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Janet E Hux

Publications and source records attributed to Janet E Hux.

At least 19 recordsLinked to original sources
PubMed2006

Testing multiple statistical hypotheses resulted in spurious associations: a study of astrological signs and health.

OBJECTIVES: To illustrate how multiple hypotheses testing can produce associations with no clinical plausibility. STUDY DESIGN AND SETTING: We conducted a study of all 10,674,945 residents of Ontario aged between 18 and 100 years in 2000. Residents were randomly assigned to equally sized derivation and validation cohorts and classified according to their astrological sign. Using the derivation cohort, we searched through 223 of the most common diagnoses for hospitalization until we identified two for which subjects born under one astrological sign had a significantly higher probability of hospitalization compared to subjects born under the remaining signs combined (P<0.05). RESULTS: We tested these 24 associations in the independent validation cohort. Residents born under Leo had a higher probability of gastrointestinal hemorrhage (P=0.0447), while Sagittarians had a higher probability of humerus fracture (P=0.0123) compared to all other signs combined. After adjusting the significance level to account for multiple comparisons, none of the identified associations remained significant in either the derivation or validation cohort. CONCLUSIONS: Our analyses illustrate how the testing of multiple, non-prespecified hypotheses increases the likelihood of detecting implausible associations. Our findings have important implications for the analysis and interpretation of clinical studies.

Adolescent↗
PubMed2006

Diabetes mellitus and breast cancer: a retrospective population-based cohort study.

PURPOSE: Evidence suggests that women with type 2 diabetes may be at increased risk of breast cancer, possibly due to chronic exposure to insulin resistance and/or hyperinsulinemia. The purpose of this study was to compare the incidence of breast cancer in postmenopausal women with and without diabetes. METHODS: Using population-based validated health databases from Ontario, Canada, this retrospective cohort study compared breast cancer incidence between women, aged 55-79 years, with newly diagnosed diabetes (n=73,796) to women without diabetes (n=391,714). RESULTS: Women with diabetes were slightly older, were more likely to reside in a lower income neighborhood, had greater comorbidity, and had more annual physician visits than women without diabetes. After 2.2 million person-years of follow-up from 1994 to 2002, breast cancer incidence was 2.97/1000 person-years in the diabetes group and 2.75/1000 person-years in the non-diabetes group. After adjustment for age and income, there was a significant increase in breast cancer among women with diabetes (hazard ratio, HR, 1.08, 95% confidence interval, CI, 1.01-1.16, p=0.021). CONCLUSION: This study found a small but significant increase in incident breast cancer in a predominantly postmenopausal population of women with diabetes, when compared to women without diabetes. These results support the possibility that insulin resistance or some other aspect of type 2 diabetes may promote breast cancer, and may further direct treatment and prevention strategies.

Age Factors↗
PubMed2006

Increased prevalence of prior breast cancer in women with newly diagnosed diabetes.

OBJECTIVE: There is growing evidence of a link between type 2 diabetes and breast cancer, possibly through insulin resistance and/or hyperinsulinemia. Because insulin levels are at their highest prior to the development of diabetes, breast cancer risk may be even greater during the pre-diabetes period. RESEARCH DESIGN AND METHODS: In this cross-sectional study, women aged 55-79 years living in Ontario, Canada, with newly diagnosed diabetes from 1994 to 2002 were identified from a validated, population-based database (N = 82,390). Prior history of breast cancer in this group was recorded from 1964 until their diabetes diagnosis from a linkable cancer registry, and was compared to a similarly aged comparison group without diabetes (N = 411,950). RESULTS: Prior breast cancers were identified in 3.7% of women with diabetes and in 3.1% women without diabetes (odds ratio, OR 1.22, 95% confidence interval, CI 1.17-1.27, p < 0.0001). The mean time from breast cancer diagnosis to diabetes diagnosis was 7.9 years. The likelihood of a breast cancer history remained significantly higher in women with diabetes after adjustment for age, income and physician visits (OR 1.13, 95% CI 1.09-1.18, p < 0.0001). CONCLUSIONS: These results suggest that breast cancer risk may be increased in the pre-diabetes phase and may have implications for screening and prevention strategies. Further studies are required to better characterize the processes that link insulin resistance, diabetes and breast cancer.

