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George Wells

Publications and source records attributed to George Wells.

46 records · Page 3Linked to original sources
PubMed2002

Meta-analyses of therapies for postmenopausal osteoporosis. V. Meta-analysis of the efficacy of hormone replacement therapy in treating and preventing osteoporosis in postmenopausal women.

OBJECTIVE: To review the effect of hormone replacement therapy (HRT) on bone density and fractures in postmenopausal women. DATA SOURCE: We searched MEDLINE and EMBASE from 1966 to 1999, the Cochrane Controlled Register, citations of relevant articles, and proceedings of international meetings for eligible randomized controlled trials. We contacted osteoporosis investigators to identify additional studies, and primary authors for unpublished data. STUDY SELECTION: We included 57 studies that randomized postmenopausal women to HRT or a control (placebo or calcium/vitamin D) and were of at least 1 yr in duration. Seven of these studies reported fractures. DATA ABSTRACTION: For each study, three independent reviewers assessed the methodological quality and abstracted the data. DATA SYNTHESIS: HRT showed a trend toward reduced incidence of vertebral fractures [relative risk (RR) 0.66, 95% confidence interval (CI) 0.41-1.07; 5 trials] and nonvertebral fractures (RR 0.87, 95% CI 0.71-1.08; 6 trials). HRT had a consistent effect on bone mineral density (BMD) at all sites. The difference between HRT and control in the percent change in bone density at 2 yr was 6.76 (5.83, 7.89; 21 trials) at the lumbar spine and 4.53 (3.68, 5.36; 14 trials) and 4.12 (3.45, 4.80; 9 trials) at the forearm and femoral neck, respectively. CONCLUSIONS: HRT has a consistent, favorable and large effect on bone density at all sites. The data show a nonsignificant trend toward a reduced incidence in vertebral and nonvertebral fractures.

Estrogen Replacement Therapy↗
PubMed2002

Meta-analyses of therapies for postmenopausal osteoporosis. VI. Meta-analysis of calcitonin for the treatment of postmenopausal osteoporosis.

OBJECTIVE: To review the effect of calcitonin on bone density and fractures in postmenopausal women. DATA SOURCE: We searched MEDLINE and EMBASE from 1966 to 2000 and examined citations of relevant articles and the proceedings of international osteoporosis meetings. We contacted osteoporosis investigators to identify additional studies and primary authors for unpublished data. STUDY SELECTION: We included 30 studies that randomized women to calcitonin or an alternative (placebo or calcium and/or vitamin D) and measured bone density or fracture incidence for at least 1 yr. DATA EXTRACTION: For each trial, three independent reviewers assessed the methodological quality and abstracted data. DATA SYNTHESIS: Calcitonin reduced the incidence of vertebral fractures, with a pooled relative risk (RR) of 0.46 [95% confidence interval (CI) 0.25-0.87, P = 0.02, n = 1404, 4 trials]. However, the RR from the one relatively large randomized controlled trial (RCT) was 0.79 (95% CI 0.62-1.00, P = 0.05, n = 1108). For nonvertebral fractures, the pooled RR was 0.52 (95% CI 0.22-1.23, P = 0.14, n = 1481, 3 trials). Once again, the single large trial showed a less impressive effect than the smaller trials (RR 0.80, 95% CI 0.59-1.09, P = 0.16, n = 1245). For bone density of the lumbar spine, the pooled weekly dose of 250 to 2800 IU per week resulted in significant increase in the weighted mean difference (WMD) of 3.74 (2.04-5.43, P < 0.01, n = 2260, 24 trials). The combined forearm showed a similar effect, with a WMD of 3.02 (95% CI 0.98-5.07, P < 0.01, n = 468, 9 trials). At the femoral neck, the pooled weighted mean difference showed a nonsignificant trend toward benefit, WMD 3.80 (95% CI -0.32-7.91, P = 0.07, 9 trials, n = 513). Methodologically weaker studies tended to show greater effects on bone density, and the lumbar spine results suggested the possibility of publication bias. CONCLUSIONS: Calcitonin likely increases bone density in postmenopausal women predominantly at the lumbar spine and forearm for weekly doses of greater than 250 IU, although the true effect may be smaller than the pooled estimate would suggest. Calcitonin likely reduces the risk of vertebral fracture; its effect on nonvertebral fracture remains uncertain.

