Inadequate predialysis care and mortality after initiation of renal replacement therapy.

Adequacy of chronic kidney disease (CKD) care is traditionally measured as early or late, but this does not reflect the effect of cumulative or consistent care. Here we relate alternate measures of CKD care to mortality and other outcomes in patients with end-stage renal disease (ESRD) who started renal replacement therapy (RRT) between 1998 and 2008. CKD care was defined traditionally as early or late, and alternatively as cumulative care (total visits) and consistency of care in the critical period immediately prior to start of RRT (consistent critical period care required visits in 3 or more of the 6 months prior to RRT start). The primary outcome was 1-year mortality, with secondary outcomes of inpatient start and access creation. Of 12,143 patients aged 18-97 years at the start of RRT, 75.9% had early CKD care. Only 38.3% of the early group had high cumulative (over 10 visits) and consistent critical period care. The 1-year mortality of 15.8% was more likely with late care, lower cumulative care, and inconsistent critical period care. Both cumulative care and consistent critical period care independently predicted mortality, as well as secondary outcomes. Alternate measures of CKD care are important predictors of outcomes in ESRD and should be considered when reporting adequacy of care. Thus, patients traditionally classified as receiving early CKD care often do not receive adequate care immediately prior to initiating RRT.

Variation in the practice of preoperative medical consultation for major elective noncardiac surgery: a population-based study.

BACKGROUND: Patients scheduled for major elective noncardiac surgery frequently undergo preoperative medical consultations. However, the factors that determine whether individuals undergo consultation and the extent of interhospital variation remain unclear. METHODS: The authors used population-based administrative databases to conduct a cohort study of patients, aged 40 yr or older, who underwent major elective noncardiac surgery in Ontario, Canada, between April 2004 and February 2009. Multilevel logistic regression models were used to identify patient- and hospital-level predictors of consultation. RESULTS: Within the cohort of 204,819 patients who underwent surgery at 79 hospitals, 38% (n = 77,965) underwent preoperative medical consultation. Although patient- and surgery-level factors did predict consultation use, they explained only 5.9% of variation in consultation rates. Differences in rates across hospitals were large (range, 10-897 per 1,000 procedures), were not explained by surgical procedure volume or hospital teaching status, and persisted after adjustment for patient- and surgery-level factors. The median odds of undergoing consultation were 3.51 times higher if the same patient had surgery at one randomly selected hospital as opposed to another. CONCLUSIONS: One-third of surgical patients undergo preoperative medical consultation. Although patient- and surgery-level factors are weak predictors of consultation use, the individual hospital is the major determinant of whether patients undergo consultation. Additional research is needed to better understand the basis for this substantial interhospital variation and to determine which patients benefit most from preoperative consultation.

Selection bias explains apparent differential mortality between dialysis modalities.

The relative risk of death for patients treated with peritoneal dialysis compared with those treated with hemodialysis appears to change with duration of dialysis therapy. Patients who start dialysis urgently are at high risk for mortality and are treated almost exclusively with hemodialysis, introducing bias to such mortality comparisons. To better isolate the association between dialysis treatment modality and patient mortality, we examined the relative risk for mortality for peritoneal dialysis compared with hemodialysis among individuals who received ≥4 months of predialysis care and who started dialysis electively as outpatients. From a total of 32,285 individuals who received dialysis in Ontario, Canada during a nearly 8-year period, 6,573 patients met criteria for elective, outpatient initiation. We detected no difference in survival between peritoneal dialysis and hemodialysis after adjusting for relevant baseline characteristics. The relative risk of death did not change with duration of dialysis therapy in our primary analysis, but it did change with time when we defined our patient population using the more inclusive criteria typical of previous studies. These results suggest that peritoneal dialysis and hemodialysis associate with similar survival among incident dialysis patients who initiate dialysis electively, as outpatients, after at least 4 months of predialysis care. Selection bias, rather than an effect of the treatment itself, likely explains the previously described change in the relative risk of death over time between hemodialysis and peritoneal dialysis.

Predicting the risk of 1-year mortality in incident dialysis patients: accounting for case-mix severity in studies using administrative data.

