Biomedical subjects

Siu L Hui

Publications and source records attributed to Siu L Hui.

At least 19 recordsLinked to original sources

PubMed2007

FGF23 concentrations vary with disease status in autosomal dominant hypophosphatemic rickets.

UNLABELLED: We measured FGF23 concentrations in subjects with ADHR. FGF23 and serum phosphate correlated positively in controls and negatively in subjects with ADHR. Elevated FGF23 concentrations were associated with lower phosphate values. The variable phenotype in ADHR may be caused by fluctuations in FGF23. INTRODUCTION: Autosomal dominant hypophosphatemic rickets (ADHR) is a rare disorder of phosphaturia, hypophosphatemia, inappropriately low/normal calcitriol, and rickets/osteomalacia. ADHR is caused by mutations in a circulating peptide, fibroblast growth factor 23 (FGF23). We present the first report of FGF23 concentrations in subjects with ADHR. The aim was to test the hypotheses that subjects with ADHR have elevated FGF23 concentrations and that FGF23 concentrations are associated with disease severity. MATERIALS AND METHODS: This was an observational study at a tertiary referral center. Subjects were from three kindreds with FGF23 mutations causing ADHR (n = 42). Controls were participants from these families without mutations (n = 55). Fasting blood and urine samples were obtained. Biochemistries were determined, and FGF23 concentrations were measured using two ELISAs. RESULTS: Three cases are presented illustrating activity of disease and FGF23 concentrations. One case shows persistent hypophosphatemia and elevation of FGF23 concentrations, whereas another shows remission of hypophosphatemia corresponding to a decrease in previously elevated FGF23 concentrations. Overall cross-sectional group differences were nonsignificant for serum phosphate and FGF23 concentrations. C-terminal FGF23 concentration in controls was 61.0 +/- 28.6 (SD) RU/ml (median, 52.5 RU/ml), and in subjects with mutations was 148.8 +/- 374.5 RU/ml (median, 63.1 RU/ml). Mean intact FGF23 concentration in controls was 44.7 +/- 14.9 pg/ml (median, 40.4 pg/ml), and in subjects with mutations was 83.2 +/- 233.0 pg/ml (median, 39.0 pg/ml). C-terminal FGF23 concentrations were at least +2 SD in 10/42(24%), and intact FGF23 concentrations were at least +2 SD in 3/34(9%). Phosphate correlated positively with C-terminal and intact FGF23 in both controls and in subjects with mutations with phosphate >2.5 mg/dl but correlated significantly negatively with C-terminal and intact FGF23 in ADHR subjects with phosphate < or =2.5 mg/dl. CONCLUSIONS: Elevated FGF23 concentrations are associated with hypophosphatemia in ADHR, and remission of the phenotype is associated with lower FGF23 concentrations. FGF23 has an opposite relationship with phosphate in ADHR compared with controls. We conclude that ADHR symptoms and disease severity likely fluctuate with FGF23 concentrations.

Adolescent↗

PubMed2006

Autosomal dominant osteopetrosis: clinical severity and natural history of 94 subjects with a chloride channel 7 gene mutation.

