Biomedical subjects

Robert A Lew

Publications and source records attributed to Robert A Lew.

6 recordsLinked to original sources

PubMed2003

Association of hospital and surgeon volume of total hip replacement with functional status and satisfaction three years following surgery.

OBJECTIVE: To evaluate whether hospital volume and surgeon volume of total hip replacements (THRs) are associated with patient-reported functional status and satisfaction with surgery 3 years postoperatively. METHODS: We performed a population-based cohort study of a stratified random sample of Medicare beneficiaries who underwent elective primary or revision THR in Ohio, Pennsylvania, or Colorado in 1995. The primary outcomes were the self-reported Harris hip score and a validated scale measuring satisfaction with the results of surgery. Both outcomes were assessed 3 years postoperatively. Hospital volume was defined as the aggregate number of elective primary and revision THRs performed on Medicare beneficiaries in the hospital in 1995. High-volume hospitals were defined as those in which >100 such procedures are performed annually, and low-volume centers were defined as those in which </=12 procedures (primary THR cohort) or </=30 procedures (revision cohort) are performed annually. RESULTS: In unadjusted analyses, patients who underwent surgery in low-volume centers had worse functional status 3 years following primary and revision THR compared with patients whose surgery was performed in higher-volume centers. Patients whose revision THR was performed by a low-volume surgeon also had worse function. After adjustment for sociodemographic and clinical variables, however, the association between higher hospital volume and better functional status following primary THR was weak and statistically nonsignificant, and no statistically significant or clinically important associations between hospital or surgeon volume and functional status following revision THR was observed. Patients who underwent elective primary THR in low-volume centers were more likely to be dissatisfied with the results of surgery compared with patients whose surgeries were performed in high-volume centers. Similarly, patients whose surgeons performed </=12 procedures per year were more likely to be dissatisfied with the results of revision THR than were patients whose surgeons performed >12 procedures per year. CONCLUSION: Hospital volume and surgeon volume have little effect on 3-year functional outcome following THR, after adjusting for patient sociodemographic and select clinical characteristics. However, satisfaction with primary THR is greater among patients who underwent surgery in high-volume centers, and satisfaction with revisions is greater among patients whose operations were performed by higher-volume surgeons. Referring clinicians should incorporate these findings into their discussion of referral choices with patients considering THR. Conclusions regarding the effect of volume on longevity of the implants must await longer-term followup studies. Finally, further research is warranted to better understand the association between hospital and surgeon procedure volume and patient satisfaction with surgery.

Aged↗

PubMed2003

Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial.

Specific receptors for vitamin D have been identified in human muscle tissue. Cross-sectional studies show that elderly persons with higher vitamin D serum levels have increased muscle strength and a lower number of falls. We hypothesized that vitamin D and calcium supplementation would improve musculoskeletal function and decrease falls. In a double-blind randomized controlled trial, we studied 122 elderly women (mean age, 85.3 years; range, 63-99 years) in long-stay geriatric care. Participants received 1200 mg calcium plus 800 IU cholecalciferol (Cal+D-group; n = 62) or 1200 mg calcium (Cal-group; n = 60) per day over a 12-week treatment period. The number of falls per person (0, 1, 2-5, 6-7, >7 falls) was compared between the treatment groups. In an intention to treat analysis, a Poisson regression model was used to compare falls after controlling for age, number of falls in a 6-week pretreatment period, and baseline 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D serum concentrations. Among fallers in the treatment period, crude excessive fall rate (treatment - pretreatment falls) was compared between treatment groups. Change in musculoskeletal function (summed score of knee flexor and extensor strength, grip strength, and the timed up&go test) was measured as a secondary outcome. Among subjects in the Cal+D-group, there were significant increases in median serum 25-hydroxyvitamin D (+71%) and 1,25-dihydroxyvitamin D (+8%). Before treatment, mean observed number of falls per person per week was 0.059 in the Cal+D-group and 0.056 in the Cal-group. In the 12-week treatment period, mean number of falls per person per week was 0.034 in the Cal+D-group and 0.076 in the Cal-group. After adjustment, Cal+D-treatment accounted for a 49% reduction of falls (95% CI, 14-71%; p < 0.01) based on the fall categories stated above. Among fallers of the treatment period, the crude average number of excessive falls was significantly higher in the Cal-group (p = 0.045). Musculoskeletal function improved significantly in the Cal+D-group (p = 0.0094). A single intervention with vitamin D plus calcium over a 3-month period reduced the risk of falling by 49% compared with calcium alone. Over this short-term intervention, recurrent fallers seem to benefit most by the treatment. The impact of vitamin D on falls might be explained by the observed improvement in musculoskeletal function.

Accidental Falls↗

PubMed2003

Rates and outcomes of primary and revision total hip replacement in the United States medicare population.

