European Journal of Clinical Pharmacology

, Volume 67, Issue 3, pp 301–308

Primary-care prescribing of anti-osteoporotic-type medications following hospitalisation for fractures

Authors

    • Department of Pharmacology & Therapeutics, Trinity Centre for Health SciencesSt. James’s Hospital
  • Kath Bennett
    • Department of Pharmacology & Therapeutics, Trinity Centre for Health SciencesSt. James’s Hospital
  • Joe Marry
    • Osteoporosis and Bone Health Clinic, Medicine for the ElderlySt. James’s Hospital
  • J. B. Walsh
    • Osteoporosis and Bone Health Clinic, Medicine for the ElderlySt. James’s Hospital
  • Miriam C. Casey
    • Osteoporosis and Bone Health Clinic, Medicine for the ElderlySt. James’s Hospital
Pharmacoepidemiology and Prescription

DOI: 10.1007/s00228-010-0942-y

Cite this article as:
McGowan, B.M., Bennett, K., Marry, J. et al. Eur J Clin Pharmacol (2011) 67: 301. doi:10.1007/s00228-010-0942-y

Abstract

Purpose

We examined the prescribing of antiosteoporotic medications pre- and post hospital admission in patients with fragility fractures as well as factors associated with prescribing of these treatments following admission.

Methods

We identified all patients aged ≥55 years at a large teaching hospital between 2005 and 2008 with a fracture using the Hospital In-Patient Enquiry (HIPE) system. These data were linked to prescribing data from the Health Service Executive Primary Care Reimbursement Services (HSE-PCRS) scheme before and after discharge (821 patients). Logistic regression analysis was used to examine the likelihood of prescription of antiosteoporotic medication pre- and post discharge in relation to year of discharge, age, gender, and type of fracture.

Results

Prescribing of antiosteoporotic treatment before fracture increased from 2.6% [95% confidence interval (CI) 2.23–2.93%] in 2005 to 10.6% (95% CI 9.32–11.86) by 2008, whereas post fracture prescribing increased from 11% (95% CI 9.64–12.36) to 47% (95% CI 43.6–50.3). In patients discharged from hospital in 2007, postfracture prescribing was 31.8% (95% CI 28.66–35.02) at 12 months, increasing to 50.3% (95% CI 46.6–53.9) at 24 months. The highest rate of prescribing was in the 65- to 69-year age group [odds ratio (OR) 8.51, 95% CI 1.75–41.35]. Patients discharged in 2008 were eight times more likely to be treated than patients discharged in 2005 (OR 8.01, 95% CI 4.55–14.09).

Conclusion

The percentage of patients on antiosteoporotic treatment post fracture increased significantly from 2005 to 2008. This may be largely due to the introduction of the Osteoporosis Clinic to the hospital in 2005.

Keywords

OsteoporosisPrescribingFragility fracturesLinkageDatasets

Introduction

Whereas the exact figures for the prevalence of osteoporosis in Ireland are unknown, as many remain undiagnosed, the World Health Organisation (WHO) estimates applied to the Irish population suggest this could be in the region of 300,000, accounting for >25% of the >50 age group [1]. Fragility fractures that are a direct result of osteoporosis cause significant morbidity, and consequently reductions in quality of life, and mortality. Furthermore the risk of future fractures increases from 1.5 to 9.5 fold following a fragility fracture [24]. There are on average 7,250 admissions to Irish public hospitals each year for treatment of fall-related injuries, utilising 5.2% of the 1.8 million hospital bed days used by older people, with an average length of stay of 12.7 days. The results of an Irish Burden of Illness Study demonstrated that fall-related injuries in the elderly cost the Irish health care system approximately €402 million each year [5].