CONTEXT: Autosomal dominant osteopetrosis (ADO) is a sclerosing bone disorder caused by heterozygous mutations in the chloride channel 7 (ClCN7) gene. The clinical manifestations of this disease have not been well characterized since the discovery of the genetic basis of ADO. OBJECTIVES: The primary objectives were to improve our understanding of ADO clinical characteristics and to study the natural history of the disease in the largest series of patients reported to date. DESIGN AND SETTING: This study was primarily a retrospective cross-sectional analysis of individuals with a ClCN7 mutation that was conducted over a 4-yr period at a tertiary referral center and through family reunions. Longitudinal data on a subset of subjects were also studied. PATIENTS AND INTERVENTIONS: We studied 311 subjects from 11 ADO families, including 62 individuals with ADO (patients with the classic clinical phenotype based on radiographs and/or biochemistry), 32 unaffected gene carriers (subjects with the gene mutation but no radiographic and/or biochemical phenotype), and 217 controls who did not harbor a ClCN7 gene mutation. Clinical data were collected through patient interviews and examinations, medical records, and/or self-reported responses on a questionnaire that was completed by all subjects. MAIN OUTCOME MEASURES: The prevalence of fracture, osteomyelitis, visual loss, and bone marrow failure was determined. Differences in clinical manifestations were analyzed according to affected vs. carrier status, age, and underlying genotype. RESULTS: Ninety-two percent of ADO subjects had at least one sequela of the disease. Gene carriers did not have an increased risk of disease manifestations, although they were found to have significant increases in bone mineral density (P < 0.05). Compared with controls, subjects with ADO had a significantly increased prevalence of fracture (84 vs. 36%; P < 0.0001) and osteomyelitis (16 vs. 0.9%; P < 0.0001). Severe fractures (defined as > or =10 fractures of any type and/or greater than one hip/femur fracture) were identified only in ADO subjects, and osteomyelitis typically occurred in the maxilla or mandible in older adults. Visual loss, which typically had its onset in childhood, and bone marrow failure occurred in 19 and 3% of ADO subjects, respectively. Adults were more likely to manifest an ADO clinical characteristic, but no definitive genotype-phenotype relationship could be concluded. Longitudinal data suggest that the ADO clinical phenotype worsens over time. CONCLUSIONS: ADO caused by mutations in the CLCN7 gene is a frequently symptomatic disease manifested by a high rate of fracture, osteomyelitis, visual loss, and occasional bone marrow failure. The sequelae of ADO, which can be identified as early as infancy, appear to worsen over time. Fracture is the most prevalent consequence of ADO, although other more severe manifestations of disease can occur and should not be confused with recessive forms of osteopetrosis, particularly when identified in early childhood.

Adolescent↗

PubMed2006

Effectiveness of collaborative care for older adults with Alzheimer disease in primary care: a randomized controlled trial.

CONTEXT: Most older adults with dementia will be cared for by primary care physicians, but the primary care practice environment presents important challenges to providing quality care. OBJECTIVE: To test the effectiveness of a collaborative care model to improve the quality of care for patients with Alzheimer disease. DESIGN, SETTING, AND PATIENTS: Controlled clinical trial of 153 older adults with Alzheimer disease and their caregivers who were randomized by physician to receive collaborative care management (n = 84) or augmented usual care (n = 69) at primary care practices within 2 US university-affiliated health care systems from January 2002 through August 2004. Eligible patients (identified via screening or medical record) met diagnostic criteria for Alzheimer disease and had a self-identified caregiver. INTERVENTION: Intervention patients received 1 year of care management by an interdisciplinary team led by an advanced practice nurse working with the patient's family caregiver and integrated within primary care. The team used standard protocols to initiate treatment and identify, monitor, and treat behavioral and psychological symptoms of dementia, stressing nonpharmacological management. MAIN OUTCOME MEASURES: Neuropsychiatric Inventory (NPI) administered at baseline and at 6, 12, and 18 months. Secondary outcomes included the Cornell Scale for Depression in Dementia (CSDD), cognition, activities of daily living, resource use, and caregiver's depression severity. RESULTS: Initiated by caregivers' reports, 89% of intervention patients triggered at least 1 protocol for behavioral and psychological symptoms of dementia with a mean of 4 per patient from a total of 8 possible protocols. Intervention patients were more likely to receive cholinesterase inhibitors (79.8% vs 55.1%; P = .002) and antidepressants (45.2% vs 27.5%; P = .03). Intervention patients had significantly fewer behavioral and psychological symptoms of dementia as measured by the total NPI score at 12 months (mean difference, -5.6; P = .01) and at 18 months (mean difference, -5.4; P = .01). Intervention caregivers also reported significant improvements in distress as measured by the caregiver NPI at 12 months; at 18 months, caregivers showed improvement in depression as measured by the Patient Health Questionnaire-9. No group differences were found on the CSDD, cognition, activities of daily living, or on rates of hospitalization, nursing home placement, or death. CONCLUSIONS: Collaborative care for the treatment of Alzheimer disease resulted in significant improvement in the quality of care and in behavioral and psychological symptoms of dementia among primary care patients and their caregivers. These improvements were achieved without significantly increasing the use of antipsychotics or sedative-hypnotics. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00246896.

Activities of Daily Living↗

PubMed2006

Human ALOX12, but not ALOX15, is associated with BMD in white men and women.