BACKGROUND: Information on the epidemiology of primary total hip replacement is limited, and we are not aware of any reports on the epidemiology of revision total hip replacement. The objective of this study was to characterize the rates and immediate postoperative outcomes of primary and revision total hip replacement in persons sixty-five years of age and older residing in the United States. METHODS: We used Medicare claims submitted by hospitals, physicians, and outpatient facilities between July 1, 1995, and June 30, 1996, to identify individuals who had undergone elective primary total hip replacement for a reason other than a fracture (61,568 patients) or had had revision total hip replacement (13,483 patients). Annual incidence rates of primary and revision total hip replacement were calculated, and multivariate modeling was used to evaluate the association between patient characteristics and surgical rates. The rates of occurrence of five complications within ninety days postoperatively were also evaluated, and relationships between those outcomes and patient characteristics were assessed with use of multivariate models adjusted for hospital and surgeon volume. RESULTS: The rates of primary total hip replacement were three to six times higher than the rates of revision total hip replacement. Women had higher rates than men, and whites had higher rates than blacks. The rates of primary and revision total hip replacement increased with age until the age of seventy-five to seventy-nine years and then declined. The rates of complications occurring within ninety days after primary total hip replacement were 1.0% for mortality, 0.9% for pulmonary embolus, 0.2% for wound infection, 4.6% for hospital readmission, and 3.1% for hip dislocation. The rates after revision total hip replacement were 2.6%, 0.8%, 0.95%, 10.0%, and 8.4%, respectively. Factors associated with an increased risk of an adverse outcome included increased age, gender (men were at higher risk than women), race (blacks were at higher risk than whites), a medical comorbidity, and a low income. CONCLUSIONS: Analysis of United States Medicare population data showed that the rates of total hip replacement increased with age up to the age of seventy-five to seventy-nine years and that blacks had a significantly lower rate of total hip replacement than whites. The overall rates of adverse outcomes were relatively low, but they were significantly higher after revision than after primary total hip replacement. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See p. 2 for complete description of levels of evidence.

Age Factors↗

PubMed2002

Using antineutrophil cytoplasmic antibody testing to diagnose vasculitis: can test-ordering guidelines improve diagnostic accuracy?

BACKGROUND: Antineutrophil cytoplasmic antibodies (ANCAs) are strongly associated with Wegener granulomatosis, Churg-Strauss angiitis, microscopic polyangiitis, and pauci-immune glomerulonephritis, referred to collectively as ANCA-associated vasculitis (AAVs). It is unclear how accurate ANCA measurement is for diagnosing AAV in diverse populations or whether proposed ANCA test-ordering guidelines improve test performance. METHODS: We assembled a retrospective case series of hospitalized and ambulatory patients from 2 academic medical centers to assess the diagnostic accuracy of ANCA measurement by enzyme-linked immunosorbent assay in identifying cases of AAV. In addition, we assessed the effect of applying proposed ANCA test-ordering guidelines on test performance. RESULTS: For ANCA testing, sensitivity was 81%; specificity, 98%; positive predictive value, 54%; and negative predictive value, 99%. There were no significant changes in operating characteristics after applying the guideline criteria. Using guidelines would have decreased ANCA test ordering by 23% and would have decreased the false-positive rate by 27%. No cases of AAV would have been missed if only patients fulfilling the guidelines were ANCA tested. CONCLUSION: A positive result on an enzyme-linked immunosorbent assay ANCA test, as it is currently ordered, is not a definitive diagnostic indicator of AAV. Compliance with guidelines for ANCA testing would decrease the number of false-positive results and has the potential to reduce total test expenditures.

Adult↗

PubMed2002

Sun protection policies and environmental features in US elementary schools.

OBJECTIVE: To assess current sun protection policies and the receptiveness to new policies at elementary schools in the United States. DESIGN: A cross-sectional telephone survey. SETTING: General educational community. PATIENTS OR OTHER PARTICIPANTS: In 1998, a random sample of 1000 public elementary schools in the United States was selected (proportional to population size) from 27 metropolitan areas chosen from the 58 US cities regularly reporting the UV index in 1997. A final sample of principals from 412 elementary schools completed the survey. INTERVENTION: None. MAIN OUTCOME MEASURES: Only 3.4% of schools had a sun protection policy. The most common reasons for not having a policy included the principal's lack of awareness (n = 113) or organizational barriers in the school districts (n = 77). Most principals (84.2%) said that students were outdoors during midday hours. Many principals (48.3%) were willing to adopt a sun protection policy. Most schools (72.8%) had shade structures but the majority (67.3%) reportedly covered less than one fifth of the grounds. Most principals (76.4%) were willing to increase the amount of shade structures. CONCLUSIONS: The low frequency of sun protection policies and shade structures calls for national efforts to change policies and environments to increase sun protection at US schools. Research is needed to demonstrate the efficacy of these changes.

Child↗

PubMed2002

Measuring clinically important changes with patient-oriented questionnaires.

BACKGROUND: The measurement of the patient's experience with a condition or an illness is an important and quantifiable outcome and an example of action research. By making these concerns paramount, the goals and processes of health care can be redirected from anatomical and physiologic restoration to patient-oriented outcomes. At the same time, research can illuminate the complex mechanisms responsible. METHODS: Critical, analytic synthesis and review of the research evaluating the ability of self-administered questionnaires to capture clinically meaningful changes. RESULTS: Responsiveness is differentiated from sensitivity, and statistical methods for evaluating sensitivity of instruments are referenced. Techniques for evaluating whether differences in instrument sensitivity could have occurred by chance are presented, and methods for assessing a clinically meaningful change are discussed. CONCLUSION: Responsiveness is the key psychometric property of an instrument if it is to be incorporated into daily practice. Improving responsiveness is a major research priority.

California↗