Aged↗
PubMed2005

Reduced screening mammography among women with diabetes.

BACKGROUND: Despite regular health care, preventive health issues may be neglected in patients with chronic diseases such as diabetes. Case-control studies in the United States have shown lower mammogram rates in women with diabetes; however, it is not known whether the presence of diabetes mellitus affects mammography use in a Canadian setting, where there is universal access to health care. METHODS: Using health databases in Ontario from April 1, 1999, to March 31, 2002, this retrospective cohort study observed women aged 50 to 67 years, who were free of breast cancer, until their first mammogram in a 2-year period. Mammogram rates were compared between women who had had diabetes for a minimum of 2 years (n = 69 168) and women without diabetes (n = 663 519). RESULTS: Compared with women without diabetes, diabetic patients were older, had more physician visits, were more often from a lower-income neighborhood, and, in those 65 years or older, were less likely to be taking estrogen. The odds ratio of having a mammogram during the 2-year period was 0.68 (95% confidence interval, 0.67-0.70; P<.001) for women with diabetes, and adjustment for age and other covariates did not modify this effect. CONCLUSIONS: Women with diabetes were significantly less likely to have had a mammogram during a 2-year period than were women without diabetes, despite more health care visits. These results suggest that, because of the complexity involved in diabetes care, routine preventive care such as cancer screening is often neglected. These findings highlight the need for better organization of primary care for patients with chronic diseases.

Aged↗
PubMed2005

Propensity score methods gave similar results to traditional regression modeling in observational studies: a systematic review.

OBJECTIVE: To determine whether adjusting for confounder bias in observational studies using propensity scores gives different results than using traditional regression modeling. METHODS: Medline and Embase were used to identify studies that described at least one association between an exposure and an outcome using both traditional regression and propensity score methods to control for confounding. From 43 studies, 78 exposure-outcome associations were found. Measures of the quality of propensity score implementation were determined. The statistical significance of each association using both analytical methods was compared. The odds or hazard ratios derived using both methods were compared quantitatively. RESULTS: Statistical significance differed between regression and propensity score methods for only 8 of the associations (10%), kappa = 0.79 (95% CI = 0.65-0.92). In all cases, the regression method gave a statistically significant association not observed with the propensity score method. The odds or hazard ratio derived using propensity scores was, on average, 6.4% closer to unity than that derived using traditional regression. CONCLUSIONS: Observational studies had similar results whether using traditional regression or propensity scores to adjust for confounding. Propensity scores gave slightly weaker associations; however, many of the reviewed studies did not implement propensity scores well.

Bias↗
PubMed2005

Diabetic patients with prior specialist care have better glycaemic control than those with prior primary care.

OBJECTIVE: To compare glycaemic control, as reflected in the A1c level, of diabetic patients with primary care vs. with specialist care. METHODS: The study used administrative data from eastern Ontario, Canada, and a database containing the results of all A1c tests from this region between 1 September 1999 and 1 September 2000. To avoid referral bias, diabetic patients with an index specialist visit were selected and separated into those with exclusively primary care previously (n = 974) and those with prior specialist care (n = 3533). We compared A1c levels measured within 30 days of the index visit and hence attributable to the prior care. To control for confounding between the groups, both multiple linear regression and propensity score-based matching were used. RESULTS: After controlling for confounders, patients with prior specialist care had significantly lower A1c levels (P < 0.0001). Other predictors of lower A1c included older age, shorter diabetes duration, rural residence and higher neighbourhood income. In propensity score-matched cohorts, the A1c level was 8.3 +/- 2.0% with prior primary care vs. 7.9 +/- 1.6% with prior specialist care (P < 0.0001). CONCLUSIONS: Specialist care prior to the index visit was associated with a lower A1c level than prior primary care. This difference would result in reductions in diabetes complications for patients with ongoing specialist care.

Aged↗
PubMed2005

Clinical inertia in response to inadequate glycemic control: do specialists differ from primary care physicians?

