Osteoporosis International

, Volume 19, Issue 3, pp 349–356

Adherence to alendronate in male veterans

Authors

    • University of Wisconsin School of Medicine and Public Health
    • University of Wisconsin Osteoporosis Clinical Center & Research Program
    • Department of MedicineUW School of Medicine and Public Health
  • E. D. Swenson
    • University of Wisconsin School of Medicine and Public Health
  • B. Baltz
    • University of Wisconsin School of Pharmacy
  • A. A. Schuna
    • William S. Middleton Veterans Affairs Medical Center
  • A. N. Jones
    • University of Wisconsin School of Medicine and Public Health
    • University of Wisconsin Osteoporosis Clinical Center & Research Program
  • M. E. Elliott
    • University of Wisconsin School of Pharmacy
    • William S. Middleton Veterans Affairs Medical Center
Original Article

DOI: 10.1007/s00198-007-0471-4

Cite this article as:
Hansen, K.E., Swenson, E.D., Baltz, B. et al. Osteoporos Int (2008) 19: 349. doi:10.1007/s00198-007-0471-4

Abstract

Summary

In one Veterans Affairs’ medical center, alendronate non-adherence was more likely in male veterans who smoke or report side effects, and less likely in men undergoing bone densitometry during therapy. Providers urgently need programs to increase adherence to osteoporosis medications. Initial programs should target patients with risk factors for non-adherence.

Introduction

Adherence to osteoporosis therapy in men is unknown. We hypothesized that ca. 50% of men at one center would be adherent to alendronate and one or more patient-specific factors would associate with adherence.

Methods

We conducted a retrospective chart review study of male veterans to determine the rates and predictors of alendronate adherence over two years. We excluded women, men who received primary care elsewhere and those who took alendronate for indications other than low bone mass. We defined adherence as a medication possession ratio ≥80% in the first 24 months of therapy.

Results

Adherence in the first 12 and 24 months of therapy was 59% and 54%, respectively. In multivariate analyses, non-adherence was more likely in men using tobacco (OR 2.08, 95% CI 1.13, 3.84, p = 0.02) and reporting side effects (OR 2.06, 95% CI 1.14, 3.73, p = 0.02) and less likely in men undergoing bone density during therapy (OR 0.49, 95% CI 0.26, 0.90, p = 0.02).

Conclusions

Alendronate non-adherence is more likely in male veterans who smoke or report side effects, and less likely in men having bone densitometry during therapy. Providers urgently need programs to increase adherence to osteoporosis medications. Initial programs should target patients with risk factors for non-adherence.

Keywords

AdherenceAlendronateMedication possession ratioMenOsteoporosisTreatment

Introduction

The rate of osteoporotic fracture is increasing worldwide as the population ages, with substantial human, economic and social costs [1, 2]. Postmenopausal women are most affected, but men are also at risk. Men experience 25–30% of hip fractures and by age 50 have a 14–25% lifetime risk of osteoporotic fracture [24]. Men may develop osteoporosis secondary to excess alcohol, smoking, glucocorticoid therapy, hypogonadism, immobility, low body weight, increasing age and vitamin D deficiency with secondary hyperparathyroidism [57]. Clinical trials document the anti-fracture efficacy of osteoporosis therapy in men [812].

Significant advances in osteoporosis therapies should substantially reduce rates of fragility fracture in older individuals. However, the efficacy of osteoporosis medication depends on medication adherence, commonly evaluated using the medication possession ratio. The medication possession ratio is calculated as the number of days a medication was supplied between the dates of the first and last prescription, divided by the number of days between the dates of the first and last prescription [13]. Fracture risk reduction is minimal below a bisphosphonate medication possession ratio of 50%, and steadily increases as this ratio rises to ca. 80% and beyond [1417]. Unfortunately, the medication possession ratio of postmenopausal women ranges from 34% to 70% [16, 1821]. Although men often suffer from osteoporosis, their adherence rate is unknown, as they are rarely included in osteoporosis adherence studies [20].

