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Biomedical subjects

D A Redelmeier

Publications and source records attributed to D A Redelmeier.

At least 19 recordsLinked to original sources
PubMed1999

Adhesive tape and intravascular-catheter-associated infections.

Adhesive tape is placed in close contact with intravascular catheters for extended periods and could theoretically contribute to local infections. We found that 74% of specimens of tape collected in one hospital were colonized by pathogenic bacteria. However, only 5% of specimens had significant growth from an inner layer obtained by discarding the outside layer from each roll. We suggest that adhesive tape is a potential source of pathogenic bacteria and that discarding the outer layer from a partially used roll might be a simple method for reducing the risk of infection to patients.

Bacteria↗
PubMed1999

Electromotive drug administration of lidocaine as an alternative anesthesia for transurethral surgery.

PURPOSE: A multicenter study was undertaken to evaluate the safety, efficacy and cost of electromotive drug administration of intravesical lidocaine to produce bladder local anesthesia as an alternative to traditional methods of spinal or general anesthesia. MATERIALS AND METHODS: A total of 94 patients were enrolled in the study who had either a history of bladder tumor that required cold cup bladder biopsy with fulguration for possible recurrence as a comparison trial, a bladder tumor treated with transurethral resection/fulguration or benign prostatic hyperplasia/carcinoma treated with transurethral resection. Pain scores using a Verbal Rating Scale were recorded for each individual biopsy, fulguration and resection event. Data for direct and indirect costs were collected using a standardized form for each patient to capture the details of the procedure, including times, drugs and disposables for each patient. RESULTS: There was a significant reduction in pain for patients who received electromotive intravesical lidocaine compared to no anesthesia for biopsy (p<0.03). Similarly, electromotive intravesical lidocaine for bladder biopsy and transurethral bladder tumor resection/fulguration was associated with higher patient satisfaction compared to previous treatments (p<0.00002). In contrast, electromotive intravesical lidocaine was insufficient for 3 of 6 transurethral prostatic resections. The cost per patient was about $146 Cdn less with electromotive intravesical lidocaine than with conventional general/spinal anesthesia. CONCLUSIONS: Electromotive intravesical lidocaine may be a safe, effective and affordable form of anesthesia for the ambulatory care of patients requiring transurethral bladder biopsy, resection or fulguration with a potential for cost savings.

Aged↗
PubMed1998

Preventing Mycobacterium avium complex in patients who are using protease inhibitors: a cost-effectiveness analysis.

BACKGROUND: Practice guidelines recommending Mycobacterium avium complex (MAC) prophylaxis for patients with HIV disease were based on clinical trials in which individuals did not receive protease inhibitors. OBJECTIVE: To estimate the cost-effectiveness of strategies for MAC prophylaxis in patients whose treatment regimen includes protease inhibitors. DESIGN: Decision analysis with Markov modelling of the natural history of advanced HIV disease. Five strategies were evaluated: no prophylaxis, azithromycin, rifabutin, clarithromycin and a combination of azithromycin plus rifabutin. MAIN OUTCOME MEASURES: Survival, quality of life, quality-adjusted survival, health care costs and marginal cost-effectiveness ratios. RESULTS: Compared with no prophylaxis, rifabutin increased life expectancy from 78 to 80 months, increased quality-adjusted life expectancy from 50 to 52 quality-adjusted months and increased health care costs from $233000 to $239800. Ignoring time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $44300 per life year. Adjusting for time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $41500 per quality-adjusted life year (QALY). In comparison with rifabutin, azithromycin was associated with increased survival, increased costs and an incremental cost-effectiveness ratio of $54300 per QALY. In sensitivity analyses, prophylaxis remained economically attractive unless the lifetime chance of being diagnosed with MAC was less than 20%, the rate of CD4 count decline was less than 10 x 10(6) cells/l per year, or the CD4 count was greater than 50 x 10(6) cells/l. CONCLUSION: MAC prophylaxis increases quality-adjusted survival at a reasonable cost, even in patients using protease inhibitors. When not contraindicated, starting azithromycin or rifabutin when the patient's CD4 count is between 50 and 75 x 10(6) cells/l is the most cost-effective strategy. The main determinants of cost-effectiveness are CD4 count, viral load, place of residence and patient preference.

