Introduction
Osteoporosis is a major health burden worldwide [
1], affecting more than 22 million women and 5.5 million men in the European Union [
2]. Osteoporosis is common among older populations and affects people of both genders, but is more prevalent in women [
1,
3,
4].
The disease is associated with an increased risk of fracture, and vertebral fractures are among the most common type of osteoporotic fracture [
1,
5]. Vertebral fractures may cause severe pain and loss of function, but can also present with mild or no symptoms [
5]; this may explain why only 30% of these fractures come to clinical attention. Fractures of this nature have a substantial impact on the individual’s health-related quality of life (HRQoL) [
6].
HRQoL is a multidimensional concept that encompasses the physical, psychological, social and somatic domains of functioning and well-being [
7,
8]. In addition, HRQoL may offer prognostic benefits for prediction of clinical complications and mortality [
9]. The need to improve HRQoL in older people is widely acknowledged [
10], and identification of variables associated with HRQoL is a prerequisite for such effort [
11]. It is well documented through research that people with osteoporosis who have suffered vertebral fracture experience poorer HRQoL compared to those who do not have osteoporosis or have not experienced vertebral fracture [
6,
8,
12,
13]. Vertebral fractures are particularly associated with reduced HRQoL in its physical domain, as well as with pain and reduced physical function [
13].
Kerr et al. [
14] state that osteoporosis and fracture can have a profound impact on physical function, and that this impact accumulates over time. The experience of fracture may lead to a downward spiral of decline in physical function due to pain and loss of bone and muscle strength. This may in turn result in decreased mobility, activity restriction and reduced ability to carry out daily activities, and increased risk of new fractures.
Among the older population generally, impaired function is a predictor of reduced HRQoL [
15]. In elderly men and women with osteoporotic fractures, lower quality of life was associated with reduced walking speed [
16]. As far as we know, only one study has investigated the relationship between HRQoL and physical function in people with vertebral fracture in particular. A study by Bergland et al. [
17] (
n = 89) on older women with osteoporosis and vertebral fracture found that those in the 75% group with the highest maximum walking speed and those in the 75% group with best performance on balance had better scores on HRQoL compared to those in the 25% group with lowest maximum walking speed and poorer performance on balance [
17].
Pain is another factor that may influence HRQoL [
18]. Back pain is common in osteoporosis patients, even where there is no history of vertebral fracture, and research has revealed a negative association between back pain and balance, as well as mobility [
19]. Furthermore, pain intensity is found to have a negative impact on physical HRQoL, walking speed, balance and leg strength in women with osteoporosis with and without vertebral fracture [
20].
In summary, people with osteoporosis and vertebral fracture experience reduced HRQoL, physical function and increased pain. HRQoL is a key indicator of people’s health status, and identification of variables associated with it is pivotal in preventing decline in these individuals’ HRQoL. To our knowledge, this study is the first to study the relationship between HRQoL, physical function and pain in a population of older women with osteoporosis and vertebral fracture. This knowledge is key, since we know that some of these factors may be modifiable. Identification of factors that account for variations in HRQoL among people with vertebral fracture may guide intervention strategies for enhanced HRQoL in this patient group. Decline in physical function and the associated lower HRQoL are reported to respond positively to exercise interventions [
21,
22]. Additionally, a recent review concluded that pain after osteoporotic fracture requires a multifaceted approach, including both pharmacological (i.e., pain medication) and non-pharmacological (e.g. physical exercise, physiotherapy) interventions [
23].
This study’s objective is to examine the independent associations between various HRQoL subscales and physical function (i.e., walking speed, balance, muscle strength) as well as pain and sociodemographic factors in older women diagnosed with osteoporosis and vertebral fracture. To perform a comprehensive investigation we applied both a generic and a disease-specific HRQoL instruments to examine differences between the instruments’ associations with physical function, pain and sociodemographic factors [
6,
7]. We hypothesized that those with poor generic and disease-specific HRQoL had lower levels of physical function and higher levels of pain.
