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Biomedical subjects

R W Chang

Publications and source records attributed to R W Chang.

At least 19 recordsLinked to original sources
PubMed2001

Reduction in mortality after inappropriate early discharge from intensive care unit: logistic regression triage model.

OBJECTIVE: To develop a predictive model to triage patients for discharge from intensive care units to reduce mortality after discharge. DESIGN: Logistic regression analyses and modelling of data from patients who were discharged from intensive care units. SETTING: Guy's hospital intensive care unit and 19 other UK intensive care units from 1989 to 1998. PARTICIPANTS: 5475 patients for the development of the model and 8449 for validation. MAIN OUTCOME MEASURES: Mortality after discharge and power of triage model. RESULTS: Mortality after discharge from intensive care was up to 12.4%. The triage model identified patients at risk from death on the ward with a sensitivity of 65.5% and specificity of 87.6%, and an area under the receiver operating curve of 0.86. Variables in the model were age, end stage disease, length of stay in unit, cardiothoracic surgery, and physiology. In the validation dataset the 34% of the patients identified as at risk had a discharge mortality of 25% compared with a 4% mortality among those not at risk. CONCLUSIONS: The discharge mortality of at risk patients may be reduced by 39% if they remain in intensive care units for another 48 hours. The discharge triage model to identify patients at risk from too early and inappropriate discharge from intensive care may help doctors to make the difficult clinical decision of whom to discharge to make room for a patient requiring urgent admission to the unit. If confirmed, this study has implications on the provision of resources.

APACHE↗
PubMed2001

Arthritis prevalence and activity limitations in older adults.

OBJECTIVE: To evaluate the prevalence of arthritis and activity limitations among older Americans by assessing their demographic, ethnic, and economic characteristics. METHODS: Data from the Asset and Health Dynamic Survey Among the Oldest Old (AHEAD), a national probability sample of community-dwelling adults born before 1924, were analyzed cross-sectionally. Arthritis that resulted in a physician's visit or a joint replacement not associated with a hip fracture was ascertained by self-report. RESULTS: The prevalence of arthritis in older adults ranged from 25% in non-Hispanic whites to 40% in non-Hispanic blacks to 44% in Hispanics. A higher prevalence of arthritis was associated with less education as well as lower income and less wealth. The prevalence of limitations in activities of daily living (ADL) among non-Hispanic white, non-Hispanic black, and Hispanic adults who reported arthritis only was 29%, 30%, and 37%, respectively, and increased to 48%, 57%, and 56%, respectively, among those reporting arthritis plus other chronic conditions, after adjustment for age and sex. CONCLUSION: Non-Hispanic black and Hispanic older adults reported having arthritis at a substantially higher frequency than did non-Hispanic whites. In addition, Hispanics reported higher rates of ADL limitations than did non-Hispanic whites with comparable disease burden. Further study is needed to confirm and elucidate the reasons for these racial and economic disparities in older populations.

Activities of Daily Living↗
PubMed2001

European randomised trial of dual versus triple tacrolimus-based regimens for control of acute rejection in renal allograft recipients.

Two large multicentre studies have shown superiority of tacrolimus-based immunosuppressive regimens compared with standard cyclosporine-based therapy in renal transplantation. In these studies, tacrolimus was used in a triple drug regimen of tacrolimus, corticosteroids, and azathioprine. The present study aimed to determine whether a tacrolimus-based dual regimen achieves a similar efficacy and safety profile compared with conventional triple therapy. In this prospective, open, multicentre trial, 249 patients were randomised to receive either dual therapy (n = 125) of oral tacrolimus (initial daily dose of 0.2 mg/kg) and oral prednisone or additionally, as a triple therapy (n = 124), oral azathioprine. The primary endpoint was the incidence of acute rejection at month 3. In addition, all patients were included into a follow-up evaluation at 1 year after transplantation. Both treatment groups had similar baseline characteristics. At month 3, patient survival was 97.6 % (dual) and 96.7 % (triple); graft survival was 92.7 % (dual) and 91.7 % (triple). The incidence of treated acute rejection confirmed by biopsy was 27.4 % (dual) and 24.8 % (triple); difference 2.6 %, 95 % CI [-9.4 %-12.9 %], P = 0.755. The incidence of corticosteroid-resistant rejection (biopsy-confirmed) was 9.7 % (dual) and 10.7 % (triple). The overall adverse events profile was similar; leukopenia (1.6 % vs 11.6 %, P = 0.002) was more frequent with triple therapy. Between months 4 and 12, six (dual) and eight (triple) patients had a rejection. At month 12, patient survival was 95.6 % (dual) and 93.6 % (triple); graft survival was 91.8 % (dual) and 90.7 % (triple). Tacrolimus proved to be efficacious and safe with both dual and triple low-dose regimens. The addition of azathioprine to a tacrolimus/corticosteroid-based therapy did not result in an increased efficacy.

