You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.
 

CME/CE

Hemoglobin A1C Levels Strongly Linked to Subsequent Mortality in Diabetes

  • Authors: News Author: Laurie Barclay, MD
    CME Author: Laurie Barclay, MD
  • CME/CE Released: 6/9/2008
  • THIS ACTIVITY HAS EXPIRED
  • Valid for credit through: 6/9/2009
Start Activity


Target Audience and Goal Statement

This article is intended for primary care clinicians, endocrinologists, diabetologists, and other specialists who care for patients with increased hemoglobin A1C levels.

The goal of this activity is to provide medical news to primary care clinicians and other healthcare professionals in order to enhance patient care.

Upon completion of this activity, participants will be able to:

  1. Describe the association between hemoglobin A1C levels and subsequent all-cause mortality in both men and women without a previous diagnosis of diabetes.
  2. Describe the association between hemoglobin A1C levels and subsequent mortality from specific disease categories in both men and women without a previous diagnosis of diabetes.


Disclosures

As an organization accredited by the ACCME, Medscape, LLC requires everyone who is in a position to control the content of an education activity to disclose all relevant financial relationships with any commercial interest. The ACCME defines "relevant financial relationships" as financial relationships in any amount, occurring within the past 12 months, including financial relationships of a spouse or life partner, that could create a conflict of interest.

Medscape, LLC encourages Authors to identify investigational products or off-label uses of products regulated by the US Food and Drug Administration, at first mention and where appropriate in the content.


Author(s)

  • Laurie Barclay, MD

    Laurie Barclay, MD is a freelance reviewer and writer for Medscape.

    Disclosures

    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.

Editor(s)

  • Brande Nicole Martin

    Brande Nicole Martin is the News CME editor for Medscape Medical News.

    Disclosures

    Disclosure: Brande Nicole Martin has disclosed no relevant financial information.

CME Author(s)

  • Laurie Barclay, MD

    Laurie Barclay, MD, is a freelance reviewer and writer for Medscape.

    Disclosures

    Disclosure: Laurie Barclay, MD, has disclosed no relevant financial relationships.


Accreditation Statements

    For Physicians

  • Medscape, LLC is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

    Medscape, LLC designates this educational activity for a maximum of 0.25 AMA PRA Category 1 Credit(s)™ . Physicians should only claim credit commensurate with the extent of their participation in the activity. Medscape Medical News has been reviewed and is acceptable for up to 300 Prescribed credits by the American Academy of Family Physicians. AAFP accreditation begins 09/01/07. Term of approval is for 1 year from this date. This activity is approved for 0.25 Prescribed credits. Credit may be claimed for 1 year from the date of this activity. AAFP credit is subject to change based on topic selection throughout the accreditation year.


    AAFP Accreditation Questions

    Contact This Provider

    For Nurses

  • This Activity is sponsored by Medscape Continuing Education Provider Unit.

    Medscape is an approved provider of continuing nursing education by the New York State Nurses Association, an accredited approver by the American Nurses Credentialing Center's Commission on Accreditation.

    Awarded 0.25 contact hour(s) of continuing nursing education for RNs and APNs; None of these credits is in the area of pharmacology.

    Provider Number: 6FDKKC-PRV-05

    Contact This Provider

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]


Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page.

Follow these steps to earn CME/CE credit*:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. Medscape encourages you to complete the Activity Evaluation to provide feedback for future programming.

You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 5 years; at any point within this time period you can print out the tally as well as the certificates by accessing "Edit Your Profile" at the top of your Medscape homepage.

*The credit that you receive is based on your user profile.

CME/CE

Hemoglobin A1C Levels Strongly Linked to Subsequent Mortality in Diabetes

Authors: News Author: Laurie Barclay, MD CME Author: Laurie Barclay, MDFaculty and Disclosures
THIS ACTIVITY HAS EXPIRED

CME/CE Released: 6/9/2008

Valid for credit through: 6/9/2009

processing....

June 9, 2008 — Hemoglobin A1C (A1C) levels are strongly associated with subsequent mortality in both men and women without a previous diabetes diagnosis, according to the results of the largest study to date of A1C levels and subsequent mortality risk, reported in the June issue of Diabetes Care.

"Only a few prospective studies have examined the associations between A1C among subjects initially free of diabetes and subsequent risk of mortality," write Naomi Brewer, MMedSci, from the Centre for Public Health Research, Massey University in Wellington, New Zealand, and colleagues. "Each of these studies found associations with subsequent mortality. A1C levels have also been associated with mortality in patients with type 1 diabetes and nondiabetic chronic kidney disease and with incident cardiovascular disease."

The goal of this study was to evaluate the association between A1C concentration and mortality rate in a New Zealand population. From 1999 to 2001, participants were offered A1C testing during a Hepatitis Foundation screening campaign for hepatitis B. These participants were anonymously linked to the database for national mortality through December 31, 2004. Cox regression was used to estimate hazard ratios (HRs) adjusted for age, ethnicity, smoking, and sex.

Of 47,904 participants, 71% were Mâori, 12% Pacific, 5% Asian, and 12% other. A1C was less than 4.0% in 142 participants, 4.0% to less than 5.0% (reference category) in 12,867, 5.0% to less than 6.0% in 30,222, 6.0% to less than 7.0% in 2669, and 7.0% or higher in 1596 participants. In addition, 408 participants had a previous diagnosis of diabetes.

