The effect of specialist care within the first year on subsequent outcomes in 24,232 adults with new-onset diabetes mellitus: population-based cohort study

BACKGROUND

Although specialty care has been shown to improve short-term outcomes in patients hospitalised with acute medical conditions, its effect on patients with chronic conditions treated in the ambulatory care setting is less clear.

OBJECTIVE

To examine whether specialty care (ie, consultative care provided by an endocrinologist or a general internist in concert with a patient's primary care doctor) within the first year of diagnosis is associated with improved outcomes after the first year for adults with diabetes mellitus treated as outpatients.

DESIGN

Population-based cohort study using linked administrative data.

SETTING

The province of Saskatchewan, Canada.

SAMPLE

24 232 adults newly diagnosed with diabetes mellitus between 1991 and 2001.

METHOD

The primary outcome was all-cause mortality. Analyses used multivariate Cox proportional hazards models with time-dependent covariates, propensity scores and case mix variables (demographic, disease severity and comorbidities). In addition, restriction analyses examined the effect of specialist care in low-risk subgroups.

RESULTS

The median age of patients was 61 years, and over a mean follow-up of 4.9 years 2932 (12%) died. Patients receiving specialty care were younger, had a greater burden of comorbidities, and visited doctors more often before and after their diabetes diagnosis (all p< or =0.001). Compared with patients seen by primary care doctors alone, patients seen by specialists and primary care doctors were more likely to receive recommended treatments (all p< or =0.001), but were more likely to die (13.1% v 11.7%, adjusted hazard ratio (HR) 1.17, 95% confidence interval (CI) 1.08 to 1.27). This association persisted even in patients without comorbidities or target organ damage (adjusted HR 1.16, 95% CI 1.01 to 1.34).

CONCLUSION

Specialty care was associated with better disease-specific process measures but not improved survival in adults with diabetes cared for in ambulatory care settings.

Assessing responsiveness of generic and specific health related quality of life measures in heart failure

Background

Responsiveness, or sensitivity to clinical change, is an important consideration in selection of a health-related quality of life (HRQL) measure for trials or clinical applications. Many approaches can be used to assess responsiveness, which may affect the interpretation of study results. We compared the relative responsiveness of generic and heart failure specific HRQL instruments, as measured both by common psychometric indices and by external clinical criteria.

Methods

We analyzed data collected at baseline and 6-weeks in 298 subjects with heart failure on the following HRQL measures: EQ-5D (US, UK, and VAS Scoring), Kansas City Cardiomyopathy Questionnaire (KCCQ) (Clinical and Overall Summary Score), and RAND12 (Physical and Mental Component Summaries). Three external indicators of clinical change were used to classify subjects as improved, deteriorated, or unchanged: 6-minute walk test, New York Heart Association (NYHA) class, and physician global rating of change. Four responsiveness statistics (T-test, effect size, Guyatt's responsiveness statistic, and standardized response mean) were used to evaluate the responsiveness of the select measures. The median rank of each HRQL measure across responsiveness indices and clinical criteria was then determined.

Results

Average age of subjects was 60 years, 75 percent were male, and had moderate to severe heart failure symptoms. Overall, the KCCQ Summary Scores had the highest relative ranking, irrespective of the responsiveness index or external criterion used. Importantly, we observed that the relative ranking of responsiveness of the generic measures (i.e. EQ-5D, RAND12) was influenced by both the responsive indices and external criterion used.

Conclusion

The disease specific KCCQ was the most responsive HRQL measure assessing change over a 6-week period, although generic measures provide information for which the KCCQ is not suitable. The responsiveness of generic HRQL measures may be affected by the index used, as well as the external criterion to classify patients who have clinically change or remained stable.

Statins and outcomes in patients admitted to hospital with community acquired pneumonia: population based prospective cohort study

OBJECTIVES

To determine whether statins reduce mortality or need for admission to intensive care in patients admitted to hospital with community acquired pneumonia; and to assess whether previously reported improvements in sepsis related outcomes were a result of the healthy user effect.

DESIGN

Population based prospective cohort study.

SETTING

Six hospitals in Capital Health, Edmonton, Alberta, Canada.

PARTICIPANTS

Adults admitted to hospital with pneumonia and categorised according to use of statins for at least one week before admission and during hospital stay.

MAIN OUTCOME MEASURES

Composite of in-hospital mortality or admission to an intensive care unit.

RESULTS

Of 3415 patients with pneumonia admitted to hospital, 624 (18%) died or were admitted to an intensive care unit. Statin users were less likely to die or be admitted to an intensive care unit than non-users (50/325 (15%) v 574/3090 (19%), odds ratio 0.80, P=0.15). After more complete adjustment for confounding, however, the odds ratios changed from potential benefit (0.78, adjusted for age and sex) to potential harm (1.10, fully adjusted including propensity scores, 95% confidence interval 0.76 to 1.60).

