yutaka aoki morgan state university school of community health and policy october 21, 2010

Potential need for race-specificdiagnostic criteria and healthcare delivery

for thyroid hormone abnormalities

Yutaka AokiMorgan State University

School of Community Health and Policy

October 21, 2010Seventh National Conference on Quality Health

Care for Culturally Diverse Populations

http://www.morgan.edu/

Thyroid health racial disparities Yutaka Aoki

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Racial disparities & SES:Brief Overview

• Race represents many factors

• Minority race/ethnicity often associated w/– Lower income– Lower education– Etc.

• These correlates often termed collectively as socioeconomic status (SES)


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SES as basis for Racial Disparities in Health

• SES is often mediator in many racial disparities – E.g., in asthma, cardiovascular disease, etc.– Minority race

Low SES (common in minority) Limited access to high-quality healthcare More/severe disease

• Other mediators– Unhealthy life style?– Stress/discrimination?– Limited access to grocery (fresh fruits & vegetables)?– Others


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Known racial difference with genetic basis

• Some racial difference has biological/genetic bases, e.g.:– Sickle Cell Disease more common in African

Americans (AAs)

• Genetics non-modifiable unlike:• Unhealthy life style—may be modified through

behavioral intervention• Discrimination—may be modified through societal

changes


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Biology/Generics or SES?

• Often answer is not “one or the other”

• Could be intertwined– E.g., in breast cancer


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Intertwined Relationship:Breast Cancer in Case

Lower incidence & higher mortality in AAs

• Thought as access-to-care issue– Mammography in last 2 years: 63% in blacks

vs. 67% in whites (Chagpar et al, 2008, Surgery)

• Has turned out breast cancer of black women tend to be more fatal type– i.e., different breast cancer in minority (Dunn et

al., 2010, Breast Cancer Res Treat)


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Disease itself, not just risk for same disease, may vary across races

• Different manifestations—signs and symptoms

• Different description of same symptoms by patients

• Distribution of disease biomarkers among individuals with or without disease– Focus of this presentation


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Case in point:Thyroid hormone abnormalities

• Different profile of thyroid health for non-Hispanic whites, blacks, and Hispanics (Aoki et al., 2007, Thyroid)

• Does difference arise from: – Biological difference?– Access to care/SES?

• This presentation deals with:– Unanswered questions – Implications


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Thyroid hormone basics:Signs and symptoms

• Hypothyroidism—too little thyroid hormone– Signs and symptoms decreased metabolism– Weight gain, sluggishness/tiredness,

depression, slow heart beats, etc.

• Hyperthyroidism—too much thyroid hormone– Symptoms and signs of increased

metabolism– Weight loss, bone loss, restlessness, rapid

heart beats, high appetite, etc.


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Thyroid hormone basics: Diagnosis

• Measure serum T4 (thyroxine)– Low T4—hypothyroidism– High T4—hyperthyroidism

• Serum TSH (thyroid stimulating hormone) actually used more often for dx, though– High TSH—hypothyroidism– Low TSH—hyperthyroidism

• Note flip in high/low– T4 and TSH negatively associated– People with high T4 tend to have low TSH, vice versa


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African American (AA)-white difference in thyroid health

• AAs have:– Higher total T4, lower TSH than whites– Lower hypothyroidism prevalence– Higher hyperthyroidism prevalence

(Aoki et al., 2007, Thyroid)

• Biological basis—Caucasians adapted to colder climate in Europe (vs. Africa)

• Is “access to care” a factor?– Largely unanswered (but probably not so)


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Thyroid hormone abnormality’slong-term consequences

• Hypothyroidism can cause/associated with:– CVD (Ochs et al., 2008, Ann Intern Med)

• Treatment for hypothyroidism associated with:– More hospitalizations, greater use of non-thyroid

prescription medications (Aoki, unpublished)

• Hyperthyroidism can cause/associated with:– CVD (Ochs et al., 2008, Ann Intern Med)– Osteoporosis (Biondi et al., 2005, Eur J Endocrinol)


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Higher CVD mortality/morbidity for blacks