It is projected that the population of people over 65 years in Ireland will more than double, from 436,001 in 2002 to 1,002,280 in 2031, or from 11% to 18% of the population. Consequently, the number of fractures sustained by this age group is expected to double unless adequate measures are put in place to diagnose and treat osteoporosis and consequently reduce the risk of fragility fractures. There have been significant advances in the treatment of osteoporosis since the mid-1990s with the availability of new oral pharmaceutical products such as the bisphosphonates. The efficacy of these products in reducing the risk of fracture is most evident in patients with established osteoporosis [68]. Other pharmacological treatments available at the time of the study included calcium and vitamin D preparations, strontium ranelate, raloxifene and parathyroid hormone (teriparatide), as well as some combination products. Despite the availability of proven effective pharmacotherapy for managing osteoporosis, studies are continuing to show that post fracture treatment with antiosteoporotic medications remains suboptimal [919]. These findings are particularly relevant in light of the fact that a history of fracture is one of the strongest predictors of future osteoporosis-related fractures.

A physician-led osteoporosis clinic as part of a comprehensive bone health service was introduced to St. James’s Hospital in 2004. The clinic contains a dual-energy X-ray absorptiometry (DXA) scan. The osteoporosis unit assesses all patients who present to the hospital with classical osteoporotic-type fractures, such as hip and colles’ fracture, as well as assessing for the presence of vertebral fractures using vertebral morphometry in all referrals for DXA. The clinic provides a service to other specialities in the hospital, such as rheumatology and gastroenterology, as well as serving the local primary care physicians. Patients who have had a fracture or who may be at risk of sustaining a fracture are referred to the clinic that provides specialised bone biochemistry, a clinical nurse specialist assessment of falls and fracture risk, advice and subsequently a medical consultation. All physicians within both primary and secondary care have open access to refer patients to the Osteoporosis Clinic.

The aims of this study were to examine the trends in prescribing of anti-osteoporotic-type medications in patients admitted to St. James’s Hospital for treatment of an osteoporotic-type fracture prior to and subsequent to their discharge from hospital between 2005 and 2008 and examine factors associated with prescribing of these therapies following discharge, using a linked database of hospitalisation and prescribing data.

Methodology

The Hospital In-Patient Enquiry system (HIPE)

Data on hospital admissions for fracture was obtained from the local Hospital In-Patient Enquiry system (HIPE) from St. James’s Hospital, which is one of the largest teaching hospitals in Ireland. HIPE data are the only source of morbidity data available nationally for acute hospital services in Ireland. More than 60 acute-care public hospitals participate in HIPE, reporting on close to1 million records annually. Data cover approximately 96% of all admissions to a hospital. HIPE is a computer-based discharge abstracting system designed to collect demographic, clinical and administrative data on discharges and deaths from acute general hospitals nationally. The information from HIPE data used in this study is as follows: dates of admission and discharge; date of birth; sex; medical-card status and diagnosis (principal and secondary). The most important aspect of this process is the coding of the diagnoses and procedures performed using the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM). Each HIPE discharge record represents details of one admission and there may be more than one admission in any given year. There were no risk-factor data available from this database.

By identifying the specific codes for fractures, we examined data on all patients who were admitted to hospital for treatment of both typical and atypical osteoporotic-type fractures between 2005 and 2008. A list of all fracture types included in the analyses based on ICD-10 coding can be found in Appendix “1”. Patients who had sustained a fracture as a direct result of severe trauma, such as a road traffic accident, were excluded from the study. Only fractures sustained as a result of minimal trauma (defined as a fall from standing height or less, or a similar degree of injury) were included.

The HSE-PCRS pharmacy database

The Health Service Executive Primary Care Reimbursement Services (HSE-PCRS; formerly the General Medical Services) scheme provides free health care to approximately 30% of the Irish population (approximately 1.2 million). Eligibility is means tested and all medicines are dispensed free of charge to patients registered under this scheme. The service was also made available to all those >70 years of age from July 2001 until December 2008. Whereas the HSE-PCRS population cannot be considered representative of the entire population—as the elderly, the young and the socially disadvantaged are overrepresented—it is estimated to account for approximately 70% of all medicines dispensed in primary care [20].

The HSE-PCRS pharmacy database contains demographic details on patients (age and gender); information related to the medicine dispensed, including name, strength and quantity of the drug dispensed; together with the associated cost and dispensing fee. All prescription items are coded using the WHO Anatomical Therapeutic Chemical (ATC) classification system. The study was carried out over a 6-year period involving prescription data between January 2004 and July 2009. All prescriptions for medications for prophylaxis and treatment of osteoporosis [bisphosphonates, vitamin D and its active metabolites calcitriol and alfacalcidol, strontium ranelate, parathyroid hormone (teriparatide) and the hormone replacement therapies raloxifene and tibolone] were identified for the Eastern Regional Health Board in which the large teaching hospital is situated.

