Uninsured Have Higher Rates of Stroke, Death

Caroline Cassels

April 11, 2007

April 11, 2007 — A lack of health insurance among US residents is associated with increased rates of stroke and death, a new study shows.

Investigators found that individuals without health insurance are much more likely to forgo routine physical examinations and are less likely to be aware they have high blood pressure, diabetes, or hypercholesterolemia.

Interestingly, however, while a lack of health insurance was linked to an increased stroke risk, the same did not hold true for myocardial infarction (MI) risk.

"We speculate that this may relate to the relative importance of hypertension as a risk factor for stroke," the study's principal investigator, Angela Fowler-Brown, MD, from Beth Israel Deaconess Medical Center, in Boston, Massachusetts, said in a statement.

"Hypertension is the most powerful risk factor for stroke, and in our study we found that hypertension was significantly less likely to be well-controlled in those lacking insurance.

"While hypertension is also an important risk factor for myocardial infarction, other factors such as inflammation, cholesterol, and inherited traits may be of greater relative importance in the development of MI than in stroke," she added.

The study is published in the April issue of the Journal of General Internal Medicine.

Uninsured Have More CVD Risk Factors

Using data from 15,792 participants enrolled in the Atherosclerosis Risk in Communities, a longitudinal epidemiologic study, investigators estimated the hazard of MI, stroke, and death associated with insurance status.

At study entry, participants were 45 to 64 years old and were enrolled between 1987 and 1989. Data on cardiovascular risk factors, personal medical histories, socioeconomic status, and family history were collected at baseline. In addition, all study participants underwent physical examination and cardiovascular and laboratory testing. Patients were also asked about their insurance status.

Individuals were then reevaluated using the same tests every 3 years for a total of 4 visits. In addition, annual telephone surveys assessed changes in health status.

The study's primary outcomes included incident MI, stroke, and all-cause mortality. Frequency of routine physical examinations, awareness of a personal diagnosis of cardiovascular risk factors, and adequate control of cardiovascular risk factors were secondary study end points.

Compared with insured individuals, subjects who reported being uninsured at least once were more likely to be female and nonwhite, with lower education levels and family income.

Uninsured individuals were also more likely to have cardiovascular risk factors, diabetes, hypertension, and higher body mass index and be current smokers.

Number of Uninsured "Alarming"

Within the total study group there were 444 strokes, 968 MIs, and 1,157 deaths. After adjustment for baseline characteristics, a lack of insurance was associated with an increased risk for stroke and all-cause death compared with those who had health insurance.

Adjusted risk of stroke and death associated with lack of insurance

Hazard Ratio
(95% CI)
1.22 – 2.22
1.03 – 1.53

In addition, the authors report, individuals who were not insured were less likely to undergo routine physical examinations and had a higher adjusted risk of being unaware of a personal diagnosis of hypertension or hyperlipidemia compared with their insured counterparts.

According to the authors, the number of US residents without health coverage is "alarming." According to 2005 estimates, 46.6 million US residents, or 15.9% of the population, are without health insurance coverage.

"We believe our findings underscore the great importance of medical insurance in maintaining the health of the population. As medical science continues to advance, we fear that the health disparities between those who have access to medical care through insurance and those who do not may continue to grow," said Dr. Fowler-Brown.

J Gen Intern Med. 2007;22:502–507. Abstract


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