To the Editor: The data of Rostand et al. (March 16 issue)1 on 94 patients with hypertension followed for a mean of 4.8 years suggest that 15 percent of such patients are likely to have progressive renal insufficiency despite apparently good blood-pressure control. The authors also observed that black patients are twice as likely as white patients to have decreases in renal function. Their observation that compliance and the level of education affect outcome suggests that the progression is also related to social issues. These issues are important and are in accord with our own observations in 6880 patients with. © 1989, Massachusetts Medical Society. All rights reserved.