Lifelong physical activity in maintaining bone strength in older men and women of the Age, Gene/Environment Susceptibility-Reykjavik Study.

UNLABELLED: We examined if lifelong physical activity is important for maintaining bone strength in the elderly. Associations of quantitative computerized tomography-acquired bone measures (vertebral and femoral) and self-reported physical activity in mid-life (mean age, 50 years), in old age (≥65 years), and throughout life (recalled during old age) were investigated in 2,110 men and 2,682 women in the AGES-Reykjavik Study. Results conclude lifelong physical activity with continuation into old age (≥65 years) best maintains better bone health later in life. INTRODUCTION: Skeletal loading is thought to modulate the loss of bone in later life, and physical activity is a chief means of affecting bone strength by skeletal loading. Despite much discussion regarding lifelong versus early adulthood physical activity for preventing bone loss later in life, inconsistency still exists regarding how to maintain bone mass later in life (≥65 years). METHODS: We examined if lifelong physical activity is important for maintaining bone strength in the elderly. RESULTS: The associations of quantitative computerized tomography-acquired vertebral and femoral bone measures and self-reported physical activity in mid-life (mean age, 50 years), in old age (≥65 years), and throughout life (recalled during old age) were investigated in 2,110 men and 2,682 women in the AGES-Reykjavik Study. CONCLUSION: Our findings conclude that lifelong physical activity with continuation into old age (≥65 years) best maintains better bone health in the elderly.

Postinfectious glomerulonephritis: Is there a role for steroids?

The role of steroids in treatment of postinfectious glomerulonephritis (PIGN) has been controversial. The reason for such controversy is the risk of infection relapse associated with steroid therapy. Steroids may have a place in the treatment of resistant cases where renal function does not improve despite aggressive antibiotic therapy as well as in patients with crescentic form of PIGN. We report a case of a 39 year-old Caucasian man who was diagnosed with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia resulting in acute IgA dominant PIGN that failed to respond to antibiotic treatment alone, but responded significantly to steroids in addition to antibiotics. This anecdotal experience suggests that steroids could be considered in conjunction with antibiotic therapy for the treatment of refractory cases of PIGN or crescentic form of PIGN. More studies with long-term follow-up of patients treated with steroids in addition to antimicrobial agents are required to quantify the risk of infection relapse with steroid therapy.

Evaluating a New Risk Marker's Predictive Contribution in Survival Models.

Although the area under the receiver operating characteristic (ROC) curve (AUC) is the most popular measure of the performance of prediction models, it has limitations, especially when it is used to evaluate the added discrimination of a new risk marker in an existing risk model. Pencina et al. (2008) proposed two indices, the net reclassification improvement (NRI) and integrated discrimination improvement (IDI), to supplement the improvement in the AUC (IAUC). Their NRI and IDI are based on binary outcomes in case-control settings, which do not involve time-to-event outcome. However, many disease outcomes are time-dependent and the onset time can be censored. Measuring discrimination potential of a prognostic marker without considering time to event can lead to biased estimates. In this paper, we extended the NRI and IDI to time-to-event settings and derived the corresponding sample estimators and asymptotic tests. Simulation studies showed that the time-dependent NRI and IDI have better performance than Pencina's NRI and IDI for measuring the improved discriminatory power of a new risk marker in prognostic survival models.

Factors associated with the awareness and practice of evidence-based obstetric care in an African setting.

