Warren J. McIsaac
University of Toronto
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Featured researches published by Warren J. McIsaac.
Social Science & Medicine | 2000
Sheryl Dunlop; Peter C. Coyte; Warren J. McIsaac
This paper assesses the extent to which Canadas universal health care system has eliminated socio-economic barriers in the use of physician services by examining the role of socio-economic status in the differential use of specific, publicly-insured, primary and specialist care services. Data from the 1994 National Population Health Survey, a nationally representative survey, were analysed using multiple logistic regression. In order to control for the association between primary and specialist utilisation, a two-staged least squares method was used for models explaining specialist utilisation. Health need, as measured by perceived health status and number of health problems, was found to be consistently associated with increased physician utilisation, for both primary and specialist visits. Whereas the likelihood of an individual making at least one visit to a primary care physician was found to be independent of income, those with lower incomes were more likely to be frequent users of primary care, that is, make at least six visits to a primary care physician. Even after adjusting for the greater utilisation of primary care services by those in lower socio-economic groups, and, therefore, their higher exposure to the risk of referral, the utilisation of specialist visits was greater for those in higher socio-economic groups. Canadians lacking a regular medical doctor were less likely to receive primary and specialist care, even after adjustments for socio-economic variables such as income and education. Although financial barriers may not directly impede access to health care services in Canada, differential use of physician services with respect to socio-economic status persists. After adjusting for differences in health need, Canadians with lower incomes and fewer years of schooling visit specialists at a lower rate than those with moderate or high incomes and higher levels of education attained despite the existence of universal health care.
Hypertension | 2012
Alexander G. Logan; M. Jane Irvine; Warren J. McIsaac; András Tislér; Peter G. Rossos; Anthony C. Easty; Denice S. Feig; Joseph A. Cafazzo
Lowering blood pressure reduces cardiovascular risk, yet hypertension is poorly controlled in diabetic patients. In a pilot study we demonstrated that a home blood pressure telemonitoring system, which provided self-care messages on the smartphone of hypertensive diabetic patients immediately after each reading, improved blood pressure control. Messages were based on care paths defined by running averages of transmitted readings. The present study tests the systems effectiveness in a randomized, controlled trial in diabetic patients with uncontrolled systolic hypertension. Of 244 subjects screened for eligibility, 110 (45%) were randomly allocated to the intervention (n=55) or control (n=55) group, and 105 (95.5%) completed the 1-year outcome visit. In the intention-to-treat analysis, mean daytime ambulatory systolic blood pressure, the primary end point, decreased significantly only in the intervention group by 9.1±15.6 mmHg (SD; P<0.0001), and the mean between-group difference was 7.1±2.3 mmHg (SE; P<0.005). Furthermore, 51% of intervention subjects achieved the guideline recommended target of <130/80 mmHg compared with 31% of control subjects (P<0.05). These improvements were obtained without the use of more or different antihypertensive medications or additional clinic visits to physicians. Providing self-care support did not affect anxiety but worsened depression on the Hospital Anxiety and Depression Scale (baseline, 4.1±3.76; exit, 5.2±4.30; P=0.014). This study demonstrated that home blood pressure telemonitoring combined with automated self-care support reduced the blood pressure of diabetic patients with uncontrolled systolic hypertension and improved hypertension control. Home blood pressure monitoring alone had no effect on blood pressure. Promoting patient self-care may have negative psychological effects.
Osteoporosis International | 2004
Suzanne M. Cadarette; Warren J. McIsaac; Gillian Hawker; Liisa Jaakkimainen; Alison Culbert; Gihane Zarifa; Ebele Ola; Susan Jaglal
The purpose of this study was to determine the validity of the Osteoporosis Risk Assessment Instrument (ORAI), Osteoporosis Self-Assessment Tool (OST) chart and equation, and a criterion based on body weight for identifying women with asymptomatic primary osteoporosis. Prospective recruitment and chart abstractions from family practices of three University affiliated hospitals were completed for women aged 45 years or more with baseline bone mineral density (BMD) testing results by dual energy X-ray absorptiometry. Those taking bone active medication other than hormone therapy, with prior fragility fracture or with risk factors for secondary osteoporosis were excluded. Women were categorized as being normal, osteopenic or osteoporotic by lowest BMD T-score at either the femoral neck or lumbar spine (L1–L4). Sensitivity, specificity and area under the receiver operating characteristic (ROC) curve to identify those with osteoporosis were determined for each decision rule. The positive predictive value (PPV) for detecting osteoporosis after using a second cut point to convert each decision rule into a risk index (low, moderate or high risk) was also determined. The sensitivity of the decision rules to identify women with osteoporosis ranged from 92% to 95% and specificity from 35% to 46%. The area under the ROC curves were significantly better for the ORAI (0.80), OST chart (0.82) and OST equation (0.82) compared with the body weight criterion (0.73). PPV for detecting osteoporosis ranged from 30% to 58% among women deemed at high risk. These data confirm the validity of the ORAI, the OST chart and the OST equation as screening tools for BMD testing. Further evidence is required to confirm the validity of the body weight criterion.