Acute Disease↗
PubMed1998

Impact of joint impairment on disability-specific domains at four years.

The objective of this study was to assess the longitudinal impact of joint impairment on overall disability and crossing domain-specific thresholds for physical activity, mobility, dexterity, instrumental activities of daily living (IADL), and activities of daily living (ADL) that are associated with use of long-term care. This 4-year longitudinal study observed 484 persons older than age 60. Logistic regression assessed the contribution of demographics, psychological mediators, lower- and upper-extremity joint impairment, and comorbidities to increased domain-specific self-reported disability above a threshold associated with use of long-term care. Lower-extremity joint impairment and age predicted crossing thresholds by year 4 in physical activity, mobility, IADL, and ADL disability that were associated with use of long-term care. Lower-extremity joint impairment is a strong risk factor for future disability that is associated with use of long-term care.

Activities of Daily Living↗
PubMed1998

Markers of glutamatergic neurotransmission and oxidative stress associated with tardive dyskinesia.

OBJECTIVE: Tardive dyskinesia is a movement disorder affecting 20%-40% of patients treated chronically with neuroleptic drugs. The dopamine supersensitivity hypothesis cannot account for the time course of tardive dyskinesia or for the persistence of tardive dyskinesia and the associated structural changes after neuroleptics are discontinued. The authors hypothesized that neuroleptics enhance striatal glutamatergic neurotransmission by blocking presynaptic dopamine receptors, which causes neuronal damage as a consequence of oxidative stress. METHOD: CSF was obtained from 20 patients with schizophrenia, 11 of whom had tardive dyskinesia. Markers for oxidative stress, including superoxide dismutase, lipid hydroperoxide, and protein carbonyl groups, and markers for excitatory neurotransmission, including N-acetylaspartate, N-acetylaspartylglutamate, aspartate, and glutamate, were measured in the CSF specimens. Patients were also rated for tardive dyskinesia symptoms with the Abnormal Involuntary Movement Scale. RESULTS: Tardive dyskinesia patients had significantly higher concentrations of N-acetylaspartate, N-acetylaspartylglutamate, and aspartate in their CSF than patients without tardive dyskinesia when age and neuroleptic dose were controlled for. The significance of the higher levels of protein-oxidized products associated with tardive dyskinesia did not pass Bonferroni correction, however. Tardive dyskinesia symptoms correlated positively with markers of excitatory neurotransmission and protein carbonyl group and negatively with CSF superoxide dismutase activity. CONCLUSIONS: These findings suggest that there are elevated levels of oxidative stress and glutamatergic neurotransmission in tardive dyskinesia, both of which may be relevant to the pathophysiology of tardive dyskinesia.

Adult↗
PubMed1997

Effect of age and osteoarthritis on knee proprioception.

OBJECTIVE: To test the hypotheses that 1) knee position sense declines with age; 2) patients with osteoarthritis (OA) have worse knee position sense than elderly controls; and 3) knee position sense is correlated with functional status. METHODS: The threshold for detection of knee joint displacement was measured in 30 patients with bilateral knee OA (Kellgren/Lawrence grade > or =2 in both knees), 29 elderly controls (who met clinical and radiographic criteria for exclusion of OA), and 25 young controls. Range of motion, laxity, radiographic severity, and functional status were also assessed. RESULTS: A moderate correlation was found between joint displacement detection threshold and age (r = 0.598 and r = 0.501 for the right knee and the left knee, respectively). The threshold was substantially and significantly different between the OA patients and the elderly controls. Proprioceptive impairment was associated with worse disease-specific functional status. CONCLUSION: Proprioception declines with age, and is further impaired in elderly patients with knee OA. Poor proprioception may contribute to functional impairment in knee OA.

Adult↗
PubMed1997

Rehabilitation advances in the treatment of arthritis and musculoskeletal disease.

