Supplementary data to the study of ESRD Map in Japan.

To the Editor: Our recent study1 has added more convincing evidence for renoprotection of angiotensin-converting enzyme inhibitors (ACEIs) by asking whether the use of ACEIs may explain our previously disclosed important findings [i.e., regional variations in incidence of end-stage renal disease (ESRD)] in Japan2. In this study, we used the amounts of expense spent on ACEIs as an explanation. This was, however, a surrogate marker for a real use of ACEIs. Therefore, we next retrieved data regarding the real use of ACEIs from Nephro-Database in one large nephrology care center in Japan (Kimitsu Hospital)3. The rationale for using this database was that the hospital was the only nephrology center in its catchment area, excluding patients and hospital-based bias, and, more importantly, that the age-, sex- and underlying disease-adjusted cumulative incidence of ESRD was significantly higher than other areas in Japan, for example, in 1997, 178.9 per 1 million in the area, and 127.1 in Japan as a whole, allowing us to compare ACEIs with other potential risk factors in the area where progression of renal failure was far accelerated. We conducted a retrospective chart review of 74 consecutive patients who had started renal replacement therapy (RRT) between January 1993 and December 2000. Multiple logistic regression analysis clearly demonstrated an independently favorable role of "a usage of ACEIs (dose over the least officially recommended one)" against inception of RRT among antihypertensive agents Table 1. Thus, we could confirm the conclusion1 in a local area of Japan on a micro level, as well.