AIDS-Related Opportunistic Infections↗
PubMed1998

The treatment of unrelated disorders in patients with chronic medical diseases.

BACKGROUND: Patients can have several illnesses concurrently, yet some of these diseases may be neglected if one problem consumes attention. We conducted a population-based analysis in Ontario, Canada - where universal health insurance is provided - to determine whether unrelated disorders are less likely to be treated in patients with chronic diseases. METHODS: We studied the 1,344,145 residents of Ontario in 1995 who were 65 or older and eligible to receive prescription medications free of charge as part of the Ontario Drug Benefit program. Patients with diabetes mellitus were identified by prescriptions for insulin, pulmonary emphysema by prescriptions for ipratropium bromide, and psychotic syndromes by prescriptions for haloperidol. For each chronic disease, we selected an unrelated treatment: estrogen-replacement therapy for patients with diabetes mellitus, lipid-lowering medications for those with pulmonary emphysema, and medical treatment of arthritis for those with psychotic syndromes. RESULTS: The 30,669 patients with diabetes mellitus were less likely to receive estrogen-replacement therapy than the other subjects in the study (2.4 percent vs. 5.9 percent, P<0.001). The disease was associated with a 60 percent reduction in the odds of estrogen treatment (odds ratio, 0.40; 95 percent confidence interval, 0.37 to 0.43). Findings were similar for the 56,779 patients with pulmonary emphysema, who were less likely to receive lipid-lowering medications (odds ratio, 0.69; 95 percent confidence interval, 0.67 to 0.72; P<0.001), and the 17,336 patients with psychotic syndromes, who were less likely to receive medical treatments for arthritis (odds ratio, 0.59; 95 percent confidence interval, 0.57 to 0.62; P<0.001). CONCLUSIONS: In patients 65 or older who have chronic medical diseases and who receive prescription medications free of charge, unrelated disorders are undertreated. Clinicians caring for patients with chronic diseases should remain alert to other disorders and minimize the number of missed opportunities for treating them.

Aged↗
PubMed1998

Shopping around for hospital services: a comparison of the United States and Canada.

CONTEXT: Historical comparisons indicate that US hospitals are more expensive than Canadian hospitals, but health care system reform might have changed the relative costs and timeliness of health care in the 2 countries. OBJECTIVE: To estimate the price and convenience of selected hospital services in the United States and Canada for patients in 1997 had they paid out-of-pocket. DESIGN: Cross-sectional telephone survey conducted May 1996 to April 1997. PARTICIPANTS: The 2 largest acute care general hospitals from every city in the United States and Canada with a population greater than 500000. MEASURES: Each hospital was telephoned and asked their price and waiting time for 7 services: magnetic resonance imaging of the head without gadolinium; a screening mammogram; a 12-lead electrocardiogram; a prothrombin time measurement; a session of hemodialysis; a screening colonoscopy; and a total knee replacement. Waiting times were measured in days until earliest appointment and charges were converted to American currency. RESULTS: Overall, 48 US and 18 Canadian hospitals were surveyed. Median waiting times were significantly shorter in American hospitals for 4 services, particularly a magnetic resonance imaging of the head (3 days vs 150 days; P<.001). Median charges were significantly higher in American hospitals for 6 services, particularly for a total knee replacement ($26805 vs $10651; P<.001). Individual services showed no association between shorter waiting times and higher prices within each country, with the exception of a total knee replacement in the United States. CONCLUSION: US hospitals still provide higher prices and faster care than Canadian hospitals for patients who pay out-of-pocket.

Canada↗
PubMed1998

Measuring injury severity: time for a change?