The current literature is reviewed related to three disease processes commonly encountered by the physiatrist, rheumatologist, and internist in clinical practice, including osteoarthritis, rheumatoid arthritis, and osteoporosis. These diseases often have effects beyond the pathology that has an impact on the individual's function and integration into society. Emphasis is on the specific rehabilitative approach to the individual.

Arthritis↗
PubMed1997

Role of growth hormone status in the outcome of total knee replacement.

The objective was to assess whether the aging related, variable decline in growth hormone influences total knee replacement outcome. In this prospective cohort study, consecutive patients who underwent unilateral total knee replacement and who met criteria were enrolled from the practice of 1 orthopaedic surgeon at a university hospital. Participants were evaluated 1 month before and 3 months after total knee replacement. Evaluators were not involved in patient care. The primary outcome measure was the Medical Outcome Study 36-item Short Form Health Survey Physical Functioning Scale score 3 months after total knee replacement. In a multiple regression analysis performed to assess the influence of growth hormone status, controlling for social support, body mass index, gender, previous reconstruction, mental health, motivation, and baseline physical functioning, only mental health contributed significantly to outcome. Mental health accounted for 18% of outcome variance. Growth hormone levels did not predict functional status after total knee replacement. Psychological status contributes significantly to total knee replacement physical functional outcome.

Age Factors↗
PubMed1997

Predictors of decline in manual performance in older adults.

OBJECTIVE: To determine factors that predict decline in manual performance using a multivariate model of determinants of functional limitation. DESIGN: Longitudinal observational study. SETTINGS: Ambulatory general medicine clinics, residences of homebound individuals, and a continuing care retirement community. PARTICIPANTS: Subjects were 485 persons more than 60 years of age and included continuing care retirement community (CCRC) residents (n = 215), chronically homebound older persons (n = 65), and ambulatory older adults (n = 205). Mean age at baseline was 78 years. MEASUREMENT: Independent variables included demographics, physician measures of upper-extremity joint impairment, comorbidities derived from physical examination and chart abstract, self-assessed arthritis pain, depression, and anxiety. The major dependent variable was 2-year decline in timed manual performance below a threshold associated with need for long-term care services. RESULTS: The proportion of subjects who exceed a Timed Manual Performance Test threshold of 350 seconds increased slowly from baseline through Year 4 for all age groups but rose rapidly from Year 4 to Year 6 for the oldest group (> 85 years at baseline). Using a discrete survival model, we found that age, education, grip strength, and psychological status predicted crossing the manual performance threshold within a 2-year period. CONCLUSIONS: The findings, coupled with earlier findings that upper extremity joint impairment predicted both grip strength and manual performance, suggest that joint impairment may be an important risk factor for future functional limitation. Since diminished hand function has been shown to predict dependency, development and testing of interventions to maintain or restore upper extremity joint function and reduce pain would appear to be a high research priority.

Age Factors↗
PubMed1996

A cost-effectiveness analysis of total hip arthroplasty for osteoarthritis of the hip.

OBJECTIVE: To quantify the trade-off between the expected increased short- and long-term costs and the expected increase in quality-adjusted life expectancy (QALE) associated with total hip arthroplasty (THA) for persons with functionally significant hip osteoarthritis. DESIGN: A cost-effectiveness study was performed from the societal perspective by constructing stochastic tree, decision analytic models designed to estimate lifetime functional outcomes and costs of THA and nonoperative managements. MAIN OUTCOME MEASURES: A modified four-state American College of Rheumatology functional status classification was used to measure effectiveness. These functional classes were assigned utility values to allow the relative effectiveness of THA to be expressed in quality-adjusted life years (QALYs). Lifetime costs included costs associated with primary and potential revision surgeries and long-term care costs associated with the functionally dependent class. DATA USED IN THE COST-EFFECTIVENESS MODEL: Probability and incidence rate data were summarized from the literature. The THA hospital cost data were obtained from local teaching hospitals' cost accounting systems. Estimates of recurring medical costs for functionally significant hip osteoarthritis and for custodial care were derived from the literature. RESULTS: The THA cost-effectiveness ratio increases with age and is higher for men than for women. In the base-case scenario for 60-year-old white women who have functionally significant but not dependent hip osteoarthritis, the model predicts that THA is cost saving because of the high costs of custodial care associated with dependency due to worsening hip osteoarthritis and that the procedure increases QALE by about 6.9 years. In the base-case scenario for men aged 85 years and older, the average lifetime cost associated with THA is $9100 more than nonoperative management, with an average increase in QALE of about 2 years. Thus, the THA cost-effectiveness ratio for men aged 85 years and older is $4600 per QALY gained, less than that of procedures intended to extend life such as coronary artery bypass surgery or renal dialysis. Worst-case analysis suggests that THA remains minimally cost-effective for this oldest age category ($80,000/QALY) even if probabilities, rates, utilities, costs, and the discount rate are simultaneously varied to extreme values that bias the analysis against surgery. CONCLUSIONS: For persons with hip osteoarthritis associated with significant functional limitation, THA can be cost saving or, at worst, cost- effective in improving QALE when both short- and long-term outcomes are considered. Further research is needed to determine whether this procedure is actually being used in this cost-effective manner, especially in older age categories.

