Associations between birth weight and antihypertensive medication in black and white medicaid recipients

The blood pressures of hypertensive patients living in the southeastern region of the United States are less responsive to several classes of antihypertensive medications. Birth weights are lower among blacks and those living in the Southeast, and evidence suggests that this developmental difference increases blood pressure. As an initial step in addressing the possibility that birth weight influences response to anti hypertensive therapy, we examined the relationship between birth weight and class of antihypertensive medication among 3236 Medicaid beneficiaries in South Carolina with high blood pressure. Birth weight, obtained from birth certificates, was not related to use of either diuretics or beta blockers. However, among black women, there was an inverse association between birth weight and use of calcium channel antagonists (P=0.03), which persisted after adjustment for the number of antihypertensive medications. Among white men, low and high birth weights were associated with greater use of angiotensin converting enzyme inhibitors than in men of normal birth weight (P=0.002 for quadratic trend [U-shaped]). This association remained after adjustment for comorbid conditions, including congestive heart failure and diabetes mellitus, which were associated with birth weight and for which angiotensin converting enzyme inhibitors are recommended. The findings indicate that birth weight is associated with use of calcium channel antagonists in black women and angiotensin converting enzyme inhibitors in white men. These observations suggest that further study of the relationship between birth weight and blood pressure responses to various antihypertensive medications may help elucidate pathophysiological factors contributing to geographic and racial disparities in therapeutic efficacy.