BACKGROUND: The Injury Severity Score (ISS) does not take into account multiple injuries in the same body region, whereas a New ISS (NISS) may provide a more accurate measure of trauma severity by considering the patient's three greatest injuries regardless of body region. The purpose of this study was to evaluate the ISS and NISS in patients with blunt trauma. METHODS: Consecutive individuals treated from January of 1992 to September of 1996 at one institution were included if they had sustained blunt trauma and satisfied triage standards (n = 2,328). For each patient, we computed the ISS and the NISS to determine how often the two scores were identical or discrepant. Discrepant cases were then further analyzed using receiver operating characteristic curves to determine which score better predicted short-term mortality. RESULTS: The mean ISS was 25 +/- 13, and the mean NISS was 33 +/- 18. The two predictive scores were identical in 32% of patients and discrepant in 68% of patients. Patients with identical scores had a lower mortality rate than patients with discrepant scores (10% vs. 13%; p < 0.02). In patients with discrepant scores, the area under the receiver operating characteristic curves was greater for the NISS than the ISS (0.852 vs. 0.799; p < 0.001), and greater amounts of discrepancy were associated with increasing rates of mortality (p < 0.001). CONCLUSIONS: The NISS often increases the apparent severity of injury and provides a more accurate prediction of short-term mortality. The benefit associated with using the NISS rather than the ISS must be weighed against the disadvantages of changing a scoring system and the potential for still greater improvements.

Abbreviated Injury Scale↗
PubMed1998

Improved diagnostic accuracy of inferior petrosal sinus sampling over imaging for localizing pituitary pathology in patients with Cushing's disease.

The majority of patients with Cushing's disease can be cured by transsphenoidal microsurgery; however, precise localization of the pituitary source of ACTH is not always possible by standard imaging techniques. Bilateral venous sampling from the inferior petrosal sinuses (IPSS) is also useful for diagnosing Cushing's disease, but the interpretation of discordant findings between IPSS and imaging remains problematic. We tested the ability of imaging and IPSS to localize an ACTH-secreting pituitary lesion in comparison to definitive histopathological examination of the pituitary in patients with Cushing's disease (n = 37). Bilateral IPS catheterization was technically feasible in 32 patients and provided evidence of lateralization in 31 patients. Histological examination confirmed a corticotropic adenoma in 28 patients and corticotropic hyperplasia in 2 patients; Crooke's hyaline change was found in 7 patients, among whom 1 subsequently was found to have an ectopic sphenoid corticotropic adenoma, and the remainder had suspected microadenomas that were not identified microscopically. Accurate localization of the pituitary lesion was more frequent when based on IPSS results than on imaging studies (70% vs. 49%, P < 0.06). The 2 tests provided directly discrepant results for 8 patients; among these, IPSS was more likely than imaging to agree with final pathology (63% vs. 13%, P < 0.10). Imaging was entirely normal for another 9 patients, in whom IPSS accurately localized the lesion for the majority (89%; 95% confidence interval: 50-99%). We suggest that IPSS is an effective tool for localizing pituitary pathology and planning surgery for patients with Cushing's disease.

Adrenocorticotropic Hormone↗
PubMed1997

Association between cellular-telephone calls and motor vehicle collisions.

BACKGROUND: Because of a belief that the use of cellular telephones while driving may cause collisions, several countries have restricted their use in motor vehicles, and others are considering such regulations. We used an epidemiologic method, the case-crossover design, to study whether using a cellular telephone while driving increases the risk of a motor vehicle collision. METHODS: We studied 699 drivers who had cellular telephones and who were involved in motor vehicle collisions resulting in substantial property damage but no personal injury. Each person's cellular-telephone calls on the day of the collision and during the previous week were analyzed through the use of detailed billing records. RESULTS: A total of 26,798 cellular-telephone calls were made during the 14-month study period. The risk of a collision when using a cellular telephone was four times higher than the risk when a cellular telephone was not being used (relative risk, 4.3; 95 percent confidence interval, 3.0 to 6.5). The relative risk was similar for drivers who differed in personal characteristics such as age and driving experience; calls close to the time of the collision were particularly hazardous (relative risk, 4.8 for calls placed within 5 minutes of the accident, as compared with 1.3 for calls placed more than 15 minutes before the accident; P<0.001); and units that allowed the hands to be free (relative risk, 5.9) offered no safety advantage over hand-held units (relative risk, 3.9; P not significant). Thirty-nine percent of the drivers called emergency services after the collision, suggesting that having a cellular telephone may have had advantages in the aftermath of an event. CONCLUSIONS: The use of cellular telephones in motor vehicles is associated with a quadrupling of the risk of a collision during the brief time interval involving a call. Decisions about regulation of such telephones, however, need to take into account the benefits of the technology and the role of individual responsibility.