OBJECTIVE: Diabetic patients with inadequate glycemic control ought to have their management intensified. Failure to do so can be termed "clinical inertia." Because data suggest that specialist care results in better control than primary care, we evaluated whether specialists demonstrated less clinical inertia than primary care physicians. RESEARCH DESIGN AND METHODS: Using administrative data, we studied all non-insulin-requiring diabetic patients in eastern Ontario aged 65 or older who had A1c results >8% between September 1999 and August 2000. Drug intensification was measured by comparing glucose-lowering drug regimens in 4-month blocks before and after the elevated A1c test and was defined as 1) the addition of a new oral drug, 2) a dose increase of an existing oral drug, or 3) the initiation of insulin. Propensity score-based matching was used to control for confounding between groups. RESULTS: There were 591 patients with specialist care and 1,911 with exclusively primary care. In the matched cohorts, 45.1% of patients with specialist care versus 37.4% with primary care had drug intensification (P = 0.009). Most of this difference was attributed to specialists' more frequent initiation of insulin in response to elevated A1c. CONCLUSIONS: Fewer than one-half of patients with high A1c levels had intensification of their medications, regardless of specialty of their physician. Specialists were more aggressive with insulin initiation than primary care physicians, which may contribute to the lower A1c levels seen with specialist care. Interventions assisting patients and physicians to recognize and overcome clinical inertia should improve diabetes care in the population.

Aged↗
PubMed2005

Time trends and geographic disparities in acute complications of diabetes in Ontario, Canada.

OBJECTIVE: This study examines whether acute diabetes complication rates have fallen in recent years and whether geographic factors influence these trends. RESEARCH DESIGN AND METHODS: A population-based time-trend analysis of acute complications of diabetes was conducted using linked administrative and census data from Ontario, Canada. The study population included all adults identified through a province-wide electronic diabetes registry between 1994 and 1999 (n = 577,659). The primary outcome was hospitalizations for hyper- and hypoglycemia and emergency department visits for diabetes. RESULTS: Between 1994 and 1999, rates of hospitalization for hyper- and hypoglycemic emergencies decreased by 32.5 and 76.9%, respectively; emergency department visits for diabetes fell by 23.9%. On multivariate analysis, fiscal year was an independent predictor of acute diabetes complications, with individuals in our cohort experiencing a decline in risk of approximately 6% per year for either being hospitalized with hyper- or hypoglycemia or requiring an emergency department visit for diabetes. After accounting for variation in physician service use, diabetic individuals living in rural areas or Aboriginal communities were nearly twice as likely to have an acute complication, whereas those residing in remote areas of the province were nearly three times as likely to experience an event. CONCLUSIONS: Although our findings suggest an overall improvement in diabetes care in Ontario, certain subgroups of the population continue to experience higher rates of complications that are potentially preventable through good ambulatory care. Measures to improve access to timely and effective outpatient care may further reduce rates of acute complications among the diabetic population.

Acute Disease↗
PubMed2004

Risk modification for diabetic patients. Are other risk factors treated as diligently as glycemia?

BACKGROUND: The importance of glucose control is recognized both by patients with diabetes and their physicians. However, other preventative interventions, such as using medications to manage lipid and blood pressure levels, are underused for diabetic patients. OBJECTIVES: To determine whether patients with diligent glucose management are more likely to use medications that treat lipids and blood pressure. METHODS: Administrative data records were evaluated for all diabetic patients aged 65 or older residing in Ontario in 1999 without pre-existing coronary artery disease (n=161,553). Measures of diligent glucose management were insulin use and frequent capillary glucose testing ((3) 2 per day). Outcomes were prescription of a lipid-lowering drug or antihypertensive drug. Using multivariate modeling, odds ratios for each diligence measure were determined for each outcome, adjusting for age, sex, comorbidities, and other covariates. RESULTS: Patients using insulin did not have a clinically important difference in lipid-lowering drug use (adjusted odds ratio 0.9, 99% confidence interval 0.9 - 1.0, P=0.002) or antihypertensive drug use (adjusted odds ratio 1.1, 99% confidence interval 1.0 - 1.1, P<0.001) versus non-users. Adjusted odds ratios for frequent glucose testing were not significantly different from unity for either lipid-lowering or antihypertensive drug use. CONCLUSIONS: Patients who required and were capable of diligent glucose management, which is invasive, expensive and time-consuming, were no more likely to use medications to control lipids or blood pressure. Preventative care for patients with diabetes may be too focused on glycemic control, and may be neglecting the management of other cardiovascular risk factors.

