Reduced Lung Function and Subarachnoid Hemorrhage_ Similar Mechanisms_ (Printer-friendly)

7/29/2019 Reduced Lung Function and Subarachnoid Hemorrhage_ Similar Mechanisms_ (Printer-friendly)

http://slidepdf.com/reader/full/reduced-lung-function-and-subarachnoid-hemorrhage-similar-mechanisms-printer-friendly 1/7

7/09/12 Reduced Lung Function and Subarachnoid Hemorrhage: Similar Mechanisms? (printer-friendly)

1/7www.medscape.org/viewarticle/769518_print

www.medscape.org

This article is a CME certified activity. To earn credit for this activity visit:

http://www.medscape.org/viewarticle/769518

CME Information

CME Released: 09/04/2012; Valid for credit through 09/04/2013

Target Audience

This article is intended for primary care clinicians, neurologists, pulmonologists, cardiologists, and other

specialists who care for patients with reduced lung function.

Goal

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

order to enhance patient care.

Learning Objectives

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

1. Identify major risk factors for low lung function.

2. Describe the association between reduced long function and subarachnoid hemorrhage.

Credits Available

Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™

Family Physicians - maximum of 0.25 AAFP Prescribed credit(s)

All other healthcare professionals completing continuing education credit for this activity will be issued a

certificate of participation.

Physicians should claim only the credit commensurate with the extent of their participation in the activity.

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 enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™ .

Physicians should claim only the credit commensurate with the extent of their participation in the activity.

This enduring material activity, Medscape Education Clinical Briefs, has been reviewed and is acceptable for up to

300 Prescribed credits by the American Academy of Family Physicians. AAFP accreditation begins September

1, 2011. Term of approval is for 1 year from this date. Each Clinical Brief is approved for .25 Prescribed credits.

Credit may be claimed for 1 year from the date of each Clinical Brief. Physicians should claim only the credit

commensurate with the extent of their participation in the activity.

Note: Total credit is subject to change based on topic selection and article length.

Medscape, LLC staff have disclosed that they have no relevant financial relationships.





As an organization accredited by the ACCME, Medscape, LLC, requires everyone who is in a posit ion 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)

Pam Harrison

AAFP Accreditation Questions

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 onapplicability 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. To receive AMA PRA

Category 1 Credit™, you must receive a minimum score of 70% on the post-test.

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. We encourage 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 6 years; at any point within this time period

you can print out the tally as well as the certificates from the CME/CE Tracker.

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

Hardware/Software Requirements

To access activities, users will need:

A computer with an Internet connection.

Internet Explorer 7.x or higher, Firefox 4.x or higher, Safari 2.x or higher, or any other W3C standards

compliant browser.

Adobe Flash Player and/or an HTML5 capable browser may be required for video or audio playback.

Occasionally other additional software may be required such as PowerPoint or Adobe Acrobat Reader .





Pam Harrison is a freelance writer for Medscape.

Pam Harrison has disclosed no relevant financial relationships.

Editor(s)

Laurie E. Scudder, DNP, NP

Nurse Planner, Continuing Professional Education Department, Medscape, LLC; Clinical Assistant Professor,

School of Nursing and Allied Health, George Washington University, Washington, DC

Disclosure: Laurie E. Scudder, DNP, NP, has disclosed no relevant financial relationships.

CME Author(s)

Désirée Lie, MD, MSEd

Clinical Professor, Family Medicine, University of California, Irvine, Orange, California; Director of Research and

Patient Development, Family Medicine, University of California, Irvine, Medical Center, Rossmoor, California

Disclosure: Désirée Lie, MD, MSEd, has disclosed the following relevant financial relationship:

Served as a nonproduct speaker for: "Topics in Health" for Merck Speaker Services

CME Reviewer(s)

Sarah Fleischman

CME Program Manager, Medscape, LLC

Disclosure: Sarah Fleischman has disclosed no relevant financial relationships.

News Author: Pam Harrison

CME Author: Désirée Lie, MD, MSEd

According to the current study by Engström and colleagues, subarachnoid hemorrhage (SAH) accounts for 1% to

10% of strokes worldwide and is associated with higher mortality risk and earlier onset vs other forms of stroke.

Risk factors include older age, female sex, family history, smoking, hypertension, and excessive alcohol intake.

Although low lung function has been linked to a risk for all-cause stroke, it is not clear if it is associated with an

increased risk for SAH.

This is a prospective cohort study among participants who had lung function assessed to determine if there is an

association between low lung function, as measured by forced expiratory volume in 1 second (FEV 1) and the ratio

of FEV1 to forced vital capacity (FEV1/FVC), and the risk for SAH among men and women.