Accidents, Traffic↗
PubMed1997

Interpretation and bias in case-crossover studies.

The case-crossover design is an innovative epidemiologic technique with distinct strengths and limitations. We review the fundamental logic of this self-matching non-randomized design and direct attention to 15 concerns related to the available data, unavailable data, analytic technique, quantitative statistics, and etiologic model. Implications for each concern are discussed in the context of a recent report on whether cellular telephone calls are associated with an increased risk of a motor vehicle collision. We suggest that an understanding of the case-crossover design may help investigators explore selected questions in behavioral medical research.

Bias↗
PubMed1997

Long-term outcomes in open pelvic fractures.

BACKGROUND: Open pelvic fractures represent one of the most devastating injuries in orthopedic trauma. The purpose of this study was to document the injury characteristics, complications, mortality, and long-term, health-related quality of life outcomes in patients with open pelvic fractures. METHODS: The trauma registry at an adult trauma center was used to identify all multiple system blunt trauma patients with a pelvic fracture from January of 1987 to August of 1995 (n = 1,179). Demographic data, mechanism of injury, and fracture type were determined from hospital records. Short-term outcome measures included infectious complications, mortality, and length of stay in hospital. Long-term outcomes of survivors were obtained by telephone interview using the SF-36 Health Survey and the Functional Independence Measure. RESULTS: Open pelvic fractures were uncommon, occurring in 44 patients (4%). Patients with open fractures were about 9 years younger, on average, than patients with closed fractures (30 vs. 39, p < 0.001). Similarly, patients with open fractures were more likely to be male (75 vs. 57%, p < 0.02), more likely to have been involved in a motorcycle crash (27 vs. 6%, p < 0.001), and more likely to have an unstable pelvic ring disruption (45 vs. 25%, p < 0.001). Open pelvic fracture patients required more blood than closed pelvic fracture patients, both in the first day (16 vs. 4 units, p < 0.001) and during the total hospital admission (29 vs. 9 units, p < 0.001). Five patients with perineal wounds did not receive a diverting colostomy; in turn, these individuals had a total of six pelvic infectious complications (one abscess, two with osteomyelitis, and three perineal wound infections). Overall, 11 patients died, six patients were lost to follow-up, and 27 were long-term survivors (mean duration of 4 years). Chronic disability was common after a pelvic fracture, with problems related to physical role performance and physical functioning, and was particularly severe after an open pelvic fracture (p < 0.05 for both as measured by the SF-36). CONCLUSIONS: Patients with open pelvic fractures often survive, need to be treated with massive blood transfusions, and often require a colostomy. They are frequently left with chronic pain and residual disabilities in physical functioning and physical roles, and many remain unemployed years after injury.

Activities of Daily Living↗
PubMed1997

Long-term outcomes in blunt trauma: who goes back to work?