Results
The participants’ mean age was 74.2 years (SD 5.8) (Table
1). The mean number of years of school attendance (education) was 13.1 (SD 3.4). Of the participants, 45.1% were living alone, and the mean score for pain (NRS) in the preceding week was 3.4 (SD2.5). Mean BMI was 23.2 kg/m
2 and the presence of comorbidities, defined as 4 or more self-reported diagnoses, was found in 40.5% of the participants. The mean walking speed was 1.21 m/s (SD 0.30). Regarding the HRQoL instruments, the subscale with the best score in SF-36 was SF (mean 84.1, SD 20.5) while in QUALEFFO-41 the highest score was observed in Physical Function (mean 17.2, SD 13.2). In SF-36’s subscale SF, a ceiling effect was found in the 52% who achieved the top score of 100.
Table 1
Characteristics of the study population. Means, standard deviations, percentages, minimum - maximum and 95% confidence interval
Age, mean (SD) | 74.2 (5.8) | 65–89 | 73.3–75.1 |
Education, in years, mean (SD) | 13.1 (3.4) | 7–22 | 12.6–13.7 |
Living alone Yes % | 45.1 | | |
No % | 54.9 | | |
BMI, mean (SD) | 23.2 (3.7) | 15.8–35.3 | 22.6–23.8 |
Comorbidity Yes % | 40.5 | | |
No % | 59.5 | | |
Pain last week, NRS, (0–10), mean (SD) | 3.4 (2.5) | 0–10 | 2.9–3.8 |
Pain categories, % mild (0–3) | 52.1 | | |
% moderate (4–6) | 36.1 | | |
% severe (7–10) | 11.8 | | |
Physical function |
FR cm, mean (SD) | 34.1 (6.4) | 18–56 | 33.1–35.1 |
Walking speed m/s, mean (SD) | 1.21 (0.30) | 0.30–1.94 | 1.16–1.26 |
Armcurls, mean (SD) | 15.2 (3.8) | 4–28 | 14.5–15.8 |
30sSTS, mean (SD) | 12.6 (3.9) | 1–26 | 12.0–13.3 |
HRQoL |
SF-36, mean (SD)a |
Physical functioning (PF) | 67.6 (22.9) | 10–100 | 63.8–71.3 |
Role physical (RP) | 63.0 (29.0) | 0–100 | 58.3–67.7 |
Bodily pain (BP) | 58.8 (23.7) | 10–100 | 54.9–62.6 |
General health (GH) | 63.7 (23.3) | 10–100 | 59.9–67.5 |
Vitality (VT) | 53.9 (16.6) | 10–90 | 51.2–56.6 |
Social functioning (SF) | 84.1 (20.5) | 25–100 | 80.7–87.4 |
Role emotional (RE) | 63.1 (20.6) | 0–80 | 59.8–66.5 |
Mental health (MH) | 71.6 (13.2) | 24–88 | 69.5–73.8 |
Physical Component Score (PCS) | 43.0 (10.0) | 18.8–62.7 | 41.4–44.6 |
Mental Component Score (MCS) | 49.7 (6.6) | 24.8–62.0 | 48.6–50.8 |
QUALEFFO-41, mean (SD)# |
Score Pain | 35.3 (25.2) | 0–95 | 31.2–39.4 |
Physical Function | 17.2 (13.2) | 0–55.9 | 15.1–19.4 |
Score Leisure and Social Activities | 25.8 (21.1) | 0–95 | 22.4–29.3 |
Score Views about Health in General | 44.8 (22.5) | 0–100 | 41.0–48.6 |
Score Mood | 34.3 (12.9) | 8.3–75 | 32.2–36.4 |
Total Score Qualeffo | 26.7 (13.1) | 7.5–65.3 | 24.6–28.8 |
Additional file
1 shows the results of the univariable linear regression analyses. The univariable analyses show that pain was significantly associated with all subscales of both SF-36 (with the exception of MCS) and QUALEFFO-41 (standardized β ranged from − 0.77 to − 0.24 in SF-36, and from 0.76 to 0.28 in QUALEFFO-41). Walking speed was also significantly associated with all subscales of both SF-36 (with the exception of MCS) and QUALEFFO-41 (standardized β ranged from 0.67 to 0.22 in SF-36, and from − 0.62 to – 0.24 in QUALEFFO-41). The highest values of the standardized βs were observed in the associations between the independent variable pain and the BP subscale in SF-36 and the Score Pain subscale in QUALEFFO-41 (Additional file
1).