The contribution of reduced lung function to the development of SAH is comparable with the effects of

hypertension and smoking — both known risk factors for SAH, new research shows.

Investigators from Lund University in Sweden found that reduced lung function, expressed as both FEV 1 and the

ratio of FEV1 and FVC (FEV1/FVC), was significantly associated with an increased incidence of SAH.

At a mean follow-up of 25.7 years, patients in the lowest quartile of FEV1 had an unadjusted hazard ratio (HR) of

2.64 for SAH compared with patients in the highest FEV1 quartile.

Reduced Lung Function and Subarachnoid Hemorrhage: SimilarMechanisms? CME

CME Releas ed: 09/04/2012; Valid for credit through 09/04/2013





Increased risk for SAH remained significant after established risk factors for SAH were taken into account, at an

HR of 2.2 for the lowest vs the highest FEV1 quartiles. Furthermore, results were consistent when analysis was

restricted to nonsmokers.

In contrast, no significant association was noted between SAH and FVC. Unlike FEV1 and FEV1/FVC, both of

which are measures of pulmonary obstruction, FVC is more related to the volume of the lungs and often is

increased in chronic obstructive lung disease compared with reductions in both FEV 1 and FEV1/FVC.

"Our hypothesis is that matrix degradation of vessel walls, which is the major reason for SAH, and degradation of

lung tissue, which is a major reason for reduced FEV1, share common mechanisms," co-investigator Gunnar

Engström, MD, PhD, also from Lund University in Sweden, told Medscape Medical News. "And results suggest

that pulmonary obstruction and not lung volumes are of importance for the risk of SAH."

This study was published online August 7 in Stroke.

Incidence Higher in Women

Previous studies had shown that reduced lung function increases the risk for all-cause as well as ischemic stroke,

but whether reduced lung function also increases the risk for SAH had not been previously studied.

Investigators sought to elucidate the relationship between lung function and the incidence of SAH in a large

prospective cohort from an urban population.

Between 1974 and 1992, a large-scale screening program — The Malmo Preventive Project — was carried out to

detect individuals at high risk for cardiovascular disease.

Spirometry was performed in complete birth cohorts during most but not all of the screening period. For this

analysis, a total of 20,534 men and 7237 women, with a mean age of 44 years at baseline, were included.

At baseline, FEV1, FVC, and FEV1/FVC were 95.3%, 97%, and 98.2% of predicted, respectively, in men. In

women, corresponding values were 95.8%, 97.4%, and 99.7%, respectively.

At follow-up, 98 men and 47 women had experienced an SAH, corresponding to an overall crude incidence of 20.3

per 100,000 person-years. The incidence of SAH was higher in women at 26.5 per 100,000 person-years than in

men at 18.3 per 100,000 person-years.

Mean age at SAH was 59 years.

Table. Adjusted Hazard Ratios for SAH in Relationship to Quartiles (Q) of FEV1 and FEV1 /FVC

Q4 (highest) Q3 Q2 Q1 (lowest) P Value for Trend

FEV1/HR 1 2.01 1.58 2.24 .014

FEV1/FVC 1 1.39 2.30 1.92 .003

FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; HR, hazard ratio; SAH,

subarachnoid hemorrhage.

"In the present cohort of middle-aged, healthy individuals, the risk of SAH was more than doubled in subjects with

FEV1 in the lowest quartile as compared with those with FEV1 in the highest quartile, taking several possible





confounders into account," the authors write.

When adjusted for smoking, "the HR for SAH in subjects with reduced lung function was even higher when the

analysis was restricted to nonsmokers," they add.

Results were independent of systolic blood pressure — another important risk factor for SAH — as well as

antihypertensive treatment at baseline. No significant interaction with hypertension was noted.

"Low FEV1 is a new risk factor for SAH, which may give new insights into the pathogenesis of SAH and help us toidentify individuals at higher risk," Dr. Engström concluded. "[In the meantime], the first preventive measure

patients can take to reduce SAH risk is to stop smoking and reduce exposure to environmental smoke, while the

second most important way is to measure blood pressure regularly and treat hypertension with antihypertensive

drugs."

Novel Finding

Ralph Sacco, MD, from the University of Miami, Leonard Miller School of Medicine, in Florida, told Medscape

Medical News that identification of reduced lung volume as a risk factor for SAH is a "novel finding" that has not, to

his knowledge, been reported before. "There have been other studies showing a relationship with reduced lung

function with CVD [cardiovascular disease] and ischemic stroke, as the authors discuss," he noted.

However, identifying any new risk factor for SAH is not easy, as Dr. Sacco suggested, because SAH is much

less frequent than other forms of stroke. Dr. Sacco also noted that Swedish investigators did control for other

important risk factors for SAH, including smoking and hypertension.

