Biomedical subjects

J A Robbins

Publications and source records attributed to J A Robbins.

At least 19 recordsLinked to original sources

PubMed2004

Risk factors for hip fracture in women with high BMD: EPIDOS study.

Hip fractures are common among older women. At the present time, major efforts are being made to identify women with low bone mineral density (BMD). However, more than half of hip fractures occur in women who would not classically be considered osteoporotic by BMD. This study aimed to identify factors associated with hip fracture in women with high BMDs. A total of 7598 French women aged over 74 participated in the EPIDOS study and had BMD measured by dual energy X-ray absorptiometry. Analysis was carried out comparing women with and without hip fractures over more than 3 years of follow-up. The participants were divided into three groups based on femoral neck BMD, so as to have equal numbers in each group (cut-off points=0.601 g/cm(2), and 0.683 g/cm(2)). Multiple risk factors thought to be associated with hip fracture were tested in the high and low BMD groups to search for those whose effect was stronger in the high BMD group. Age adjusted Cox regression was used. Results for continuous variables are reported per standard deviation change. Positive interaction between higher BMD, hip fracture and the following factors were found: age (P<0.01), ultrasound attenuation (P<0.05), urinary deoxypyridinoline (DPD) (P<0.05), left quadriceps strength (P<0.05) and right and left foot coordination (P<0.05). The following factors had a larger hazards ratio in those in the upper third of BMD than the low and were statistically significant: femoral neck BMD, nulliparity, age, ultrasound attenuation and speed, prior fracture, urinary deoxypyridinoline, left grip strength and foot coordination. Multiple factors appear to be more strongly associated with hip fractures in women with high BMD than low. They appear to cluster as factors that may relate to bone turnover and architecture and others which are more subtle measures of left-sided coordination.

Age Factors↗

PubMed2001

Administration of abciximab to patients receiving tirofiban or eptifibatide: effect on platelet function.

OBJECTIVES: The goal of this study was to evaluate platelet function and to preliminarily assess the clinical safety of sequential treatment with tirofiban or eptifibatide followed by abciximab in patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: An increasing number of acute coronary syndrome (ACS) patients are treated early with tirofiban or eptifibatide. Some later require PCI and may benefit from switching to abciximab, for which long-term benefits have been reported. METHODS: Fifty ACS patients planned for PCI were enrolled. Twenty-five patients received tirofiban followed by abciximab. Ten patients received eptifibatide followed by abciximab. Fifteen patients received only abciximab. All patients had blood samples drawn six times during the therapeutic course. Platelet function was evaluated by ADP- and TRAP-induced aggregation, flow cytometry analysis of fibrinogen binding and the cone and plate(let) analyzer, which tests shear rate-dependent platelet activation. RESULTS: Administered after tirofiban, abciximab caused a significant further decline in platelet function, as evidenced by all methods. Administered after eptifibatide, abciximab caused a significant further reduction in platelet function, as assessed by the cone and plate(let) analyzer and fibrinogen binding methods. The platelet inhibition achieved by the combination therapy was always greater than or equal to that achieved by abciximab alone. There were no major bleeding or severe thrombocytopenia episodes. Three of the 35 combination therapy patients and one of the 15 who received abciximab alone had minor bleeding. CONCLUSIONS: This is the first in vivo study of combination intravenous platelet glycoprotein IIb/IIIa inhibitor therapy. Administration of abciximab immediately after tirofiban or eptifibatide therapy effectively inhibits platelet function and appears to be safe.

Abciximab↗

PubMed2001

The fluid mechanics of bolus ejection from the oral cavity.