UNLABELLED: The Alox15 gene was recently identified as a negative regulator of peak BMD in mice. Polymorphisms in human ALOX12, but not ALOX15, were significantly associated with spine BMD in white men and women, suggesting that ALOX12 may contribute to normal variation in BMD. INTRODUCTION: Osteoporosis is a complex disease with both genetic and environmental risk factors. A major determinant of osteoporosis is peak BMD, which is a highly heritable trait. Recently, the arachidonate 15-lipoxygenase (Alox15) gene was identified as a negative regulator of peak BMD in mice. MATERIALS AND METHODS: To assess the contribution of lipoxygenase genes to normal BMD variation in healthy white men and women, we performed population- and family-based association studies of two arachidonate lipoxygenase genes: ALOX15, which is the human homolog of mouse Alox15, and ALOX12, which is functionally similar to Alox15. Single nucleotide polymorphisms (SNPs) distributed across the two genes were genotyped. BMD was measured at the femoral neck and lumbar spine in 411 men 18-61 years of age and 1291 premenopausal women 20-50 years of age. RESULTS: Moderate evidence of association was found between spine BMD and six SNPs in the ALOX12 gene in both men and women (p = 0.0052-0.050). Furthermore, the most common SNP haplotype in ALOX12 showed evidence of significant association with high spine BMD in men (p = 0.0083), whereas the second most common haplotype was associated with high spine BMD in women (p = 0.0081). CONCLUSIONS: Polymorphisms in the ALOX12 gene may contribute to normal variation in spine BMD.

Adolescent↗

PubMed2006

Sensitivity of fibroblast growth factor 23 measurements in tumor-induced osteomalacia.

CONTEXT: Tumor-induced osteomalacia (TIO) is a paraneoplastic syndrome of hypophosphatemia, decreased renal phosphate reabsorption, normal or low serum 1,25-dihydryxyvitamin-D concentration, myopathy, and osteomalacia. Fibroblast growth factor 23 (FGF23) is a phosphaturic protein overexpressed in tumors that cause TIO and is, at least partly, responsible for the manifestations of TIO. OBJECTIVE: The objective of this study was to determine the sensitivity of FGF23 measurements in TIO. DESIGN: FGF23 concentrations were measured on stored samples with three ELISAs. SETTING: This study was conducted at subspecialty referral centers. PATIENTS: Twenty-two patients with suspected TIO, 13 with confirmed tumors, were studied. INTERVENTIONS: There were no interventions in this study. MAIN OUTCOME MEASURE: FGF23 concentration was the main outcome measure of this study. RESULTS: Elevated FGF23 concentrations were detected using the Immunotopics C-terminal assay in 16 of 22 TIO patients (for a sensitivity of 73%), the Immunotopics Intact assay in five of 22 patients (sensitivity, 23%), and the Kainos Intact assay in 19 of 22 patients (sensitivity, 86%). In the 13 patients with confirmed tumors, the sensitivity was higher with all assays: 92% for the Immunotopics C-terminal assay, 38% for the Immunotopics Intact assay, and 100% for the Kainos assay. CONCLUSION: The Kainos Intact assay was the most sensitive, followed by the Immunotopics C-terminal assay. The findings of normal FGF23 concentrations in some patients with TIO may indicate that FGF 23 is not responsible for the hypophosphatemia in these patients or that FGF23 secretion by some tumors is partially responsive to serum phosphate. Normal FGF23 concentrations should be interpreted in relation to the serum phosphate and 1,25-dihydryxyvitamin-D concentrations.

Adolescent↗

PubMed2006

Heritability of changes in bone size and bone mass with age in premenopausal white sisters.

UNLABELLED: Femoral neck area expands and BMD decreases in premenopausal women. We used longitudinal DXA measurements on 388 premenopausal white sisters to show significant heritability of the rates of change in femoral neck area, BMC, and BMD. INTRODUCTION: Bone mass and structure are highly heritable. However, genetic effects on age-related changes in bone mass and structure in adults have been much less studied. MATERIALS AND METHODS: DXA measurements were made on 388 healthy white premenopausal sisters from 178 families. Rates of change in femoral neck area, BMC, and BMD, as well as body weight, were calculated from two measurements made an average of 5.7 years apart. Mixed models were used to test whether bone changes were related to age or weight change. Variance components models were used to estimate the heritability of the rates of change. A method was proposed to correct for the underestimation of heritabilities caused by measurement errors of the rates of change. RESULTS: Femoral neck area increased with age, whereas BMD decreased. All of the rates of change at the femoral neck were positively correlated with weight change, but the rates of femoral neck changes did not vary with age. Adjusted for weight change, change in femoral neck BMC became negative. Significant heritabilities (0.29-0.36) were detected for changes in femoral neck BMC, BMD, and area adjusted for weight changes. Correction for DXA measurement error in the rate estimates increased the heritability estimates (from 0.29-0.36 range to 0.37-0.64 range). CONCLUSIONS: Rates of change are heritable for femoral neck area, BMC, and BMD in premenopausal white women.