BACKGROUND: Administrative databases are increasingly being used to study the incident dialysis population and have important advantages. However, traditional methods of risk adjustment have limitations in this patient population. OBJECTIVE: Our objective was to develop a prognostic index for 1-year mortality in incident dialysis patients using administrative data that was applicable to ambulatory patients, used objective definitions of candidate predictor variables, and was easily replicated in other environments. RESEARCH DESIGN: Anonymized, administrative health data housed at the Institute for Clinical Evaluative Sciences in Toronto, Canada were used to identify a population-based sample of 16,205 patients who initiated dialysis between July 1, 1998 and March 31, 2005. The cohort was divided into derivation, validation, and testing samples and 4 different strategies were used to derive candidate logistic regression models for 1-year mortality. The final risk prediction model was selected based on discriminatory ability (as measured by the c-statistic) and a risk prediction score was derived using methods adopted from the Framingham Heart Study. Calibration of the predictive model was assessed graphically. RESULTS: The risk of death during the first year of dialysis therapy was 16.4% in the derivation sample. The final model had a c-statistic of 0.765, 0.763, and 0.756 in the derivation, validation, and testing samples, respectively. Plots of actual versus predicted risk of death at 1-year showed good calibration. CONCLUSION: The prognostic index and summary risk score accurately predict 1-year mortality in incident dialysis patients and can be used for the purposes of risk adjustment.

Antipsychotic drugs and the risk of hyperglycemia in older adults without diabetes: a population-based observational study.

OBJECTIVE: To determine whether current antipsychotic use among older persons without diabetes is associated with a higher risk of hospital visits for hyperglycemia, as previous studies in this population have yielded conflicting results. DESIGN, SETTING AND PARTICIPANTS: A nested case-control study within a population-based cohort of persons aged 66 years or older without diabetes, who initiated antipsychotic therapy between April 1, 2002, and March 31, 2006. Cohort members were identified using health databases from Ontario, Canada, and were followed from treatment start until March 31, 2007. MEASUREMENTS: Cases were patients with a hospital visit (emergency department visit or hospital admission) for hyperglycemia. We matched each case with up to 10 controls. We compared the risk of hyperglycemia among current antipsychotic users to that of remote users (discontinued > 180 days). RESULTS: The cohort consisted of 44,121 subjects, mean age of 78.3 years, followed for a mean of 2.2 years. Compared to remote antipsychotic use, current treatment with any antipsychotic was associated with a significantly increased risk of hospital visits for hyperglycemia (adjusted odds ratio [aOR]: 1.52; 95% confidence interval [CI]: 1.07-2.17). The risk was elevated for both atypical (aOR: 1.44; 95% CI: 1.01-2.07) and typical (aOR: 2.86; 95% CI: 1.46-5.59) antipsychotic agents. CONCLUSIONS: Current use of either atypical or typical antipsychotic agents was associated with a significantly increased risk of hospital visits for hyperglycemia among older persons without diabetes. These findings highlight the need for close glucose monitoring during antipsychotic therapy in older populations.

Using administrative datasets to study outcomes in dialysis patients: a validation study.

BACKGROUND: The use of administrative health data and other secondary data sources to conduct research are increasing, and the quality of these data requires careful scrutiny to ensure that findings of studies based on them are accurate. METHODS: We conducted a multicenter, chart-abstraction study in Ontario, Canada to evaluate the ability of linked administrative databases to identify important baseline demographic and treatment information, changes in dialysis treatment modality over time, and the occurrence of important outcome events in incident dialysis patients. The medical record was considered the reference standard. RESULTS: Within administrative databases, demographic information was very well coded, as was the location where individuals started dialysis, the first treatment modality, the first outpatient modality, and the treatment that was in use 90 days after the start of therapy. The ability to accurately recreate an individual patient's entire dialysis treatment history using physician billing claims was somewhat limited. The treatment changes were often identified in the correct temporal sequence, but the dates that the events occurred did not agree well. Finally, important outcomes including the death and kidney transplantation were captured well, although the recovery of kidney function could not be evaluated because of poor inter-rater reliability. CONCLUSIONS: This validation study provides important information concerning the ability to detect variables related to dialysis care using administrative datasets. Validation work should focus not only on the ability of secondary data to identify baseline comorbidities, but should also attempt to verify that other key variables required to conduct analyses are reliably captured.