The squeezing action of the tongue against the palate provides driving forces to propel swallowed material out of the mouth and through the pharynx. Transport in response to these driving forces, however, is dependent on the material properties of the swallowed bolus. Given the complex geometry of the oral cavity and the unsteady nature of this process, the mechanics governing the oral phase of swallowing are not well understood. In the current work, the squeezing flow between two approaching parallel plates is used as a simplified mathematical model to study the fluid mechanics of bolus ejection from the oral cavity. Driving forces generated by the contraction of intrinsic and extrinsic lingual muscles are modeled as a spatially uniform pressure applied to the tongue. Approximating the tongue as a rigid body, the motion of tongue and fluid are then computed simultaneously as a function of time. Bolus ejection is parameterized by the time taken to clear half the bolus from the oral cavity, t(1/2). We find that t(1/2) increases with increased viscosity and density and decreases with increased applied pressure. In addition, for low viscosity boluses (mu approximately 100 cP), density variations dominate the fluid mechanics while for high viscosity boluses (mu approximately 1000 cP), viscosity dominates. A transition region between these two regimes is found in which both properties affect the solution characteristics. The relationship of these results to the assessment and treatment of swallowing disorders is discussed.

Biomechanical Phenomena↗

PubMed2001

Patient gender differences in the diagnosis of depression in primary care.

Our purpose was to explore why women are more likely than men to be diagnosed as depressed by their primary care physician. Women were found to have more depressive symptoms as self-reported on the Beck Depression Inventory (BDI). Women having high BDI scores (reflecting significant depression) were more likely than men with high BDI scores to be diagnosed by their primary care physician (p = 0.0295). Female patients made significantly more visits to the clinic than men. For both sexes, patients with greater numbers of primary care clinic visits were more likely to be diagnosed as depressed. Logistic regression revealed that gender has both a direct and indirect (through increased use) effect on the likelihood of being diagnosed as depressed. Patient BDI score, clinic use, educational level, and marital status were all significantly related to the diagnosis of depression. Controlling all other independent variables, women were 72% more likely than men to be identified as depressed, but this effect did not achieve statistical significance (p = 0.0981). In gender-specific analyses, BDI and clinic use were again significantly related to the diagnosis of depression for both sexes. However, educational and marital status predicted depression diagnosis only for women. Separated, divorced, or widowed women were almost five times as likely to be diagnosed as depressed as those who were never married, all other factors being equal. Clinic use and BDI scores were found to be important correlates of the diagnosis of depression. There was some evidence of possible gender bias in the diagnosis of depression.

Adult↗

PubMed2001

Predictors of patient referrals by primary care residents to specialty care clinics.

BACKGROUND AND OBJECTIVES: Physician referral patterns significantly impact costs, quality of care, and access to the health system. This paper examines factors predictive of patient referrals to specialists by primary care residents. METHODS: New adult patients (n=509) were randomly assigned to primary care residents at a university medical center. Patient referrals to specialists were monitored for 1 year of care. Self-reported patient health status, sociodemographic information, number of primary care visits, and physician practice style behaviors were incorporated into statistical analyses predicting specialty referrals. RESULTS: Patients who were referred to specialty care were significantly older, had poorer physical health, and saw their primary care physicians more often than patients who were not referred. Patients were most frequently referred to surgical specialty clinics. After controlling for physical health status, gender, and age, more frequent visits to a primary care resident physician who had a technically oriented style of care was associated with a greater total number of specialty clinic referrals. CONCLUSIONS: Patient variables, as well as physician practice style, have an important impact on the specialty referral process. Although the appropriateness of referrals was not evaluated, these findings have implications for health care delivery.

Adult↗

PubMed2000

Sociodemographic factors and the assignment of do-not-resuscitate orders in patients with acute myocardial infarctions.

OBJECTIVES: This study examined the impact of sociodemographic and clinical factors, measured at the individual or ecological (zip code) level, on the assignment of do-not-resuscitate (DNR) orders. DESIGN: This was a retrospective study (analysis of secondary data). SUBJECTS: We used a probability sample of 974 patients admitted to 30 medium to large California hospitals with acute myocardial infarctions in 1990 to 1991; the sample was originally designed to validate risk adjustment with administrative data. METHODS: Multivariate logistic regression was used to adjust DNR assignment for age, gender, race, probability of death, functional impairments, payment source, hospital teaching status, and ecological measures of educational attainment, home ownership, and income. RESULTS: DNR assignment was inversely associated with black race and positively associated with age, probability of death, cognitive impairment, and poor nutritional status. When the probability of death was very low, DNR orders were assigned less frequently to men than to women (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.2 to 0.7 at probability of death = 0.10). However, men were significantly more likely to receive a DNR order than women when the probability of death was very high (OR, 4.4; 95% CI, 1.2 to 16.3 at probability of death = 0.90). CONCLUSIONS: Older, white, sicker, or functionally impaired patients receive DNR orders more often than younger, black, healthier, or functionally intact patients do. Adjusting for these factors, DNR assignment is associated with gender through an interaction involving the probability of death. Future studies should reexamine the impact of these factors on DNR assignment and explore the role of patient values and patient-physician communication barriers.