Adult↗

PubMed2005

Polymorphisms in the estrogen receptor beta (ESR2) gene are associated with bone mineral density in Caucasian men and women.

CONTEXT: A major determinant of osteoporotic fractures is peak bone mineral density (BMD), which is a highly heritable trait. Recently, we identified significant linkage for hip BMD in premenopausal sister pairs at chromosome 14q (LOD score = 3.5), where the estrogen receptor beta gene (ESR2) is located. OBJECTIVE: The objective of the study was to determine whether ESR2 polymorphisms are associated with normal BMD variation. DESIGN: This was a population-based genetic association study, using 11 single nucleotide polymorphisms (SNPs) distributed across the ESR2 gene. SETTING: The study was conducted at an academic research laboratory and medical center. PATIENTS AND OTHER PARTICIPANTS: A total of 411 healthy men (aged 18-61 yr) and 1291 healthy premenopausal women (aged 20-50 yr) living in Indiana participated in the study. INTERVENTION(S): There were no interventions. MAIN OUTCOME MEASURE(S): The main outcome measures were SNP genotype distributions and their association with BMD at the femoral neck and lumbar spine. RESULTS: Significant association of spine BMD was found with three SNPs in men and one SNP in women (P < or = 0.05). The conditional linkage analysis using the ESR2 haplotypes showed that the ESR2 gene accounts for, at most, 18% of the original linkage. CONCLUSIONS: ESR2 polymorphisms are significantly associated with bone mass in both men and women. However, the ESR2 gene is not entirely responsible for our original linkage, and an additional gene(s) in chromosome 14q contributes to the determination of BMD.

Adult↗

PubMed2005

Hospital resource utilization in childhood cancer.

To describe the patterns and predictors of hospital resource utilization in a cohort of children with newly diagnosed cancer, a retrospective cohort study of 195 consecutively diagnosed children with cancer at a single large Midwestern children's hospital was conducted. Patients were diagnosed between November 1995 and March 1997. All hospital encounters for these patients starting from the time of diagnosis to 3 years from diagnosis were identified using hospital administrative data. The patients were categorized into four diagnostic groups: lymphoid malignancies (acute lymphoblastic leukemia and lymphoma), myeloid leukemias (acute myeloid leukemia and chronic myeloid leukemia), central nervous system tumors, and solid tumors. Hospital charges and length of stay for patients in each diagnostic category were described. Predictive models for total resource consumption (total hospital charges) and intensive care use were derived. One hundred sixty-five of the 195 were admitted to Riley Hospital for Children at least once during the 3-year period following diagnosis. Among these 165, mean age at diagnosis was 6.9 years (minimum newborn, maximum 18.7 years). The ratio of boys to girls was 99:66 (1.5:1). The distribution of 165 diagnoses was as follows: 65 (39%) with lymphoid malignancy, 13 (8%) with myeloid leukemia, 36 (22%) with central nervous system tumors, and 51 (31%) with solid tumors. Sixty-two patients (38%) used the pediatric intensive care unit (PICU) at least once; 22 patients (13%) underwent stem cell transplantation. Sixty-five patients (39%) entered clinical trials. One hundred thirty-nine patients (84%) were alive at the end of 3 years. Three-year cumulative hospital charges were USD 16 million--almost USD 100,000/child hospitalized. Half of these charges were incurred in the first 4.5 months after diagnosis. Half of all hospital charges accrued to only 12.7% of patients; these patients were more likely to have a diagnosis of myeloid leukemia, to have undergone stem cell transplantation, and to have used the PICU. There were three independent predictors of hospital charges (log transformed): stem cell transplantation, PICU utilization, and death within 3 years of diagnosis. PICU utilization was predicted by tumor type (myeloid leukemia and central nervous system tumors were positive predictors of PICU utilization; lymphoid malignancy and solid tumors were negative predictors), stem cell transplantation, and death within 3 years of diagnosis. The authors conclude that hospitalization for childhood cancer is common, costly in the short term, and to some extent predictable. These data suggest that failures of current treatment not only lead to death but also add significantly to hospital resource utilization.

