Follicle-stimulating hormone modestly predicts improvement in semen parameters in men with infertility treated with clomiphene citrate.

Clomiphene citrate is a commonly prescribed empiric medical therapy for male infertility, but outcomes data and response rates remain incompletely understood. We retrospectively reviewed our single-institutional experience of infertile men prescribed clomiphene. Clomiphene treatment in the final cohort of 140 men was associated with a modest increase in median sperm concentration from 2.2 to 2.5 million/ml (p < 0.001). A total of 46/140 (33%) of men upgraded according to World Health Organization concentration categories. Clomiphene treatment in 26/113 (23%) of previously ineligible men became eligible for intrauterine insemination. Using both univariate and multivariable regression, pre-treatment follicle-stimulating hormone was inversely associated with change in semen concentration with clomiphene treatment. On binary logistic regression, follicle-stimulating hormone level was inversely related to World Health Organization concentration category upgrade (p = 0.01). Unfortunately, 17/140 (12%) of men paradoxically worsened on clomiphene, but no predictors for this could be identified. In summary, clomiphene citrate confers a clinically relevant but modest benefit in a subset (1/3rd ) of infertile men, particularly those with lower pre-treatment follicle-stimulating hormone levels. Men with elevated follicle-stimulating hormone over 15 IU/ml are less likely to benefit from treatment and should be counselled on other relevant treatment alternatives.

Clinical correlates and heritability of QT interval duration in blacks: the Jackson Heart Study.

BACKGROUND: Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of the QT interval and estimate its heritability in the Jackson Heart Study. METHODS AND RESULTS: The Jackson Heart Study comprises a sample of blacks residing in Jackson, Miss, of whom 5302 individuals with data at the baseline examination were available for study. Jackson Heart Study participants on QT-altering medications, with bundle-branch block, paced rhythm, atrial fibrillation/flutter, or other arrhythmias were excluded, resulting in a sample of 4660 individuals eligible for analyses. The relation between QT and potential covariates was tested using multivariable stepwise linear regression. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routine in a subset of 1297 Jackson Heart Study participants in 292 families; the remaining sample included unrelated individuals. In stepwise multivariable linear regression analysis, covariates significantly associated with QT interval duration included R-R interval, sex, QRS duration, age, serum potassium, hypertension, body mass index, coronary heart disease, diuretic use, and Sokolow-Lyon voltage (P < or = 0.01 for all). The heritability of QT interval duration in the age-, sex-, and R-R interval-adjusted model and in the fully adjusted model was 0.41 (SE, 0.07) and 0.40 (SE, 0.07; P < 10(-11) for both), respectively. CONCLUSIONS: There is substantial heritability of adjusted QT interval in blacks, supporting the need for further investigation to identify its genetic determinants.