Aged↗
PubMed2004

The growing volume of diabetes-related dialysis: a population based study.

BACKGROUND: End-stage renal failure requiring dialysis is one of the most serious complications of diabetes mellitus, and diabetes is the most common cause of end-stage renal failure. The aim of this large, observational study is to describe the population-based incidence and prevalence rates and outcomes of diabetic individuals in Ontario, Canada who require dialysis therapy. METHODS: Two cohorts of patients, those with diabetes and those without, were created between April 1, 1994 and March 31, 2000 (total of approximately 8.4 million) and followed until March 31, 2001 using several large, linked administrative databases at the Institute for Clinical Evaluative Sciences. The incidence, prevalence and mortality on dialysis for each cohort were determined. A multivariate Cox proportional hazards analysis, adjusting for age, sex and co-morbidity, was used to determine the independent impact of diabetes on patient survival. RESULTS: The average annual incidence rate of dialysis was 12 times greater in persons with diabetes (130 per 100,000) vs without diabetes (11 per 100,000). By 1999-2000, diabetic patients comprised 51% of the incident dialysis population. The average annual prevalence rate was 10 times greater in the diabetic cohort. Patients with diabetes had more co-morbidities at the start of dialysis and poorer 3 year survival (55 vs 68%; P < 0.0001). CONCLUSIONS: The incident and prevalent rates of dialysis for patients with diabetes mellitus are many times the rates of those without diabetes. Patients with diabetes mellitus often start dialysis with significant co-morbidities, which may contribute to the relatively high rate of mortality on dialysis.

Cohort Studies↗
PubMed2004

Late creation of vascular access for hemodialysis and increased risk of sepsis.

The creation of fistulas or grafts before starting dialysis is recommended, but whether it reduces major adverse events is largely unknown. The objective of this study was to determine if early access creation was associated with a reduced risk of hospitalization from sepsis and mortality. Fistulas or grafts created at least 4 mo before starting hemodialysis were defined as Early creations (n = 1240), and accesses created between 4 mo and 1 mo before starting hemodialysis were defined as Just Prior creations (n = 997). Accesses created within 1 mo of starting dialysis or after were defined as Late creations (reference group, n = 3687). Hemodialysis catheter use was defined as insertion, removal, or manipulation of a catheter before the occurrence of sepsis. Eighty percent of accesses were fistulas. Early access creation was associated with a relative risk (RR) of sepsis of 0.57 (95% CI, 0.41 to 0.79) compared with Late access creation. Catheter use increased the risk of sepsis by 1.41 (95% CI, 1.14 to 1.81). The risk of sepsis with Early creation decreased to 0.48 (95% CI, 0.35 to 0.65) if catheter use was not adjusted. Early access creation was associated with lower mortality (RR 0.76; 95% CI 0.58 to 1.00), but this association became nonsignificant if catheter use and sepsis were adjusted. Catheter use and sepsis independently increased mortality. This study demonstrates that fistula creation at least 4 mo before starting chronic hemodialysis is associated the lowest risk of sepsis and death, primarily by reducing the use of hemodialysis catheters.

Aged↗
PubMed2003

Educating physicians to reduce benzodiazepine use by elderly patients: a randomized controlled trial.

BACKGROUND: Benzodiazepine use by elderly patients is associated with adverse outcomes including increased risk of falls and fractures, motor vehicle accidents and cognitive impairment. Recent studies suggest that individualized feedback and education to physicians may improve drug prescribing. In this study, we evaluated an intervention to address the inappropriate prescribing of benzodiazepines for elderly patients. METHODS: We identified 1624 primary care physicians who wrote at least 10 prescriptions for the target drugs in a 2-month period and randomly assigned these physicians to the intervention group or the control group. We obtained data from the Ontario Drug Benefit claims database, which covers all Ontario residents aged 65 years and over for drugs selected from a minimally restrictive formulary. Every 2 months for 6 months, confidential profiles of benzodiazepine prescription use coupled with evidence-based educational bulletins were mailed to the intervention group. The control group received feedback and educational bulletins about first-line antihypertension drug prescribing for elderly patients. Our main outcome measures were reductions in the proportion of each physician's total benzodiazepine prescriptions for long-acting agents, combinations of benzodiazepines with other psychoactive medications (including other benzodiazepines) and long-term benzodiazepine therapy. RESULTS: After randomization, 168 physicians agreed to be in the intervention group and 206 in the control group. Their demographic and prescribing characteristics were similar. Although the proportion of long-acting benzodiazepine prescriptions decreased by 0.7% in the intervention group between the baseline period and the end of the intervention period (from 20.3%, or a mean of 29.5 prescriptions, to 19.6%, or a mean of 27.7 prescriptions) and increased by 1.1% in the control group (from 19.8%, or a mean of 26.4 prescriptions, to 20.9%, or a mean of 27.7 prescriptions) (p = 0.036), this difference was not clinically significant. There was no significant difference over the study period in either combination prescribing of benzodiazepines or in prescriptions for long-term benzodiazepine therapy. INTERPRETATION: We did not find that a program of confidential feedback and educational material offered to Ontario primary care physicians had a clinically significant impact on their benzodiazepine prescribing.

