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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
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↗
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↗
PubMed1996

Predictors of change in walking velocity in older adults.

OBJECTIVE: To determine factors that predict change in walking velocity in older people using a multivariate model. DESIGN: Longitudinal observational study. SUBJECTS: A total of 588 persons older than age 60, including subjects residing in a continuing care retirement community (CCRC) (n = 248), and homebound (n = 79) and ambulatory (n = 261) subjects. Mean age at baseline = 77. MEASUREMENT: Independent variables included demographics, physician measures of lower-extremity joint impairment and other musculoskeletal and neurological variables, comorbidities derived from physical examination and chart abstract, self-assessed arthritis pain, depression, and anxiety. The major dependent variables were 2- and 4-year decline in walking velocity below a threshold associated with nursing home placement. MAIN RESULTS: From baseline to Year 4, median walking velocity declined from 61.8 to 53.0 m/min, and the proportion of subjects above a threshold value of 11.5 m/min declined from 95.3% to 80.4%. Age, joint impairment, and weakness of quadriceps, measured at baseline, predicted 2-year and 4-year decline in walking velocity. CONCLUSIONS: The findings indicate that joint impairment and quadriceps strength contribute significantly to crossing a clinically significant threshold in walking velocity among older people over time. Future research is needed to determine whether these risk factors can be modified through preventive interventions such as muscle-strengthening exercises and pain medication.

Activities of Daily Living↗
PubMed1995

The determinants of walking velocity in the elderly. An evaluation using regression trees.

OBJECTIVE: To determine predictors of walking velocity in the elderly. METHODS: Five hundred thirty-two persons from 3 cohorts of elderly persons (retirement community, ambulatory care medical clinic, or chronically homebound population) performed a 10-foot (for the homebound subjects) or 50-foot (for all other subjects) walk time test and underwent a standardized interview, chart review, and clinical examination. The 73 independent variables that were evaluated included demographic, musculoskeletal, neurologic, psychologic, and other comorbidity items. Least-squares and least-absolute-deviation regression tree analyses were performed to determine the strongest predictive factors associated with walking velocity. RESULTS: Sampling cohort (homebound versus non-homebound), quadriceps strength, hip flexion strength, lumbosacral spine impairment, lower joint impairment, and education were found to be associated with walking velocity. Joint pain measures were not associated with walking velocity. CONCLUSION: Muscle strength variables are better predictors of walking velocity than are joint pain variables. Thus, clinical trials and observational studies using walking velocity as an outcome need to take into consideration the influence of muscle strength on this outcome variable.

Aged↗
PubMed1994

Alteration in multijoint dynamics in patients with bilateral knee osteoarthritis.

OBJECTIVE: To document the alterations of joint motion and torque in patients with bilateral knee osteoarthritis (OA), using a well-defined functional maneuver, the sit-to-stand (STS) task. METHODS: Twelve patients with bilateral knee OA and 12 age-, sex-, and height-matched control subjects performed the STS maneuver from a stool of a standard height at their natural speeds. A motion analysis system and 2 force platforms were employed to determine the dynamic joint motion and the resultant joint torques at the ankle, knee, and hip joints. RESULTS: The results showed that OA patients exhibited substantially reduced knee extension torques, accompanied by other alterations in initial sitting posture (more extended knee and more plantar-flexed ankle), movement duration (increased), dynamic range of motion at the knee (reduced), and extension torques at the hip (increased). CONCLUSION: The alterations in joint dynamics among patients with knee OA may have revealed an adaptive motor behavior characterized by redistributing the load from impaired to less-impaired or nonimpaired joints through multijoint dynamics. Two major potential pitfalls of such a movement strategy have subsequently been postulated.

Aged↗
PubMed1994

Impact of joint impairment on longitudinal disability in elderly persons.

Recent longitudinal data indicating that arthritis is a major contributor to disability in elderly persons are based on self-reported diagnostic information. This longitudinal study included baseline physical examinations of joints of 541 persons over age 60. Previous results from a cross-sectional multivariate model of disability in this sample found that joint impairment (and, its absence, arthritis pain) explained a significant proportion of variance in overall disability. We have retested this model using generalized estimation equations (GEE) analysis to estimate the effect of joint impairment and arthritis pain on baseline and Year 2 disability. Findings indicate that baseline joint impairment contributes substantially to longitudinal disability. If direct measures of baseline joint impairment are unavailable, concurrent self-reported arthritis pain also predicts longitudinal disability well. These findings indicate that longitudinal studies should monitor arthritis pain and that symptomatic arthritis is a risk factor for future disability.

Activities of Daily Living↗
PubMed1994

Cost containment: the Middle East. Saudi Arabia.

The 1970s and early 1980s saw the phenomenal growth and development of healthcare services in Saudi Arabia. This growth was unique in that it took place in a country that lacked basic infrastructure and trained personnel, but had recently acquired great wealth. Developments that took hundreds of years to occur in other countries took only 20 yrs to attain in Saudi Arabia. This growth posed unique challenges and required novel solutions. Recently, the country has had to cope with a drastic decrease in oil revenue, as well as cutbacks in healthcare funding. Now that the basic foundations of a national healthcare service have been constructed, it remains to be seen whether gains can be consolidated and steady progress made as more and more Saudi nationals take over and run their own public and private healthcare services.

Cost Control↗