Linking HIPE data to HSE-PCRS prescription data

Each patient eligible for the HSE-PCRS medical-card scheme has a unique number. This information is recorded by the hospital administration at the time of admission, but at present it is not released to the national HIPE data. Linkage of the hospital HIPE data to the HSE-PCRS prescribing database was therefore possible and enabled a longitudinal study of patients who sustained an osteoporotic-type fracture to include their medical management before and after discharge. The type of information gathered included drug prescribed and dose and the number of patients admitted for treatment of subsequent fractures. It was also possible to identify whether the patients were on treatment or prophylaxis for osteoporosis prior to their admission as well as after their discharge. Permissions were obtained the hospital’s ethics committee and chief executive’s office and the HSE-PCRS for linkage of the HIPE database. The linkage was made via the unique card number where available and was possible for 92% of the study cohort. Once the linkage was completed, all unique identifiers were removed from the merged data set.

Statistical methods

Prescribing of antiosteoporotic therapies was considered in the 12 months pre- and up to 24 months postdischarge. At the patient level, this refers to the follow-up time that prescribing was assessed after the fracture. In relation to the proportion of antiosteoporotic medications prescribed to those with fractures, this was calculated as (number of fracture patients receiving anti-osteoporotic-type medications) / (number of patients admitted to hospital with a fracture). Descriptive analysis on the medications prescribed in the study cohort with fractures before and after discharge are presented in the form of percentages and 95% confidence intervals (CI) for categorical data and means ± standard deviation (SD) for continuous normal data. Factors associated with prescribing of antiosteoporotic medications postfracture (age, gender, type of fracture, year of admission for fracture, prescribing prefracture) were examined univariately using chi-square tests. Any factors significant at the p < 0.10 level were included in a logistic model to examine the significant predictors of prescribing of antiosteoporotic drugs after discharge. Adjusted odds ratios (OR) and 95% CIs are presented. Longer-term prescribing trends were examined to determine when patients were commenced on their antiosteoporotic-type medications after discharge. SAS (SAS Institute Inc, Cary, NC, USA, v9.1) statistical software was used for analysis. Significance at p < 0.05 is assumed.

Results

From the 1,036 patients >55 years who had sustained an osteoporotic-type fracture between January 2005 and December 2008, 86 were excluded from the study, as they did not have an HSE-PCRS number documented, and therefore, their data could not be linked. A further 71 episodes of repeat fractures (6.8%) were excluded to avoid any duplication of results, and a further 58 patients who were residing outside the Eastern Regional Health Board area were also excluded. Approximately 79% (821) of patients ≥55 years who had sustained an osteoporotic-type fracture during the study period were successfully linked to the HSE-PCRS prescribing database. The distribution of fracture types (typical osteoporotic and atypical osteoporotic), along with the age and gender of the patient cohort, are shown in Table 1. Seventy-six percent of patients were women, and the mean age of the study group was 78.14 (SD 9.53) years. Approximately 65% were ≥75 years of age, with 25% >85 years. Forty-four percent of patients admitted had sustained a hip fracture (Table 1). There was little change in the numbers of patients >55 years admitted to the teaching hospital each year for management of a fracture during the study period. The number of admissions increased from 200 in 2005 to 213 in 2008, with a slight drop in the numbers of all types of fractures in 2006 to 183.
Table 1

Types of fracture sustained between 2005 and 2008 (821 patients)

 

 Types of fracture

No of patients

% of patients

Typical

Hip

359

43.73

 

Distal radius/ulna

82

9.99

 

Tibia/fibula

71

8.65

 

Pelvis

59

7.19

 

Vertebrae

38

4.63

 

Ribs, clavicle, scapula, sternum, humerus

46

5.60

Atypical

Other

166

20.22

 

Total

821

 

Gender

Female

623

76.44

 

