NEW ORLEANS — Among patients with established cardiovascular disease, diabetes increased the risk for secondary cardiovascular hospitalization or death by 42% in a prospective analysis of data from more than 12,000 members of Kaiser Permanente Northwest.
That increased risk was seen after adjustment for a wide range of risk factors associated with cardiovascular events, and in the setting of relatively high use of guideline-recommended medications for secondary prevention.
“Cardiovascular disease prevention in patients with diabetes remains the Holy Grail. Despite widespread use of secondary prevention medications, the risk of CVD was still high. It seems unlikely that 'more of same' will be the answer,” Gregory A. Nichols, Ph.D., said at the annual scientific sessions of the American Diabetes Association.
The study, funded by GlaxoSmithKline, is the first to document CVD hospitalizations and all-cause mortality in patients with and without diabetes outside of a clinical trial, said Dr. Nichols of Kaiser Permanente NW, Portland, Ore.
The study population comprised 12,278 patients who were added to Kaiser's cardiovascular disease registry during 2000–2005 and followed through 2008 or until they died or left the health plan. Of the registry patients, 2,384 (19%) had diabetes and 9,894 (81%) did not. In both groups about 60% were male, and the mean age at baseline was 66 years.
The mean body mass index was significantly higher in the diabetic patients than in the nondiabetic patients (32.6 and 29.6 kg/m
Use of pharmacotherapy for CVD prevention was high in both groups, but the patients with diabetes were significantly more likely than were those without to be receiving antiplatelets (86% vs. 71%), ACE inhibitors and/or angiotensin receptor blockers (60% vs. 40%), beta-blockers (76% vs. 67%), and statins (71% vs. 64%).
Nonetheless, over a mean follow-up of nearly 4 years, 17% of the diabetes patients had a CVD hospitalization, compared with 10% of those without, a significant difference. Death occurred in 15% of the diabetes patients, compared with 13% of the nondiabetic patients, a nonsignificant difference. Cardiovascular disease hospitalizations occurred at an age- and sex-adjusted rate of 41 per 1,000 person-years in the diabetes group, compared with 25/1,000 in those without diabetes, Dr. Nichols reported.
The composite outcome—CVD hospitalizations and death—was greater in the diabetic group (32% vs. 23%), primarily owing to the difference in hospitalizations, he said.
Significant predictors of the composite outcome included age 65 or greater (hazard ratio 1.79), chronic kidney disease (HR 1.75), depression (1.35), and statin use (0.86). After full adjustment for those factors as well other demographic and clinical factors and medication use, the patients with diabetes were 40% more likely to be hospitalized for CVD, 34% more likely to die of all causes, and 42% more likely to experience the composite outcome.
One limitation of this study is that diabetes status was assessed only at baseline. “Undoubtedly, some portion of nondiabetic patients developed it during follow-up. Their events would be misclassified, thus making our estimates of the relative risk attributable to diabetes conservative,” noted Dr. Nichols, who disclosed that he has received research funding from GlaxoSmithKline, Merck & Co., Novartis Pharmaceuticals, and Novo Nordisk.
Over 4 years, 17% of the diabetes patients had a CVD hospitalization, versus 10% of those without. DR. NICHOLS