• Thyroid health difference may play some (small) roles

• Probably small roles because hypo/hyperthyroidism is not common:– Hypothyroid blacks may be undertreated with

current universal tx goal, yet blacks have relatively low hypothyroidism prevalence

– Hyperthyroidism, which is more common in blacks, still is relatively rare (prevalence ≈ 1%)


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Universal (non race-specific) cut-offs used for most studies

• Cut-offs has been in use for decades (with revisions)

• Apparently earlier clinical studies conducted in majority Caucasians


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“Universal” cut-offs for hyperthyroidism appropriate?Suppose a black patient has TSH = 0.08 mIU/L

(i.e., slightly below universal cut-off of 0.08 mIU/Lfor hyperthyroidism)

Standard interpretation and action•Slightly below cut-off equally bad for blacks and whites•Treat accordingly


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“Universal” cut-offs for hyperthyroidism appropriate? (cont’d)

Suppose a black patient has TSH = 0.08 mIU/L(i.e., slightly below universal cut-off of 0.08 mIU/L

for hyperthyroidism)

Alternative interpretation and action•TSH = 0.08 mIU/L may be OK for blacks, if blacks “naturally” tend to have lower TSH (and higher T4, i.e., be on hyperthyroid side)•Don’t treat


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“Universal” cut-offs for hypothyroidism appropriate?

• When treating hypothyroid black patients:– Should we try to lower TSH in range between

0.5 - 2.0 mIU/L (as currently recommended irrespective of race in NACB, 2002)?

or– Should we try to set a lower range for TSH for

blacks?(recall blacks “naturally” have lower TSH and higher T4)


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Potential healthcare implications for genetic racial difference

1. Race-specific diagnostic criteria

2. Race-specific treatment regimen

3. Culturally-sensitive strategies for patient education

• Research on #1 and #2 missing to date


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Clinical knowledge gaps

• Do we need race-specific diagnostic criteria for thyroid hormone abnormalities?

• Do we need race-specific treatment goals for thyroid hormone abnormalities?


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How to fill “clinical knowledge gap”?

• Determine whether hypothyroidism symptoms increases with decrease in T4 in a similar manner for blacks and whites

• Determine whether hyperthyroidism symptoms increases with increase in T4 in a similar manner for blacks and whites

• Determine whether hypo/hyperthyroidism treatments work similarly for blacks and whites (can use same Tx goals?)


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Challenges in research on symptoms

• Symptoms could be (reported) differently by racial groups! – E.g., for major depression (Uebelacker et al.,

2009, Psychol Med)

• “Tolerable” levels may vary by race– Physiological– Cultural

• Translation issues in healthcare setting (questionnaire/interview)


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Alternative to symptoms as outcome to study

• Use other clinical (“hard”) outcome, e.g., CVD or osteoporosis, rather than hypo/hyperthyroidism signs and symptoms, e.g.:– CVD– Total mortality– Osteoporosis– QOL


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Alternative research strategies

• Determine whether risk of CVD and other consequence of hypo/hyperthyroidism increases with decrease in thyroxine in a similar manner for blacks and whites

• Determine whether hypo/hyperthyroidism Tx works similarly for blacks and whites in CVD prevention

Both addresses race as effect modifier


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Implication for race-specific dx criteria or tx goal

Doctor/Nurse: We will treat you (black patient) differently from white patient.

• Potentially objectionable/confusing message

• Message need to be delivered culturally-sensitive, politically-correct manner


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Related debate: Need age-specific cut-offs for thyroid hormones?

• There is age-related change in distribution of thyroid hormone levels– As people age:

• T4 lowers & TSH rises• More spread for both

• Ongoing debate:– Should we have separate cut-offs for elderly?

• Yes. (Surks &Hollowell, 2007, J Clin Endocrinol Metab)


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Summary

• Race-specific diagnostic criteria and treatment regimen may be needed for thyroid hormone abnormalities

• If the need proven, careful delivery of messages needs to be developed

yutaka aoki morgan state university school of community health and policy october 21, 2010

Documents

racial disparities ses

quality health care

hispanics aoki

thyroid hormonesymptoms

thyroid hormone basics

different breast cancer

minority limited access

breast cancer of black