Male

192

23.56

Age group

55–59

44

5.36

 

60–64

53

6.46

 

65–69

65

7.92

 

70–74

123

14.98

 

75–79

170

20.71

 

80–84

161

19.61

 

>85

205

24.97

Patients treated postfracture

Of the 821 patients admitted during the 2005–2008 period, 219 (26.6%) were subsequently prescribed anti-osteoporotic-type medications within 12 months of discharge date. If the follow-up period is extended to 24 months, the rate of prescribing increases to 33.6% (excluding patients who sustained a fracture in 2008, as 24-month follow-up data was not available on these patients at the time of the study). The types of medications prescribed post discharge are shown in Table 2. Of those who received anti-osteoporotic-type medications, 79% were treated with a bisphosphonate, of whom those treated with alendronate and risedronate accounted for 76% and 19%, respectively. Pre fracture treatment only increased from 2.58% (95% CI 2.23–2.93) in 2005 to 10.59% (95% CI 9.32–11.86) by 2008, whereas there was a more dramatic change in postfracture prescribing, which increased from 10.97% (95% CI 9.64–12.36) in 2005 to 47% (95% CI 43.6–50.3) in 2008, as illustrated in Fig. 1. If the follow-up period was extended to 24 months postdischarge, the rate of prescribing increased from 31.8% (95% CI 28.66–35.02) in 2005 to 50.3% (95% CI 46.6–53.9) in 2007. Treatments with bisphosphonates and the bisphosphonate combination products increased fourfold during the study period, particularly the prescribing of the once weekly products of alendronate and risedronate.
Table 2

Number of patients on antiosteoporotic therapies up to 12 months postfragility fracture [219 (26.6%)]

Type of medication

No. of patients

% of patients

Bisphosphonate

174

79

  Alendronate

132

 

  Ibandronate

10

 

Risedronate

33

 

Raloxifene

1

0

Vitamin D

13

6

Calcium carbonate

8

4

Strontium ranelate

12

5

Teriparatide

11

5

https://static-content.springer.com/image/art%3A10.1007%2Fs00228-010-0942-y/MediaObjects/228_2010_942_Fig1_HTML.gif
Fig. 1

Percentage of patients prescribed anti-osteoporotic-type medications prior and subsequent (within 12 months of discharge) to sustaining a fragility fracture between 2005 and 2008

Prescribing of antiosteoporotic therapies postadmission for fracture

In the univariate analysis, all factors were found to be significantly associated with prescribing of antiosteoporotic medications postfracture. These were then entered into a logistic regression model and Table 3 presents the adjusted OR and 95% CIs for predicting the prescribing of antiosteoporotic therapies postdischarge for fracture. The highest rate of prescribing postfracture was in the 65- to 69-year age group compared with the 55- to 59-year age group (OR 8.51 95% CI 1.75–41.35). It was also found that women were twice as likely as their male counterparts to be prescribed anti-osteoporotic-type medications postfracture discharge (OR 2.05, 95% CI 1.27–9.16). Patients discharged from hospital after fracture treatment in 2008 were eight times more likely to be treated with anti-osteoporotic-type medications than were patients discharged in 2005 (OR 8.01 95% CI 4.55–14.09). When compared with patients who had sustained a hip fracture, there was no increased likelihood of being prescribed antiosteoporotic medications between those having sustained a fractured radius/ulna, tibia/fibula, pelvis, vertebra or other fracture.
Table 3

Adjusted odds ratios (OR) and 95% confidence intervals (CIs) for predicting the prescribing of antiosteoporotic therapies postdischarge for fragility fracture

Patient characteristics

OR

95% CIs

Prescribing prefracture

Any vs none

4.55

2.26

9.16

Gender

Female vs male

2.05

1.27

3.33

Age group

60–64 vs 55–59

3.39

0.65

17.78

 

65–69 vs 55–59

8.51

1.75

41.35

 

70–74 vs 55–59

5.95

1.29

27.51

 

75–79 vs 55–59

6.40

1.41

29.03

 

80–84 vs 55–59

5.13

1.12

23.61

 