Activities of Daily Living↗

PubMed2000

The influence of patient age on primary care resident physician-patient interaction.

OBJECTIVES: To explore resident physician-patient interaction in primary care to address issues relevant to quality of care for older people. DESIGN: A sample of 509 new, adult, nonpregnant patients was assigned to the care of second- and third-year residents in primary care clinics. Care was compared for three subgroups of patients: older patients (65 years or older; n = 45), those aged 18 to 44 years (n = 320), and those aged 45 to 64 years (n = 144). SETTING: Observations were made at the family medicine and general internal medicine clinics at the University of California, Davis. MEASUREMENTS: Self-report by means of the Medical Outcomes Study Short Form-36 (MOS SF-36) was used to determine patient demographics and patient health status. Two measures of satisfaction were obtained gauging reaction to medical care in general and to the videotaped visit specifically. Videotapes were coded for content using the Davis Observation Code. RESULTS: Self-reported health status of older persons was poorer than that of younger groups as measured by the MOS SF-36. Differences in demographics were explored and then controlled, along with physical health status in subsequent analyses. Supporting prior studies, this study found that older patients had more return visits and reported higher levels of satisfaction than did younger comparison groups. Contrary to prior literature, older patients were found to have longer visits than did younger cohorts. The physician-patient interaction was significantly different in many areas between these three groups. Whereas older patients experienced more chatting in their visits, they were given less counseling, asked fewer questions, had less discussion about their families and their use of substances, were asked to change their health behavior habits less often, and were given less health education. For older patients, more of each visit was spent checking on compliance with earlier treatment and developing treatment plans. CONCLUSIONS: These results provide a new and more detailed view of how resident physician-patient interaction differs between older and younger groups and raise important issues on whether quality of care needs for this population are being adequately addressed, particularly regarding mental health issues.

Adolescent↗

PubMed2000

Gender differences in the utilization of health care services.

BACKGROUND: Studies have shown that women use more health care services than men. We used important independent variables, such as patient sociodemographics and health status, to investigate gender differences in the use and costs of these services. METHODS: New adult patients (N = 509) were randomly assigned to primary care physicians at a university medical center. Their use of health care services and associated charges were monitored for 1 year of care. Self-reported health status was measured using the Medical Outcomes Study Short Form-36 (SF-36). We controlled for health status, sociodemographic information, and primary care physician specialty in the statistical analyses. RESULTS: Women had significantly lower self-reported health status and lower mean education and income than men. Women had a significantly higher mean number of visits to their primary care clinic and diagnostic services than men. Mean charges for primary care, specialty care, emergency treatment, diagnostic services, and annual total charges were all significantly higher for women than men; however, there were no differences for mean hospitalizations or hospital charges. After controlling for health status, sociodemographics, and clinic assignment, women still had higher medical charges for all categories of charges except hospitalizations. CONCLUSIONS: Women have higher medical care service utilization and higher associated charges than men. Although the appropriateness of these differences was not determined, these findings have implications for health care.

Adult↗

PubMed1999

Comparison of primary care resident physicians' practice styles during initial and return patient visits.

New adult patients (n = 212) were randomly assigned to 58 primary care resident physicians. Physician practice styles during initial and return visits were analyzed using the Davis Observation Code. Compared with initial patient visits, return visits were shorter, but more work-intensive. Return visits displayed significantly less technically oriented behavior (including history taking, physical examination, and treatment planning) and fewer discussions regarding use of addictive substances; however, there was more emphasis on health behaviors and active involvement of patients in their own care. These physicians' practice style differences between initial and return patient visits suggest that physician-patient familiarity affects what happens during the medical interview.