Factors associated with non-adherence to osteoporosis medications in women include age [18, 20, 2224], daily versus weekly use [25], side effects [25, 26], number of concurrent medications [20, 27], history of fracture [18, 20, 22, 25], comorbid conditions [20, 23] and bone density measurement before [20, 23, 25, 27] and during therapy [20]. Many studies use claims or pharmacy databases to determine adherence. These databases may not include patient-specific variables, found only in medical records, that might affect adherence [1821, 28]. Additionally, many studies measure adherence for less than 12 months, whereas optimal osteoporosis therapy requires several years of therapy [29, 30].

Patient-specific risk factors for non-adherence may help health care providers target certain patients to improve their adherence and ultimately reduce fracture risk. Accordingly, in a retrospective study of male veterans receiving care at a Veterans Affairs Medical Center (VAMC), we determined adherence rates to alendronate over two years. We hypothesized that 50% of veterans would be non-adherent, and that one or more patient-specific factors would significantly associate with non-adherence.

Methods

Identification of subjects and eligibility criteria

Using VA Pharmacy Service computerized records, we identified male veterans at least 50 years of age who received their first prescription for alendronate between July 2000 and May 2004. Subjects eligible for study inclusion received primary care through the Madison, Wisconsin VAMC. Exclusion criteria included alendronate therapy for indications other than low bone mass (e.g., Paget’s disease of bone, steroid-induced osteoporosis), receipt of other bisphosphonates before the first alendronate prescription, receipt of primary care elsewhere and death or nursing home admission within the two-year interval.

The University of Wisconsin Human Subjects and William S. Middleton Veterans Affairs Research and Development Committees approved the study and authorized a waiver of written consent.

Chart review and data collection

We reviewed subjects’ medical records, including preventive care and primary care provider notes, hospital discharge summaries and problem lists. We accessed records using the Computerized Patient Record System (CPRS), a VA-wide healthcare documentation system. We recorded patient characteristics potentially associated with adherence, using a standardized chart review form (Table 1). To avoid a potential identifier, we recorded the age of men over 89 years old as “age > 89 years.”
Table 1

Demographic and other characteristics of study participants

Characteristic

n (%) or mean (standard deviation)

Age, years

71 (10)

Race

 Caucasian

178 (90%)

 Other

5 (3%)

 Unknown

15 (7%)

Weight, pounds

178 (34)

Current tobacco use

66 (33%)

Current alcohol use

104 (53%)

Clinical fracture

 Prior to alendronate

114 (58%)

 During alendronate

17 (9%)

Bone densitometry

 Before alendronate

188 (95%)

 During alendronate

128 (65%)

T-score

 Lumbar spine

−1.1 (1.7)

 Total hip

−1.9 (0.9)

 33% radius

−1.4 (1.2)

Number requiring alendronate co-pay

111 (56%)

Concomitant medications

9 (5)

Prescription for

 Calcium

164 (83%)

 Vitamin D

43 (22%)

 Multivitamin

141 (71%)

For each veteran, the number of medications being used when alendronate was first prescribed was recorded from CPRS and pharmacy records. These included prescribed oral, topical and injected medications as well as calcium, vitamin D and multivitamins. We noted for each veteran whether a co-payment was required for alendronate.

Adherence was calculated using a modification of the medication possession ratio, which we defined as the number of actual alendronate fills divided by the number of potential fills over the study interval [13]. We reviewed progress notes to record side effects and/or discontinuation of alendronate. When a health care provider stopped alendronate, the reason and the months of possible fills to that date were recorded. If the patient stopped therapy with the provider’s agreement, we recorded the number of potential fills to that date. If the veteran stopped alendronate without endorsement from his health care provider, the number of potential fills extended through the entire two-year study interval.

