leg pain, and satisfaction with surgery-were assessed 6 and 24 months postoperatively with univariate and multivariate techniques. Outcomes also were assessed in a restricted cohort of patients with at least 5 mm spondylolisthesis and/or 15 degrees scoliosis. Hospital costs were obtained from a computerized hospital cost accounting system. RESULTS: The major predictor of the decision to perform arthrodesis was the individual surgeon (P = 0.0001). Noninstrumented arthrodesis was associated with superior relief of low back pain at 6 months (P = 0.004) and 24 months (P = 0.01). This difference persisted in multivariate analyses, with borderline statistical significance. There were no significant differences in the other outcomes across treatment groups. Mean hospital costs of laminectomy alone and noninstrumented and instrumented arthrodesis were $12,615, $18,495, and $25,914, respectively (P = 0.0001). CONCLUSION: Findings were limited by the small number of participating surgeons, modest sample size that produced P values of borderline significance, and nonrandomized design. With these caveats in mind, the authors conclude: (1) The individual surgeon was a more important correlate of the decision to perform arthrodesis than clinical variables such as spondylolisthesis. (2) Noninstrumented arthrodesis resulted in superior relief of back pain after 6 and 24 months. (3) Instrumented arthrodesis was the most costly option. These results highlight the need for randomized controlled trials and cost effectiveness analyses of lumbar arthrodesis and instrumentation in patients with degenerative lumbar spinal stenosis.

Aged↗

PubMed1997

The relationship of socioeconomic status, race, and modifiable risk factors to outcomes in patients with systemic lupus erythematosus.

OBJECTIVE: To study the relationship of race, socioeconomic status (SES), clinical factors, and psychosocial factors to outcomes in patients with systemic lupus erythematosus (SLE). METHODS: A retrospective cohort was assembled, comprising 200 patients with SLE from 5 centers. This cohort was balanced in terms of race and SES. Patients provided information on socioeconomic factors, access to health care, nutrition, self-efficacy for disease management, health locus of control, social support, compliance, knowledge about SLE, and satisfaction with medical care. Outcome measures included disease activity (measured by the Systemic Lupus Activity Measure), damage (measured by the SLICC/ACR damage index), and health status (measured by the SF-36). RESULTS: In multivariate models that were controlled for race, SES, center, psychosocial factors, and clinical factors, lower self-efficacy for disease management (P < or = 0.0001), less social support (P < 0.005), and younger age at diagnosis (P < 0.007) were associated with greater disease activity. Older age at diagnosis (P < or = 0.0001), longer duration of SLE (P < or = 0.0001), poor nutrition (P < 0.002), and higher disease activity at diagnosis (P < 0.007) were associated with more damage. Lower self-efficacy for disease management was associated with worse physical function (P < or = 0.0001) and worse mental health status (P < or = 0.0001). CONCLUSION: Disease activity and health status were most strongly associated with potentially modifiable psychosocial factors such as self-efficacy for disease management. Cumulative organ damage was most highly associated with clinical factors such as age and duration of disease. None of the outcomes measured were associated with race. These results suggest that education and counseling, coordinated with medical care, might improve outcomes in patients with SLE.

Adult↗

PubMed1997

Assessment of systemic lupus erythematosus disease activity by medical record review compared with direct standardized evaluation.

OBJECTIVE: Clinical studies of systemic lupus erythematosus (SLE) often necessitate assessment of previous disease activity, which is sometimes only possible by retrospective evaluation of information from the medical record. Using the Systemic Lupus Activity Measure (SLAM), the present study compared an assessment of disease activity obtained by chart abstraction with a direct clinical assessment. METHODS: A chart SLAM was obtained using information abstracted from the clinic notes of 46 patients with SLE who were being followed up at a referral center. Chart SLAM scores were compared with SLAM scores derived from an independent assessor's direct clinical evaluation. RESULTS: Direct SLAM and chart SLAM scores were correlated (r = 0.67 by Spearman's rank correlation, P = 0.0001). Chart review scores for disease activity tended to be lower, but to an inconsistent degree, reflecting both under- and overestimation of disease activity. The overall misclassification rate on a 3-category scale (mild, moderate, or severe activity) was 59%. CONCLUSION: Although chart SLAM scores were highly correlated with direct SLAM scores, misclassification of disease activity by chart review cannot be rectified. Thus, in research, medical record review should not be used as a proxy for the direct SLAM, nor should it be considered comparable with clinical assessments in the analysis of disease activity.

Adult↗

PubMed1997

Risk factors for early work disability in systemic lupus erythematosus: results from a multicenter study.

OBJECTIVE: To study the risk factors for early work disability in systemic lupus erythematosus (SLE). METHODS: A sample of 159 SLE patients who had been employed at some time since diagnosis was drawn from a multicenter study of outcome in SLE. Disease activity, organ damage, education, income, source of health insurance, and work-related factors were measured in a standardized interview. Work disability was defined by patient self-report of not working because of SLE. The outcome measure was current work status. Seven patients were excluded from the analysis because their choice not to work was unrelated to SLE. RESULTS: An average of 3.4 years after diagnosis, 40% had quit work completely, and job modification was substantial. Univariate analysis (chi-square and t-test) showed that significant predictors of early work disability included having a high school education or less, receiving Medicaid or having no health insurance, having a job which required more physical strength, having an income below poverty level, and having greater disease activity at diagnosis. In multivariate models, significant predictors were education level (P = 0.0004), higher physical demands of the job (P = 0.0028), and higher disease activity at diagnosis (P = 0.0078). Race, sex, cumulative organ damage at diagnosis, and disease duration were not significant. CONCLUSION: Early work disability in SLE is strongly associated with some sociodemographic factors that might be amenable to intervention.

Adult↗