Osteoporosis is the most common metabolic disease of the skeleton, affecting approximately two-hundred million individuals worldwide.1 This condition is often clinically silent until fragility fractures occur. Osteoporotic fractures represent one of the most common causes of disability and constitute one of the largest items in the health care budget of many countries.2
The aim of the study was to evaluate the quality of life (QoL), pain, and limitation in functional and social activities in subjects with osteoporosis. A further aim was to analyze possible predictors of the QoL in these subjects.
MATERIALS AND METHODS
This cross-sectional study included a group of one-hundred thirty four subjects (mean age = 65.5 ± 10.4 years, range 34 – 90 years; 126 females (94%)), followed at the outpatient clinic of Orthopedic and Traumatology Department at Federico II University Hospital Napoli Italy were enrolled for this study. Sixty-four patients (47.8 %) had a previous fragility fracture. Infomed consent was obtained from each subject. Bone Mineral Density (BMD) T-score calculated by femoral and lumbar by Dual X-ray Absorptiometry (DXA) performed less than one year earlier was obtained for all patients. In accordance with the World Health Organisation (WHO)criteria,3 participants were categorised as having osteoporosis if they had T-scores lower than −2.5 SD in the femour and/or in the lumbar spine. Patients with secondary osteoporosis or cognitive deficit were excluded from the study. All subjects completed the Italian version of 41-item Quality of Life Questionnaire of the European Foundation for Osteoporosis (Qualeffo-41) for the evaluation of QoL.4 The Qualeffo-41 consists of five domains including pain (5 items), physical function (17 items), social function (7 items), general health perception (3 items), and mental function (9 items). In total, the lowest possible score is 0, and the highest possible score is 100. Higher scores reflect lower QoL. Furthermore, each subject enrolled in the study underwent a structural medical interview and the measurement of height and weight to calculate the FRAX score. The FRAX index is an algorithm designed by Kanis et al. aimed to calculate the absolute risk of global and hip osteoporotic fracture in the next 10 years in persons aged 40-90 years.5,6 The FRAX questionnaire includes 12 items: age, sex, weight, height, previous fragility fracture, parent fractured hip, current smoking, use of glucocorticoids, association of rheumatoid arthritis, presence of conditions related to osteoporosis, such as type 1 diabetes, hyperthyroidism, chronic liver disease, and premature menopause (prior to age 45), consumption of alcoholics, and BMD.
An independent sample t-test was performed to assess any differences in quality of life scores between osteoporotic and non osteoporotic patients. An age-adjusted univariate linear regression analysis was used to assess the association of independent variables (age, sex, body mass index (BMI), cigarette smoking, FRAX score (hip fracture and /or osteoporotic fracture), lumbar BMD T-score, femoral BMD T-score, and positive history of previous fragility fracture) with the Qualeffo-41 total and single domain scores. All explanatory variables that showed either an association or a trend toward an association (i.e., P < 0.10) with the outcome of interest in the univariate analysis were included in the multiple regression models. A value of P ≤ 0.05 was considered significant. Data were analyzed using SPSS software version 23.0 (SPSS, Chicago, IL, USA).
The characteristics of subjects enrolled in the study are reported in the table 1. In the study group, seventy-one patients (53%) were diagnosed with osteoporosis. The table 2 shows Qualeffo 41 total and single domain scores in osteoporotic and non-osteoporotic subjects. Osteoporotic patients had significantly higher scores in Physical Function and Social Function domain. Results of the age-adjusted univariate and multiple linear regression analyses are reported in tables 3 and 4. An increased risk of hip fracture assessed by FRAX score as well as a higher BMI were independent determinants of the total Qualeffo-41 score and accounted for 5 % and 4 %, respectively, of the variance in this outcome in the model of multivariate analysis. Unexpectdly, the positive history of fragility fracture was inversely related with the pain domain of QUALEFFO questionnaire. No relationships between BMD and QUALEFFO scores were found.
In the last decade there has been growing interest in the assessment of predictors of quality of life and personal autonomy in both young and elderly trauma patients.7,8 Skeletal conditions such as osteoporosis and related complications may also negatively impact on physical, mental, social, and emotional health with consequent deterioration in QoL.9 Indeed, fragility fractures and the fear for falling can lead to reduced mobility, reduced independence in daily living activities and even social isolation of elderly subjects.10 The results of this study, where osteoporotic patients showed worse QUALEFFO-41 scores when compared to non-osteoporotic subjects, concur with these literature data. Previous studies have found that other factors, including high BMI, previous spinal fractures fractures, and low BMD of the total neck can negatively influence QoL.11 In the current study, BMI was directly associated with impaired QoL in different QUALEFFO-41 domains, including the total score as well as the pain, general health perception, and mental function domains. Limited to the sample size of the current study group, no relationships between BMD and QoL were found. One previous study12 also failed to find significant differences in quality of life among cohorts of subjects stratified by different BMD (T-score). Moreover, the QUALEFFO 41 questionnaire has not been specifically validated so far in patients with silent vertebral fractures or in nonfractured patients with low BMD.13 In the study group, possible relationships between low BMD and QoL may have been clouded by the overwhelming association between BMI and QUALEFFO-41 scores, since BMD is higher in obese patients.14
The present study also found an inverse relationship between FRAX score and QoL. Specifically, an increased odd of fracture (higher FRAX index) directly correlated with increased scores in physical function, social function and general health perception QUALEFFO-41 domains. This data is consistent with the literature data. In a study by González Silva et al15 the Barthel index, a scale that evaluates daily life activities, was inversely related to the FRAX index.
We acknowledge some limitations of the present study. This being a cross-sectional study, it was impossible to infere the causal relationship between QoL and the explanatory variables under investigation. Also the sample size of the present study is smaller in comparison with previous larger studies in the literature. This limitation may have decreased the statistical power of some tests. In spite of this, significant influences on QoL were nevertheless found for several variables. On the other hand, the multivariate analysis represents a strength of the present study. It permitted us to accurately evaluate the effects of several variables of interest on the QoL, while simultaneously controlling for the possible influences of multiple covariables.
This study demonstrates that several aspects of QoL are reduced in osteoporotic subjects. High BMI and an increased odds of fragility fracture negatively predict some aspects of QoL.
CONFLICT OF INTEREST
The authors declare that there are no conflicts of interest.
Author contributions: the authors contributed equally
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study