We recorded bone mass measurements (g/cm2) and corresponding T-scores obtained at the L1–L4 spine, total hip and 33% radius before and during the first two years of therapy. At the time of each bone density test, height and weight were determined using a wall-mounted stadiometer and balance beam scale. Throughout the study, a single radiology technician made all measurements of bone mass, height and weight. We used body weight at time of first alendronate prescription and body mass index (obese or not obese) at the time of baseline bone density as potential variables influencing adherence.

Statistical analysis

We defined adherence as a medication possession ratio (fill rate) ≥ 80% for a given time period during which the veteran was eligible to receive alendronate, based on work indicating a higher fracture risk for adherence below 80% [14, 16]. “Non-adherence” was defined as having a medication possession ratio <80% for a given study interval. Based on our clinical experience at the VAMC, we estimated that 50% of men would be adherent to alendronate therapy. We calculated that a sample size of ca. 200 men would provide a 95% confidence interval (CI) of 43–57% adherence, using the large sample approximation for binomial variables [31]. A sample size of 200 also allowed us to compare patient variables in men adherent and non-adherent to alendronate.

We compared the characteristics of adherent and non-adherent men using the Wilcoxon rank sum and chi square tests. We calculated 95% confidence intervals for proportions using the large sample approximation for binomial variables [31]. We used univariate and multivariate tests to determine the odds ratios for non-adherence as a function of each patient variable. In multivariate analysis, we controlled for the presence of side effects and current use of tobacco. Analyses were completed using SAS (version 9.1, SAS Institute, Cary, NC) and R (version 2.4.0, The R Project for Statistical Computing, http://www.r-project.org).

Results

The pharmacy identified 1,283 veterans receiving alendronate. From this group, we excluded 530 veterans based on gender, transplant status and use of another bisphosphonate prior to alendronate. We excluded an additional 392 veterans due to receipt of primary care elsewhere, death and nursing home admission within the two-year study period. Receipt of alendronate for indications other than low bone mass and onset of alendronate outside the dates of July 2000 to May 2004 prompted exclusion of an additional 163 veterans. The remaining 198 veterans met all eligibility criteria allowing inclusion into the study.

Subjects included in the study had a mean (standard deviation) age of 71 (10) years and most (90%) were Caucasian (Table 1). Fifty-eight percent had a clinical fracture before beginning alendronate therapy. The mean T-scores in the lumbar spine, total hip and 33% radius at baseline were −1.1 (1.7), −1.9 (0.9) and −1.4 (1.2), respectively. Thirty-three percent of subjects smoked, while 53% used alcohol.

Adherence to alendronate decreased over the two-year study interval. In year one, 59% of men (CI 52–66%) were adherent. Over the two-year study interval, 54% (CI 47–60%) were adherent. By the end of year two, 28% (n = 56) had completely stopped alendronate, 14% (n = 28) at their own instigation, 14% (n = 27) with the approval of their health care provider, and for one veteran, this information was not documented. Figures 1 and 2 depict the medication possession ratios in deciles for all subjects for year one and for both years combined, respectively. For each time interval, the majority of men were adherent. In non-adherent men, Figs. 1 and 2 indicate that mean possession ratios were broadly distributed from 0% to 80%.
https://static-content.springer.com/image/art%3A10.1007%2Fs00198-007-0471-4/MediaObjects/198_2007_471_Fig1_HTML.gif
Fig. 1

Veterans’ one-year medication possession ratios for alendronate. Medication possession ratios (prescriptions filled/prescriptions available) were calculated as described in the text. Bars depict the number of men with the indicated medication possession ratio

https://static-content.springer.com/image/art%3A10.1007%2Fs00198-007-0471-4/MediaObjects/198_2007_471_Fig2_HTML.gif
Fig. 2

Veterans’ two-year medication possession ratios for alendronate. Medication possession ratios (prescriptions filled/prescriptions available) were calculated as described in the text. Bars depict the number of men with the indicated medication possession ratio