Calcitonin↗
PubMed2002

Meta-analyses of therapies for postmenopausal osteoporosis. VII. Meta-analysis of calcium supplementation for the prevention of postmenopausal osteoporosis.

OBJECTIVE: To summarize controlled trials examining the effect of calcium on bone density and fractures in postmenopausal women. DATA SOURCE: We searched MEDLINE and EMBASE up to 1998 and the Cochrane Controlled Register up to 2000, and we examined citations of relevant articles and proceedings of international meetings. We contacted osteoporosis investigators to identify additional studies, and primary authors for unpublished data. STUDY SELECTION: We included 15 trials (1806 patients) that randomized postmenopausal women to calcium supplementation or usual calcium intake in the diet and reported bone mineral density of the total body, vertebral spine, hip, or forearm, or recorded the number of fractures, and followed patients for at least 1 yr. DATA EXTRACTION: For each trial, three independent reviewers assessed the methodological quality and extracted data. DATA SYNTHESIS: We found calcium to be more effective than placebo in reducing rates of bone loss after two or more years of treatment. The pooled difference in percentage change from baseline was 2.05% [95% confidence interval (CI) 0.24-3.86] for total body bone density, 1.66% (95% CI 0.92-2.39) for the lumbar spine, 1.64% (95% CI 0.70-2.57) for the hip, and 1.91% (95% CI 0.33-3.50) for the distal radius. The relative risk (RR) of fractures of the vertebrae was 0.77, with a wide CI (95% CI 0.54-1.09); the RR for nonvertebral fractures was 0.86 (95% CI 0.43-1.72). CONCLUSIONS: Calcium supplementation alone has a small positive effect on bone density. The data show a trend toward reduction in vertebral fractures, but do not meaningfully address the possible effect of calcium on reducing the incidence of nonvertebral fractures.

Calcium↗
PubMed2002

Meta-analyses of therapies for postmenopausal osteoporosis. VIII: Meta-analysis of the efficacy of vitamin D treatment in preventing osteoporosis in postmenopausal women.

OBJECTIVE: To review the effect of vitamin D on bone density and fractures in postmenopausal women. DATA SOURCE: We searched MEDLINE and EMBASE from 1966 to 1999 and examined citations of relevant articles and proceedings of international meetings. We contacted osteoporosis investigators and primary authors to identify additional studies and to obtain unpublished data. STUDY SELECTION: We included 25 trials that randomized women to standard or hydroxylated vitamin D with or without calcium supplementation or a control and measured bone density or fracture incidence for at least 1 yr. DATA EXTRACTION: For each trial, three independent reviewers assessed the methodological quality and abstracted data. DATA SYNTHESIS: Vitamin D reduced the incidence of vertebral fractures [relative risk (RR) 0.63, 95% confidence interval (CI) 0.45-0.88, P < 0.01) and showed a trend toward reduced incidence of nonvertebral fractures (RR 0.77, 95% CI 0.57-1.04, P = 0.09). Most patients in the trials that evaluated vertebral fractures received hydroxylated vitamin D, and most patients in the trials that evaluated nonvertebral fractures received standard vitamin D. Hydroxylated vitamin D had a consistently larger impact on bone density than did standard vitamin D. For instance, total body differences in percentage change between hydroxylated vitamin D and control were 2.06 (0.72, 3.40) and 0.40 (-0.25, 1.06) for standard vitamin D. At the lumbar spine and forearm sites, hydroxylated vitamin D doses above 50 microg yield larger effects than lower doses. Vitamin D resulted in an increased risk of discontinuing medication in comparison to control as a result of either symptomatic adverse effects or abnormal laboratory results (RR 1.37, 95% CI 1.01-1.88), an effect that was similar in trials of standard and hydroxylated vitamin D. CONCLUSIONS: Vitamin D decreases vertebral fractures and may decrease nonvertebral fractures. The available data are uninformative regarding the relative effects of standard and hydroxylated vitamin D.

