Beta-blocker dosages and mortality after myocardial infarction: data from a large health maintenance organization.

BACKGROUND: Although long-term beta-blocker therapy has been found beneficial in patients after an acute myocardial infarction, these drugs are greatly underused by clinicians. Moreover, the dosages of beta-blockers used in randomized controlled trials appear to be much larger than those routinely prescribed. OBJECTIVE: To determine whether an association exists between the dosage of beta-blockers prescribed after a myocardial infarction and cardiac mortality. METHODS: We performed a retrospective cohort study of 1165 patients who survived an acute myocardial infarction from January 1, 1990, through December 31, 1992. These patients represent a subgroup of the 6851 patients hospitalized at northern California Kaiser Permanente hospitals. RESULTS: Of the 37.7% of patients prescribed beta-blocker therapy, 48.1% were treated with dosages less than 50% of the dosage found to be effective in preventing cardiac death in large randomized clinical trials (lower-dosage therapy). Compared with patients not receiving beta-blockers, those treated with lower-dosage therapy appeared to have a greater reduction in cardiovascular mortality (hazard ratio, 0.33; P=.009) than patients treated with a higher dosage (hazard ratio, 0.82; P=0.51), after adjustment for age, sex, race, disease severity, and comorbidities. CONCLUSIONS: The dosages of beta-blockers shown to be effective in randomized trials are not commonly used in clinical practice, and treatment with lower dosages of beta-blockers was associated with at least as great a reduction in mortality as treatment with higher dosages. This suggests that physicians who are reluctant to prescribe beta-blockers because of the relatively large dosages used in the large prospective clinical trials should be encouraged to prescribe smaller dosages.

First 20 months' experience with use of metformin for type 2 diabetes in a large health maintenance organization.

OBJECTIVE: To assess adherence to prescribing guidelines, continuation rates, population effects on glycemic control, and occurrence of lactic acidosis during the first 20 months of the availability of metformin in a large health maintenance organization. RESEARCH DESIGN AND METHODS: A retrospective cohort study was performed in the 90,000-member diabetes registry of Kaiser Permanente, northern California. Principal study measures were the proportions of patients started on metformin who met prescribing guidelines (previously on sulfonylureas, HbA1c, obesity, creatinine), the change in HbA1c at 6 months after starting metformin, and hospitalization rates for lactic acidosis. RESULTS: A total of 9,875 patients received metformin during this interval. At least 74% were previously treated with sulfonylureas alone, 81% had baseline HbA1c > or = 8.5%, 71% were obese, and 99% had a serum creatinine < or = 1.5 mg/dl. Among patients on sulfonylureas at baseline, those starting metformin had significantly lower HbA1c levels 6 months later than those not started, after adjustment for age, sex, and the higher baseline levels in those started (adjusted difference: 0.5%, P < 0.0001). Patients starting metformin as initial monotherapy also improved significantly, but patients previously treated with insulin (with or without sulfonyl-ureas) had slightly higher follow-up HbA1c levels than similar patients not starting metformin. Continuation of metformin at 12 months was significantly higher for patients previously treated with sulfonylureas than other groups. One probable case of lactic acidosis was identified during 4,502 person-years on metformin. CONCLUSIONS: Adherence to prescribing guidelines was relatively high during metformin's first 20 months of availability. Glycemic control improved substantially for patients previously treated with sulfonylureas. Lactic acidosis was rare.

Diabetes management in a health maintenance organization. Efficacy of care management using cluster visits.

OBJECTIVE: To evaluate the effectiveness of a cluster visit model led by a diabetes nurse educator for delivering outpatient care management to adult patients with poorly controlled diabetes. RESEARCH DESIGN AND METHODS: This study involved a randomized controlled trial among patients of Kaiser Permanente's Pleasanton, CA, center who were aged 16-75 years and had either poor glycemic control (HbA1c > 8.5%) or no HbA1c test performed during the previous year. Intervention subjects received multidisciplinary outpatient diabetes care management delivered by a diabetes nurse educator, a psychologist, a nutritionist, and a pharmacist in cluster visit settings of 10-18 patients/month for 6 months. Outcomes included change (from baseline) in HbA1c levels; self-reported changes in self-care practices, self-efficacy, and satisfaction; and utilization of inpatient and outpatient health care. RESULTS: After the intervention, HbA1c levels declined by 1.3% in the intervention subjects versus 0.2% in the control subjects (P < 0.0001). Several self-care practices and several measures of self-efficacy improved significantly in the intervention group. Satisfaction with the program was high. Both hospital (P = 0.04) and outpatient (P < 0.01) utilization were significantly lower for intervention subjects after the program. CONCLUSIONS: A 6-month cluster visit group model of care for adults with diabetes improved glycemic control, self-efficacy, and patient satisfaction and resulted in a reduction in health care utilization after the program.

