Over the 9-year study period, older women by far had the greatest exposure to long-term opioid therapy. By 2005, the prevalence of long-term opioid use was 8% to 9% among older women in both health plans. Long-term opioid use was substantially higher among older women than it was among younger women or men in any age group.
The risks and benefits of long-term opioid use among older women are not well understood.30
Older women have lower risk for opioid misuse3,31
but may be more vulnerable to adverse medical effects of opioid use such as sedation, falls, constipation, respiratory depression, accidental overdose, and medication interactions.20,30
They also have higher prevalence of concurrent use of other psychoactive medications30
and increased prevalence of comorbid chronic physical disease and frailty.18,20,30
The risks of opioid therapy for older women are likely very different from those of younger men. A recent report on unintentional overdose deaths in West Virginia reported that over two thirds such deaths involved young males, of whom fewer than half had ever been prescribed the overdose drugs. The likelihood of diversion (use without a documented prescription) decreased with age of the decedents. Among those who overdosed, obtaining prescriptions from multiple providers was more common for women than for men.32
The recent increase of long-term opioid use appears to reflect a considerable change in prescribing of opioid analgesics for chronic pain among community physicians. In the absence of well-controlled studies evaluating the safety and effectiveness of long-term opioid use, it is not possible to say whether the benefits of increased opioid prescribing outweigh the risks. However, our results indicate that large numbers of adults of all ages are now using opioids over extended periods of time, suggesting that even low rates of serious adverse events could have large effects on morbidity and mortality on a population basis. Given the large population exposure to long-term opioid use, increased surveillance of the health risks associated with extended use of these medications is needed.
We know little about how patients and their physicians make decisions regarding continuation of opioid use. The increases observed over time may be due to a variety of factors, including successful use of opioids in postoperative and hospice care,33
policies and guidelines aiming to reduce the risk faced by physicians when prescribing opioids,33,34
aggressive pharmaceutical company marketing,35
and greater availability of opioid medications. Although the data reported here cannot tell us why, it was clear that increased use of opioids occurred among persons of all ages and both genders.
The similarities across the 2 health plans in age and gender differences, and in trends of use over time, are striking. Although women in the oldest age group demonstrated the highest use, women in all 3 age groups had higher initiation as well as sustained long-term opioid use compared with men. These gender differences were observed in both health plans over all 9 years of this study. Although higher in women, increased long-term opioid use was also observed over time among males of all ages.
Although women typically report more pain conditions and greater pain severity than do men, this did not translate to use of more long-acting Schedule II medications. However, a higher percentage of women than men used sedative hypnotics concurrently with opioid medications, raising a concern about potential interactions and risks. These data cannot address the appropriateness of treatment but highlight the need for research that assesses how patients with long-term opioid use are being managed in community practice, including research on drug safety, pain, and functional outcomes.
The observed differences in opioid use between men and women could be caused by several factors, including differences in prevalence and type of pain and variables that influence the experience and severity of the pain.14
These variables include physiological factors such as hormone levels, psychosocial factors such as depression (more prevalent among women than men), different perceptual styles and coping strategies, and cultural factors, such as gender differences in norms for reporting pain.14,36,37
It is also plausible that physicians respond differently to pain problems among women and men, and hold beliefs concerning the appropriateness of prescribing opioids for different demographic subgroups. These factors have received little attention in the pain literature.38,39
Our finding of higher prevalence of long-term opioid use in older age groups, for both men and women, is consistent with most other research. For example, a telephone survey of a national sample of adults found that those aged 70 years and older were more likely to be regular opioid users.12
In one study, however, which used national data from outpatient hospital and community settings, those aged 75 years and older were more likely than were others to use NSAIDs and less likely to use opioids.19
Some clinicians may be hesitant to prescribe opioids to older patients because of their side effects and potential risks, and several studies have concluded that older patients remain at risk for undertreatment of pain.15,40
Recent guidelines from the American Geriatric Association recommend opioids over NSAIDs, which may result in a further increase in the rate at which older adults are prescribed opioid medications.6
Given the large percentage of older adults now prescribed opioids for long-term use, there is a need for large, controlled studies to assess its safety and effectiveness.
This study has several limitations. It relied on automated health care data. Information from patients on pain severity and function was not available. This study did not address the benefits or risks of opioid prescribing or use. KPNC and GHC pharmacy data are considered accurate and complete, but we do not have information on actual opioid consumption.24,25
KPNC and GHC are integrated health plans, and findings may not generalize to other types of health plans. Nevertheless, these plans cover more than 1% of the US population and results are consistent with those from general population surveys.
Our findings showed that long-term use of opioids doubled over the study period, from 1997 to 2005. The highest prevalence of long-term opioid use was among women and older persons, with 8% to 9% of older women maintaining long-term opioid use in 2005. Among persons with long-term opioid use, dosage levels were typically in the low to moderate range, predominate use of short-acting opioids was most common, and a significant minority was prescribed both opioid and sedative-hypnotic medications. Given the large and rapidly increasing level of long-term opioid use among the population at large, particularly among older persons, improved information on the safety and effectiveness of these medications is needed.