Female↗
PubMed2002

Meta-analyses of therapies for postmenopausal osteoporosis. IX: Summary of meta-analyses of therapies for postmenopausal osteoporosis.

This section summarizes the results of the seven systematic reviews of osteoporosis therapies published in this series [calcium, vitamin D, hormone replacement therapy (HRT), alendronate, risedronate, raloxifene, and calcitonin] and systematic reviews of etidronate and fluoride we have published elsewhere. We highlight the methodological strengths and weaknesses of the individual studies, and summarize the effects of treatments on the risk of vertebral and nonvertebral fractures and on bone density, including effects in different patient subgroups. We provide an estimate of the expected impact of antiosteoporosis interventions in prevention and treatment populations using the number needed to treat (NNT) as a reference. In addition to the evidence, judgements about the relative weight that one places on weaker and stronger evidence, attitudes toward uncertainty, circumstances of patients' and societal values or preferences will, and should, play an important role in decision-making regarding anti-osteoporosis therapy.

Bone Density↗
PubMed2002

The design of randomized clinical trials in critically ill patients.

There are a number of difficulties in the conduct of randomized trials in the critically ill. These include difficulties in the definition of diseases and syndromes, a heterogenous population of patients undergoing a variety of therapeutic interventions, and outcomes that may not be able to discriminate between beneficial and risky therapies. Following a brief description of different randomized clinical trials (RCTs) and design philosophies, we outline the effects of different design choices in the complex critical care environment. Once the study topic has been determined to be relevant and important, then the potential investigator must establish whether efficacy or effectiveness will be the focus of the RCT. If an effectiveness design philosophy is chosen, then broad representation of study sites, liberal eligibility criteria, easily implemented intervention study protocols, and patient-centered outcomes should be chosen. The potential investigator wishing to establish efficacy will conduct the study in the centers of excellence and adopt stringent eligibility criteria, rigorous study protocols, and opt for outcomes that will be sensitive to change. In conclusion, we describe some of the major challenges and possible solutions to help a potential investigator through the myriad of difficulties in initiating an RCT in a complex environment.

Critical Care↗
PubMed2002

Economic comparison of leflunomide and methotrexate in patients with rheumatoid arthritis: an evaluation based on a 1-year randomised controlled trial.

OBJECTIVE: To compare disease-related medical care and productivity costs, and utilities, in 482 patients with rheumatoid arthritis randomised to receive leflunomide, methotrexate or placebo during a 12-month period. DESIGN AND SETTING: Prospective pharmacoeconomic analysis of a 1-year randomised double-blind trial set in North America. PERSPECTIVE: Societal and the Ontario Ministry of Health. METHODS: Information on healthcare resources, out-of-pocket expenses, loss of working time and time spent on chores, related to the disease or the medication, were collected at 4-week intervals and at study discontinuation. Rating scale and standard gamble (SG) utilities (0 = worse; 100 = best) were collected at baseline and at 6 and 12 months or study exit. Medical care costs in Canadian dollars (Can dollars) were calculated using Ontario reimbursement schedules. US patients' expenses were converted to Can dollars using 1995 purchasing power parity. Lost wages were calculated by age and gender according to 1995 Canadian wage data. All costs were adjusted to 1999 Can dollars and arithmetic mean costs were compared using the nonparametric bootstrap. Analysis of covariance was performed to compare utilities between groups. RESULTS: Mean (standard deviation) rating scale values and SG utilities, respectively, for leflunomide, methotrexate and placebo were 67.7 (18.0), 64.8 (18.1) and 57.5 (9.2), and 80.2 (22.1), 83.2 (18.0) and 77.0 (20.5). Both leflunomide and methotrexate had higher rating scale values (p < 0.05) compared with placebo; SG utilities were significantly different between methotrexate and placebo (p < 0.05). Annualised total rheumatoid arthritisb- or drug-related costs for leflunomide, methotrexate and placebo, respectively, were Can dollars 1761, Can dollars 1280 and Can dollars 1324, and medical care costs were Can dollars 753, Can dollars 620 and Can dollars 167 (all costs exclude drug acquisition and monitoring costs). Annual drug acquisition/ routine monitoring costs were estimated, respectively, at Can dollars 3853/Can dollars 483 for leflunomide and Can dollars 258/Can dollars 599 for methotrexate. Differences between overall costs (excluding drug acquisition and monitoring costs) and medical care costs were not statistically significant. The costs of treating patients with leflunomide were significantly higher than for methotrexate when drug acquisition and monitoring costs were included (p < 0.0001). CONCLUSIONS: No statistically significant differences in utilities could be found between leflunomide or methotrexate. When drug monitoring and acquisition costs are excluded, leflunomide has an otherwise similar economic profile compared with methotrexate, the current gold standard. The acquisition cost of leflunomide is a driving factor in increasing the costs of therapy. These higher costs need to be assessed relative to the therapeutic value of leflunomide.