Adult↗

PubMed1999

Differences between family physicians' and general internists' medical charges.

OBJECTIVES: Data from 509 primary care patients were analyzed to determine whether practice style differences between family physicians and general internists generate differential utilization of health care resources leading to differential medical charges. METHODS: New adult patients were prospectively randomized to care by family physicians and general internists. Utilization of medical care services and associated charges then were monitored for 1 year of care. RESULTS: Family practice patients had a significantly higher mean number of visits to their primary care clinic and significantly fewer emergency room visits than patients assigned to Internal Medicine. Mean charges for primary care and emergency department treatment were significantly lower for patients assigned to Family Practice than for those assigned to General Internal Medicine. There were no significant differences in charges for specialty clinic visits, hospitalizations, or diagnostic services. CONCLUSIONS: Practice style differences between family physicians and general internists were associated with differential medical charges, with family physicians generating lower charges for some aspects of care.

Adult↗

PubMed1999

Physician practice style patterns with established patients: determinants and differences between family practice and general internal medicine residents.

BACKGROUND AND OBJECTIVES: This paper examines the practice style patterns of family practice and internal medicine residents for established patient visits. METHODS: New adult patients (n = 509) were prospectively and randomly assigned to family practice or internal medicine clinics at a university medical center and followed for 1 year of care by resident physicians. Initial and return visits were videotaped, and physician practice styles were analyzed using the Davis Observation Code (DOC). RESULTS: Resident physicians' practice styles with established patients during return visits were associated with various factors, depending on the DOC cluster of behaviors studied. These factors include patient gender, age, income, physical and mental health status, level of pain, number of return visits, and physician practice style displayed during the initial encounter. Family practice return visits had a greater emphasis on preventive services and counseling, compared with internal medicine return visits. Internists spent more visit time using technically oriented behaviors. CONCLUSIONS: Patient variables, as well as baseline physician behavior, have an important influence on physician practice styles during return patient visits. There are measurable differences in the established practice styles between family practice and internal medicine resident physicians, which may reflect differences in professional training programs.

Adult↗

PubMed1999

The impact of physician practice style on medical charges.

BACKGROUND: There are differences in styles of care among primary care physicians. The purpose of our study was to determine whether differences in physician practice styles and patient health status generate different medical charges. METHODS: New adult patients (N = 509) were randomized to primary care physicians, and use of medical care services and associated charges were monitored for 1 year. RESULTS: Controlling for baseline patient health status, a technically oriented style of care was associated with significantly higher specialty care, emergency department, diagnostic, and total charges. Some practice behaviors, however, were associated with lower charges; for example, a practice style emphasizing patient activation was associated with significantly lower primary care charges. Both a lower baseline patient health status and a health status that declined over the study period predicted higher charges. CONCLUSIONS: Measurable differences in practice style are associated with differing medical care charges. Patients' health status was also an important determinant of medical charges and had implications for the assessment of physician utilization patterns.

Adult↗

PubMed1998

Diabetes in older adults: comparison of 1997 American Diabetes Association classification of diabetes mellitus with 1985 WHO classification.

BACKGROUND: We aimed to compare the prevalence of abnormal glucose tolerance identified by the 1985 WHO and the 1997 American Diabetes Association (ADA) diagnostic categories based on information collected in the Cardiovascular Health Study, an epidemiological study of elderly people. METHODS: We measured glucose concentrations during fasting and 2 h after a 75 g oral glucose-tolerance test in participants aged 65-100 years in the Cardiovascular Health Study. From a 1989 cohort, we analysed the glucose measurements of 4515 individuals without a previous diagnosis of diabetes and of 262 additional measurements from an African-American cohort recruited in 1992-93. FINDINGS: In the 1989 cohort, the prevalence of untreated diabetes with ADA diagnostic fasting criteria was 7.7% versus a prevalence of 14.8% by the WHO criteria. In the African-American cohort, the prevalence of untreated diabetes was 2.7% with ADA criteria and 11.8% with WHO criteria. 3509 (77.7%) of the 4515 participants in the 1989 cohort had normal glucose concentrations according to ADA fasting criteria, compared with 2401 (53.2%) according to WHO criteria. In the African-American cohort, the corresponding numbers were 239 (91.2%) versus 153 (58.4%). All differences in prevalence of abnormal glucose tolerance between ADA and WHO classifications were significant (p<0.0001). INTERPRETATION: Among elderly individuals, there was a significant difference in the prevalence of diabetes identified by the WHO diagnostic criteria based on oral glucose-tolerance test and the ADA fasting criteria. Consequently, many individuals currently classified as non-diabetic according to ADA criteria would previously have had a diagnosis of diabetes according to WHO criteria. Longitudinal studies are needed to assess the value of the criteria in the identification of individuals at increased risk of diabetes-associated chronic complications.