Variables potentially associated with adherence were examined. In year one, three variables were significantly associated with non-adherence (Table 2). Non-adherent men were younger (69 (9) versus 72 (9) years, p = 0.03) and were more likely to smoke (46% versus 24%, p = 0.002). Additionally, non-adherent men were less likely to undergo measurement of bone mass during alendronate therapy (57% versus 70%, p = 0.05).
Table 2

Characteristics associated with adherence in year one1,2

 

Non-adherent men, n = 81 (41%)

Adherent men, n = 117 (59%)

p value3

Demographic characteristics and habits

Age, years

69 (9)

72 (9)

0.03

Caucasian race

72 (95%)

106 (99%)

0.08

Weight, pounds

179 (38)

177 (32)

0.77

Current tobacco use

37 (46%)

29 (25%)

0.002

Current acohol use

40 (53%)

57 (50%)

0.68

Clinical fracture

 Prior to alendronate

51 (63%)

63 (54%)

0.20

 During alendronate

7 (9%)

10 (9%)

0.98

Bone density characteristics

Bone densitometry measurement

 Before alendronate

77 (95%)

111 (95%)

0.95

 During alendronate

46 (57%)

82 (70%)

0.05

Baseline T-score

 Lumbar spine

−1.0 (1.5)

−1.1 (1.8)

0.43

 Mean total hip

−2.0 (1.0)

−1.9 (0.9)

0.66

 33% radius

−1.4 (1.2)

−1.5 (1.3)

0.55

Change in bone mass, g/cm2

 Lumbar spine

0.036 (0.041)

0.046 (0.051)

0.20

 Mean total hip

0.002 (0.023)

0.007 (0.024)

0.22

 33% radius

−0.005 (0.032)

−0.007 (0.081)

0.60

Treatment characteristics

Required co-pay

44 (54%)

67 (57%)

0.68

Concomitant medications

9 (6)

9 (5)

0.57

Prescription for

 Calcium

68 (80%)

99 (85%)

0.42

 Vitamin D

18 (22%)

25 (21%)

0.89

 Multivitamin

55 (68%)

86 (74%)

0.39

Side effects

34 (42%)

40 (34%)

0.27

1Adherence was defined as filling ≥80% of alendronate fills over the study interval

2Data are shown as the mean (standard deviation) or the raw number (percent)

3Analyses were conducted using the Chi-square or Wilcoxon rank sum test

During the two-year interval following onset of alendronate therapy, four variables were associated with non-adherence (Table 3). Non-adherent men were more likely to smoke (42% versus 25%, p = 0.01) and describe side effects of alendronate (47% versus 29%, p = 0.01). Non-adherent men were less likely to undergo bone mass measurement during therapy (57% versus 72%, p = 0.03). Non-adherent men who underwent bone mass measurement experienced a smaller increment in lumbar spine bone mass (0.028 (0.040) versus 0.052 (0.051) g/cm2, p = 0.003) compared to adherent men.
Table 3

Characteristics associated with adherence over two years1

 

Non-adherent men, n = 92 (46%)

Adherent men n = 106 (54%)

p value2

Demographic characteristics and habits

Age, years

70 (10)

72 (9)

0.27

Caucasian race

82/86 (95%)

96/97 (99%)

0.13

Weight, pounds

181 (40)

175 (28)

0.47

Tobacco use

39 (42%)

27 (25%)

0.01

Alcoholuse

47/87 (54%)

50/104 (48%)

0.41

Clinical fracture

 Prior to alendronate

57 (62%)

57 (54%)

0.25

 During alendronate

7 (8%)

10 (9%)

0.65

Bone density characteristics

Bone densitometry measurement

 Before alendronate

88 (96%)

100 (94%)

0.67

 During alendronate

52 (57%)

76 (72%)

0.03

Baseline T-score

 Lumbar spine

−1.0 (1.6)

−1.2 (1.8)