OBJECTIVE: To identify the factors associated with important (> or =50%) variation in awareness and practice of evidence-based obstetric interventions in an African setting where we have previously reported poor awareness and use of evidence-based reproductive interventions. DESIGN: Cross-sectional analysis of data from our Reproductive Health Interventions Study. SETTING: North-west province, Cameroon, Africa. POPULATION: Health workers including obstetricians, other physicians, midwives, nurses and other staff providing reproductive care. MAIN OUTCOME MEASURES: Prevalence ratios (PR) of uniform awareness and practice of four key evidence-based obstetric interventions from the World Health Organization Reproductive Health Library (WHO RHL): antiretrovirals to prevent mother-to-child transmission of HIV/AIDS, antenatal corticosteroids for prematurity, uterotonics to prevent postpartum haemorrhage and magnesium sulphate for seizure prophylaxis. METHODS: Comparisons of descriptive covariates, applying logistic regression to estimate independent relationships with awareness and use of evidence-based interventions. RESULTS: A total of 15.5% (50/322) of health workers were aware of all the four interventions while only 3.8% (12/312) reported optimal practice. Evidence-based awareness was strongly associated with practice (PR = 15.4; 96% CI: 4.3-55.0). Factors significantly associated with awareness were: attending continuing education, access to the WHO RHL, employment as an obstetrician/gynaecologist and working in autonomous military or National Insurance Fund facilities. Controlling for potential confounding, working as an obstetrician was associated with increased awareness (adjusted prevalence odds ratio [aPOR] = 8.3; 95% CI: 1.3-53.8) as was median work experience of 5-15 years (aPOR = 2.0; 95% CI: 1.0-3.8). Internet access was associated with increased practice (aPOR = 3.4; 95% CI: 1.0-11.8). Other potentially important variations were observed, although they did not attain statistical significance. CONCLUSIONS: Several factors including obstetric training and continuous education positively influence evidence-based awareness and practice of key obstetric interventions. Confirmation and application of this information may enhance the effectiveness of programmes to improve maternal and perinatal outcomes.

Study of perceived norms, beliefs and intended sexual behaviour among higher secondary school students in India.

The objective of this paper is to understand the intended sexual and condom behaviour patterns among teenage higher secondary school students in India. To achieve this, variables including perceived norms, perceived peer group norms, risk behaviour patterns, perceived chances of getting AIDS and relevant sociodemographic variables were regressed on intended sexual behaviour. Regression of actual sexual behaviour was carried out with perceived norms, perceived peer group norms and intended sexual behaviour as the independent variables. In this paper a conceptual model has been framed based on the theory of reasoned action, health belief model and self-efficacy theory. Cumulative scores are computed for perceived norms, perceived peer group norms, risk behaviour patterns, opinion on handling condoms and perceived chances of getting AIDS. Along with these variables, possible confounding variables such as age, gender, type of family, mother's education and father's education were considered for their effect on intended sexual and condom behaviour. The results revealed that perceived norms and perceived peer group norms showed significant association with intended sexual behaviour and actual sexual behaviour and that children of more highly educated parents are less likely to engage in sexual activities in their adolescent years.

Functional decline in Parkinson disease.

OBJECTIVES: To determine the overall rate of functional decline and to assess the progression of different signs of Parkinson disease (PD). PATIENTS AND METHODS: Patients with clinically diagnosed PD followed up for at least 3 years were included in this study. Demographic and clinical data (including the Unified Parkinson's Disease Rating Scale [UPDRS]) were analyzed by the multivariate unbalanced repeated-measurements design using the mixed-effects model to study the association between different symptoms and various demographic variables. Regression models helped estimate the rates of progression of the disease in relationship to the various components of the UPDRS. Patients were categorized as having tremor-dominant or postural instability-gait difficulty-dominant PD and the 2 categories were compared for progression of their total UPDRS scores. DESIGN: A multivariate mixed-effects model was used to study the relationship between the different symptoms and various demographic variables. Nonparametric statistical tests were used to compare the progression of symptoms in the "on" (good function) state and the "off" (poor function) state groups for 2 age-at-onset categories (< or =57 and >57 years). RESULTS: Data from 1731 visits on 297 patients (181 men) followed up for an average of 6.36 years (range, 3-17 years) were analyzed. The annual rate of decline in the total UPDRS scores was 1.34 when assessed during the on state and 1.58 when assessed during the off state. Patients with an older age at onset had more rapid progression of PD than those with a younger age at onset. Furthermore, the older-onset group had statistically significantly more progression in mentation, freezing, and parts I (mentation) and II (activities of daily living) UPDRS subscores. Handwriting was the only component of the UPDRS score that did not notably deteriorate during the observation period. Regression analysis of 108 patients whose symptoms were rated during their off state showed a faster rate of cognitive decline as age at onset increased. The slopes (ie, the annual rates of decline) of progression in the UPDRS scores, when adjusted for age at the initial visit, were steeper for the postural instability--gait difficulty--dominant group compared with the tremor-dominant group. CONCLUSION: Based on longitudinal follow-up data, our findings provide evidence for a variable course of progression of the different PD symptoms, thus implying different biochemical or degenerative mechanisms for the various clinical features associated with PD.