Adolescent↗

PubMed2005

Implementing a screening and diagnosis program for dementia in primary care.

BACKGROUND: Primary care physicians are positioned to provide early recognition and treatment of dementia. We evaluated the feasibility and utility of a comprehensive screening and diagnosis program for dementia in primary care. METHODS: We screened individuals aged 65 and older attending 7 urban and racially diverse primary care practices in Indianapolis. Dementia was diagnosed according to International Classification of Diseases (ICD)-10 criteria by an expert panel using the results of neuropsychologic testing and information collected from patients, caregivers, and medical records. RESULTS: Among 3,340 patients screened, 434 scored positive but only 227 would agree to a formal diagnostic assessment. Among those who completed the diagnostic assessment, 47% were diagnosed with dementia, 33% had cognitive impairment-no dementia (CIND), and 20% were considered to have no cognitive deficit. The overall estimated prevalence of dementia was 6.0% (95% confidence interval (CI) 5.5% to 6.6%) and the overall estimate of the program cost was $128 per patient screened for dementia and $3,983 per patient diagnosed with dementia. Only 19% of patients with confirmed dementia diagnosis had documentation of dementia in their medical record. CONCLUSIONS: Dementia is common and undiagnosed in primary care. Screening instruments alone have insufficient specificity to establish a valid diagnosis of dementia when used in a comprehensive screening program; these results may not be generalized to older adults presenting with cognitive complaints. Multiple health system and patient-level factors present barriers to this formal assessment and thus render the current standard of care for dementia diagnosis impractical in primary care settings.

Aged↗

PubMed2005

Efficiency, comprehensiveness and cost-effectiveness when comparing dictation and electronic templates for operative reports.

Surgeons typically document operative events using dictation services. Dictated reports are frequently incomplete or delayed. Electronic note templates could potentially improve this process. Using a study design of alternating four week blocks, we compared the timeliness and comprehensiveness of operative notes created through the use of electronic templates versus dictation services for five surgical procedures. Templates resulted in dramatically faster times to the presence of a verified operative report in the medical record compared to dictation services (mean 28 v. 22,440 minutes). Templates increased overall compliance with national standards for operative note documentation and avoided transcription costs. Documentation with templates took slightly more time than dictation (mean 6.77 v. 5.96 minutes; P=0.036), not including the additional time necessary to subsequently verify dictated reports. We conclude that electronic note templates can improve the timeliness and comprehensiveness of operative documentation, while decreasing transcription costs and requiring minimal additional effort on the part of surgeons.

Cesarean Section↗

PubMed2004

Contribution of the LRP5 gene to normal variation in peak BMD in women.

UNLABELLED: The role of the LRP5 gene in rare BMD-related traits has recently been shown. We tested whether variation in this gene might play a role in normal variation in peak BMD. Association between SNPs in LRP5 and hip and spine BMD was measured in 1301 premenopausal women. Only a small proportion of the BMD variation was attributable to LRP5 in our sample. INTRODUCTION: Mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene have been implicated as the cause of multiple distinct BMD-related rare Mendelian phenotypes. We sought to examine whether the LRP5 gene contributes to the observed variation in peak BMD in the normal population. MATERIALS AND METHODS: We genotyped 12 single nucleotide polymorphisms (SNPs) in LRP5 using allele-specific PCR and mass spectrometry methods. Linkage disequilibrium between the genotyped LRP5 SNPs was measured. We tested for association between these SNPs and both hip and spine BMD (adjusted for age and body weight) in 1301 healthy premenopausal women who took part in a sibling pair study aimed at identifying the genes underlying peak bone mass. Our study used both population-based (ANOVA) and family-based (quantitative transmission disequilibrium test) association methodology. RESULTS AND CONCLUSIONS: The linkage disequilibrium pattern and haplotype block structure within the LRP5 gene were consistent with that observed in other studies. Although significant evidence of association was found between LRP5 SNPs and both hip and spine BMD, only a small proportion of the total variation in these phenotypes was accounted for. The genotyped SNPs accounted for approximately 0.8% of the variation in femoral neck BMD and 1.1% of the variation in spine BMD. Results from our sample suggest that natural variation in and around LRP5 is not a major contributor to the observed variability in peak BMD at either the femoral neck or lumbar spine in white women.

