Socioeconomic Standing May Affect Statin Adherence in Men, With Unclear Consequences in Women

Among patients at low socioeconomic standing being treated with statins for primary prevention of cardiovascular disease in a single-payer healthcare system, men—but not necessarily women—are likely to be nonadherent, according to new research.

The results “call for more attention on patients with low [socioeconomic position] in Finland and other countries regardless or the health insurance and drug benefit systems,” write lead author Emma Aarnio, MSc (University of Eastern Finland, Kuopio), and colleagues.

While prior studies have examined similar situations with regard to clopidogrel after PCI and statins after MI, solutions for improving adherence are still elusive. In this study, published online last week ahead of print in Circulation: Cardiovascular Quality and Outcomes, lower income and education level as well as unemployment both predicted nonadherence in men but less so in women.

Specifically, they looked at 116,846 primary prevention patients treated with statins in Finland treated between 2001 and 2004. Over 18 months of follow-up, low socioeconomic position was associated with statin nonadherence—defined as < 80% of days covered—in men after adjustment for age, marital status, residential area, clinical characteristics, and copayment. This result was broken down by income, education, and unemployment; all appeared to play a role in likelihood of adherence for men.

Neither income nor education played a role in nonadherence for women, though women outside the labor force had slightly higher rates of nonadherence than employed women (OR 1.11; 95% 1.00-1.22).

Stronger Risk Factors Potentially at Play

“Cost-related barriers, even under universal healthcare and drug reimbursement, are a likely explanation for nonadherence among men with low [socioeconomic position] in addition to . . . unhealthy lifestyle and lower health literacy,” Aarnio and colleagues write, suggesting that these patients would benefit from “more support and more active follow-up especially at the beginning of treatment.”

Conversely, the absence of any clear relationship between socioeconomic standing and statin adherence in women “may be that there are other, stronger risk factors . . . that mask the [socioeconomic position] differences,” they say. “One of these factors may be adverse effects because, compared to men, women are more likely to report statin-related adverse events and to stop statin treatment because of them.”

Sandeep Das, MD, MPH, of the University of Texas Southwestern Medical Center (Dallas, TX), who was not associated with the study, told TCTMD he wasn’t sure whether Aarnio et al’s findings can be applied to the US population.

However, “the existence of sex differences at all is itself a good reminder that men and women differ and that it’s important to include and analyze both when looking at issues like these,” he said. “Also, the fact that that suboptimal adherence was common in a universal healthcare system, where a lot of the issues related to direct cost of care are mitigated, is a good reminder of what we already know—that there are a lot of factors beyond just drug cost that adversely impact adherence and these factors disproportionately affect the poor.”

That so many studies like this one “come out of Europe, especially Scandinavia, . . . is entirely due to the fact that these systems collect comprehensive data and are thus much better positioned to ask population level questions than we are in the US,” Das added. “Unfortunately, our fragmented health system and limited access to data hinder our ability to answer these kinds of important questions.”