>85 vs 55–59

4.91

1.08

22.36

Year of discharge

2006 vs 2005

0.80

0.38

1.68

 

2007 vs 2005

4.50

2.53

8.01

 

2008 vs 2005

8.01

4.55

14.09

Type of fracture

    
 

Radius/ulna vs hip

0.74

0.40

1.38

 

Tibia/fibula vs hip

0.41

0.18

0.93

 

Pelvis vs hip

0.70

0.34

1.46

 

Vertebra vs hip

1.20

0.54

2.68

 

Other vs hip

0.63

0.33

1.20

Discussion

The results of this study show a significant increase in the prescribing of anti–osteoporotic-type medications post fracture discharge during the study period, from 11% in 2005 to 47% in 2008 within 12 months of discharge. The availability of the once-weekly bisphosphonate products may partially explain the dramatic rise in the prescribing of bisphosphonates in this study post fracture from 2006 onwards. There is also increasing awareness among physicians in the community treating older patients to find and treat osteoporosis prior to the patient sustaining a fracture or a repeat fracture. However, the main reason for this fourfold increase is more likely to be due to the introduction of a physician-led osteoporosis clinic as part of a comprehensive bone health service to the hospital that occurred at the same time as the start of the study period. The clinic provides open access to free DXA scans and unlimited access to free antiosteoporotic medications and patient monitoring to assess tolerability and response to treatment. Vitamin D levels are measured and patients receive loading oral or intramuscular vitamin D and intravenous zolendronic acid infusion if required. Follow-up post fracture for patients attending the clinic is closely monitored, and it is important to emphasise that such services in Ireland are scarce.

Since 2005, there has been a routine orthogeriatric ward round that includes a clinical nurse specialist who focuses on the area of education and medication compliance in these patients. The increase in the prescribing of antiosteoporotic medications in this patient cohort coincides with the introduction of these services to the hospital. After an initial preassessment visit to the osteoporosis clinic, where patients are sent for a DXA scan, a letter is sent from the attending physician to the primary care physician that contains information on laboratory results, results of the DXA scan and a prescription for appropriate antiosteoporotic medications. Communication between the osteoporosis clinic multidisciplinary team and the primary care physician is therefore crucial to ensure continuity of care for patients receiving these medications.

Despite the increase in the prescribing of anti-osteoporotic-type medications, the percentage of patients receiving such pharmacotherapy remains at <50%, which is similar to the findings of other such published studies [12, 13, 2123]. Alendronate, etidronate, risedronate, raloxifene and strontium ranelate are all recommended by the UK’s National Institute for Clinical Excellence (NICE) as possible treatments for preventing bone fractures in postmenopausal women who have already had a fracture with a diagnosis of osteoporosis and also in postmenopausal women with osteoporosis who have not had a fracture. Teriparatide is also recommended as an option in patients who have osteoporosis and who have had a fragility fracture [24, 25]. Oral bisphosphonates reduce the risk of vertebral fractures by 40–50% and nonvertebral fractures by 20–40% [2631].They have dominated the market for postfracture prescribing since 2000 and particularly since 2004 with the advent of the once-weekly products that reduce the severity of the gastrointestinal side effects and are, as a result, better tolerated by patients. Bisphosphonates accounted for 79% of the prescribing of anti-osteoporotic-type medications in this study. whereas strontium ranelate and teriparatide accounted for a further 5%, respectively. A previous Irish study involving the HSE-PCRS prescribing data for 2004 and 2005 found that approximately 65% of all patients who were dispensed drugs for managing osteoporosis were prescribed the once-weekly products of alendronate and risedronate [32].