Income-related differences in mortality among people with diabetes mellitus.

BACKGROUND: Mortality has declined substantially among people with diabetes mellitus over the last decade. Whether all income groups have benefited equally, however, is unclear. We examined the impact of income on mortality trends among people with diabetes. METHODS: In this population-based, retrospective cohort study, we compared changes in mortality from Apr. 1, 1994, to Mar. 31, 2005, by neighbourhood income strata among people with diabetes aged 30 years or more in the province of Ontario, Canada. RESULTS: Overall, the annual age- and sex-adjusted mortality declined, from 4.05% in 1994/95 (95% confidence interval [CI] 3.98%-4.11%) to 2.69% in 2005/06 (95% CI 2.66%-2.73%). The decrease was significantly greater in the highest income group (by 36%) than in the lowest income group (by 31%; p < 0.001). This trend was most pronounced in the younger group (age 30-64 years): the mortality rate ratio widened by more than 40% between the lowest and highest income groups, from 1.12 to 1.59 among women and from 1.14 to 1.60 among men. Income had a much smaller effect on mortality trends in the older group, whose drug costs are subsidized: the income-related difference rose by only 0.9% over the study period. INTERPRETATION: Mortality declined overall among people with diabetes from 1994 to 2005; however, the decrease was substantially greater in the highest income group than in the lowest, particularly among those aged 30-64 years. These findings illustrate the increasing impact of income on the health of people with diabetes even in a publicly funded health care setting. Further studies are needed to explore factors responsible for these income-related differences in mortality.

Epidural anaesthesia and survival after intermediate-to-high risk non-cardiac surgery: a population-based cohort study.

BACKGROUND: Although epidural anaesthesia and analgesia have numerous benefits, their effects on postoperative survival are unclear. We therefore undertook a population-based cohort study to determine whether perioperative epidural anaesthesia or analgesia is associated with improved 30-day survival. METHODS: We used population-based linked administrative databases to do a retrospective cohort study of 259 037 patients, aged 40 years or older, who underwent selected elective intermediate-to-high risk non-cardiac surgical procedures between April 1, 1994, and March 31, 2004, in Ontario, Canada. Propensity-score methods were used to construct a matched-pairs cohort that reduced important baseline differences between patients who received epidural anaesthesia or analgesia as opposed to those that did not. We then determined the association of epidural anaesthesia with 30-day mortality within these matched-pairs. FINDINGS: Of the 259 037 patients, 56 556 (22%) received epidural anaesthesia. Within the matched-pairs cohort (n=88 188), epidural anaesthesia was associated with a small reduction in 30-day mortality (1.7%vs 2.0%; relative risk 0.89, 95% CI 0.81-0.98, p=0.02). INTERPRETATION: Epidural anaesthesia and analgesia were associated with a small improvement in 30-day survival, but this effect should be interpreted cautiously. The estimate had borderline significance, despite a large sample size. Its absolute magnitude was also small, corresponding to a number needed to treat of 477. Our study, therefore, does not provide compelling evidence that epidural anaesthesia improves postoperative survival. Nonetheless, our results support the safety of perioperative epidural anaesthesia when used for indications other than improving survival (eg, improving postoperative pain relief, preventing postoperative pulmonary complications).

Development of an algorithm to identify preoperative medical consultations using administrative data.