During follow-up, there were 815 deaths. For participants without a previous diagnosis of diabetes, HRs for all-cause mortality steadily increased from the A1C reference category to the highest category (≥ 7.0%; HR, 2.36; 95% confidence interval [CI], 1.72 - 3.25). In addition, A1C was associated with mortality from circulatory, endocrine, nutritional, metabolic, and immune diseases as well as from other and unknown causes. Although mortality rate was also increased in participants with a previous diagnosis of diabetes, this was only partially explained by their increased A1C levels.

"This is the largest study to date of A1C levels and subsequent mortality risk," the study authors write. "It confirms previous findings that A1C levels are strongly associated with subsequent mortality in both men and women without a prior diabetes diagnosis."

Limitations of this study include lack of anthropometric data and information on other cardiovascular risk factors; short follow-up time; inability to exclude the possibility that diabetes at the time of the A1C test might have led to increased glucose levels; misclassification of specific causes of death; and participants being enrolled in an intensive population-based hepatitis B screening program, which may prevent generalizability of the findings to the overall population.

"The excess mortality risk was from a range of causes but was particularly strong for endocrine, nutritional, and metabolic and immunity disorders and for cardiovascular disease," the study authors conclude. "However, A1C levels only partially accounted for the excess mortality risk in participants with a previous diagnosis of diabetes."

The Health Research Council of New Zealand supported the Centre for Public Health Research and the Research Centre for Mâori Health and Development. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 USC Section 1734 solely to indicate this fact.

Diabetes Care. 2008;31:1144-1149.

Clinical Context

Because A1C level is not affected by recent meals and can be measured without a fasting blood sample, it is a reasonable option for preliminary screening for undiagnosed diabetes. A1C is also linked to low birth weight and other risk factors for cardiovascular disease and diabetes.

Although only a few prospective studies have looked at the relationship between A1C in adults without diabetes at baseline and subsequent mortality risk, these have shown associations with subsequent mortality as have studies in patients with type 1 diabetes, nondiabetic chronic kidney disease, and incident cardiovascular disease.

Study Highlights

  • This largest study to date of A1C levels and subsequent mortality risk was performed in a New Zealand population.
  • The study aimed to characterize the association between A1C concentration and mortality in those with and without diabetes at baseline.
  • During a Hepatitis Foundation screening campaign for hepatitis B from 1999 to 2001, participants were offered A1C testing.
  • Participants were anonymously linked to the database for national mortality rates through December 31, 2004.
  • Cox regression estimated HRs adjusted for age, ethnicity, smoking, and sex.
  • Of 47,904 participants, 71% were Mâori, 12% Pacific, 5% Asian, and 12% other.
  • Mean age was 38 years; median A1C level was 5.2%.
  • The reference category for A1C level was 4.0% to less than 5.0% (n = 12,867).
  • A1C level was less than 4.0% in 142 participants, 5.0% to less than 6.0% in 30,222, 6.0% to less than 7.0% in 2669, and 7.0% or higher in 1596 participants.
  • Diabetes was previously diagnosed in 408 participants.
  • During follow-up (median duration, 4.4 years; range, 2 days to 5.3 years), there were 815 deaths.
  • In participants without a previous diagnosis of diabetes, there was a dose response for increased mortality with increasing level of A1C.
  • HRs for all-cause mortality steadily increased from the A1C reference category to the highest category (≥ 7.0%; HR, 2.36; 95% CI, 1.72 - 3.25).
  • In those without known diabetes at baseline, a 1% increase in A1C level was associated with a 16% increase in mortality rate.
  • HRs for A1C level and overall and cause-specific mortality rates were very similar in men and women.
  • Mortality rate was also increased in participants with a previous diagnosis of diabetes, but this was only partially explained by increased A1C levels.
  • When A1C level was analyzed as a continuous variable, there was no overall association of A1C level with subsequent mortality in those with a previous diabetes diagnosis at the time of A1C testing, but the investigators suggest that this group is not likely to be typical of people with diabetes.
  • A1C level was associated with mortality from circulatory, endocrine, nutritional, metabolic, and immune diseases as well as from other and unknown causes.
  • Of 47 deaths in the "endocrine, nutritional and metabolic and immunity disorders," category, 38 were from diabetes.
  • A1C level was also strongly associated with mortality from diseases of the circulatory system, particularly ischemic heart disease.
  • There were weaker associations with deaths from cancer and other and unknown causes.
  • The investigators concluded that these findings confirm previous findings that A1C levels are strongly associated with subsequent mortality in both men and women without a diagnosis of diabetes at baseline and that the excess mortality risk was strongest for endocrine, nutritional, and metabolic and immunity disorders and for cardiovascular disease.
  • Limitations of this study include lack of data on other cardiovascular risk factors, short follow-up time, inability to exclude diabetes at the time of the A1C test, misclassification of specific causes of death, and lack of generalizability to the overall population.

 

Pearls for Practice

  • In participants without a previous diagnosis of diabetes, there was a dose response for increased all-cause mortality with increasing level of A1C.
  • A1C was associated with mortality from circulatory, endocrine, nutritional, metabolic, and immune diseases as well as from other and unknown causes, with HRs very similar in men and women. Excess mortality risk was strongest for endocrine, nutritional, and metabolic and immunity disorders and for cardiovascular disease.

CME/CE Test