Sex and Racial/Ethnic Differences in Cardiovascular Disease Risk Factor Treatment and Control Among Individuals With Diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract

OBJECTIVE

To examine sex and racial/ethnic differences in cardiovascular risk factor treatment and control among individuals with diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA).

RESEARCH DESIGN AND METHODS

This study was an observational study examining mean levels of cardiovascular risk factors and proportion of subjects achieving treatment goals.

RESULTS

The sample included 926 individuals with diabetes. Compared with men, women were 9% less likely to achieve LDL cholesterol <130 mg/dl (adjusted prevalence ratio 0.91 [0.83–0.99]) and systolic blood pressure (SBP) <130 mmHg (adjusted prevalence ratio 0.91 [0.85–0.98]). These differences diminished over time. A lower percentage of women used aspirin (23 vs. 33%; P < 0.001). African American and Hispanic women had higher mean levels of SBP and lower prevalence of aspirin use than non-Hispanic white women.

CONCLUSIONS

Women with diabetes had unfavorable cardiovascular risk factor profiles compared with men. African American and Hispanic women had less favorable profiles than non-Hispanic white women.

Population-based health survey data suggest that sex and racial/ethnic disparities are present in diabetes process of care measures and cardiovascular risk factor control (1–9). Available data also indicate that sex-specific race/ethnicity differences are present in cardiovascular risk factor control, but these data are limited to Medicare and Veterans' Hospital patient populations (5,10–13). We therefore performed analyses of participants with diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA) to examine sex and sex-specific racial/ethnic differences in cardiovascular risk factor treatment and control.

RESEARCH DESIGN AND METHODS

MESA is a multicenter cohort study of 6,814 men and women age 45–84 years with no clinical evidence of cardiovascular disease at time of enrollment (14). Four MESA exam periods occurred between 2000 and 2007. The study was approved by the Institutional Review Board at all participating institutions, and all MESA participants provided informed consent. Criteria for recruitment, data collection methods, and laboratory techniques have been previously described (14). Participants were classified as having diabetes if at exam 1 they had a fasting plasma glucose ≥126 mg/dl, used oral hypoglycemic agents and/or insulin, or reported a physician diagnosis of diabetes.

Statistical analysis

Multivariate models were used to calculate predicted means for lipid, blood pressure, and A1C levels. Prevalence ratios (PRs) were calculated for percentages of participants achieving cardiovascular risk factor goals using binomial regression, with adjustment for age, MESA site, socioeconomic status variables, and either sex or race/ethnicity. Potential effects of selective attrition on longitudinal results were examined using t tests to determine if participants lost to follow-up had higher mean cardiovascular risk factor levels compared with those retained in the study. Analyses were performed using SAS version 9.1.

RESULTS

Of 926 MESA participants with diabetes at exam 1 (2000–2002), 48% were women. Four racial/ethnic groups were represented (19% non-Hispanic white [NHW], 38% African American, 31% Hispanic, and 12% Chinese). Compared with men, women were more likely to report gross family income <$20,000 (42 vs. 26%) and less than high school education (33 vs. 27%).

Cross-sectional data

At exam 1, after adjustment for age, MESA site, and race/ethnicity, systolic blood pressure (SBP) was 3.5 mmHg higher among women than men (133.7 vs. 130.2 mmHg, P < 0.01). LDL cholesterol and A1C did not differ by sex. After additional adjustment for socioeconomic status, there was no sex difference in mean SBP (Table 1 ). African American and Hispanic women had significantly higher mean SBP values than NHW women. A significantly lower percentage of women were taking aspirin (Table 1). Hispanic women reported taking less aspirin than NHW women.

Table 1.

Cardiovascular disease risk factors and aspirin use for participants with diabetes, 2000–2002

	n	LDL cholesterol (mg/dl)	SBP (mmHg)	Diastolic blood pressure (mmHg)	Pulse pressure (mmHg)	A1C (%)	Aspirin (%)
Sex
Women	448	112.6 ± 2.31	133.3 ± 1.37	68.6 ± 0.64*	64.7 ± 1.06*	7.38 ± 0.12	97 (23)*
Men	478	109.6 ± 2.14	131.1 ± 1.26	75.2 ± 0.58	55.9 ± 0.97	7.44 ± 0.11	155 (33)
Race/ethnicity and sex subgroups
NHW	176	110.5 ± 3.13	129.9 ± 91.83	69.9 ± 0.85	60.0 ± 1.42	7.18 ± 0.16	64 (38)
Women	72	110.3 ± 4.49	127.9 ± 2.67	65.9 ± 1.24	62.0 ± 2.06	7.28 ± 0.23	20 (29)
Men	104	110.3 ± 3.92	130.8 ± 2.27	73.6 ± 1.05	57.1 ± 1.75	7.14 ± 0.19	44 (44)
African American	356	112.2 ± 2.51	135.6 ± 1.49††	74.7 ± 0.69†††	60.9 ± 1.16	7.65 ± 0.13††	96 (28)†
Women	184	116.3 ± 3.18	136.8 ± 1.89‡‡	72.1 ± 0.88	64.7 ± 1.46	7.56 ± 1.16	42 (24)
Men	172	108.2 ± 3.18	134.4 ± 1.89	77.2 ± 0.87	57.2 ± 1.46	7.75 ± 0.16	54 (32)
Hispanic	285	114.1 ± 2.96	135.0 ± 1.75†	70.9 ± 0.81	64.1 ± 1.36†	7.55 ± 0.15	56 (20)†††
Women	140	113.7 ± 3.67	136.8 ± 2.18‡‡	67.0 ± 1.01	69.8 ± 1.69‡‡	7.46 ± 0.18	22 (16)‡
Men	145	114.5 ± 3.59	133.0 ± 2.12	74.7 ± 0.99	58.4 ± 1.64	7.69 ± 0.18	34 (24)
Chinese	109	107.6 ± 4.07	128.4 ± 2.41	72.3 ± 1.12	56.1 ± 1.87	7.24 ± 0.21	36 (34)
Women	52	108.9 ± 5.49	130.9 ± 3.24	68.9 ± 1.50	61.9 ± 92.50	7.54 ± 0.29	13 (26)
Men	57	106.3 ± 5.06	125.8 ± 2.99	75.6 ± 1.39	50.2 ± 2.31	7.04 ± 0.25	23 (41)