Adult↗

PubMed2004

Cross calibration in longitudinal studies.

In a long-running longitudinal study using complex machinery to obtain measurements, it is sometimes necessary to replace the machine. This can result in lack of continuity in the measurements that can overwhelm any treatment effect or time trend. We propose a Bayesian procedure implemented using Markov chain Monte Carlo to calibrate the measurements on the old machine utilizing both person-specific and population information. The goal is to convert the previous measurements to values that can be treated as though they were made on the new machine. This methodology is applied to a bone mineral density study where the first densitometer uses gadolinium as the energy source (Lunar DP-3) and the second uses X-rays (Hologic QDR-1000W). Finally, simulation results are presented to show the superiority of the proposed method over existing methods of cross calibration.

Calibration↗

PubMed2004

Selecting pre-screening items for early intervention trials of dementia--a case study.

Our goal was to review and extend statistical methods for discriminating between normal subjects and those with dementia or cognitive impairment. We compared six different methods to one constructed by expert opinion, in their brevity and predictive power. The methods include logistic regression and neural networks, with standard and least absolute shrinkage and selection operator (LASSO) variable selection, as well as decision trees with and without boosting. These methods were applied to the baseline data of a subgroup of subjects in a dementia study, using their screening interview items to predict their clinical diagnosis of normal or non-normal (cognitively impaired or demented). The derived models were then validated on a different subgroup of subjects in the same study who had the screening and clinical diagnosis two to five years later. Performance of different models was compared based on their sensitivity and specificity in the validation sample. Generally, the six statistical methods performed slightly to moderately better than the expert-opinion model. Neural networks generally performed better than the logistic and decision tree models. LASSO improved the performance of logistic and neural network models, but it eliminated few input variables in the neural network. The single decision tree performed at least as well as the standard logistic model, and with fewer items, making it an attractive pre-screening tool. Using the boosting option for decision trees did not substantially improve the performance. We recommend that for each situation, different methods of classification should be attempted to obtain optimal results for a given purpose.

Black or African American↗

PubMed2004

Confirmation of linkage to chromosome 1q for peak vertebral bone mineral density in premenopausal white women.

Peak bone mineral density (BMD) is a highly heritable trait and is a good predictor of the risk of osteoporosis and fracture in later life. Recent studies have sought to identify the genes underlying peak BMD. Linkage analysis in a sample of 464 premenopausal white sister pairs detected linkage of spine BMD to chromosome 1q (LOD 3.6). An independent sample of 254 white sister pairs has now been genotyped, and it also provides evidence of linkage to chromosome 1q (LOD 2.5) for spine BMD. Microsatellite markers were subsequently genotyped for a 4-cM map in the chromosome 1q region in all available white sister pairs (n=938), and a LOD score of 4.3 was obtained near the marker D1S445. Studies in the mouse have also detected evidence of linkage to BMD phenotypes in the region syntenic to our linkage finding on chromosome 1q. Thus, we have replicated a locus on 1q contributing to BMD at the spine and have found further support for the region in analyses employing an enlarged sample. Studies are now ongoing to identify the gene(s) contributing to peak spine BMD in women.

Adult↗

PubMed2003

An illness-death stochastic model in the analysis of longitudinal dementia data.

A significant source of missing data in longitudinal epidemiological studies on elderly individuals is death. Subjects in large scale community-based longitudinal dementia studies are usually evaluated for disease status in study waves, not under continuous surveillance as in traditional cohort studies. Therefore, for the deceased subjects, disease status prior to death cannot be ascertained. Statistical methods assuming deceased subjects to be missing at random may not be realistic in dementia studies and may lead to biased results. We propose a stochastic model approach to simultaneously estimate disease incidence and mortality rates. We set up a Markov chain model consisting of three states, non-diseased, diseased and dead, and estimate the transition hazard parameters using the maximum likelihood approach. Simulation results are presented indicating adequate performance of the proposed approach.

Aged↗

PubMed2003

Mass media release of medical research results: an analysis of antihypertensive drug prescribing in the aftermath of the calcium channel blocker scare of March 1995.