Tables
2 and
3 present the results from the multivariable linear regression analyses after backward variable selection. The variables that were assessed as associated with SF-36 and QUALEFFO-41 (
p ≤ 0.20) are presented for each subscale of the two HRQoL instruments. Pain was significantly associated with all subscales of SF-36 (Table
2) and QUALEFFO-41 (Table
3), with the exception of MH and MCS in SF-36. Pain had the highest standardized β in BP in SF-36 and in Score Pain in QUALEFFO-41, as expected. The standardized β was - 0.70 for BP and 0.70 for Score Pain. Walking speed was significantly associated with several of the subscales of SF-36 (Table
2) and QUALEFFO-41 (Table
3), with the exception of BP, VT, MH and MCS in SF-36 and the QUALEFFO-41 Score Pain and Mood subscales.
Table 2
Associations between SF-36, physical function and pain (multivariable regression)
Physical Functioning | Pain | −0.29 |
< 0.001
| −2.83 (− 3.95 to – 1.71) | 0.596 |
Functional reach | 0.21 |
0.001
| 0.78 (0.31–1.25) | |
10 m walking speed | 0.41 |
< 0.001
| 32.48 (20.67–44.28) | |
30 s Sit to Stand | 0.14 |
0.047
| 0.83 (0.01–1.66) | |
Role Physical | Pain | −0.45 |
< 0.001
| −5.36 (− 6.88 to − 3.84) | 0.502 |
Comorbidity | 0.14 |
0.029
| 8.34 (0.85–15.82) | |
Functional reach | 0.16 |
0.023
| 0.75 (0.11–1.40) | |
10 m walking speed | 0.29 |
< 0.001
| 28.85 (14.07–46.63) | |
Bodily Pain | Pain | −0.70 |
< 0.001
| −6.71 (−7.78 to – 5.64) | 0.615 |
Comorbidity | 0.14 |
0.030
| 6.47 (1.19–11.75) | |
Functional Reach | 0.08 | 0.198 | 0.30 (−0.16–0.76) | |
10 m walking speed | 0.10 | 0.148 | 7.68 (−2.75–18.10) | |
General Health | Pain | −0.26 |
0.002
| −2.52 (−4.07 to − 0.98) | 0.170 |
10 m walking speed | 0.26 |
0.002
| 21.02 (8.18–33.86) | |
Vitality | Pain | −0.31 |
< 0.001
| −2.14 (−3.20 to – 1.07) | 0.246 |
Comorbidity | 0.21 |
0.008
| 7.19 (1.91–12.47) | |
Functional reach | 0.14 | 0.109 | 0.37 (− 0.08–0.83) | |
10 m walking speed | 0.12 | 0.183 | 7.07 (−3.38–17.53) | |
Social Functioning | Living condition | 0.15 | 0.063 | 5.04 (−0.33–12.20) | 0.209 |
Pain | −0.25 |
0.003
| −2.08 (−3.42 to − 0.74) | |
Comorbidity | 0.19 |
0.017
| 7.98 (1.45–14.50) | |
10 m walking speed | 0.19 |
0.022
| 12.74 (1.85–23.63) | |
Role Emotional | Education, years | 0.20 |
0.014
| 1.17 (0.24–2.10) | 0.229 |
Pain | −0.25 |
0.003
| −2.06 (−3.41 to – 0.71) | |
Comorbidity | 0.12 | 0.151 | 4.84(−1.79–11.47) | |
10 m walking speed | 0.24 |
0.004
| 16.79 (5.33–28.26) | |
Mental Health | Living condition | 0.17 |
0.041
| 4.47 (0.18–8.76) | 0.124 |
Pain | −0.16 | 0.060 | −0.85(−1.74–0.04) | |
Comorbidity | 0.21 |
0.015
| 5.55 (1.08–10.02) | |
10 m walking speed | 0.15 | 0.062 | 0.53(−0.03–1.09) | |
PCS | Pain | −0.50 |
< 0.001
| −2.07(−2.53 to −1.62) | 0.631 |
Comorbidity | 0.11 |
0.046
| 2.27 (0.04–4.49) | |
Functional reach | 0.18 |
0.005
| 0.28 (0.09–0.47) | |
10 m walking speed | 0.26 |