Data are means ± SE or n (%). A1C was from exam 2. Comparisons were adjusted as follows: women vs. men adjusted for age, site, race/ethnicity, income, education level, and health insurance (government-sponsored vs. private vs. no insurance). African American vs. NHW adjusted for the same variables without race/ethnicity and including sex, similarly for Hispanic vs. NHW and Chinese vs. NHW. African American women vs. NHW women adjusted for same variables without sex and race/ethnicity, similarly for Hispanic women vs. NHW women and Chinese women vs. NHW women.

*P < 0.0001 for comparisons of women vs. men.

†P < 0.05,

††P < 0.01,

†††P < 0.0001 for comparisons of African American, Hispanic, and Chinese vs. NHW.

‡P < 0.05,

‡‡P < 0.01 for comparisons of African American, Hispanic, and Chinese women vs. NHW women.

A lower percentage of women achieved LDL cholesterol <130 mg/dl (69.4 vs. 77.1%, P = 0.01) and SBP <130 mmHg (42.2 vs. 57.8%, P = 0.002) compared with men. Women were 9% less likely to achieve LDL cholesterol <130 mg/dl than men (adjusted PR 0.91 [0.85–0.98]) and 9% less likely to achieve SBP <130 mmHg (adjusted PR 0.91 [0.83–0.99]). African American and Hispanic women were 31% (adjusted PR 0.69 [0.51–0.91]) and 30% (adjusted PR 0.70 [0.52–0.95]) less likely, respectively, to achieve blood pressure <130/80 mmHg compared with NHW women.

Longitudinal data

Of 926 subjects with diabetes at exam 1, 802 completed exam 2, 751 exam 3, and 719 exam 4. At exam 4, LDL cholesterol (96.4 vs. 94.6 mg/dl, P = 0.54) and SBP (130.3 vs. 127.6 mmHg, P = 0.11) did not differ between women and men. At exam 4, there was no difference in the percentage of women achieving LDL cholesterol <130 mg/dl (adjusted PR 0.97 [0.91–1.04]) or SBP <130 mmHg (adjusted PR 0.95 [0.88–1.02]) compared with men. African American women were 33% less likely to achieve blood pressure <130/80 mmHg (adjusted PR 0.67 [0.49–0.91]) compared with NHW women. Although women reported higher antihypertensive and lipid-lowering medication use compared with men at exam 1, there was no difference at exam 4 in antihypertensive (80 vs. 75%, P = 0.20) or lipid-lowering medication (51 vs. 49%, P = 0.70) use. Aspirin use increased for both sexes from 2000 to 2007; however, women remained less likely to report aspirin use at exam 4 compared with men (44 vs. 57%, P < 0.05). Aspirin use remained lower for African American and Hispanic women compared with NHW women (51 and 39% vs. 58%, respectively).

CONCLUSIONS

Among MESA participants with diabetes, at the baseline exam, a lower proportion of women achieved consensus treatment targets for SBP and LDL cholesterol, after adjustment for covariates. These differences were observed despite a greater reported use of blood pressure and lipid-lowering medications among women. African American and Hispanic women had lower proportions achieving consensus treatment goals for blood pressure and less reported use of aspirin compared with NHW women. The sex difference in LDL cholesterol and SBP control diminished over time.

Our findings are consistent with previous reports showing sex and racial/ethnic differences in cardiovascular risk factor control among individuals with diabetes (2,12,13,15). Inconsistent findings have been reported regarding sex and racial/ethnic differences in use of medications for management of cardiovascular factors (3,4,8).

There are several potential mechanisms for the sex and racial/ethnic differences we observed. Regression adjustment for socioeconomic status variables eliminated the significant sex difference in mean SBP. Socioeconomic variables may correlate with access to high-quality medical care and with personal behaviors that influence risk factor levels, including medication adherence, diet, and exercise. Our findings may also indicate a disparity in medication titration by physicians.

There are several limitations to our study. Information on medication use was self-reported and patient adherence was not recorded. Study participation may also have influenced treatment patterns because exam results were reported to the participants. Despite these limitations, our findings provide new information about sex and sex-specific race/ethnicity differences in cardiovascular risk factor treatment and control among individuals with diabetes in a contemporary multiethnic cohort with diverse sources of insurance.

In conclusion, we found that among subjects with diabetes in MESA, women had unfavorable cardiovascular risk factor profiles compared with men at baseline exam; however, these differences diminished over time. African American and Hispanic women had less favorable profiles than NHW women.