To the Editor.— Drs Garg and Grundy1continue to enhance our knowledge of the treatment of dyslipidemia in non—insulin-dependent diabetes mellitus (NIDDM) with a systematic evaluation of various treatment modalities for this disease. Their article, "Nicotinic Acid as Therapy for Dyslipidemia in Non—Insulin-Dependent Diabetes Mellitus," provides convincing evidence that nicotinic acid causes a deterioration of the glycemic control in patients with diabetes. Although this has been known for a long time, the well-controlled nature of their study provides insight into the incidence and magnitude of this effect. However, a few comments about their study deserve mention. The dose of nicotinic acid used in this study was rigidly set at 4.5 g/d. This is a high dose, almost certainly higher than the average dose used by most clinicians in nondiabetic subjects. Significant modification in all of the lipoprotein components can often be achieved with nicotinic acid doses of 2 to