Adult↗
PubMed2003

Relationship between avoidable hospitalizations for diabetes mellitus and income level.

BACKGROUND: Acute diabetic emergencies are potentially avoidable or amenable to timely and effective outpatient therapy. OBJECTIVE: To evaluate the relationship between socioeconomic status (SES) and acute complications of diabetes mellitus in Ontario. METHODS: We used a population-based cohort of persons with diabetes mellitus (N = 605 825) derived from hospital and physician service claims between April 1, 1992, and March 31, 1999. Socioeconomic status was estimated using neighborhood-level data from the 1996 Canadian Census. Outcome events were defined as 1 or more hospitalizations or emergency department visits for hyperglycemia or hypoglycemia. RESULTS: There was a clear inverse gradient between income level and event rates. Individuals in the lowest income quintile were 44% more likely to have an event than those in the highest quintile (16.4% vs 11.4%; P<.001) and had a greater propensity toward recurrent emergency department admissions (1.9 vs 1.6 episodes per patient; P<.001). The gradient was most marked in 45- to 64-year-olds (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.69-1.82) and less apparent in children (OR, 1.06; 95% CI, 0.99-1.13). The relationship between SES and events persisted after adjusting for age, sex, urban vs rural residence, comorbidity, frequency of physician visits, continuity of care, physician specialty, and geographic region (adjusted OR, 1.09 [95% CI, 1.08-1.10] per quintile level). In contrast, admission rates for non-ambulatory care-sensitive conditions (appendicitis and hip fracture) were unaffected by SES. CONCLUSION: Even when some economic barriers to accessing care are removed, patients from low-SES neighborhoods still experience an excess number of hospitalizations for conditions that should be prevented by optimal care in the ambulatory setting.

Acute Disease↗
PubMed2003

Hemodialysis infection prevention with polysporin ointment.

Hemodialysis patients in whom permanent vascular access cannot be achieved are dependent on a central venous catheter. In such patients, catheter-related infections are a common and serious complication. This study was a randomized clinical trial to determine if topical Polysporin Triple antibiotic ointment applied to the central venous catheter insertion site could reduce the incidence of catheter-related infections. A total of 169 patients receiving hemodialysis through a central venous catheter were randomized to receive Polysporin Triple or placebo using a double-blind study design. In the 6-mo study period, infections were observed in more patients in the placebo group than in the Polysporin Triple group (34 versus 12%; relative risk, 0.35; 95% CI, 0.18 to 0.68; P = 0.0013). The number of infections per 1000 catheter days (4.10 versus 1.02; P < 0.0001) and the number of bacteremias per 1000 catheter days (2.48 versus 0.63; P = 0.0004) were also greater in the placebo group. Within the 6-mo study period, there were 13 deaths in the placebo group as compared with 3 deaths in the Polysporin Triple group (P = 0.0041). When all available follow-up information was included, the difference in survival remained significant (19 versus 9 deaths; P = 0.0027). Within the first 6 mo, infections were observed in 7 of the 13 placebo subjects who died (54%) as compared with no infections in the three Polysporin Triple subjects who died. The prophylactic application of topical Polysporin Triple antibiotic ointment to the central venous catheter insertion site reduced the rate of infections and was associated with improved survival in hemodialysis patients.

Administration, Topical↗
PubMed2003

Markers of access to and quality of primary care for aboriginal people in Ontario, Canada.