Age Factors↗
PubMed1996

Ethnicity and access to care in systemic lupus erythematosus.

OBJECTIVE: To define access to care and to examine the relationship between ethnicity and access to care in systemic lupus erythematosus (SLE). METHODS: A review of published literature was supplemented with preliminary data from a pilot study. Data from patient interviews, chart reviews, and insurer surveys were collected at 2 sites and used to develop several measures of access. The relationship between ethnicity and access was examined through chi-square analyses, difference of means testing, and multivariate regression. RESULTS: Although African-American SLE patients appear less likely to be privately insured and more likely to be uninsured, no significant differences in utilization rates were detected between ethnic groups. Uninsured patients, however, had significantly fewer physician visits than both the Medicaid and the privately insured patients. Multivariate regression confirm a strong and negative relationship between physician visits and patient coinsurance rates. CONCLUSION: Careful examination of multiple dimensions of access may highlight differences between ethnic groups. Further research is necessary to document these differences and explore their relationships to outcomes.

Adolescent↗
PubMed1996

Functional outcome and patient satisfaction in total knee patients over the age of 75.

Seventy-four patients, age 75 or older, who had undergone 98 primary total knee arthroplasties were evaluated in a retrospective cohort study, with validated questionnaires that assessed self-reported pain, physical function, mental health, and satisfaction. Average follow-up period was 34 months (range, 12-67 months). Overall, 90.8% reported improvement, 88.8% were satisfied with the results of surgery, and 91.8% felt they had made the right decision. Dissatisfaction with the results correlated with poorer mental health scores, decreased physical function, and increased bodily pain scores (P < .05). Satisfaction was correlated with better pain scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and SF-36 (P < .05) but not with Hospital for Special Surgery scores (P = .328). Poor surgical results leading to revision surgery (5%) were associated with preoperative deformity greater than 20 degrees. Based on this patient-assessed outcome analysis, total knee arthroplasty is a worthwhile and beneficial procedure in the elderly.

Age Factors↗
PubMed1996

Prognostic factors for functional outcome of total knee replacement: a prospective study.

BACKGROUND: The objective was to investigate whether baseline physical functioning, medical, psychosocial, or demographic variables predict functional outcome in patients undergoing total knee replacement. METHODS: A prospective cohort study was performed between December 1991 and August 1993. Consecutive, unilateral tricompartmental total knee replacement patients aged > or = 55 yr with osteoarthritis, who met criteria, were enrolled and evaluated one month before and 3 months after total knee replacement. The primary outcome measure was the Medical Outcome Study 36 Item Short Form Health Survey (known as the SF36) Physical Functioning Scale score. The outcome evaluator was not involved in patient care. RESULTS: A hierarchical multiple regression analysis was performed to calculate the contribution of baseline variables to TKR outcome. Of the 27% of outcome variance explained by the model, demographic variables accounted for 4%, psychosocial variables (motivation, role functioning-emotional, and social functioning) for 19% (p = .013), medical variables (previous reconstruction, comorbidity, body mass index, bodily pain) for 2%, and baseline physical function for 2%. CONCLUSIONS: Psychosocial variables are significantly related to total knee replacement functional outcome. Assessment of baseline psychological and social functioning may identify a subset of patients at risk for worse outcome. Specific interventions for these patients should be developed and evaluated as components of patient management prior to and after the procedure.

Activities of Daily Living↗