Black or African American↗

PubMed1998

Risk factors for 5-year mortality in older adults: the Cardiovascular Health Study.

CONTEXT: Multiple factors contribute to mortality in older adults, but the extent to which subclinical disease and other factors contribute independently to mortality risk is not known. OBJECTIVE: To determine the disease, functional, and personal characteristics that jointly predict mortality in community-dwelling men and women aged 65 years or older. DESIGN: Prospective population-based cohort study with 5 years of follow-up and a validation cohort of African Americans with 4.25-year follow-up. SETTING: Four US communities. PARTICIPANTS: A total of 5201 and 685 men and women aged 65 years or older in the original and African American cohorts, respectively. MAIN OUTCOME MEASURES: Five-year mortality. RESULTS: In the main cohort, 646 deaths (12%) occurred within 5 years. Using Cox proportional hazards models, 20 characteristics (of 78 assessed) were each significantly (P<.05) and independently associated with mortality: increasing age, male sex, income less than $50000 per year, low weight, lack of moderate or vigorous exercise, smoking for more than 50 pack-years, high brachial (>169 mm Hg) and low tibial (< or = 127 mm Hg) systolic blood pressure, diuretic use by those without hypertension or congestive heart failure, elevated fasting glucose level (>7.2 mmol/L [130 mg/dL]), low albumin level (< or = 37 g/L), elevated creatinine level (> or = 106 micromol/L [1.2 mg/dL]), low forced vital capacity (< or = 2.06 mL), aortic stenosis (moderate or severe) and abnormal left ventricular ejection fraction (by echocardiography), major electrocardiographic abnormality, stenosis of internal carotid artery (by ultrasound), congestive heart failure, difficulty in any instrumental activity of daily living, and low cognitive function by Digit Symbol Substitution test score. Neither high-density lipoprotein cholesterol nor low-density lipoprotein cholesterol was associated with mortality. After adjustment for other factors, the association between age and mortality diminished, but the reduction in mortality with female sex persisted. Finally, the risk of mortality was validated in the second cohort; quintiles of risk ranged from 2% to 39% and 0% to 26% for the 2 cohorts. CONCLUSIONS: Objective measures of subclinical disease and disease severity were independent and joint predictors of 5-year mortality in older adults, along with male sex, relative poverty, physical activity, smoking, indicators of frailty, and disability. Except for history of congestive heart failure, objective, quantitative measures of disease were better predictors of mortality than was clinical history of disease.

Black or African American↗

PubMed1998

Physician practice styles and patient outcomes: differences between family practice and general internal medicine.

OBJECTIVES: This study compared patient health status, patient satisfaction, and physician practice style between family practice and internal medicine. METHODS: New adult patients (n = 509) were prospectively and randomly assigned to family practice or internal medicine clinics at a university medical center and followed for 1 year of care. Practice styles were characterized by the Davis Observation Code. Self-reported health status (Medical Outcomes Study, Short Form-36) and patient satisfaction also were measured. RESULTS: There were no significantly different changes in self-reported health status or patient satisfaction between family practice and internal medicine physicians during the course of the study. Family practice initial encounters, however, were characterized by a style placing greater relative emphasis on health behavior and counseling, whereas internists used a more technical style. Improved health status scores after treatment were predicted by a practice style emphasis on counseling, whereas improvements in patient satisfaction scores were predicted by a style of care stressing patient activation. Although this is the first known randomized trial studying this issue, the conclusions are limited by a 38% loss of patients from enrollment to care and a loss of 18% at the 1-year follow-up evaluation. CONCLUSIONS: There were significant differences in practice styles between family physicians and internists; however, it was the physician's behavior, not specialty per se, that affected patient outcomes. A practice style emphasizing psychosocial aspects of care was predictive of improvements in patient health status, whereas a practice style emphasizing patient activation was predictive of improvements in patient satisfaction.