OBJECTIVES: We evaluated primary care accessibility and quality for Ontario's aboriginal population. METHODS: We compared a defined aboriginal cohort with nonaboriginal populations with analogous geographic isolation and low socioeconomic status. We determined rates of hospitalization for the following indicators of adequacy of primary care: ambulatory care-sensitive (ACS) conditions and utilization of referral care-sensitive (RCS) procedures from administrative databases. RESULTS: ACS hospitalization rates, relative to the general population, were 2.54, 1.50, and 1.14 for the aboriginal population, the geographic control populations, and the socioeconomic control populations, respectively. The relative RCS procedure utilization rates were 0.64, 0.91, and 1.00, respectively. CONCLUSIONS: The increased ACS hospitalization rate and reduced RCS procedure utilization rate suggest that northern Ontario's aboriginal residents have insufficient or ineffective primary care.

Acute Disease↗
PubMed2003

Quantifying the risk of infectious diseases for people with diabetes.

OBJECTIVE: In vitro evidence shows that immune function is compromised in people with diabetes. Although certain rare infections are more common and infection-related mortality is higher, the risk of acquiring an infectious disease for diabetic patients has never been quantified. RESEARCH DESIGN AND METHODS: A retrospective cohort study using administrative data compared all people with diabetes in Ontario, Canada, on 1 April 1999 to matched nondiabetic people (n = 513,749 in each group). The risk ratios of having an infectious disease and of death attributable to infectious disease between those with and without diabetes were calculated. Secondary analysis individually examined common infectious diseases. The study was repeated using a second pair of cohorts defined in 1996 to confirm stability of the estimates. RESULTS: Nearly half of all people with diabetes had at least one hospitalization or physician claim for an infectious disease in each cohort year. The risk ratio for diabetic versus nondiabetic people was 1.21 (99% CI 1.20-1.22) in both cohort years. The risk ratio for infectious disease-related hospitalization was up to 2.17 (99% CI 2.10-2.23). The risk ratio for death attributable to infection was up to 1.92 (1.79-2.05). Many individual infections were more common in people with diabetes, especially serious bacterial infections. CONCLUSIONS: Diabetes confers an increased risk of developing and dying from an infectious disease, corroborating both in vitro evidence and commonly held clinical belief. In addition to microvascular and macrovascular sequelae, clinicians should consider infection a complication of diabetes.

Aged↗
PubMed2003

Processes and outcomes of care for diabetic acute myocardial infarction patients in Ontario: do physicians undertreat?

OBJECTIVE: To compare the health service utilization and long-term outcomes of acute myocardial infarction (AMI) patients with and without diabetes in Ontario. RESEARCH DESIGN AND METHODS: We examined 25,697 patients from Ontario (6,052 and 19,645 patients with and without diabetes, respectively) who were hospitalized because of AMI between 1 April 1992 and 31 December 1993. Using linked administrative databases, we determined the use of invasive cardiac procedures at 1 year as well as the intensity of specialty follow-up care and use of evidence-based pharmacotherapies (among elderly individuals) within the first 90 days of hospital discharge. Outcomes examined included mortality and recurrent cardiac admissions at 30 days and 5 years post AMI. Multivariable analyses adjusted for sociodemographic and case-mix characteristics, attending physician specialty, and admitting hospital characteristics. RESULTS: Despite being at significantly higher risk for death at baseline, diabetic patients were less likely to be followed-up by a cardiologist (22.2 vs. 25.6%, P < 0.001), to receive myocardial revascularization (12.6 vs. 14.9%, P < 0.001), to receive beta-blockers (34.2 vs. 44.0%, P < 0.001), and to receive aspirin therapy (59.7 vs. 63.5%, P < 0.001) after AMI than their nondiabetic counterparts. Diabetes was an important independent predictor of 5-year morbidity (adjusted hazard ratio 1.52, 95% CI 1.45-1.59) and 5-year mortality outcomes (1.57, 1.50-1.63). Variations in processes of care were marginally associated with higher nonfatal complication rates for diabetic patients. CONCLUSIONS: When managing AMI patients with diabetes in Ontario, physician treatment aggressiveness does not correspond appropriately to the baseline risk of patients.

Aged↗