0.40

 Mean total hip

−2.0 (0.9)

−1.9 (0.9)

0.36

 33% Radius

−1.3 (1.2)

−1.6 (1.3)

0.12

Change in bone mass, g/cm2

 Lumbar spine

0.028 (0.040)

0.052 (0.051)

0.003

 Mean total hip

0.001 (0.025)

0.008 (0.022)

0.06

 33% radius

−0.006 (0.030)

−0.006 (0.085)

0.28

Treatment characteristics

Required co-pay

48 (52%)

63 (59%)

0.30

Concomitant medications

10 (5)

9 (5)

0.34

Prescription for

 Calcium

77 (84%)

87 (82%)

0.76

 Vitamin D

21 (23%)

22 (21%)

0.72

 Multivitamin

65 (71%)

76 (72%)

0.87

Side effects

43 (47%)

31 (29%)

0.01

Osteoporosis clinic referral

18 (20%)

13 (12%)

0.20

1Adherence was defined as filling ≥80% of alendronate fills over the study interval

2Analyses were conducted using the Chi-square or Wilcoxon rank sum test

In order to determine if variables noted above were independently associated with non-adherence, we carried out univariate and multivariate analyses (Table 4). In multivariate analyses, we determined that non-adherent men were significantly more likely to use tobacco (OR 2.08, 95% CI 1.13, 3.84, p = 0.02) or to report side effects (OR 2.06, 95% CI 1.14, 3.73, p = 0.02) but less likely to undergo measurement of bone mass during therapy (OR 0.49, 95% CI 0.26, 0.90, p = 0.02). In univariate analysis, more than nine current medications conferred a greater odds ratio for non-adherence, but this relationship did not persist in multivariate analysis.
Table 4

Odds ratios for non-adherence over two years1

Variable

Univariate odds ratio (95% CI)

p value

Multivariate odds ratio (95% CI)2,3

p value

Demographic characteristics and habits

Age > 70 years

0.69 (0.38, 1.26)

0.20

0.98 (0.52, 1.86)

0.96

Caucasian race

0.22 (0, 2.23)

0.19

0.19 (0.02, 1.76)

0.14

Weight > 178 pounds4

1.40 (0.77, 2.56)

0.25

1.49 (0.83, 2.67)

0.18

Tobaccouse2

2.14 (1.13, 4.12)

0.01

2.08 (1.13, 3.84)

0.02

Alcohol use

1.27 (0.69, 2.34)

0.47

1.24 (0.69, 2.24)

0.48

Clinical fracture

 Prior to alendronate

1.40 (0.76, 2.57)

0.25

1.32 (0.73, 2.37)

0.36

 During alendronate

0.79 (0.24, 2.42)

0.80

0.78 (0.28, 2.21)

0.64

Bone density characteristics

Bone mass measurement

 Before alendronate

1.32 (0.30, 6.56)

0.75

1.14 (0.30, 4.29)

0.85

 During alendronate

0.51 (0.27, 0.97)

0.04

0.49 (0.26, 0.90)

0.02

Osteoporosis by bone densitometry

 Any site

0.72 (0.39, 1.32)

0.31

0.75 (0.42, 1.36)

0.35

 Lumbar spine

0.58 (0.26, 1.26)

0.16

0.55 (0.26, 1.17)

0.12

 Mean total hip

1.41 (0.72, 2.78)

0.34

1.47 (0.77, 2.81)

0.24

 33% radius

0.95 (0.42, 2.15)

1.0

1.10 (0.51, 2.39)

0.81

Treatment characteristics

Required co-pay

0.68 (0.37, 1.26)

0.20

0.92 (0.51, 1.68)

0.79

Over nine current medications

1.86 (0.99, 3.50)

0.04

1.75 (0.93, 3.29)

0.08

Prescription for

 Calcium

1.12 (0.50, 2.55)

0.85

1.13 (0.52, 2.43)