CONCLUSIONS

Statins are not associated with reduced mortality or need for admission to an intensive care unit in patients with pneumonia; reports of benefit in the setting of sepsis may be a result of confounding.

A meta-analysis of the association between adherence to drug therapy and mortality

OBJECTIVE

To evaluate the relation between adherence to drug therapy, including placebo, and mortality.

DESIGN

Meta-analysis of observational studies.

DATA SOURCES

Electronic databases, contact with investigators, and textbooks and reviews on adherence. Review methods Predefined criteria were used to select studies reporting mortality among participants with good and poor adherence to drug therapy. Data were extracted for disease, drug therapy groups, methods for measurement of adherence rate, definition for good adherence, and mortality.

RESULTS

Data were available from 21 studies (46,847 participants), including eight studies with placebo arms (19,633 participants). Compared with poor adherence, good adherence was associated with lower mortality (odds ratio 0.56, 95% confidence interval 0.50 to 0.63). Good adherence to placebo was associated with lower mortality (0.56, 0.43 to 0.74), as was good adherence to beneficial drug therapy (0.55, 0.49 to 0.62). Good adherence to harmful drug therapy was associated with increased mortality (2.90, 1.04 to 8.11).

CONCLUSION

Good adherence to drug therapy is associated with positive health outcomes. Moreover, the observed association between good adherence to placebo and mortality supports the existence of the "healthy adherer" effect, whereby adherence to drug therapy may be a surrogate marker for overall healthy behaviour.

Dose-response relation between sulfonylurea drugs and mortality in type 2 diabetes mellitus: a population-based cohort study

BACKGROUND

Over the past 30 years, the relation between use of sulfonylureas to treat type 2 diabetes and the risk of cardiovascular events has been vigorously debated. The purpose of this study was to determine if the risk of death changes with level of exposure to sulfonylurea drugs.

METHODS

This was a retrospective, inception cohort study using administrative data from Saskatchewan Health (1991-1999). The 5795 subjects, identified by their first-ever dispensation for an oral antidiabetic agent, were grouped according to their use of such agents during follow-up. Potential subjects using insulin or combination therapy were excluded. Exposure level was defined by daily dose and degree of adherence. Separate multivariate Cox proportional-hazard models were constructed for each monotherapy group and used to calculate the risk of death associated with higher versus lower exposure category. Disease severity indicators were identified among the administrative data and entered as covariates in each model. The main outcomes were all-cause mortality and death from an acute ischemic event.

RESULTS

The mean age of the cohort members was 66.3 (standard deviation [SD] 13.4) years; 43.4% were female; and their mean duration of follow-up was 4.6 (SD 2.1) years. First-generation sulfonylureas were used exclusively by 120 subjects; glyburide, by 4138; and metformin, by 1537. A greater risk of death was associated with higher daily doses of the first-generation sulfonylureas (adjusted hazard ratio [HR] 2.1, 95% confidence interval [CI] 1.0-4.7) and glyburide (HR 1.3, 95% CI 1.2-1.4), but not metformin (HR 0.8, 95% CI 0.7-1.1). Similar associations were observed for death caused by an acute ischemic event.

INTERPRETATION

Higher exposure to sulfonylureas was associated with increased mortality among patients newly treated for type 2 diabetes. The same relation was not observed with metformin. This implies that the manner in which blood glucose concentration is lowered may be as important as achieving recommended glucose targets.

Improved clinical outcomes associated with metformin in patients with diabetes and heart failure

OBJECTIVE

Metformin is considered contraindicated in patients with heart failure because of concerns over lactic acidosis, despite increasing evidence of potential benefit. The aim of this study was to evaluate the association between metformin and clinical outcomes in patients with heart failure and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Using the Saskatchewan Health databases, 12,272 new users of oral antidiabetic agents were identified between the years 1991 and 1996. Subjects with incident heart failure (n = 1,833) were identified through administrative records based on ICD-9 code 428 and grouped according to antidiabetic therapy: metformin monotherapy (n = 208), sulfonylurea monotherapy (n = 773), or combination therapy (n = 852). Multivariate Cox proportional hazards models were used to assess differences in all-cause mortality, all-cause hospitalization, and the combination (i.e., all-cause hospitalization or mortality).