Examining the direct costs and effectiveness of syphilis detection by selective screening and partner notification.

Selective screening and partner notification are two principal means of preventing and controlling syphilis in the United States, yet few studies have been undertaken to compare and evaluate the cost or effectiveness of detecting syphilis using either strategy. The objective of this paper is to assess from the perspective of a health department the cost-effectiveness of selective screening compared with the strategy of partner notification in the detection of early syphilis in Houston, Texas, in 1994 and 1995. The cost-effectiveness analysis was performed using the recurring direct costs associated with detecting syphilis by both strategies. The middle estimates for the total direct costs associated with selective screening and partner notification were $579,101 and $229,529, respectively, for the 1466 and the 567 cases of early syphilis detected. On a cost per case basis, selective screening was more cost-effective than partner notification in the detection of primary, secondary and maternal syphilis cases. However, when consideration was given to prophylactic treatment, partner notification was more cost-effective in the detection of all early stage disease. Our findings suggest that the relative benefit of partner notification over selective screening depends on prophylactic treatment and an increase in worker productivity.

Safety climate and its association with injuries and safety practices in public hospitals in Costa Rica.

In response to growing concern for occupational health and safety in the public hospital system in Costa Rica, a cross-sectional survey of 1,000 hospital-based health care workers was conducted in 1997 to collect baseline data that are being used to develop worker training programs in occupational health in Costa Rica. The objectives of this survey were to: 1) describe the safety climate within the national hospital system, 2) identify factors associated with safety, and 3) evaluate the relationship between safety climate and workplace injuries and safety practices of employees. The safety climate was found to be very poor. The two most significant predictors of safety climate were training and administrative support for safety. Safety climate was a statistically significant predictor of workplace injuries and safety practices, respectively, and there was an underreporting rate of 71% of workplace injuries. These findings underscore the need for improvement of the safety climate in the public hospital system in Costa Rica.

Stress in Air Force aviators facing the combat environment.

BACKGROUND: This paper evaluates the effect of stress on four squadrons of United States Air Force aviators in tactical high performance aircraft deployed for combat operations compared with U.S. based aircrew using the Beck Depression Inventory (BDI) as the evaluating instrument. METHODS: This is a retrospective cross-sectional study consisting of 42 aviators in deployed squadrons stationed overseas and involved in a contingency mission, and 15 subjects stationed in the U.S. and not exposed to combat conditions. Each subject was administered the test instrument, which was completed in privacy and with complete anonymity. RESULTS: The hypotheses of interest were: a) the proportion of individuals in the population of fighter aircrew who would report excessive stress is 0; and b) no significant differences would exist in the proportion of individuals with excessive stress in the various squadrons. Using statistical methodology, these hypotheses were rejected. CONCLUSION: It is concluded that more studies in each given circumstance are necessary.

Patient classification system: an optimization approach.

A patient classification system was developed integrating a patient acuity instrument with a computerized nursing distribution method based on an optimization algorithm. The objective was to minimize the total number of nursing personnel used by optimally assigning the nursing staff to meet the acuity needs of the various clinical units in the hospital. The validity of the model to assign staff was established by a 30-day comparison with the existing manual method of assignment.

Screening for diabetic retinopathy. The wide-angle retinal camera.