The New England Journal of Medicine | 2001
Peter C. Coyte; Ruth Croxford; Warren J. McIsaac; William B. Feldman; Jacob Friedberg
BACKGROUND Otitis media is the most common medical problem in young children. The usual surgical treatment is myringotomy with insertion of tympanostomy tubes. There is debate about the usefulness of concomitant adenoidectomy or adenotonsillectomy. We examined the effects of these adjuvant procedures on the rates of reinsertion of tympanostomy tubes and rehospitalization for conditions related to otitis media. METHODS Using hospital discharge records for the period 1995 through 1997, we examined the results of surgery for all 37,316 children (defined as persons 19 years of age or younger) in Ontario, Canada, who received tympanostomy tubes as their first surgical treatment for otitis media. We determined the time to the first readmission for conditions related to otitis media and the time to the first reinsertion of tympanostomy tubes. RESULTS As compared with treatment involving the insertion of tympanostomy tubes alone, adjuvant adenoidectomy was associated with a reduction in the likelihood of reinsertion of tympanostomy tubes (relative risk, 0.5; 95 percent confidence interval, 0.5 to 0.6; P<0.001) and the likelihood of readmission for conditions related to otitis media (relative risk, 0.5; 95 percent confidence interval, 0.5 to 0.6; P<0.001). The risk of these outcomes was further reduced if an adjuvant adenotonsillectomy was performed. The effect was age-related. Children as young as one year appeared to benefit from adjuvant adenotonsillectomy; the benefit of an adjuvant adenoidectomy was apparent in two-year-olds and was greatest for children three years of age or older. CONCLUSIONS Performing an adenoidectomy at the time of the initial insertion of tympanostomy tubes substantially reduces the likelihood of additional hospitalizations and operations related to otitis media among children two years of age or older.
Journal of Hypertension | 2008
Alexander G. Logan; Andrea Dunai; Warren J. McIsaac; M. Jane Irvine; András Tislér
Objective Guidelines recommend home blood pressure monitoring (HBPM) to improve blood pressure control, but the attitudes of primary care physicians and their hypertensive patients towards its use are not known. Methods A 28-item self-administered survey about home blood pressure monitoring was mailed to a random sample of 1418 primary care physicians in Ontario and 765 (55%) were returned. Of the 478 physicians treating hypertension, 299 agreed to give surveys to their hypertensive patients. We received 149 patient surveys. Results The majority of primary care physicians (63%) often or almost always encouraged their hypertensive patients to monitor their own blood pressure at home. Only 13%, however, preferred home blood pressure monitoring to office or ambulatory readings for diagnostic purposes and 19%, to guide therapy. Physicians had concerns about patients becoming preoccupied with home monitoring (70%) and the accuracy of home devices (65%). Most patients (78%) had a device at home, and 84% indicated that their doctor encouraged them to measure blood pressure. Yet, 80% received no advice from their physician on the type of device to purchase, only 8% had specific training on proper measurement technique, 68% did not regularly take the results to the doctor and 39% did nothing specific about alarming readings. Conclusions Primary care physicians prefer office or ambulatory to home readings to make diagnostic and therapeutic decisions. While home monitoring is popular among patients, its clinical usefulness is undermined by the lack of reliable purchasing information, standard measurement protocols, proper training on measurement technique and specific instructions on handling and interpreting results.