Adult↗

PubMed1997

Combined enalapril and felodipine extended release (ER) for systemic hypertension. Enalapril-Felodipine ER Factorial Study Group.

This multicenter, placebo-controlled, double-blind trial of factorial design evaluated the safety and efficacy of combination treatment with the angiotensin-converting enzyme inhibitor, enalapril, and the vascular selective calcium antagonist felodipine extended release (ER) in patients with essential hypertension. After a 4-week, single-blind placebo baseline period, 707 patients with sitting diastolic blood pressures (BPs) in the range of 95 to 115 mm Hg received placebo, enalapril (5 or 20 mg), felodipine ER (2.5, 5, or 10 mg), or their combinations for an 8-week double-blind treatment period. All doses of enalapril and felodipine ER had a statistically significant (p < 0.05) additive effect in reducing both systolic and diastolic BP. The trough to peak ratios for the combinations ranged from 0.63 (enalapril 5 mg-felodipine ER 2.5 mg) to 0.79 (enalapril 20 mg-felodipine ER 10 mg) and were consistent with effective BP control with 1 dose/day. Patients aged > or = 65 years demonstrated a greater reduction in diastolic BP. Combinations of enalapril-felodipine ER were associated with less drug-induced peripheral edema (4.1%) compared to felodipine ER monotherapy (10.8%). There were no serious drug-related adverse effects observed during the study. In this trial, the combination of enalapril and felodipine ER effectively lowered BP and was generally well tolerated with an excellent safety profile when used in the treatment of hypertension.

Aged↗

PubMed1996

A penetration-aspiration scale.

The development and use of an 8-point, equal-appearing interval scale to describe penetration and aspiration events are described. Scores are determined primarily by the depth to which material passes in the airway and by whether or not material entering the airway is expelled. Intra- and interjudge reliability have been established. Clinical and scientific uses of the scale are discussed.

Deglutition↗

PubMed1996

Current estrogen-progestin and estrogen replacement therapy in elderly women: association with carotid atherosclerosis. CHS Collaborative Research Group. Cardiovascular Health Study.

The cardioprotective effects of combined estrogen/progestin replacement therapy have been questioned. Therefore, we have compared carotid arterial wall thickening and the prevalence of carotid stenosis in elderly women (> or = 65 years old) currently using replacement estrogen/progestins (E + P) with arterial pathology and its prevalence in women using unopposed estrogens (E). This cross-sectional study used baseline data from all 2962 women participating in the Cardiovascular Health Study, a population-based study of coronary heart disease and stroke in elderly adults. Users of hormone replacement therapy (HRT) were categorized as never (n = 1726), past (n = 787), current E (n = 280), or current E + P (n = 73). Maximal intimal-medial thicknesses of the internal and common carotid arteries and stenosis of the internal carotid arteries were measured by ultrasonography. Current E + P users resembled current E users in most respects, although some lifestyle factors were more favorable among E + P users. Current E + P use and current E use (as compared with no use) were associated with smaller internal carotid wall thicknesses (-0.22 mm; P = 0.003; and -0.09 mm; P = 0.05, respectively) and smaller common carotid wall thicknesses (-0.05 mm; P = 0.03; and -0.02 mm; P = 0.1, respectively) and lower odds ratios (OR) for carotid stenosis (> or = 1% vs. 0%); OR = 0.61; 95% confidence interval [CI]: 0.36 to 1.01; and OR = 0.91, 95% CI: 0.67 to 1.24, respectively), after adjustment for current lifestyle and risk factors. When both groups of current HRT users were compared, there were no significant differences in carotid wall thicknesses or prevalence of carotid stenosis. For this sample of elderly women, both current E + P therapy and current E therapy were associated with decreased measures of carotid atherosclerosis. These measures did not differ significantly between the two groups of HRT users.

Aged↗