OBJECTIVE: To define the test characteristics of four methods of screening for diabetic retinopathy. RESEARCH DESIGN AND METHODS: Four screening methods (an exam by an ophthalmologist through dilated pupils using direct and indirect ophthalmoscopy, an exam by a physician's assistant through dilated pupils using direct ophthalmoscopy, a single 45 degrees retinal photograph without pharmacological dilation, and a set of three dilated 45 degrees retinal photographs) were compared with a reference standard of stereoscopic 30 degrees retinal photographs of seven standard fields read by a central reading center. Sensitivity, specificity, and positive and negative likelihood ratios were calculated after dichotomizing the retinopathy levels into none and mild nonproliferative versus moderate to severe nonproliferative and proliferative. Two sites were used. All patients with diabetes in a VA hospital outpatient clinic between June 1988 and May 1989 were asked to participate. Patients with diabetes identified from a laboratory list of elevated serum glucose values were recruited from a DOD medical center. RESULTS: The subjects (352) had complete exams excluding the exam by the physician's assistant that was added later. The sensitivities, specificities, and positive and negative likelihood ratios are as follows: ophthalmologist 0.33, 0.99, 72, 0.67; photographs without pharmacological dilation 0.61, 0.85, 4.1, 0.46; dilated photographs 0.81, 0.97, 24, 0.19; and physician's assistant 0.14, 0.99, 12, 0.87. CONCLUSIONS: Fundus photographs taken by the 45 degrees camera through pharmacologically dilated pupils and read by trained readers perform as well as ophthalmologists for detecting diabetic retinopathy. Physician extenders can effectively perform the photography with minimal training but would require more training to perform adequate eye exams. In this older population, many patients did not obtain adequate nonpharmacological dilation for use of the 45 degrees camera.

Cost-effectiveness of alternative methods for diabetic retinopathy screening.

OBJECTIVE: To assess from the perspectives of a government delivery system and patients, the cost-effectiveness of the 45-degrees retinal camera compared to the standard ophthalmologist's exam and an ophthalmic exam by a physician's assistant or nurse practitioner technician, for detecting nonproliferative and proliferative diabetic retinopathy. RESEARCH DESIGN AND METHODS: Comparison of 45-degrees fundus photographs with and without pharmacological pupil dilation taken by technicians and interpreted by experts, direct and indirect ophthalmoscopy by ophthalmologists, and direct ophthalmoscopy by technicians with seven-field stereoscopic fundus photography (reference standard). Costs were estimated from market prices and actual resource use. The study included 352 patients attending outpatient diabetes and general-medicine clinics at VA and DOD facilities. RESULTS: Medical system costs per true positive were: 45-degrees photos with dilation, $295; 45-degrees photos without dilation, $378; ophthalmologist, $390; and technician, $794. Patient costs per true positive were: 45-degrees photos with dilation, $139; 45-degrees photos without dilation, $171; ophthalmologist, $306; and technician, $1009. Cost-effectiveness is sensitive to program size due to high fixed cost of the camera methods but not to prevalence. Cost-effectiveness of the technician exam is strongly affected by its sensitivity. CONCLUSIONS: Primary-care screening with retinal photographs through pharmacologically dilated pupils for diabetic retinopathy is an appropriate and cost-effective alternative to screening by an ophthalmologist in this setting. Ophthalmologists are scarce, primary-care physicians are extremely busy, and large clinics allow fixed equipment costs to be spread across many patients.

Statistical methods that distinguish between attributes of assessment: prolongation of life versus quality of life.

The authors propose a method to generate information relevant to the decision tree that adds additional perspective to the characterization of health quality during survival. Their approach uses survival data to distinguish two attributes of utility: prolongation of life and quality of life (QOL). Health-state transition probabilities correspond to the prolongation of life and are modeled in a discrete-time transient semi-Markov process. Quality-of-life-state transition probabilities are derived from the assumptions of a simple recurrent Markov process. They reflect events within the health-state sojourn time that differentiate perceptions of pain and suffering over a short fixed time period. Outcomes for these two dimensions of utility are highly relevant to the assessment of medical technology that might prolong life at the cost of increased pain and suffering, implying a reduced QOL. The methods are demonstrated on a subset of follow-up data from the Beta-Blocker Heart Attack Trial (BHAT).

Cardiovascular mortality trends in Harris County, Texas: 1980 to 1986.

Cardiovascular diseases are the leading causes of death in Texas and in the United States. This study determines the trend in mortality rates attributed to cardiovascular diseases in Harris County from 1980 to 1986. The region of the county that does not include the City of Houston was specifically studied. Mortality of cardiovascular diseases in these two areas follow patterns similar to that of the United States in the same time period. Both the entire county and Harris County excluding Houston show declines in cardiovascular mortality rates in the 7-year period. The populations were divided into four ethnic categories (white, black, Hispanic and "other"), and each ethnic group reported significant declines in overall cardiovascular mortality except in the "other" population, which showed an increase in the male group. Significant downward trends were noticed in the white and Hispanic population in the two major subcategories of cardiovascular diseases: diseases of the heart and cerebrovascular diseases. The black population in each geographic area studied was consistently higher in cardiovascular mortality than the other three ethnic groups observed (white, Hispanic and "other"). Knowledge of cardiovascular disease mortality rates by ethnicity, sex, and age as well as temporal changes in mortality rates within Harris County are important for health planners in continuing and implementing programs aimed at awareness, prevention, and treatment of cardiovascular diseases.