Effect of a copayment on use of the emergency department in a health maintenance organization.

BACKGROUND: Use of the emergency department for nonemergency care is frequent and costly. We studied the effect of a copayment on emergency department use in a group-model health maintenance organization (HMO). METHODS: We examined the use of the emergency department in 1992 and 1993 by 30,276 subjects who ranged in age from 1 to 63 years at the start of the study and belonged to the Kaiser Permanente HMO in northern California. We assessed their use of various HMO services and their clinical outcomes before and after the introduction of a copayment of $25 to $35 for using the emergency department. This copayment group was compared with two randomly selected control groups not affected by the copayment. One control group, with 60,408 members, was matched for age, sex, and area of residence to the copayment group. The second, with 37,539 members, was matched for these factors and also for the type of employer. RESULTS: After adjustment for age, sex, socioeconomic status, and use of the emergency department in 1992, the decline in the number of visits in 1993 was 14.6 percentage points greater in the copayment group than in either control group (P<0.001 for each comparison). Visits for urgent care did not increase among subjects in any stratum defined by age and sex, and neither did the number of outpatient visits by adults and children. The decline in emergency visits for presenting conditions classified as "always an emergency" was small and not significant. For conditions classified as "often an emergency". "sometimes not an emergency", or "often not an emergency", the declines in the use of the emergency department were larger and statistically significant, and they increased with decreasing severity of the presenting condition. Although our ability to detect any adverse effects of the copayment was limited, there was no suggestion of excess adverse events in the copayment group, such as increases in mortality or in the number of potentially avoidable hospitalizations. CONCLUSIONS: Among members of an HMO, the introduction of a small copayment for the use of the emergency department was associated with a decline of about 15 percent in the use of that department, mostly among patients with conditions considered likely not to present an emergency.

Effect of beta-adrenergic blocking agents on mortality rate in patients not revascularized after myocardial infarction: data from a large HMO.

We investigated whether patients who do not undergo coronary angiography and therefore any form of revascularization after a myocardial infarction derive greater benefit from chronic beta-blocker therapy than patients who undergo coronary angiography. With multivariate analyses, treatment with beta-blockers was a much stronger predictor of survival in patients who did not undergo coronary angiography (relative risk = 0.38, p = 0.005) than in those patients who did undergo catheterization (p < 0.05 for interaction). Our findings provide direct support for the recommendation by the American College of Cardiology/American Heart Association task force that beta-blocker therapy should be initiated for all infarct survivors who do not undergo revascularization and who have no contraindications.

Variation among hospitals in coronary-angiography practices and outcomes after myocardial infarction in a large health maintenance organization.

BACKGROUND: Wide geographic variation in the use of coronary angiography after myocardial infarction has been documented internationally and within the United States. An associated variation in clinical outcomes has not been consistently demonstrated. METHODS: We assessed the risk of death from heart disease and of any heart disease event (death, reinfarction, or rehospitalization) over a follow-up period of one to four years in 6851 patients hospitalized with acute myocardial infarction at 16 Kaiser Permanente hospitals from 1990 through 1992. The percentage of patients who underwent angiography within three months after infarction ranged from 30 to 77 percent. We selected a subcohort of 1109 patients from three hospitals with higher rates of angiography and four with lower rates for a record review to assess the severity of infarction, the number of coexisting conditions, treatments received, and the appropriateness and necessity of angiography, using established criteria. RESULTS: The rates of angiography were inversely related to the risk of death from heart disease (P= 0.03) and the risk of heart disease events (P<0.001) among the 16 hospitals after adjustment for age, sex, race, coexisting conditions, and the location of the infarction (subendocardial vs. transmural). In the subcohort, 440 patients met criteria indicating that angiography was necessary and 669 did not. Among the former, patients treated at hospitals with higher rates of angiography had a lower risk of death and of any heart disease event than those treated at hospitals with lower rates (hazard ratios, 0.67 and 0.72, respectively). Among the latter, the apparent benefits of being treated at hospitals with higher angiography rates were smaller (hazard ratios, 0.85 to 0.90 for death and any heart disease event, respectively). CONCLUSIONS: During the one to four years after myocardial infarction, patients treated at hospitals with higher rates of angiography had more favorable outcomes than those treated at hospitals with lower rates. This association was stronger among patients for whom published criteria indicated that angiography was necessary.