0.76

 Vitamin D

1.13 (0.54, 2.35)

0.73

1.10 (0.54, 2.23)

0.79

 Multivitamin

0.95 (0.49, 1.85)

0.88

1.0 (0.53, 1.89)

0.99

Side effects3

2.11 (1.14, 3.98)

0.01

2.06 (1.14, 3.73)

0.02

1We compared male veterans with this characteristic to men without this characteristic. We calculated men’s odds ratios for non-adherence in univariate and multivariate analyses, the latter controlling for current tobacco use and presence of side effects. In these analyses ”CI” denotes the confidence interval

2The multivariate odds ratio was adjusted for the presence of side effects

3The multivariate odds ratio was adjusted for current tobacco use

4Data were also analyzed using a body mass index ≥25 to indicate obesity, with similar results

Discussion

Among 198 male veterans who started alendronate for treatment of low bone mass, we hypothesized a 50% adherence rate. We found adherence rates in the first 12 and 24 months of therapy of 59% (CI 52–66%) and 54% (CI 47–60%), respectively. We also hypothesized that one or more patient-specific characteristics would significantly relate to adherence. In univariate and multivariate analyses, non-adherent men were more likely to use tobacco and report side effects but less likely to undergo measurement of bone mass during therapy, confirming our secondary hypothesis.

Ours is the first study to investigate rates of alendronate adherence exclusively in men. Male adherence to alendronate proved similar to that reported in postmenopausal women, for whom bisphosphonate adherence is 34% to 70% in year one [1821, 28] and 27% to 43% in year two of therapy [16, 18]. In one study, in which 4% of 40,000 study subjects were men, female gender associated with increased adherence (relative risk 1.16, CI 1.08–1.25) [20], but the adherence rate in men was not separately reported.

To our knowledge, ours is the first study to link smoking with non-adherence to osteoporosis medications. In studies with other medications, smoking associated with non-adherence [3234]. The link may result from psychosocial factors or patients’ health beliefs that undermine medication adherence and hamper other health pursuits including smoking cessation [3234]. Additionally, a greater number of comorbidities and/or total number of medications associated with the health consequences of smoking may negatively affect adherence [3234].

We recommend smoking cessation to all men with osteoporosis. We base this on studies indicating that approximately five years after men stop smoking, their risk of fragility fracture decreases to that of non-smokers [35]. However, there is no evidence that smoking cessation itself improves non-adherence. Further research is needed to determine why smoking associates with medication non-adherence.

Previously reported patient characteristics associated with bisphosphonate non-adherence include side effects, daily versus weekly dosing, greater number of co-morbid conditions and medications, younger age, high cost of medication, lack of fracture and lack of bone density measurement [18, 2227, 36]. These patient characteristics are not necessarily unique to osteoporosis adherence studies, as many of these factors associated with adherence to antihypertensive and lipid-lowering medications [37, 38].

Unlike other researchers, we found no association between non-adherence and the cost of medication, number of comorbid diseases or history of fracture [20, 25, 39]. This may be due to several factors. First, the out-of-pocket cost of alendronate is less than in other studies, as our veterans have a low monthly co-pay ($3 to $8) for alendronate. Second, although we did not record the number of comorbidities, the number of current medications may serve as a surrogate marker of this parameter. In univariate analysis, more than nine current medications conferred a greater odds ratio for non-adherence, but this relationship did not persist in multivariate analysis. Third, the lack of association between clinical fracture and adherence may relate to our small sample size, the lack of fracture as a universal motivator to take medication, or the patient’s lack of belief or understanding that alendronate decreases the risk of new fracture.

It is not surprising that patient-reported side effects associate with non- adherence to bisphosphonate therapy. Patients may appropriately or inappropriately discontinue medication due to real or perceived side effects. The clinician may not recognize that the patient has stopped a medication, nor be aware of the side effects that led to this decision. Such a scenario may be most likely in patients without fracture or those with urgent or multiple medical issues. Asking the patient if he is taking the medication and whether he is having side effects is a reasonable approach. Notably, patients who experience gastrointestinal side effects with one bisphosphonate may later tolerate the same or another oral bisphosphonate [40].