BACKGROUND: Preoperative consultation by internal medicine specialists may help improve the care of patients undergoing major surgery. Population-based administrative data are an efficient approach for studying these consultations at a population-level. However, administrative data in many jurisdictions lack specific codes to identify preoperative medical consultations, as opposed to consultations for nonoperative indications. OBJECTIVE: To develop an accurate claims-based algorithm for identifying preoperative medical consultations before major elective noncardiac surgery. RESEARCH DESIGN: We conducted a multicenter cross-sectional study in Ontario, Canada. Preoperative medical consultations identified by medical record abstraction were compared with those identified by linked administrative data (physician service claims, hospital discharge abstracts). SUBJECTS: We randomly selected 606 individuals, aged older than 40 years, who underwent elective intermediate-to-high-risk noncardiac surgery at 8 randomly selected hospitals between April 1, 2002 and March 31, 2004. RESULTS: Medical record abstraction identified preoperative medical consultations in 317 patients (52%). The optimal claims-based algorithm for identifying these consultations was a physician service claim for a consultation by a cardiologist, general internist, endocrinologist, geriatrician, or nephrologist within 4 months before the index surgical procedure. This algorithm had a sensitivity of 90% (95% confidence interval [CI]: 86-93), specificity of 92% (95% CI: 88-95), positive predictive value of 93% (95% CI: 89-95), and negative predictive value of 90% (95% CI: 86-93). CONCLUSIONS: A simple claims-based algorithm can accurately identify preoperative medical consultations before major elective noncardiac surgery. This algorithm may help enhance population-based evaluations of preoperative care, provided that the requisite linked administrative healthcare data are present.

The impact of non-fee-for-service reimbursement on chronic disease surveillance using administrative data.

OBJECTIVE: Use of physician service claims and other administrative data is increasingly being advocated for chronic disease surveillance. However, such data may be vulnerable to reimbursement policy changes. We sought to determine how non-fee-for-service (non-FFS) primary care affects the detection of diabetes using physician claims data. METHODS: Ontarians over age 66 with diabetes and receiving care in a non-FFS setting were identified using prescription claims for glucose-lowering drugs written by non-FFS physicians. We compared the date of incident treatment in this cohort with the diagnosis date in the Ontario Diabetes Database, a validated administrative data algorithm to detect persons with diabetes. We assessed the rate of detection and, among detected cases, whether detection was late (more than 6 months after the index prescription). Survival methods were used to assess detection over time. RESULTS: Only 49.7% of prescription-defined diabetes cases were detected within six months of the index prescription; 23.7% remained undetected after up to nine years of follow-up. Detected individuals had higher rates of hospitalization for vascular complications than missed cases (15.1% vs 4.8%, p < 0.0001), suggesting that they were at a more advanced stage of disease. CONCLUSIONS: Non-FFS reimbursement arrangements for primary care physicians appear to undermine the utility of administrative data for chronic disease surveillance, leading to both decreased sensitivity and biased detection. Provisions for alternative means to collect diagnostic information should be considered as these arrangements are introduced.

Injury in First Nations communities in Ontario.

BACKGROUND: High and variable rates of injury have been reported in Aboriginal communities in Canada. This has not been well studied for specific injury types. We sought to compare the rate and categories of injuries leading to hospital admission among those in First Nations communities relative to those living in small northern and southern communities in Ontario. METHODS: Administrative data were used to define the study populations. The incidence of all-cause injury and specific injury categories for residents living in Ontario's Aboriginal communities (N = 28,816) was determined for 2004 using hospital discharge data. Comparisons were made with residents of small communities in northern (N = 211,834) and southern Ontario (N = 650,002). Age- and sex-adjusted rates were calculated. RESULTS: All-cause-injury age- and sex-adjusted rates were 2.5 times higher for those living in First Nations communities compared to those living in northern communities. Relative risks (RR) for specific injury types in First Nations compared with northern communities were: assault (RR = 5.5 in females and 4.8 in males), intentional self-harm (RR = 5.9 in females and 5.2 in males) and accidental poisoning (RR = 4.9 in females and 3.7 in males). Differences were also seen between northern and southern communities: assault (RR = 2.8 in females and 3.5 in males), intentional self-harm (RR = 2.1 in females and 1.4 in males) and accidental poisoning (RR = 2.2 in females and 1.7 in males). DISCUSSION: Injuries severe enough to require a hospital admission were higher in First Nations communities in northern Ontario relative to those in northern and southern Ontario communities. Higher rates of certain injuries were also noted in northern compared with southern communities. This underscores the importance of using a geographic comparison group.

Trends in diabetes prevalence, incidence, and mortality in Ontario, Canada 1995-2005: a population-based study.