0.001
| 8.80 (3.90–13.70) | |
30 s Sit to Stand | 0.11 | 0.099 | 0.28(−0.05–0.61) | |
MCS | Comorbidity | 0.22 |
0.008
| 2.95 (0.78–5.13) | 0.082 |
Living condition | 0.23 |
0.005
| 3.08 (0.94–5.23) | |
Table 3
Associations between Qualeffo-41, physical function and pain (multivariable regression)
Score Pain | Pain | 0.70 |
< 0.001
| 7.09 (5.98–8.19) | 0.604 |
BMI | 0.10 | 0.076 | 0.66 (−0.07–1.40) | |
Comorbidity | −0.18 |
0.001
| −9.08 (−14.56–3.59) | |
Physical Function | Education, years | −0.13 |
0.024
| −0.49 (− 0.91 to – 0.07) | 0.632 |
Pain | 0.36 |
< 0.001
| 1.97 (1.36–2.57) | |
BMI | 0.11 |
0.042
| 0.39 (0.01–0.77) | |
Comorbidity | −0.14 |
0.016
| −3.66 (−6.63 to – 0.68) | |
Functional reach | −0.25 |
< 0.001
| −0.52 (− 0.78 to – 0.26) | |
10 m walking speed | −0.34 |
< 0.001
| −15.44 (−21.41 to-9.48) | |
Score Leisure and | Education, years | −0.17 |
0.006
| −1.09 (− 1.86 to – 0.31) | 0.549 |
Social Activities | Pain | 0.28 |
< 0.001
| 2.41 (1.31–3.51) | |
Functional reach | −0.18 |
0.002
| −0.74 (−1.21 to– 0.27) | |
10 m walking speed | −0.34 |
< 0.001
| −25.73 (−37.34 to-14.12) | |
30 s Sit to Stand | − 0.12 | 0.099 | − 0.70 (−1.54–0.14) | |
Score views about | Education, years | − 0.12 | 0.131 | − 0.79 (− 1.82–0.24) | 0.277 |
Health in General | Pain | 0.31 |
< 0.001
| 2.85 (1.39–4.31) | |
Comorbidity | −0.15 | 0.054 | −7.18 (−14.47–0.12) | |
10 m walking speed | −0.26 |
0.003
| −19.82 (−32.55 to −7.08) | |
Score Mood | Living condition | −0.16 | 0.055 | −4.21 (−8.50–0.09) | 0.104 |
Pain | 0.22 |
0.011
| 1.14 (0.26–2.04) | |
10 m walking speed | −0.14 | 0.107 | −5.97 (−13.27–1.32) | |
Total Score | Education, years | −0.15 |
0.006
| −0.57 (− 0.97 to − 0.16) | 0.658 |
Pain | 0.49 |
< 0.001
| 2.65 (2.07–3.22) | |
Comorbidity | −0.15 |
0.008
| −3.90 (−6.74 to – 1.13) | |
Functional reach | −0.18 |
0.003
| −0.39 (− 0.64 to – 0.13) | |
10 m walking speed | −0.31 |
< 0.001
| −14.12 (−19.77 to – 8.48) | |
Among the multivariable models (Tables
2 and
3), the model with total QUALEFFO-41 score as its dependent variable, and living condition, pain, comorbidity, FR and walking speed as significant independent variables, accounted for 65.8% of the variance. This was the highest explained variance across all the models (Table
3). Pain was the largest unique contributor (standardized β 0.49,
p < 0.001), while walking speed was the second largest (standardized β − 0.31,
p < 0.001).
Discussion
This study’s key findings show that pain and physical function were, independently of one another, associated with both SF-36 and QUALEFFO-41. These findings may have implications for the tailoring of health care interventions aimed at addressing HRQoL in older women with osteoporosis and vertebral fracture. These results support previous research that suggests that pain management and exercise interventions are important for this group [
21‐
23].