RESULTS

Average age of subjects was 72 years, 57% were male, and average follow-up was 2.5 +/- 2.0 (SD) years. Compared with sulfonylurea therapy, fewer deaths occurred in subjects receiving metformin: 404 (52%) for sulfonylurea monotherapy versus 69 (33%) for metformin monotherapy (hazard ratio [HR] 0.70 [95% CI 0.54-0.91]) and 263 (31%) for combination therapy (0.61 [0.52-0.72]). A reduction in deaths or hospitalizations was also observed: 658 (85%) for sulfonylurea monotherapy versus 160 (77%) for metformin monotherapy (0.83 [0.70-0.99]) and 681 (80%) for combination therapy (0.86 [0.77-0.96]). There was no difference in time to first hospitalization between study groups.

CONCLUSIONS

Metformin, alone or in combination, in subjects with heart failure and type 2 diabetes was associated with lower morbidity and mortality compared with sulfonylurea monotherapy.

Risk factors for new-onset diabetes mellitus in patients receiving protease inhibitor therapy

BACKGROUND

Metabolic complications including diabetes mellitus (DM) have been associated with protease inhibitor (PI) therapy. Risk factors for the development of DM are not well-defined.

OBJECTIVES

To determine risk factors for the development of new-onset DM in patients initiated on PI therapy.

METHODS

A retrospective cohort study was conducted to identify predictors of developing DM in subjects started on PI therapy between January 1997 and January 2003. Diabetes cases were defined as physician documentation of DM in the outpatient medical chart and/or those subjects receiving an antidiabetic agent. Logistic regression was used to examine the relationship between new-onset DM and demographic characteristics, and between new-onset DM and total treatment days with PI therapy. Body mass index could not be entered into the model due to missing height measurements.

RESULTS

A total of 496 subjects on PI therapy were included, of which 18 (3.6%) developed DM. The mean age of the subjects was 43.4+/-9.4 years (range 19 to 77) and the mean duration of therapy was 3.0+/-1.9 years (range 0.17 to 7.9). In the multivariate model, older subjects were more likely to develop DM (OR 1.12, 95% CI 1.05 to 1.19; P=0.001). This corresponds to a 12% increased risk of DM for each one-year increase in age. Subjects that weighed more had an increased risk (OR 1.06, 95% CI 1.03 to 1.10; P=0.001), as did those belonging to a non-Aboriginal minority group when compared with Caucasians (OR 6.67, 95% CI 1.56 to 28.41; P=0.01). A longer duration of PI therapy was also significantly associated with developing DM (OR 1.52, 95% CI 1.07 to 2.17; P=0.02).

CONCLUSION

A longer duration of PI therapy is associated with an increased risk of developing DM. As with HIV-negative subjects, demographic characteristics such as age, weight and ethnicity were important predictors of developing DM in the present study.

Secondary Failure Rates Associated with Metformin and Sulfonylurea Therapy for Type 2 Diabetes Mellitus

STUDY OBJECTIVE

To determine whether metformin therapy, compared with sulfonylurea therapy, is associated with a delayed onset of secondary failure in patients with type 2 diabetes mellitus.

DESIGN

Retrospective cohort study.

DATA SOURCE

Outpatient prescription database from Saskatchewan Health, Saskatchewan, Canada.

PATIENTS

Two cohorts-5077 individuals receiving sulfonylurea monotherapy and 1652 receiving metformin monotherapy for 2 years or longer-identified from a population of 12,272 new users of oral antidiabetic agents between 1991 and 1996 and who were followed through 1999.

MEASUREMENTS AND MAIN RESULTS

The association between initial drug therapy and onset of secondary failure was evaluated using multivariate Cox proportional hazard models in which the sulfonylurea monotherapy cohort was the reference group. Secondary failure was defined as progression to combination oral therapy or a switch in oral therapy; each component (e.g., time to combination therapy or first switch) of this definition, including start of insulin therapy, was assessed as a secondary outcome. The subjects' mean age was 63.8 years, and 3787 (56.3%) were men. Subjects were followed for a mean +/- SD of 5.7 +/- 1.8 years. Metformin monotherapy was associated with a delay in the onset of secondary failure (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.82-0.98), in the progression to combination therapy (HR 0.79, 95% CI 0.71-0.87), and in the start of insulin therapy (HR 0.65, 95% CI 0.51-0.82). Of note, patients receiving metformin monotherapy first were more likely than those receiving sulfonylurea monotherapy first to switch treatments (HR 1.43, 95% CI 1.17-1.75).

CONCLUSION

Compared with sulfonylurea therapy, metformin therapy appears to be associated with a delay in the onset of secondary failure.

Generalizability and persistence of a multifaceted intervention for improving quality of care for rural patients with type 2 diabetes

OBJECTIVE

Most quality improvement efforts for type 2 diabetes have neglected cardiovascular risk factors and are limited by a lack of information about generalizability across settings or persistence of effect over time.