BACKGROUND: Disclosure of medical research results to the public creates tension between lay medical reporters and the medical profession. OBJECTIVE: To explore the early effect of media attention on the risks associated with short-acting calcium channel blockers (CCBs) for treating hypertension after publication at a national meeting and following publication. DESIGN: Time-series analysis of prescription claims data. SETTING AND DATA SOURCE: National third-party pharmaceutical benefits manager. PATIENTS: Employed or retired persons and their families, 18 years of age or older, receiving prescription benefits from 1 of 4 national companies that contracted with the pharmaceutical benefits manager exclusively for prescription drug coverage. MEASUREMENTS: Prescription claims for antihypertensive drugs by fill date converted to a percentage of all cardiovascular drug claims. Data were grouped into weekly intervals before and immediately after the national release of negative information about CCBs on March 10, 1995 and following publication of the results on August 23, 1995. RESULTS: The most prevalent antihypertensive drugs were diuretics (21% of cardiovascular prescription claims) and calcium channel blockers (19%). A 10% decline in prescriptions filled for CCBs occurred 4 weeks following the intense media attention. Only prescriptions for long-acting calcium channel blockers declined. Alpha-1-blocker prescriptions increased by approximately the same amount that prescriptions for CCBs declined, suggesting substitution of one drug for the other. Changes in diuretic or beta-blocker prescriptions filled were not statistically significant. No immediate change in other cardiovascular drug classes occurred following journal publication. CONCLUSIONS: Intense media publicity regarding a controversial study measurably and unpredictably changed prescription claims.

Adolescent↗

PubMed2003

A randomized trial of two quality improvement strategies implemented in a statewide public community-based, long-term care program.

BACKGROUND: It has not been demonstrated that the implementation of computerized quality improvement strategies can improve client-centered outcomes in public community based, long-term care (CBLTC) programs. OBJECTIVES: To test and evaluate 2 innovative computer-assisted, client-centered quality improvement strategies for public community-based, long-term care. The first strategy, the Normative Treatment Planning (NTP) program, assesses needs, prescribes services, and evaluates outcomes. The second strategy, the Client Feedback System (CFS) program, provides service vendors with feedback on client perceptions of services. RESEARCH DESIGN: A 2 x 2 factorial design with the 2 strategies using cluster randomization. SUBJECTS: A total of 2222 clients (86% of eligible program clients) enrolled in Indiana's state case management program and/or the Medicaid home and community-based services waiver program for the aged and disabled as of January 1, 1995. MEASURES: Outcomes of needs met and client satisfaction were measured through telephone surveys every 6 months for 2 years. RESULTS: A total of 1006 participants (45%) completed the 2-year evaluation study. For the group using only the NTP program, perception of needs met and client satisfaction were significantly better than the control group over the 2 years. During this period, the group using only the CFS program had significantly better client satisfaction than the control group. However, the effect sizes of the significant differences were small, and no statistically significant effects were found for the group using both programs. CONCLUSIONS: Client-centered quality improvement strategies can be implemented to enable public CBLTC programs to meet client needs better and increase client satisfaction.

Activities of Daily Living↗

PubMed2003

Difference in bone mass between black and white American children: attributable to body build, sex hormone levels, or bone turnover?

A cross-sectional study of 232 healthy children, with about equal numbers of boys and girls and blacks and whites, aged 4 to 16 yr, was conducted to investigate the racial differences in bone mineral. Bone mineral content (BMC) by dual x-ray absorptiometry was found to be similar between blacks and whites at the spine after controlling for age and Tanner stage. However, total body BMC was higher in blacks, compared with whites of the same age and Tanner stage. Height and weight alone reduced the racial difference in BMC from 152 g to 66 g in girls and from 163 g to 105 g in boys, in whom the difference was further reduced to 66 g after accounting for lean and fat body mass and subscapular skinfold. The only significant sex hormone was androstenedione, which explained another 4-5 g of the racial difference in total body BMC for both boys and girls. Among the biochemical variables, only 25OH vitamin D reduced the residual racial difference in total body BMC to 39 g in girls, whereas serum PTH, urine free deoxypyridinoline ratio, and 1,25(OH)(2) vitamin D reduced the residual difference to 25 g in boys. The residual racial differences in bone mass were not statistically significant.

Adolescent↗