Given this, the association between reduced lung function and SAH identified in the current study may indeed be

a true one, although further studies are needed to confirm the association, and mechanism studies would be

helpful, as Dr. Sacco indicated.

This study was supported by the Swedish Heart and Lung Foundation, the Swedish Stroke Foundation,

Lundstrom's Foundation, the Swedish Research Council, and funds from both Lund University and Skane

University Hospital. Dr. Engström has disclosed that he is employed as a senior epidemiologist by AstraZeneca

R&D. Dr. Sacco has disclosed no relevant financial relationships.

Stroke. Published online August 7, 2012.

The Malmo Preventive Project was conducted in Sweden between 1974 and 1992.

22,444 men were examined between 1974 and 1984, with 10,902 women examined between 1977 and

1992.

Participation rate was 71%.

After exclusion of those with prior stroke, myocardial infarction, angina, and missing information, 20,534men and 7237 women were analyzed for this study.

Participants received baseline measurements for blood pressure, body mass index (BMI), alcohol

screening, physical activity assessment, spirometry, and blood tests for cholesterol, glucose, and

erythrocyte sedimentation rate (ESR).

Spirometry was performed with a specific apparatus measuring FEV1 and FVC in the standing position

without nose clips.

FEV1, FVC, and FEV1/FVC were expressed as percentages of predicted values.

Mean age was 43 years for men, 44 years for women at baseline.

All participants were monitored until the end of 2008, death, emigration, or occurrence of SAH, whichever

came first.Patients with SAH were extracted from the stroke register and other patients ascertained from the death

register by the International Classification of Diseases, 8th Revision, 9th Revision, and 10th Revision,

codes.

The risk for SAH was analyzed and expressed as HR by quartiles of FEV1 and FVC.





Low values of FEV1 and FVC were associated with current smoking, higher systolic blood pressure, use of

antihypertensive medication, physical inactivity, alcohol consumption, higher BMI, high cholesterol levels,

and elevated ESR.

At a mean of 25.7 years of follow-up, 98 men and 47 women had SAH for an incidence of 20.3 per 100,000

person-years (26.5 in women and 18.3 in men).

Mean time from screening to SAH was 14.6 years, and mean age at SAH was 59 years.

Low FEV1 and low FEV1/FVC were associated with an increased risk for SAH.

The crude HR for SAH for the lowest vs the highest quartile of FEV1 was significant at 2.64. The HRremained significant at 2.24 after adjustment for other risk factors (BMI, cholesterol, diabetes, physical

inactivity, and ESR).

The association was stronger among older participants.

In nonsmokers, the HR was 1.52 for FEV1 and 1.53 for FEV1/FVC.

In participants with normal blood pressure, the HR was 1.96 for FEV1 and 1.66 for FEV1/FVC after

adjustment.

In men, the HR was 2.68 for FEV1 and 1.68 for FEV1/FVC.

In women, the respective HRs were 1.47 and 2.42.

The authors concluded that low lung function was associated with an increased risk for SAH in both men

and women and that the incidence of SAH was higher in women vs men, reflecting existing findings.

Risk factors for low lung function include current smoking, higher systolic blood pressure, use of

antihypertensive medication, physical inactivity, alcohol consumption, higher BMI, high cholesterol levels,

and elevated ESR.

Low lung function is associated with an increased risk for SAH among both men and women, independent

of other risk factors.

To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 70% on the post-test.

A 50-year-old smoker with a BMI of 30 kg/m2 and a blood pressure of 120/80 mm Hg would like to

reduce his risk for low lung function. Which of the following best describes potential strategies to

accomplish this goal?

Increase both physical activity and alcohol intake

Stop smoking and reduce alcohol intake

Reduce BMI and start taking a statin

Stop smoking and use an antihypertensive medication

At 5 years later, the patient described in the first question is in the lowest quartile of FEV1. Which

of the following best describes his risk for SAH vs someone with an FEV1 in the fourth (highest)

quartile?

Increased 2-fold

Similar

Increased only if his blood pressure is also increased

Increased 5 times

Save and Proceed







Medscape Education © 2012 Medscape, LLC

Disclaimer

The material presented here does not necessarily reflect the views of Medscape, LLC, or companies that support

educational programming on www.medscape.org. These materials may discuss therapeutic products that have

not been approved by the US Food and Drug Administration and off-label uses of approved products. A qualified

healthcare professional should be consulted before using any therapeutic product discussed. Readers should

verify all information and data before treating patients or employing any therapies described in this educational

activity.



Documents

Reduced Lung Function and Subarachnoid Hemorrhage_ Similar Mechanisms_ (Printer-friendly)