Canadian Journal of Infectious Diseases & Medical Microbiology | 2006
Warren J. McIsaac; Tony Mazzulli; Joanne Permaul; Rahim Moineddin; Donald E. Low
BACKGROUND There are currently limited data regarding the prevalence of antimicrobial-resistant organisms causing community-acquired urinary tract infections among adult women in Canada. Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line empirical antibiotic treatment, unless resistance of Escherichia coli to TMP-SMX exceeds 20%. OBJECTIVE To assess current levels of TMP-SMX-resistant E coli in community-acquired cases of urinary tract infection in adult women. METHOD Assessment of urine culture reports obtained from 21 laboratories across Canada, submitted by family physicians for women aged 16 years and older. RESULTS In 2199 adult women with a positive urine culture, 1079 (49.1%) of pathogens isolated were resistant to at least one antibiotic and 660 (30.0%) were multidrug-resistant (resistant to two or more antibiotics). TMP-SMX resistance was seen in 245 of 1613 (15.2%) E coli isolates (95% CI 13.5 to 17.0). This proportion was higher in women 50 years of age and older (155 of 863 isolates [18.0%]; P=0.001), in British Columbia (70 of 342 isolates [20.5%]) and in Ontario (62 of 370 isolates [16.8%]) when compared with eastern provinces (65 of 572 isolates [11.4%]; P=0.001). Fluoroquinolone-resistant E coli occurred in 107 of 1557 (6.9%) isolates (95% CI 5.7 to 8.2), with the highest level found in British Columbia (54 of 341 isolates [15.8%]; P=0.001). CONCLUSION TMP-SMX continues to be appropriate as first-line empirical treatment of acute cystitis in adult women in Canada, as resistance remains below 20%. However, TMP-SMX resistance is higher in older women and in some provinces. The level of fluoroquinolone-resistant E coli is highest in British Columbia.
Canadian Journal of Infectious Diseases & Medical Microbiology | 2004
Warren J. McIsaac; Tony Mazzulli; Rahim Moineddin; Janet Raboud; Susan Ross
BACKGROUND Increasing rates of trimethoprim-sulfamethoxazole (TMP-SMX) resistance among uropathogens have raised concerns about its continued role in empirical treatment of acute uncomplicated cystitis in adult women. OBJECTIVE To determine current rates of antibiotic resistance among uropathogens in the community. METHODS Urine culture reports from adult women with symptoms of cystitis attending the offices of family physicians from across Canada were examined. Antibiotic sensitivities and the total number of antibiotics an organism was resistant to was determined. RESULTS In 446 women, 235 (61.4%) positive urine cultures were identified. Of these, 38.2% were resistant to at least one antibiotic and 21.5% were resistant to two or more antibiotics. The rate of ampicillin resistance was 34.1%. For TMP-SMX, resistance was reported in 10.8% of samples. Antibiotic resistance was higher in British Columbia (55%) and western provinces (48%), compared with Ontario (33.3%) and the eastern provinces (26.3%, P=0.04, Fishers exact test). Multidrug resistance was also higher in western Canada (33.9%) than in eastern Canada (16.6%, P=0.007). CONCLUSIONS TMP-SMX resistance in Canada remains within current recommended guidelines, allowing for its continued use as a first line empirical treatment for acute cystitis in adult women. The reasons for higher rates of antibiotic resistance in western Canada merit further study.
Canadian Journal of Infectious Diseases & Medical Microbiology | 2008
Warren J. McIsaac; Preeti Prakash; Susan Ross
INTRODUCTION There are few Canadian studies that have assessed prescribing patterns and antibiotic preferences of physicians for acute uncomplicated cystitis. A cross-Canada study of adult women with symptoms of acute cystitis seen by primary care physicians was conducted to determine current management practices and first-line antibiotic choices. METHODS A random sample of 2000 members of The College of Family Physicians of Canada were contacted in April 2002, and were asked to assess two women presenting with new urinary tract symptoms. Physicians completed a standardized checklist of symptoms and signs, indicated their diagnosis and antibiotics prescribed. A urine sample for culture was obtained. RESULTS Of the 418 responding physicians, 246 (58.6%) completed the study and assessed 446 women between April 2002 and March 2003. Most women (412 of 420, for whom clinical information about antibiotic prescriptions was available) reported either frequency, urgency or painful urination. Physicians would have usually ordered a urine culture for 77.0% of the women (95% CI 72.7 to 80.8) and prescribed an antibiotic for 86.9% of the women (95% CI 83.3 to 90.0). The urine culture was negative for 32.8% of these prescriptions. The most commonly prescribed antibiotic was trimethoprim/sulfamethoxazole (40.8%; 95% CI 35.7 to 46.1), followed by fluoroquinolones (27.4%; 95% CI 22.9 to 32.3) and nitrofurantoin (26.6%; 95% CI 22.1 to 31.4). CONCLUSION Empirical antibiotic prescribing is standard practice in the community, but is associated with high levels of unnecessary antibiotic use. While trimethoprim/sulfamethoxazole is the first-line empirical antibiotic choice, fluoroquinolone antibiotics have become the second most commonly prescribed empirical antibiotic for acute cystitis. The effect of current prescribing patterns on community levels of quinolone-resistant Escherichia coli may need to be monitored.