RESEARCH DESIGN AND METHODS

We previously reported 6-month results of a controlled study of an intervention that improved cardiovascular risk factors for rural patients with type 2 diabetes. We subsequently provided the identical intervention to the control region after the main study was completed. The primary outcome was 10% improvement in systolic blood pressure, total cholesterol, or HbA(1c). We compared the previously reported 6-month effect of the original intervention with the effect of the crossed-over intervention to the former control region and remeasured outcomes in the original intervention region 12 months later.

RESULTS

Our analysis included 200 original intervention and 181 crossed-over intervention subjects. The age of the population was 62.4 +/- 12.4 years (mean +/- SD), and 54.3% were women. A similar proportion of patients in the crossed-over intervention group achieved improvement in the primary composite outcome compared with the original intervention group (38 vs. 44%, respectively; P = 0.29). In adjusted analyses, we observed less improvement in blood pressure (adjusted odds ratio 0.40 [95% CI 0.17-0.75]) but greater improvements in total cholesterol (1.86 [0.93-3.7]) with the crossed-over intervention compared with the original intervention. We observed sustained improvements in total cholesterol and HbA(1c) levels in the original intervention group, whereas previous large gains in control of blood pressure diminished over time.

CONCLUSIONS

We found that our intervention was generalizable across settings, and its effect persisted over time. Nevertheless, without ongoing intervention or reinforcement, we noted some loss of the original benefits that had accrued. Future translational work should incorporate interventions such as ours into ongoing systems of rural care.

A multicenter disease management program for hospitalized patients with heart failure

BACKGROUND

Despite the availability of proven therapies, outcomes in patients with heart failure (HF) remain poor. In this 2-stage, multicenter trial, we evaluated the effect of a disease management program on clinical and economic outcomes in patients with HF.

METHODS AND RESULTS

In Stage 1, a pharmacist or nurse assessed each patient and made recommendations to the physician to add or adjust angiotensin-converting enzyme (ACE) inhibitors and other HF medications. Before discharge (Stage 2), patients were randomized to a patient support program (PSP) (education about HF, self-monitoring, adherence aids, newsletters, telephone hotline, and follow-up at 2 weeks, then monthly for 6 months after discharge) or usual care. In Stage 1 (766 patients) ACE inhibitor use increased from 58% on admission to 83% at discharge (P < .0001), and the daily dose (in enalapril equivalents) increased from 11.3 +/- 8.8 mg to 14.5 +/- 8.8 mg (P < .0001). In Stage 2 (276 patients) there was no difference in ACE inhibitor adherence, but a reduction in cardiovascular-related emergency room visits (49 versus 20, P = .030), hospitalization days (812 versus 341, P = .003), and cost of care (2,531 Canadian dollars less per patient) in favor of the PSP.

CONCLUSION

Simple interventions can improve ACE inhibitor use and patient outcomes.

Reduced mortality associated with the use of ACE inhibitors in patients with type 2 diabetes

OBJECTIVE

ACE inhibitor therapy is widely used in lower-risk patients with type 2 diabetes to reduce mortality, despite limited evidence to support this clinical strategy. The aim of this study was to evaluate the association between ACE inhibitor use and mortality in patients with diabetes and no cardiovascular disease. RESEARCH DESIGN AND SETTINGS: Using the Saskatchewan health databases, 12,272 new users of oral hypoglycemic agents were identified between the years of 1991 and 1996. We excluded 3,202 subjects with previous cardiovascular disease. Of the remaining subjects, 1,187 "new users" of ACE inhibitors were identified (ACE inhibitor cohort). Subjects not receiving ACE inhibitor therapy throughout the follow-up period served as the control cohort (n = 4,989). Subjects were prospectively followed until death or the end of 1999. Multivariate Cox proportional hazards models were used to assess differences in all-cause and cardiovascular-related mortality between cohort groups.

RESULTS

Subjects were 60.7 +/- 13.7 years old, 43.6% female, and were followed for an average of 5.3 +/- 2.1 years. Mean duration of ACE inhibitor therapy was 3.6 +/- 1.8 years. We observed significantly fewer deaths in the ACE inhibitor group (102 [8.6%]) compared with the control cohort (853 [17.1%]), with an adjusted hazard ratio (HR) and 95% CI of 0.49 (0.40-0.61) (P < 0.001). Cardiovascular-related mortality was also reduced (40 [3.4%] vs. 261 [5.2%], adjusted HR, 0.63 [0.44-0.90]; P = 0.012).

CONCLUSIONS

The use of ACE inhibitors was associated with a significant reduction in all-cause and cardiovascular-related mortality in a broad spectrum of patients with type 2 diabetes and no cardiovascular disease.