BACKGROUND: The prevalence of diabetes has been increasing greatly, but WHO's predicted 39% rise in the global rate of diabetes from 2000 to 2030 might be an underestimate. We aimed to assess diabetes trends in Ontario, Canada. METHODS: Using population-based data, including a validated diabetes database from the province of Ontario, Canada, we examined trends in diabetes prevalence and mortality from 1995 to 2005, and incidence from 1997 to 2003, in adults aged 20 years or older. FINDINGS: Age-adjusted and sex-adjusted diabetes prevalence increased by 69%, from 5.2% in a population of 7,908,562 in 1995 to 8.8% of 9,276,945 in 2005. Prevalence increased by 27% from 6.9% in a population of 8,457,720 in 2000 to 8.8% of 9,276,945 in 2005. Although prevalence rates have remained higher in people aged 50 years or older (7.1% of 3,675,554) than in those aged 20-49 years (3.5% of 5 601 391), rates increased to a greater extent in the younger population (94%vs 63%, p<0.0001). A 31% increase occurred in yearly incidence over 6 years, from 6.6 per 1000 in 1997 to 8.2 per 1000 in 2003. The adjusted mortality rate in people with diabetes fell by 25% from 1995 to 2005. INTERPRETATION: The prevalence of diabetes in Ontario, Canada increased substantially during the past 10 years, and by 2005 already exceeded the global rate that was predicted for 2030. This increase in prevalence is attributable to both rising incidence and declining mortality. Effective public-health interventions aimed at diabetes prevention are needed, as well as improved resources to manage the greater number of people living longer with the disease.

Risk of development of diabetes mellitus after diagnosis of gestational diabetes.

BACKGROUND: It is generally appreciated that gestational diabetes is a risk factor for type 2 diabetes. However, the precise relation between these 2 conditions remains unknown. We sought to determine the incidence of diabetes mellitus after diagnosis of gestational diabetes. METHODS: We used a population-based database to identify all deliveries in the province of Ontario over the 7-year period from Apr. 1, 1995, to Mar. 31, 2002. We linked these births to mothers who had been given a diagnosis of gestational diabetes through another administrative database that records people with diabetes on the basis of either physician service claims or hospital admission records. We examined database records for these women from the time of delivery until Mar. 31, 2004, a total of 9 years. We determined the presence of diabetes mellitus according to a validated administrative database definition for this condition. RESULTS: We identified 659 164 pregnant women who had no pre-existing diabetes. Of these, 21 823 women (3.3%) had a diagnosis of gestational diabetes. The incidence of gestational diabetes rose significantly over the 9-year study period, from 3.2% in 1995 to 3.6% in 2001 (p < 0.001). The probability of diabetes developing after gestational diabetes was 3.7% at 9 months after delivery and 18.9% at 9 years after delivery. After adjustment for age, urban or rural residence, neighbourhood income quintile, whether the woman had a previous pregnancy, whether the woman had hypertension after the index delivery, and primary care level before the index delivery, the most significant risk factor for diabetes was having had gestational diabetes during the index pregnancy (hazard ratio 37.28, 95% confidence interval 34.99-40.88; p < 0.001). Age, urban residence and lower income were also important factors. When analyzed by year of delivery, the rate of development of diabetes was higher among the latest subcohort of women with gestational diabetes (delivery during 1999-2001) than among the earliest subcohort (delivery during 1995 or 1996) (16% by 4.7 years after delivery v. 16% by 9.0 years). INTERPRETATION: In this large population-based study, the rate of development of diabetes after gestational diabetes increased over time and was almost 20% by 9 years. This estimate should be used by clinicians to assist in their counselling of pregnant women and by policy-makers to target these women for screening and prevention.

Exercise interventions in obese youth: are they effective?

Given the increasing prevalence of childhood obesity, effective and cost-efficient strategies to enhance children's physical activity levels are needed. Unfortunately, exercise interventions evaluated to date have had little impact on overweight and obesity in youth. Physical activity counseling interventions have emerged as an effective and inexpensive alternative to traditional, structured exercise programs in adults, and may be an interesting option for the treatment of obesity in youth.

Deficiencies in the quality of diabetes care: comparing specialist with generalist care misses the point.

