To the Editor.
—The article by Dr Kimmel and colleagues1 provides important information on the relationship between percutaneous transluminal coronary angioplasty (PTCA) procedure volume and major complications. However, it is important to clarify the comparison the authors made with our study of PTCA patients in California.2 Based on an earlier publication of our results that reports only the descriptive unadjusted association between PTCA volumes and outcomes, the authors correctly state that our study did not adjust for demographic and clinical factors. However, a later article, published in May 1995,3 provides multivariate-adjusted results along with detailed analyses. The hospital discharge data used in our study did not include the range of clinical variables available to Kimmel and colleagues. Nonetheless, our findings3 are quite similar to those of Kimmel and colleagues, although some differences do persist.We found, as did Kimmel and colleagues, that adverse outcomes (coronary artery
Phillips KA, Luft HS, Ritchie JL. Coronary Angioplasty Procedure Volume and Major Complications. JAMA. 1996;275(8):595. doi:10.1001/jama.1996.03530320019021