BACKGROUND: Trauma patients continue to improve after discharge from the trauma center, but the completeness of this recovery remains uncertain. The purpose of this study was to compare the characteristics of patients who do and who do not return to work after blunt trauma. METHODS: Consecutive survivors of blunt trauma discharged from a regional trauma center over a 1-year interval (July of 1994 to June of 1995) were included in the study. Patients completed the SF-36 Health Survey and some additional questions related to employment status both at discharge and again after 1 year. Our principal analysis compared patients who were employed and unemployed at 1-year follow-up. RESULTS: Complete data were available for 195 patients. The typical patient was a young man who had been in a motor vehicle collision and had an injury severity score of 25. At 1-year follow-up, 101 patients had returned to work and 94 remained unemployed. Employed individuals were younger (31 vs. 44 years, p < 0.0001), less severely injured (mean injury severity score 23 vs. 27, p < 0.001), and more likely to hold professional jobs (50 vs. 16%, p < 0.0001). Patterns of injury and operative procedures were similar for employed and unemployed patients. However, the average employed patient had fewer days in the intensive care unit (2 vs. 5 days, p < 0.001), a shorter total hospitalization (19 vs. 28 days, p < 0.01), and was more likely to be discharged to home (62 vs. 39%, p < 0.01). At discharge, those who went on to employment had marginally better SF-36 Health Survey scores on seven of the eight scales (all except general health). During the year after discharge, both groups improved significantly, although employed individuals to a greater extent on all scales of the SF-36 Health Survey. CONCLUSIONS: Almost one half of the multiple system blunt trauma patients remain unemployed 1 year after hospital discharge. Those patients who return to work are usually young professionals with a lower severity of injury. Functional status at discharge predicts future employment status, but underestimates the extent of long-term recovery.

Absenteeism↗
PubMed1997

Interpreting small differences in functional status: the Six Minute Walk test in chronic lung disease patients.

Functional status measurements are often difficult to interpret because small differences may be statistically significant but not clinically significant. How much does the Six Minute Walk test (6MW) need to differ to signify a noticeable difference in walking ability for patients with chronic obstructive pulmonary disease (COPD)? We studied individuals with stable COPD (n = 112, mean age = 67 yr, mean FEV1 = 975 ml) and estimated the smallest difference in 6MW distances that was associated with a noticeable difference in patients' subjective comparison ratings of their walking ability. We found that the 6MW was significantly correlated with patients' ratings of their walking ability relative to other patients (r = 0.59, 95% confidence interval [CI]: 0.54 to 0.63). Distances needed to differ by 54 m for the average patient to stop rating themselves as "about the same" and start rating themselves as either "a little bit better" or "a little bit worse" (95% CI: 37 to 71 m). We suggest that differences in functional status can be statistically significant but below the threshold at which patients notice a difference in themselves relative to others; an awareness of the smallest difference in walking distance that is noticeable to patients may help clinicians interpret the effectiveness of symptomatic treatments for COPD.

Aged↗
PubMed1996

On the belief that arthritis pain is related to the weather.

There is a widespread and strongly held belief that arthritis pain is influenced by the weather; however, scientific studies have found no consistent association. We hypothesize that this belief results, in part at least, from people's tendency to perceive patterns where none exist. We studied patients (n = 18) for more than I year and found no statistically significant associations between their arthritis pain and the weather conditions implicated by each individual. We also found that college students (n = 97) tend to perceive correlations between uncorrelated random sequences. This departure of people's intuitive notion of association from the statistical concept of association, we suggest, contributes to the belief that arthritis pain is influenced by the weather.

Arthritis, Rheumatoid↗
PubMed1996

Assessing the minimal important difference in symptoms: a comparison of two techniques.

We have developed a method for estimating the minimally important difference (MID) for health status measures. Whereas the conventional approach requires patients to judge themselves relative to their memories, our method requires patients to judge themselves relative to others with the same condition. In this study we examined whether our method (based on between-patient differences) and the conventional method (based on within-patient changes) provides comparable estimates of the MID for one health status measure: the Chronic Respiratory Questionnaire. Patients with chronic obstructive pulmonary disease who were participating in a supervised respiratory rehabilitation program were included if they were in stable health (n = 112). Their mean score per question in the Chronic Respiratory Questionnaire was 4.5 (range, 1 to 7; where bigger values indicate better health). Our method estimated that the MID was 0.5 (95% confidence interval 0.4 to 0.7). This estimate was similar to the MID previously found using the conventional method. These observations support the role of the Chronic Respiratory Questionnaire for measuring patient's symptoms, the validity of our approach for assessing the MID, and an estimate on the order of 0.5 as the threshold for this particular health status measure.

Adaptation, Psychological↗