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Purpose: Osteoporosis is a chronic disease of the bone, whose incidence increases progressively with aging. The main consequences of osteoporosis are fragility fractures, which have considerable medical, social, and economic implications. Adequate treatment of osteoporosis must be considered as a compelling public health intervention. Bisphosphonates (BPs) represent the most significant advance in this field in the past decade, and they are widely used in the treatment of osteoporosis. However, evidence for their effectiveness is limited to secondary prevention, whereas their effect in primary prevention is uncertain and needs further investigation., Methods: Using administrative data collected in the "Biphosphonates Efficacy-Safety Tradeoff" (BEST) study, a nested case-control study was conducted by including 56,058 participants, aged 55 years who were started on oral BPs from 2003 to 2005. Cases were the 1,710 participants who were hospitalized for osteoporotic fractures until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio of fracture associated with categories of treatment duration., Results: Compared with participants assuming BPs for less than 1 year, those who remained on therapy for at least 2 years had a 21% (95% confidence interval (CI) 7 to 33%) fracture risk reduction., Conclusion: This study provides evidence that BPs, dispensed for primary prevention of osteoporotic fractures, are associated with a reduced risk of osteoporotic fractures after at least 2 years of treatment.

Purpose: Different strategies applicable to control for confounding by indication in observational studies were compared in a large population-based study regarding the effect of bisphosphonates (BPs) for secondary prevention of fractures., Methods: The cohort was drawn from healthcare utilization databases of 13 Italian territorial units. Patients aged 55 years or more who were hospitalized for fracture during 2003-2005 entered into the cohort. A nested case-control design was used to compare BPs use in cohort members who did (cases) and who did not experience (controls) a new fracture until 2007 (outcome). Three designs were employed: conventional-matching (D1 ), propensity score-matching (D2 ), and user-only (D3 ) designs. They differed for (i) cohort composition, restricted to patients who received BPs straight after cohort entry (D3 ); (ii) using propensity score for case-control matching (D2 ); and (iii) compared groups of BPs users versus no users (D1 and D2 ) and long-term versus short-term users (D3 )., Results: Bisphosphonate users had odds ratios (95% confidence interval) of 1.20 (1.01 to 1.44) and 0.95 (0.74 to 1.24) by applying D1 and D2 designs, respectively. Statistical evidence that long-term BPs use protects the outcome onset with respect to short-term use was observed for user-only design (D3 ) being the corresponding odds ratio (95% confidence interval) 0.64 (0.44 to 0.93)., Conclusions: User-only design yielded closer results to those seen in RCTs. This approach is one possible strategy to account for confounding by indication., (Copyright © 2014 John Wiley & Sons, Ltd.)

Background: Data on the effect of oral bisphosphonates (BPs) on risk of upper gastrointestinal complications (UGIC) are conflicting. We conducted a large population-based study from a network of Italian healthcare utilization databases aimed to assess the UGIC risk associated with use of BPs in the setting of secondary prevention of osteoporotic fractures., Methods: A nested case-control study was carried out within a cohort of 68,970 patients aged 45 years or older, who have been hospitalized for osteoporotic fracture from 2003 until 2005. Cases were the 804 patients who experienced hospitalization for UGIC until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio (OR) associated with current and past use of BPs (i.e. for drug dispensation within 30 days and over 31 days prior the outcome onset, respectively) after adjusting for several covariates., Results: Compared with patients who did not use BPs, current and past users had OR (and 95% confidence interval) of 0.86 (0.60 to 1.22) and 1.07 (0.80 to 1.44) respectively. There was no difference in the ORs estimated according with BPs type (alendronate or risedronate) and regimen (daily or weekly), nor with co-therapies and comorbidities., Conclusions: Further evidence that BPs dispensed for secondary prevention of osteoporotic fractures are not associated with increased risk of severe gastrointestinal complications is supplied from this study. Further research is required to clarify the role BPs and other drugs of co-medication in inducing UGIC.

Background: Oral bisphosphonates (BPs) are the primary agents for the treatment of osteoporosis. Although BPs are generally well tolerated, serious gastrointestinal adverse events have been observed., Aim: To assess the risk of severe upper gastrointestinal complications (UGIC) among BP users by means of a large study based on a network of Italian healthcare utilization databases., Methods: A nested case-control study was carried out by including 110,220 patients aged 45 years or older who, from 2003 until 2005, were treated with oral BPs. Cases were the 862 patients who experienced the outcome (hospitalization for UGIC) until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio (OR) associated with current use of BPs after adjusting for several covariates. A set of sensitivity analyses was performed in order to account for sources of systematic uncertainty., Results: The adjusted OR for current use of BPs with respect to past use was 0.94 (95% CI 0.81 to 1.08). There was no evidence that this risk changed either with BP type and regimen, or concurrent use of other drugs or previous hospitalizations., Conclusions: No evidence was found that current use of BPs increases the risk of severe upper gastrointestinal complications compared to past use.