Like Solomon et al. [20], we found that non-adherent men were less likely to undergo measurement of bone mass during alendronate therapy. However, we cannot conclude that measurement of bone mass during therapy increases adherence to alendronate therapy. Men who are motivated to take osteoporosis medication are probably more likely to return for follow up visits and comply with (or request) additional tests, including bone densitometry. Additionally, clinicians may opt to defer repeat bone mineral density studies on patients whom they know to be poorly compliant with osteoporosis therapy. Further studies are needed to clarify the influence of repeated bone density testing on medication adherence. Likewise, it is probable that good adherence causes increased lumbar spine bone mass during therapy, rather than the other way around.

Our study and others emphasize the need to improve adherence to osteoporosis therapy. Improved adherence may result from increased patient-provider communication or nurse monitoring of therapy [26, 41, 42]. A nurse clinic visit at 12, 24 and 36 weeks improved adherence by 57% when compared to a single clinic visit one year following onset of raloxifene therapy [42]. Phone calls, letters to patients, educational programs, or rewards for excellent adherence (e.g., medication discounts, clinic visit travel reimbursement, or cafeteria vouchers) may increase adherence and improve the care of patients with chronic illnesses [26, 4145].

The VA CPRS could serve as a tool to enhance adherence. For patients starting alendronate, the CPRS could be used to automatically send letters at predefined intervals, encouraging adherence and requesting the patient to call the VA regarding medication problems. During bone densitometry measurements the radiology technician could confirm adherence and tolerability of alendronate with simple yes/no questions, recording responses on the report sent to the provider. Programmers could design a template of orders ensuring that a bone density test is ordered one year following initiation of osteoporosis medication.

Our study has limitations. Patient variables associated with adherence in male veterans at one center may not apply to men treated elsewhere. Information acquired from chart reviews may be incomplete. For example, patients or providers may under-report side effects when compared to prospectively collected rates of side effects within a clinical trial. Two different investigators reviewed each chart to verify data accuracy prior to analysis, yet this data collection may still be subjective. We based adherence on number of fills, rather than number of tablets ingested or proper intake of alendronate. However, the medication possession ratio is the most commonly used research method to judge adherence [13, 26, 45]. Finally, our relatively small sample size may limit detection of all factors associated with non-adherence among male veterans.

Despite these limitations, our study has strengths. We examined the charts of individual subjects to document patient-specific factors including tobacco use and side effects, information that is often unavailable in claims or pharmacy databases. The study focused exclusively on men, a population rarely included in osteoporosis adherence studies. In multivariate analysis, we found that smoking, side effects and lack of bone mass measurement during therapy were independently associated with non-adherence to alendronate treatment. Side effects and lack of bone mass measurement have previously been associated with non-adherence to antiresorptive therapy in women. Within the current report, similar relationships have now been observed in men, and an association between smoking and non-adherence was also found.

In summary, men are at high risk of osteoporotic fracture. Medications, if taken regularly, can reduce the risk of fracture. Despite this, we found only half of the veterans at one VAMC remained adherent to alendronate therapy in the two years following initial prescription. Current tobacco use, occurrence of side effects and lack of bone mass measurement significantly associated with non-adherence. Recognition of these and other factors associated with non-adherence may help clinicians identify and counsel high-risk patients. The non-adherence rates observed in this study and others demand a formal program to improve patient adherence to osteoporosis therapy. Phone calls, letters or email reminders, educational programs or rewards for excellent adherence may prove to increase adherence to osteoporosis therapies and thereby decrease rates of osteoporotic fracture. Prospective studies should investigate strategies to increase adherence, improve skeletal health and lessen the personal and economic costs of fractures in men.

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2007