Long-term follow-up of weight status of subjects in a behavioral weight control program.

Few studies have examined the long-term effectiveness of behavioral weight control programs. Interpretation of the results from these studies has been limited due to small sample size, use of only one sex, and the number of evaluation parameters. A 2-year follow-up study was designed to assess the effectiveness of a behavioral weight control program on 123 obese male and 386 obese female subjects. Body weights were measured by dietitians at baseline and after an 8-week treatment program. Two-year follow-up weights were self-reported from a mailed questionnaire. The subjects' mean weight at baseline was 185.6 +/- 43.4 lb (no. = 509). Their mean percent over ideal body weight at baseline was 29.7%. Following an 8-week treatment period, mean weight was 176.4 +/- 41.3 lb (no. = 509), yielding a mean weight loss of 9.2 +/- 6.4 lb. Weight change after the 8-week treatment period ranged from a loss of 37 lb to a gain of 5 lb. The 2-year follow-up study showed that mean weight of the 498 subjects was 179.8 +/- 42.9 lb, yielding a mean weight loss of 5.8 +/- 15.5 lb. Weight change ranged from a loss of 71 lb to a gain of 47 lb. After 2 years, 325 subjects (65.3%) were still below their baseline weights, 182 subjects (36.6% of the entire study group) had maintained or enhanced the weight loss achieved during treatment, and 80 subjects (16.1%) weighed at least 10% less than their baseline weight.(ABSTRACT TRUNCATED AT 250 WORDS)

An illness-death process with time-dependent covariates.

A general model for the illness-death stochastic process with covariates has been developed for the analysis of survival data. This model incorporates important baseline and time-dependent covariates in order to make an appropriate adjustment for the transition and survival probabilities. The follow-up period is subdivided into small intervals and a constant hazard is assumed for each interval. An approximation formula is derived to estimate the transition parameters when the exact transition time is unknown. The method developed is illustrated with data from a study on the prevention of the recurrence of a myocardial infarction and subsequent mortality, the Beta-Blocker Heart Attack Trial (BHAT). This method provides an analytical approach with which the effectiveness of the treatment can be compared between the placebo and propranolol treatment groups with respect to fatal and nonfatal events simultaneously.

Effect of a rotating bed on the incidence of pulmonary complications in critically ill patients.

The risk of nosocomial pneumonia and atelectasis is high among critically ill immobilized patients. We hypothesized that continuous turning on the kinetic treatment table would reduce their incidence. Sixty-five critically ill patients, immobilized because of head injury or traction, were prospectively randomized for treatment in a conventional bed (n = 38) or the kinetic treatment table (n = 27). Patients were well matched for baseline demographic and pulmonary risk factors. Patients in the conventional bed group had a higher incidence of cigarette smoking. The combined incidence of significant atelectasis or pneumonia was higher (66%) in the conventional vs. kinetic treatment table (33%) groups (p less than .01). Atelectasis, pneumonia, adult respiratory distress syndrome, requirements for ventilator treatment, for PEEP, and for an FIO2 greater than 0.50 were not significantly different, but tended to be higher in the control group. Survival and the incidence of decubitus ulcers were similar.

A computer program for an illness-death process with time-dependent covariates.

This paper presents a computer program for estimating transition probabilities between states in a stochastic model for an illness-death process which incorporates time-dependent covariates. Parameters are estimated by the method of maximum likelihood using the Newton-Raphson iterative procedure. The program provides the standard normal deviate statistics as well as the value of the maximum of the likelihood function which can be used on repeated applications to test hypotheses concerning coefficients associated with covariates. Although this program is demonstrated by using a model with two 'illness' states and two 'death' states, it is also suitable for analyzing data with models involving fewer states, such as the analysis of survival time with covariates assuming a proportional hazard model.