Main findings
In our nationwide population of older people, about 16% of the women and 3% of the men used any osteoporosis drug, which is low compared with the estimated osteoporosis occurrence in Sweden [
13]. Thus, it seems like osteoporosis is undertreated in elderly Swedes and particularly in the oldest old (≥90 years). These findings are in concordance with results from previous studies regarding age and treatment with osteoporosis drugs [
15,
28,
31,
32]. One reason for this finding may include physicians’ wish to minimise polypharmacy in the frail oldest old [
32]. However, use of many drugs was strongly associated with use of osteoporosis drugs [
28,
32], so this explanation seems less probable. Other explanations might be physicians’ and elderly patients’ attitudes and knowledge of osteoporosis and osteoporosis drugs, older patient’s lack of communication skills (maybe due to cognitive impairment) and non-adherence in the oldest old [
33].
The prevalence of bisphosphonates was generally low (5% for women and 1% for men) and higher age, particularly in women, was associated with decreased use of bisphosphonates. Treatment with bisphosphonates is well-documented in the elderly and these drugs have an overall favourable safety profile [
6,
8,
34]. The cost-effectiveness of bisphosphonates in the elderly has also been established [
8,
35‐
37]. Thus, there seem to be opportunities for improvement in treatment with bisphosphonates in older Swedes. Nevertheless, the Hip Intervention Program Study Group concludes that the bisphosphonate risedronate reduces the risk of hip fracture in elderly women with confirmed osteoporosis but not in elderly women selected primarily on the basis of risk factors other than low BMD [
38]. The selective oestrogen receptor modulator raloxifene is a newer type of osteoporosis drug, and, hence, not as well-studied as the bisphosphonates. Raloxifene is mainly regarded as suitable for postmenopausal women, who would previously been prescribed HRT [
15,
34], which would explain the decreased use in the older participants in our study.
The most common type of osteoporosis drug was calcium + vitamin D supplements, which is in concordance with previous research [
31]. Calcium + vitamin D supplements are regarded as less potent than bisphosphonates and raloxifene, and are most likely only effective in deficient patients [
8,
34]. In women, the prevalence and likelihood of use of calcium + vitamin D supplements were lowest in the oldest old, even though frail older women confined to institutions sustain fewer fractures if given calcium + vitamin D supplements [
39]. To our knowledge, there are no evidence-based guidelines supporting a reduced use in the oldest old women.
In concordance with previous studies [
17,
31,
32,
40,
41], it seems as if men are particularly undertreated for osteoporosis, although mortality for most osteoporotic fractures has been reported to be higher in men than in women [
42]. Nevertheless, osteoporosis in men has only recently been broadly recognised [
43] and the treatment rates may be expected to increase as the awareness of male osteoporosis improves. Moreover, the stronger association observed in our study between use of other drugs and use of osteoporosis drugs in men, indicates that males treated for osteoporosis may have more comorbid conditions than their female counterparts. Thus, men seem to be in a worse condition than women when treated for osteoporosis.
Furthermore, living in an urban area was associated with a higher probability of osteoporosis treatment. Explanations for this finding may be a higher rate of osteoporosis and fractures in urban areas [
44‐
47] longer distance to BMD testing in rural areas [
28] and availability of specialist care.
Limitations
The cross-sectional design of our study does not allow us to draw conclusions regarding causality. The SPDR does not include information about the underlying indications and diagnoses for prescription of drugs. We also lacked information about comorbidity. However, we did control for a proxy for overall comorbidity (i.e., number of other drugs) [
27,
28].
We analysed data on elderly patients registered in the SPDR from October to December 2005, which corresponded to 91% of the population aged 75 years and older in Sweden (according to Statistics Sweden’s census data from 31 December 2005). The SPDR does not include data on over-the-counter drugs, which only concerns calcium + vitamin D supplements in this study. Calcium + vitamin D supplements can be purchased both with and without a prescription in Sweden. However, we were specifically interested in prescribing practise regarding osteoporosis drugs. Therefore, the lack of information about use of non-prescription drugs was not a substantial problem in this particular study. Also, the register does not include drugs used in hospitals or from drug storerooms sometimes used in nursing homes, which may lead to an underestimation of older people’s drug use. Moreover, our method is built on an assumption that all current drugs were dispensed during the observed 3-month period, which is based on the fact that drugs are prescribed for use during at most 90 days in Sweden. Therefore, we might have missed drugs that were dispensed before the 3-month period and used at a slower rate than intended. At the same time, we might have included drugs that were dispensed during the 3-month period but discontinued prematurely. In addition, our method is based on interpretations of the dispensed drugs’ dosages written by the prescribers, as well as assumptions about DDDs when information about dosage was incomplete or missing (about 15% of the regularly used drugs) [
24,
25].
Finally, a general limitation of studies on drug registers is that data on dispensed drugs are not synonymous with neither prescribed nor used drugs. Some prescriptions may never be filled at pharmacies and adherence to treatment can be low [
33].