Medical Care | 2010
S. Samuel Bederman; Warren J. McIsaac; Peter C. Coyte; Hans J. Kreder; Nizar N. Mahomed; James G. Wright
Background:Degenerative disease of the lumbar spine is common. Although surgery can benefit selected patients, variation in surgical referrals reduces overall access to care. Objectives:To compare the actual referral practices for patients with degenerative disease of the lumbar spine with recommendations for surgical referral based on clinical practice guidelines (CPGs) and family physician (FP) opinions. Research Design:An expert panel of primary and specialist physicians, using a Delphi process, came to a consensus on referral recommendations from CPGs based on a series of clinical vignettes. The vignettes were also presented to practicing FPs in Ontario, Canada, to determine their preferences for (or likelihood of) referral. Subjects:We assembled a 10-member multispecialty expert panel. Practicing FPs were randomly sampled, stratified by county, and their patients were sampled purposefully by the FP. Measures:Respondents, both panelists and FPs, were asked to rate the appropriateness of surgical referral for a series of clinical vignettes. Patients reported their clinical symptoms and whether they had been referred to a surgeon. Using random-effects probit regression, predictions were compared with actual referral. Receiver operating characteristic curves were constructed and area under the curve (AUC) was measured. Results:Consensus of the panel on recommendations for referral was achieved after 2 iterations (Cronbach &agr; = 0.96). Based on responses from 107 patients and 61 FPs, we found poor concordance of both predicted FP preferences (AUC 0.57) and CPG recommendations (AUC 0.64) with actual referral. Conclusions:Referral practices are poorly predicted by CPG recommendations and individual FP opinions, based on clinical factors. Understanding other nonclinical factors may be more important in reducing variation in referrals and improving access.
Canadian Journal of Infectious Diseases & Medical Microbiology | 2013
Warren J. McIsaac; Rahim Moineddin; Christopher Meaney; Tony Mazzulli
BACKGROUND Trimethoprim-sulfamethoxazole (TMP-SMX) has been a traditional first-line antibiotic treatment for acute cystitis; however, guidelines do not recommend TMP-SMX in regions where Escherichia coli resistance exceeds 20%. While resistance is increasing, there are no recent Canadian estimates from a primary care setting to guide prescribing decisions. METHODS A total of 330 family physicians assessed 752 women with suspected acute cystitis between 2009 and 2011. Physicians documented clinical features and collected urine for cultures for 430 (57.2%) women. The proportion of resistant isolates of E coli and exact binomial 95% CIs were estimated nationally, and compared regionally and demographically. These estimates were compared with those from a 2002 national study. RESULTS The proportion of TMP-SMX-resistant E coli was 16.0% nationally (95% CI 11.3% to 21.8%). This was not statistically higher than 2002 (10.9% [P=0.14]). TMP-SMX resistance was increased in women ≤50 years of age (21.4%) compared with older women (10.7% [P=0.037]). In women with no antibiotic exposure in the previous three months, TMP-SMX-resistant E coli remained more prevalent in younger women (21.8%) compared with older women (4.4% [P=0.003]). The proportion of ciprofloxacin-resistant E coli was 5.5% nationally (95% CI 2.7% to 9.9%), and was increased compared with 2002 (1.1% [P=0.036]). Ciprofloxacin resistance was highest in British Columbia (17.7%) compared with other regions (2.7% [P=0.003]), and was increased compared with 2002 levels in this province (0.0% [P=0.025]). Nitrofurantoin-resistant E coli levels were low (0.5% [95% CI 0.01% to 2.7%). DISCUSSION The proportion of TMP-SMX-resistant E coli causing acute cystitis in women in Canada remains below 20% nationally, but may exceed this level in premenopausal women. Ciprofloxacin resistance has increased, notably in British Columbia. Nitrofurantoin resistance levels are low across the country. These observations indicate that TMP-SMX and nitrofurantoin remain appropriate empirical antibiotic agents for treating cystitis in primary care settings in Canada.