Diabetes and Depression Combo Hikes MI Risk

BARCELONA — Individuals who have both diabetes and depression have an increased likelihood of having a myocardial infarction (MI), a large Swedish study affirmed.

The odds of having an MI compared with individuals without either condition were greatest among those ages 45 to 64, with the strongest association seen in women (OR 7.1, 95% CI 6.1-8.2), according to Karin Rådholm, of Linköping University in Sweden.

The corresponding odds ratio for men in that age group was 2.8 (95% CI 2.5-3.2), Rådholm reported at the European Association for the Study of Diabetes meeting here.

The chances of having an MI were also elevated — but to a lesser extent — in men and women who had either diabetes or depression, but not both.

Previous studies have shown an association between diabetes and depression, and a study published last year showed that treating both conditions simultaneously in the primary care setting was associated with improved glycemic control. Patients with both conditions have been shown to have an increased cardiovascular risk.

Rådholm and colleagues explored the link between diabetes, depression, and MI using data on 3,738,524 individuals ages 45 to 84 from Swedish national registries of prescription drug use, hospitalizations, and deaths. The analysis excluded those who had had an MI before the beginning of the study period.

Prescriptions for medications for diabetes and depression were used as surrogates for the conditions themselves.

The researchers divided the patients into four groups, which could be shuffled each of the 3 years of the study, based on drug use:

• Neither type of medication
• Anti-diabetics only
• Antidepressants only
• Both types of drugs

During the 3-year follow-up, 1.2% of the participants had a first MI. Of those, 37% were fatal.

In the older half of the cohort (ages 65 to 84), all three of the drug groups carried an increased likelihood of having an MI, with odds ratios ranging from just over 1.0 to about 3.0 compared with non-users. The greatest odds were observed in those taking both types of medication and in women versus men.

The findings were similar in the younger half of the cohort (ages 45 to 64), with odds ratios ranging from just over 1.0 to about 7.0. The results were not changed by adjustment for the use of anti-hypertensives.

The findings were not surprising, according to Ewan Pearson, PhD, MBBChir, of the University of Dundee in Scotland. “It’s a very nice, large study that establishes the fact that people with diabetes and people with depression have higher rates of cardiovascular events,” said Pearson, who co-chaired the session at which Rådholm presented the results.

What is noteworthy is the large sample size used in the analysis, he said.

“A study of 3.7 million is incredible,” he said. “It just shows the utility of these massive population resources that Sweden has access to.”

Rådholm acknowledged that the study was limited by the lack of information on the indications for use of antidepressants, noting, for example, that tricyclics can be used for neuralgias and other conditions. The analysis also lacked information on important confounders, such as smoking, lipid levels, and lifestyle.