Dataset Information

Consistency of Hemoglobin A1c Testing and Cardiovascular Outcomes in Medicare Patients With Diabetes.

ABSTRACT:

Background

Annual hemoglobin A1c testing is recommended for patients with diabetes mellitus. However, it is unknown how consistently patients with diabetes mellitus receive hemoglobin A1c testing over time, or whether testing consistency is associated with adverse cardiovascular outcomes.

Methods and results

We identified 1 574 415 Medicare patients (2002-2012) with diabetes mellitus over the age of 65. We followed each patient for a minimum of 3 years to determine their consistency in hemoglobin A1C testing, using 3 categories: low (testing in 0 or 1 of 3 years), medium (testing in 2 of 3 years), and high (testing in all 3 years). In unweighted and inverse propensity-weighted cohorts, we examined associations between testing consistency and major adverse cardiovascular events, defined as death, myocardial infarction, stroke, amputation, or the need for leg revascularization. Overall, 70.2% of patients received high-consistency testing, 17.6% of patients received medium-consistency testing, and 12.2% of patients received low-consistency testing. When compared to high-consistency testing, low-consistency testing was associated with a higher risk of adverse cardiovascular events or death in unweighted analyses (hazard ratio [HR]=1.21; 95% CI, 1.20-1.23; P<0.001), inverse propensity-weighted analyses (HR=1.16; 95% CI, 1.15-1.17; P<0.001), and weighted analyses limited to patients who had at least 4 physician visits annually (HR=1.15; 95% CI, 1.15-1.16; P<0.001). Less-consistent testing was associated with worse results for each cardiovascular outcome and in analyses using all years as the exposure.

Conclusions

Consistent annual hemoglobin A1c testing is associated with fewer adverse cardiovascular outcomes in this observational cohort of Medicare patients of diabetes mellitus.

SUBMITTER: Goodney PP

PROVIDER: S-EPMC5015285 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

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Publications

Consistency of Hemoglobin A1c Testing and Cardiovascular Outcomes in Medicare Patients With Diabetes.

Goodney Philip P PP Newhall Karina A KA Bekelis Kimon K Gottlieb Daniel D Comi Richard R Chaudrain Sushela S Faerber Adrienne E AE Mackenzie Todd A TA Skinner Jonathan S JS

Journal of the American Heart Association 20160810 8

<h4>Background</h4>Annual hemoglobin A1c testing is recommended for patients with diabetes mellitus. However, it is unknown how consistently patients with diabetes mellitus receive hemoglobin A1c testing over time, or whether testing consistency is associated with adverse cardiovascular outcomes.<h4>Methods and results</h4>We identified 1 574 415 Medicare patients (2002-2012) with diabetes mellitus over the age of 65. We followed each patient for a minimum of 3 years to determine their consisten ...[more]

PMID: 27509909

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Project description:BackgroundMajor (above-knee or below-knee) amputation is a complication of diabetes and is seen more common among black and Hispanic patients. While amputation rates have declined for patients with diabetes in the last decade, it remains unknown if these improvements have equitably extended across racial groups and if measures of diabetic care, such as hemoglobin A1c testing, are associated with these improvements. We set out to characterize secular changes in amputation rates among black, Hispanic, and white patients, and to determine associations between hemoglobin A1c testing and amputation risk.MethodsWe identified 11,942,840 Medicare patients (55% female) with diabetes over the age of 65 years between 2002 and 2012 and followed them for a mean of 6.6 years. Of these, 86% were white, 11.5% were black, and 2.5% were Hispanic. We recorded the occurrence of major amputation and hemoglobin A1c testing during this time period and studied secular changes in amputation rate by race (black, Hispanic, and white). Finally, we examined associations between amputation risk and hemoglobin A1c testing. We measured both the presence of any testing and testing consistency using 3 categories: poor consistency (hemoglobin A1c testing in 0-50% of years), medium consistency (testing in 50-90% of years), and high consistency (testing in >90% of the years in the cohort).ResultsBetween 2002 and 2012, the average major lower-extremity amputation rate in diabetic Medicare patients was 1.78 per 1,000 per year for black patients, 1.15 per 1,000 per year for Hispanic patients, and 0.56 per 1,000 per year for white patients (P < 0.001). Over the study period, the incidence of major amputation in Medicare patients with diabetes declined by 54%, from 1.15 per 1,000 in 2002 to 0.53 per 1,000 in 2012 (rate ratio = 0.53, 95% CI = 0.51-0.54). The reduction in amputation rate was similar across racial groups: 52% for black patients, 61% for Hispanic patients, and 55% for white patients. In multivariable analysis adjusting for patient characteristics, including race, any use of hemoglobin A1c testing was associated with a 15% decline in amputation risk (hazard ratio, 0.85; 95% CI, 0.83-0.87; P < 0.001). High consistency hemoglobin A1c testing was associated with a 39% decline in amputation (hazard ratio, 0.61; 95% CI, 0.59-0.62; P < 0.0001).ConclusionsAlthough more frequent among racial minorities, major lower-extremity amputation rates have declined similarly across black, Hispanic, and white patients over the last decade. Hemoglobin A1c testing, particularly the consistency of testing over time, may be an effective component metric of longitudinal quality measures toward limiting amputation in all races.

