Real World Effectiveness of Rosiglitazone Added to Maximal (Tolerated) Doses of Metformin and a Sulphonylurea Agent

Response to Roy et al.

I read with interest the article by Roy et al. (1) regarding the use of triple oral therapy in their minority population. I would like to point out our similar experience in the U.K. with a few take-home messages.

We studied 32 consecutive patients with type 2 diabetes (18 men and 14 women, aged 53 ± 10.6 years [means ± SD], diabetes duration 7.2 ± 5.4 years) in an inner city teaching hospital. Sixteen were South Asians, 8 Afro-Carribeans, and 8 Caucasians. All were on maximal doses of metformin (1,000 mg b.i.d.) and a sulfonylurea (gliclazide, 160 mg b.i.d.) with A1C of 9.20 ± 1.4%.

Our target A1C was also <7.5%, as recommended by the National Institute of Clinical Evidence in the U.K. (2). We used triple oral therapy in all patients, using either 4 mg rosiglitazone (14 patients) or 30 mg pioglitazone (18 patients) in a random fashion. After triple oral therapy, A1C (measured at 4 months) was 8.2 ± 1.6. Thirteen of 32 patients (41%) responded with an A1C <7.5% and remained at this level at 1 year. Nine of these 13 respondents (69%) were South Asians; therefore, this was not surprising given that they are usually more insulin resistant (3). Despite the success of glitazones, the majority of our patients have needed insulin (15 of 19; 4 patients unwilling). Glitazone use was particularly successful in those with a prestart mean A1C of 9.1 (±2.0%), in keeping with suggestions that glitazones work best if used early in the course of the disease process in type 2 diabetes (4).

Thus, our experience in an inner-city ethnic population (where a lot of patients are disinclined to use insulin) is that triple oral therapy can be successful with proper patient selection, but with a precondition that if A1C is not <7.5% after 6 months of use, then the patient will need insulin. We would recommend a trial of triple oral therapy for 1) taxi/heavy goods vehicle drivers (with obvious implications if insulin commenced) and 2) individuals in whom prestart A1C is no higher than 9.0%, particularly in the minority population.