Cadarette et al found in their study of hip-fracture patients in Pennsylvania, USA, that prescribing osteoporotic-type medications improved from 4% in 1995 to 31% in 2004 [21]. A systematic review of 20 studies between 1997 and 2003 by Elliott-Gibson et al. [12] found that rates of treatment for postfracture patients with osteoporotic medications were generally low, with bisphosphonate prescribing ranging from 0.5% to 38%.Only six of the studies reported treatment rates >10%. A number of studies have attempted to identify contributory factors to the relatively low levels of prescribing of medications for managing osteoporosis, particularly in patients who have sustained a fragility fracture [33, 34]. Barriers to osteoporosis management that have been identified include the lack of and fragmented continuity of care of patients postfracture, communication difficulties between health care providers and concerns over the cost-effectiveness and the side effects of the bisphosphonates [23, 35]. Elsewhere successful programs have been put in place to provide direct intervention for fracture patients, such as a study published by Kuo et al. [36] involving 155 minimal-trauma fracture patients who were offered specific medical assessment, bone mineral density (BMD) and laboratory investigations, treatment recommendations and a second follow-up at 8.6 months. The results of their study showed that direct intervention improved osteoporosis care two- to fivefold, maintaining long-term treatment in 90% of osteoporotic and 73% of osteopenic individuals requiring therapy. However, a small proportion of patients (20%) did not agree to follow-up postfracture, and of those that did have BMD levels and assessment, only 43% were advised antiresorptive therapy based on risk factors and BMD levels. Cuddihy et al. [11] found in their study of 105 patients who sustained a distal forearm fracture that only 65% agreed to participate in the study.

The results of our study also found that post fracture prescribing in patients discharged from hospital in 2007 was 32% at 12 months; however, this increased to 50% at 24 months. The main reason for this increase in prescribing after the 12-month follow-up period is probably due to the emphasis that the multidisciplinary team place on the importance of the patient continuing to take anti-osteoporotic-type treatments. There are great efforts made by the clinical nurse specialists in identifying, encouraging and monitoring these patients to reduce their risk of subsequent fragility fractures. Based on the findings of Kuo et al. and Cuddihy et al., it is likely that a certain number of fracture patients in our study who did not receive anti-osteoporotic-type medications were not treated for similar reasons, i.e. unwilling or unable to attend for follow-up treatment or did not require antiresorptive therapy based on risk factors and BMD levels

With an increasing ageing population, one would expect the incidence of fragility fractures to increase on a yearly basis; however, this was not evident during the 4-year study period. The low percentage of men with fragility fractures is consistent with previously reported rates, which have ranged from 0% to 34% [37, 38]. Whereas NICE guidance on the use of antiosteoporotic medications only includes women, most local and national guidelines on managing osteoporosis now include men. The results of our study showed that the highest rate of prescribing was in the 65- to 69-year old age group compared with the 55- to 59-year old age group, and prescribing patterns did not differ between fracture types.

There are a number of limitations to this study. Firstly, there was no information available from either of the two linked databases in relation to risk factors associated with fracture. Therefore, it was not possible to examine the differences in treatment uptake by category of fracture risk. Secondly, the study was carried out in a hospital where there is direct access to an osteoporosis clinic, so one would expect more prescribing of antiosteoporotic medications in this patient group compared with patients who do not have access to such services. However, it is important to point out that even though the changes in prescribing of anti-osteoporotic-type medications to postfracture patients coincided with the introduction of the osteoporosis clinic and therefore were likely to be associated, this cause–effect relationship cannot be drawn due to the study design. Whereas we did not have a comparator group to compare the prescribing of osteoporosis medications in patients who do not have direct access to an osteoporosis clinic, it was possible to compare our results with results of published studies from other European countries The study was carried out over a 4-year period, with the majority of prescribing data relating to 2006 onwards, therefore not long enough to examine in more detail longer-term prescribing patterns, adherence levels and incidence of repeat fractures. We did not have information on actual diagnosis and confounders that might be associated with fractures and prescribing.

In summary, this study has demonstrated a dramatic increase in the prescribing of predominantly bisphosphonate medications to patients admitted to hospital for treatment of a fragility fracture between 2005 and 2008. Bisphosphonates accounted for the majority of this increase. Factors associated with this increased prescribing were previous prescribing, female gender, more recent year of discharge and age group.

Acknowledgements

We thank the Health Research Board in Ireland for providing funding for this project. We also thank the HSE-PCRS scheme for providing data on which the study was based, and the staff in the Coding Office at St. James’s Hospital, Dublin, who provided the HIPE data and facilitated the linkage of the data sets.

Conflict of interest

None declared.

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© Springer-Verlag 2010