The quality of diabetes care delivered to patients falls below the expectations of practice guidelines and clinical trial evidence. Studies in many jurisdictions with varying health care systems have shown that recommended processes of care occur less often than they should; hence, outcomes of care are inadequate. Many studies comparing care between specialists and generalists have found that specialists are more likely to implement processes of care. However, this provides little insight into improving quality of care, as the difference between specialists and generalists in these studies is small compared to the overall deficiency in quality. Therefore, future research should instead focus on ways to implement high quality care, regardless of specialty. To date, few methodologically rigorous studies have uncovered interventions that can improve quality of care. The development of such interventions to help all physicians implement better quality care could greatly benefit people with diabetes.

Administrative data algorithms can describe ambulatory physician utilization.

OBJECTIVE: To validate algorithms using administrative data that characterize ambulatory physician care for patients with a chronic disease. DATA SOURCES: Seven-hundred and eighty-one people with diabetes were recruited mostly from community pharmacies to complete a written questionnaire about their physician utilization in 2002. These data were linked with administrative databases detailing health service utilization. STUDY DESIGN: An administrative data algorithm was defined that identified whether or not patients received specialist care, and it was tested for agreement with self-report. Other algorithms, which assigned each patient to a primary care and specialist physician, were tested for concordance with self-reported regular providers of care. PRINCIPAL FINDINGS: The algorithm to identify whether participants received specialist care had 80.4 percent agreement with questionnaire responses (kappa=0.59). Compared with self-report, administrative data had a sensitivity of 68.9 percent and specificity 88.3 percent for identifying specialist care. The best administrative data algorithm to assign each participant's regular primary care and specialist providers was concordant with self-report in 82.6 and 78.2 percent of cases, respectively. CONCLUSIONS: Administrative data algorithms can accurately match self-reported ambulatory physician utilization.

Thiazolidinediones and cardiovascular outcomes in older patients with diabetes.

CONTEXT: Thiazolidinediones (TZDs), used to treat type 2 diabetes, are associated with an excess risk of congestive heart failure and possibly acute myocardial infarction. However, the association between TZD use and cardiovascular events has not been adequately evaluated on a population level. OBJECTIVE: To explore the association between TZD therapy and congestive heart failure, acute myocardial infarction, and mortality compared with treatment with other oral hypoglycemic agents. DESIGN, SETTING, AND PATIENTS: Nested case-control analysis of a retrospective cohort study using health care databases in Ontario. We included diabetes patients aged 66 years or older treated with at least 1 oral hypoglycemic agent between 2002 and 2005 (N = 159 026) and followed them up until March 31, 2006. MAIN OUTCOME MEASURES: The primary outcome consisted of an emergency department visit or hospitalization for congestive heart failure; secondary outcomes were an emergency department visit or hospitalization for acute myocardial infarction and all-cause mortality. The risks of these events were compared between persons treated with TZDs (rosiglitazone and pioglitazone) and other oral hypoglycemic agent combinations, after matching and adjusting for prognostic factors. RESULTS: During a median follow-up of 3.8 years, 12 491 patients (7.9%) had a hospital visit for congestive heart failure, 12,578 (7.9%) had a visit for acute myocardial infarction, and 30 265 (19%) died. Current treatment with TZD monotherapy was associated with a significantly increased risk of congestive heart failure (78 cases; adjusted rate ratio [RR], 1.60; 95% confidence interval [CI], 1.21-2.10; P < .001), acute myocardial infarction (65 cases; RR, 1.40; 95% CI, 1.05-1.86; P = .02), and death (102 cases; RR, 1.29; 95% CI, 1.02-1.62; P = .03) compared with other oral hypoglycemic agent combination therapies (3478 congestive heart failure cases, 3695 acute myocardial infarction cases, and 5529 deaths). The increased risk of congestive heart failure, acute myocardial infarction, and mortality associated with TZD use appeared limited to rosiglitazone. CONCLUSION: In this population-based study of older patients with diabetes, TZD treatment, primarily with rosiglitazone, was associated with an increased risk of congestive heart failure, acute myocardial infarction, and mortality when compared with other combination oral hypoglycemic agent treatments.

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.

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.

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.