Project description:BackgroundProposed payment reforms in the US healthcare system would hold providers accountable for the care delivered to an assigned patient population. Annual hemoglobin A1c (HbA1c) tests are recommended for all diabetics, but some patient populations may face barriers to high quality healthcare that are beyond providers' control. The magnitude of fine-grained variations in care for diabetic Medicare beneficiaries, and their associations with local population characteristics, are unknown.MethodsHbA1c tests were recorded for 480,745 diabetic Medicare beneficiaries. Spatial analysis was used to create ZIP code-level estimated testing rates. Associations of testing rates with local population characteristics that are outside the control of providers--population density, the percent African American, with less than a high school education, or living in poverty--were assessed.ResultsIn 2009, 83.3% of diabetic Medicare beneficiaries received HbA1c tests. Estimated ZIP code-level rates ranged from 71.0% in the lowest decile to 93.1% in the highest. With each 10% increase in the percent of the population that was African American, associated HbA1c testing rates were 0.24% lower (95% CI -0.32--0.17); for identical increases in the percent with less than a high school education or the percent living in poverty, testing rates were 0.70% lower (-0.95--0.46) and 1.6% lower (-1.8--1.4), respectively. Testing rates were lowest in the least and most densely populated ZIP codes. Population characteristics explained 5% of testing rate variations.ConclusionsHbA1c testing rates are associated with population characteristics, but these characteristics fail to explain the vast majority of variations. Consequently, even complete risk-adjustment may have little impact on some process of care quality measures; much of the ZIP code-related variations in testing rates likely result from provider-based differences and idiosyncratic local factors not related to poverty, education, or race.

Project description:BACKGROUND:Patients' understanding of the hemoglobin A1c (HbA1c) has been linked to better diabetes care outcomes (glycemic control, self-care). This is concerning given low documented rates of HbA1c understanding. In this non-blinded, randomized trial, we compared two formats for communicating the HbA1c, selected based on input from people with diabetes, to standard presentation to assess their impact on participants' glycemic control and diabetes-related perceptions. METHODS:To design the tested formats, we interviewed 25 patients with diabetes and reviewed a range of possible formats, including color-based scales and graphs. The interviews were recorded, transcribed, and subjected to thematic analysis. Synthesizing interviewees' feedback, we selected two formats, one using a combination of words and colors (Words) and one using a color-coded graph (Graph), for further evaluation. We then randomized adults with poorly controlled diabetes to receive mailed information on their current diabetes control in one of three ways: 1) standard lab report (control), 2) Words format, or 3) Graph format. The primary outcome was HbA1c change at 6 months. Also examined were changes in participants' diabetes-related perceptions and choice of participation incentive. RESULTS:Of the 234 enrolled participants, 76.9% were Black, and their median baseline HbA1c was 9.1% (interquartile range 8.4-10.4). There were no between-arm differences in HbA1c change (-?1.04% [SD 2.2] Control vs. -0.59% [SD 2.0] Words vs. -0.54% [SD 2.1] Graph, p >?0.05 for all comparisons). Participants in the Words arm had an increase in the accuracy of their perceptions of diabetes seriousness (p =?0.04) and in the number of participants reporting a diabetes management goal (p =?0.01). CONCLUSIONS:The two patient-informed communication formats did not differentially impact glycemic control among adults with inadequately controlled diabetes. However, a significant proportion of participants in the Words arm had an increase in the accuracy of their perception of diabetes seriousness, a potential mediating factor in positive diabetes-related behavioral changes. With increasing use of patient-facing online portals, thoughtfully designed approaches for visually communicating essential, but poorly understood, information like the HbA1c to patients have the potential to facilitate interpretation and support self-management. CLINICAL TRIAL REGISTRATION:Prospectively registered as NCT01886170.

Dataset Information

Consistency of Hemoglobin A1c Testing and Cardiovascular Outcomes in Medicare Patients With Diabetes.

Background

Methods and results

Conclusions

Publications

Consistency of Hemoglobin A1c Testing and Cardiovascular Outcomes in Medicare Patients With Diabetes.

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