One key finding of the present study is the significant association between HRQoL and pain, which was observed in most subscales in both SF-36 and QUALEFFO-41 (Tables
2 and
3), suggesting that pain may influence several dimensions of HRQoL. Pain after vertebral fracture is common [
5], and an understanding of the complex underlying mechanisms of osteoporotic pain is key for its proper management [
23]. The existing literature verifies that pain has negative influence on physical function with respect to walking speed, balance and mobility [
19,
20] in women with osteoporosis. This corresponds well with the results of the present study, which found that pain was independently associated with the PF subscale in SF-36 and Physical Function in QUALEFFO-41. In addition, our findings highlight the importance of pain management. This finding is consistent with Liu-Ambrose et al. [
19], who demonstrated that the high prevalence of back pain among older women with osteoporosis underscores the importance of pain management in the treatment of osteoporosis. Furthermore, regarding exercise recommendations for individuals with osteoporosis or osteoporotic vertebral fracture [
43], there is limited evidence that pain is reduced after short-term (i.e., 10-week) intervention. Therefore, based on our findings, we recommend that proper pharmacological pain management be incorporated into interventions for patients with osteoporosis and vertebral fracture [
23].
Another key finding is the significant association between physical function, measured by walking speed, and HRQoL. The existing literature shows that mobility is a predictor of quality of life in both older people in general [
15] and in people with osteoporosis [
8]. Both studies [
8,
15] mentioned included men and women, and it is uncertain whether the results can be generalized to women with osteoporosis and vertebral fracture. Walking speed is recommended as a useful clinical indicator of well-being [
44,
45]. In general, older people with the ability to walk faster than 1.0 m/s are considered to have good functional status, lower risk of health events, and better survival prognosis [
45,
46]. The mean walking speed observed in the present study is 1.21 m/s, which may indicate that the women included in our study have relatively good physical function. The present study and the existing literature suggest that walking speed may be an important measure to consider for the maintenance and enhancement of HRQoL. Furthermore, studies have shown that exercise can improve walking speed in older women with osteoporosis and vertebral fracture [
21].
The present study extends the results of a previous study on the association between HRQoL and physical function in older women with osteoporosis and vertebral fracture [
17], which also observed significant associations between HRQoL and walking speed. However, measurements of pain were not included. Additionally, the sample size was smaller, and maximum walking speed was used as a measure of mobility. Thus, comparison with the present study should be made with caution. An study observed a significant association between PCS (SF-12, a shorter version of SF-36) and walking speed as well as mobility in a population of people with osteoporotic fractures [
16]. Findings showed that walking speed and mobility, measured by TUG, were related to PCS of SF-12 (a shorter version of SF-36). However, the population included both men and women and the participants had suffered different types of osteoporotic fractures, not only vertebral fractures.
Furthermore, our study highlights that the strength of the association between pain and walking speed varies across the different subscales of the two HRQoL instruments. Subscales representing physical function, physical role or participation have stronger associations than do subscales representing emotional or mental aspects. This pattern can be found in both the SF-36 and QUALEFFO-41 (Tables
2 and
3). Similar results are found in studies investigating HRQoL [
13,
20]. Interestingly, there were comparable results across the generic (SF-36) and disease-specific (Qualeffo-41) HRQoL instrument regarding associations with physical function and pain. The disease-specific instruments are reckoned to be more sensitive to the specific disease [
6], which may indicate that the burden of disease for our study population were moderate. This is also supported by the relatively high functioning of the women. On the other hand, our study’s SF-36 scores are slightly lower than the scores of women from comparable age groups who participated in a recent study by Jacobsen et al. [
47], as part of a sample representing the general population of Norwegians across age groups ranging from 18 to 90 years. This is in line with several studies reporting that living with osteoporosis and vertebral fracture affects HRQoL negatively [
12,
13,
48]. Furthermore, our participants have better mean scores of QUALEFFO-41 subscales compared to the mean scores of QUALEFFO-41 subscales reported by Bergland et al. [
17]. This indicates better HRQoL for our population, since lower QUALEFFO-41 scores represent better HRQoL.
This study has several limitations. First, the women included in this cross-sectional study were recruited for a randomized controlled trial aimed at potentially improving their physical function and HRQoL through an exercise programme. The participants may be fitter and a have higher level of physical function than the general population of older women who have osteoporosis and have experienced vertebral fracture. Second, all participants were living in urban areas and no men were included. This limits the generalizability of the results. Third, we have no data regarding about how many fractures the participants had, which would have facilitated the analysis of subgroups depending on the number of fractures experienced. Finally, the study is cross-sectional, and no causal relations can be established.
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