1. BACKGROUND RESULTS OBJECTIVES METHODS CONCLUSIONS REFERENCES
The combination of Body Mass Index (BMI) and high sensitivity C-Reactive Protein (hs-CRP) predict a higher risk for Obstructive Sleep Apnea in Asymptomatic Women than does BMI and CRP alone
Gina Lundberg MD FACC, Josephine Kooijman, Danny Eapen MD, Stacy Jaskwhich NP
Saint Joseph’s Hospital Heart Center for Women and Emory Women’s Heart Center, Atlanta, Georgia
BACKGROUND
RESULTS
The age-adjusted odds ratio for predicting an elevated OSA score (>3) was 9.3 (95% CI 6-15). for a BMI >30 kg/m2.
When BMI groups were combined with hsCRP quartiles, the OR for the highest point score was 11.7 (95% CI 5-27).
Body Mass Index (BMI) has been demonstrated to be strongly associated with the development and presence of obstructive sleep apnea (OSA).1
OSA has been associated with elevated levels of inflammation, reflected by hsCRP, a marker of inflammation and cardiovascular risk.2
The use of hs-CRP as an adjunct to BMI to allow for a better risk stratification for OSA has not been well studied
OBJECTIVES
In multivariate models adjusted for age, diabetes, CRP/BMI interaction, the OR for BMI >30 kg/m2 was 7.3 (95% CI 4-13). For the hsCRP/BMI score, it was 10.9 (95% CI 3-46).
To determine whether combining hs-CRP with BMI indices would provide better risk stratification for women at risk for OSA than hs-CRP or BMI alone.
METHODS
Design: Cross-Sectional, Case-Control
Subjects: 507 asymptomatic women from the community without a known history of hypertension or coronary disease
Data Collected: Demographics, anthropometrics, clinical history, 12-point OSA questionnaire. A sleep apnea score of >3 considered high risk. A simple, individual and combined BMI point and hs-CRP point system were created.
Data Collection Period:
Biomarker Measurements: Plasma measures of hs-CRP were measured using enzyme linked immunosorbent assay (ELISA) technique
Statistical Analyses: Continuous variables are presented as means (±SD) and categorical variables as proportions (%) with one-way analysis of variance and χ2 tests used to determine differences. Data were analyzed as continuous variables log transformed (given not normally distributed and with cut points assigned based on accepted values.  Logistic regressison analyses performed. Statistical analyses were conducted utilizing the Statistical Package for Social Sciences 19 (IBM SPSS, Inc., Chicago Ill., USA)
Figure 1: Forest Plot of Age-Adjusted Odds Ratio of variables tested for the prediction of an elevated OSA score (>3).
Table 1: Baseline characteristics, lipids, hs-CRP levels between 2 groups of women divided by elevated sleep apnea score. A OSA score of >3/12, signified increased risk of OSA
CONCLUSIONS
-While there is no difference in age between the groups, those with elevated sleep apnea scores (OSA score) had significantly increased BMI, blood pressure, worse fasting lipid profiles and more components of metabolic syndrome.
- 73% with an elevated OSA score had a hs-CRP >3 mg/L
The combination of BMI and hs-CRP may be a better risk stratification screening tool in identifying asymptomatic women from the community at highest risk for OSA than is BMI or hs-CRP alone.
REFERENCES
A simple BMI point system was assigned to each subject based on normal BMI (<25 kg/m2), 1 point; overweight (BMI kg/m2 ), 2 points; obese (BMI >30 kg/m2), 3 points.
A simple hs-CRP point score was made based on quartiles of hsCRP st Quartile (0.4± 0.2 mg/L), 1 point. 2nd Quartile (0.9± 0.2 mg/L), 2 points; 3rd Quartile (1.8± 0.4 mg/L), 3 points; 4th Quartile (5.8± 2.5 mg/L), 4 points.
A combined hsCRP/BMI score was created for each individual adding up the individual BMI and hsCRP points
Young T, Shahar E, Nieto FJ, et al. Predictors of sleep-disordered breathing in community-dwelling adults: the Sleep Heart Health Study. Arch Intern Med. 2002;162(8):
Shamsuzzaman ASM, Winnicki M, Lanfranchi P, et al. Elevated C- reactive protein in patients with obstructive sleep apnea. Circulation. 2002; 105: 2462–2464.