By Pam Harrison
WebMD Health News
March 23, 2017
Statin therapy increases the risk of new-onset diabetes in elderly women by 33%, and the higher the dose, the greater the risk, a new analysis of the observational Australian Longitudinal Study on Women's Health shows.
"Clearly, statins have beneficial effects, including a reduction in the risk of cardiovascular events; however, the dose-response effect we observed suggests that it may be wise to avoid using higher doses of statins in older women," lead author Mark Jones, MD, senior lecturer, school of public health, the University of Queensland, Brisbane, Queensland, told Medscape Medical News in an email.
"GPs and their elderly female patients should be aware of the risks," Dr Jones added in a University of Queensland statement, noting that those elderly women taking statins "should be carefully and regularly monitored for increased blood glucose to ensure early detection and management of diabetes."
And, he and his colleagues suggest, it may be the case that statins could be stopped altogether in some elderly women.
Women Take Statins on Average, for 6.5 Years
The new analysis included 8372 Australian women aged between 76 and 82 years at baseline who were followed for 10 years; it is published in the March issue of Drugs and Aging.
Dr Jones and colleagues note that the majority of participants in statin trials have been males and that females, especially elderly ones, have been underrepresented.
"Our group has expertise and experience in women's health, including being involved with the Australian Longitudinal Study on Women's Health for the past 20 years, and we focused on the older cohort of women [in this study] because we thought this is a population that has generally not been included in clinical trials," Dr Jones explained to Medscape Medical News.
Previous studies have also shown an association between use and onset of diabetes, he and his colleagues add, and while often the benefits of statins are said to outweigh the risk of diabetes, this depends on the indication for statins in the first place. For example, statin use in primary prevention of cardiovascular disease remains controversial, they say.
The primary outcome of their analysis, new-onset diabetes, was based on a new prescription for insulin, insulin analogues, or other glucose-lowering agents. And statin exposure was determined based on prescriptions dispensed between July 1, 2002 and August 31, 2013.
"We found that almost 50% [49%] of women in their late seventies and eighties in the study took statins, and 5% were diagnosed with new-onset diabetes," Dr Jones noted.
The mean interval for which women took a statin was 6.5 years.
While women could have taken different statins at different doses over the 10-year follow-up interval, the greatest proportion of participants received atorvastatin followed by simvastatin, the researchers explain.
And when there was a change in the dose of a statin, it tended to be toward a higher dose over time.
Risk of Diabetes Ranged From 17% to 51%
The risk of new-onset diabetes went from a low of 17% with the lowest doses of a statin to a high of 51% for those taking the highest doses.
At an adjusted hazard ratio (HR) of 1.33% for the overall cohort, this risk translates into a number-needed-to-harm of 131 patients for every 5 years of treatment with a statin.
New-Onset Diabetes by Statin Dose ∗
|Statin dose||Hazard ratio||P|
|Very high dose||1.51||0.004|
∗ Compared with no statin use
"What's most concerning was that we found a 'dose effect,' where the risk of diabetes increased as the dosage of statins increased, [and] over the 10 years of the study, most of the women progressed to higher doses of statins," Dr Jones observed.
He and his colleagues therefore recommend that ongoing risk assessment is "critical" to ensure optimal health outcomes and quality of life in older women.
Deprescribe Statins in Older Women
The results suggest "elderly women should not be exposed to higher doses of statins," they add.
Indeed, in some cases, it may be wiser to stop statins altogether in this patient group, they note, adding that, in their study, around one-third of users didn't fill a prescription for statins in the last 6 months prior to death or end of follow-up.
"The women in our study would have been aged 86 to 92 at the end of follow-up and, depending upon reason for initial prescribing—primary or secondary prevention—serious consideration could perhaps now be recommended for statin deprescribing in women of this age," they conclude.
The authors had no relevant financial relationships.