Adolescent↗
PubMed2002

Decreased mitochondrial proton leak and reduced expression of uncoupling protein 3 in skeletal muscle of obese diet-resistant women.

Weight loss in response to caloric restriction is variable. Because skeletal muscle mitochondrial proton leak may account for a large proportion of resting metabolic rate, we compared proton leak in diet-resistant and diet-responsive overweight women and compared the expression and gene characteristics of uncoupling protein (UCP)2 and UCP3. Of 1,129 overweight women who completed the University of Ottawa Weight Management Clinic program, 353 met compliance criteria and were free of medical conditions that could affect weight loss. Subjects were ranked according to percent body weight loss during the first 6 weeks of a 900-kcal meal replacement protocol. The highest and lowest quintiles of weight loss were defined as diet responsive and diet resistant, respectively. After body weight had been stable for at least 10 weeks, 12 of 70 subjects from each group consented to muscle biopsy and blood sampling for determinations of proton leak, UCP mRNA expression, and genetic studies. Despite similar baseline weight and age, weight loss was 43% greater, mitochondrial proton leak-dependent (state 4) respiration was 51% higher (P = 0.0062), and expression of UCP3 mRNA abundance was 25% greater (P < 0.001) in diet-responsive than in diet-resistant subjects. There were no differences in UCP2 mRNA abundance. None of the known polymorphisms in UCP3 or its 5' flanking sequence were associated with weight loss or UCP3 mRNA abundance. Thus, proton leak and the expression of UCP3 correlate with weight loss success and may be candidates for pharmacological regulation of fat oxidation in obese diet-resistant subjects.

Body Weight↗
PubMedDate not supplied

Factors associated with pressure ulcers in adults in acute care hospitals.

OBJECTIVES: To identify and describe the relationship of factors associated with pressure ulcers in adults in acute care hospitals. DESIGN: Cross-sectional prevalence studies. SETTING: University teaching hospital. PATIENTS: Prevalence studies conducted from 1993 to 1995 with a total of 1992 subjects served as the derivation sample and a 1996 prevalence study with 581 subjects served as the validation sample. MAIN OUTCOME MEASURES: Pressure ulcers and the Braden risk assessment subscale scores. DATA ANALYSIS: Logistic regression analysis was used to derive a model that fit the data and performed well at identifying factors associated with pressure ulcers. Performance of the model, in terms of calibration, was statistically evaluated using the Hosmer-Lemeshow goodness-of-fit test. The effectiveness of the model, in terms of discrimination, was assessed by considering the cut-off values using 2 by 2 classification tables to measure the overall percentage of subjects correctly classified in the validation sample. MAIN RESULTS: Factors associated with pressure ulcers in adults in acute care hospitals were identified as age, male gender, sensory perception, moisture, mobility, nutrition, and friction/shear. Three interactions were also found to be associated with pressure ulcers; 2 interactions (age and sensory perception and moisture and sensory perception) were negatively associated and 1 interaction (nutrition and gender/male) was positively associated with pressure ulcers. The Hosmer-Lemeshow goodness-of-fit test for the derivation sample (0.76) and the validation sample (0.79) indicated that the model was well calibrated and a good fit. The overall percentage of subjects correctly classified using the validation sample was 88%, indicating that the model performed well. CONCLUSIONS: This study enhances the knowledge of the relationship of factors associated with pressure ulcers in adults in acute care populations and enhances the use and relative importance of particular Braden Scale subscales.

Acute Disease↗