Impact of prescription drugs on second fragility fractures among US Medicare patients

Drugs that increase the risk of fracture are commonly prescribed to survivors of a fragility fracture. This study shows that starting new high-risk medications after fracture increases the risk of a second, potentially preventable fracture. For most drug classes, however, it is safe to continue medications taken before the fracture.

INTRODUCTION

Most patients who survive a fragility fracture are subsequently exposed to prescription drugs that have been linked to increased fracture risk. This study was designed to quantify the extent to which current prescribing practices result in potentially preventable second fractures.

METHODS

We analyzed a cohort of 138,526 Medicare beneficiaries who returned to the community after a fragility fracture. Post-fracture drug use was defined using retail pharmacy fills. The risk of second fracture associated with individual drug classes was analyzed using Cox proportional hazard models. Data were further analyzed to determine whether there is a difference in risk between continuing previous therapy and initiating new therapy after fracture.

RESULTS

Many drug classes previously identified as increasing fracture risk were not associated with increased fracture risk in this cohort. Discontinuing therapy at the time of fracture was only beneficial for patients taking selective serotonin reuptake inhibitors; however, initiating therapy in previous non-users increased second fracture risk for five classes of drugs (selective serotonin reuptake inhibitors, tricyclic antidepressants, antipsychotics, proton pump inhibitors, and non-benzodiazepine hypnotics).

CONCLUSION

Discontinuing high-risk drugs after fracture was not generally protective against subsequent fractures. Preventing the addition of new medications may result in greater improvements in post-fracture care.

Oral bisphosphonates and upper gastrointestinal toxicity: a study of cancer and early signals of esophageal injury

SUMMARY

We evaluated the association between bisphosphonate use and (1) upper gastrointestinal cancer, (2) upper endoscopy, (3) incident Barrett's esophagus, and (4) prescription antacid initiation among Medicare beneficiaries. We found no bisphosphonate-cancer association and negative bisphosphonate-Barrett's association.

INTRODUCTION

Bisphosphonates can irritate the esophagus; a cancer association has been suggested. Widespread bisphosphonates use compels continued investigation of upper gastrointestinal toxicity.

METHODS

Using a 40% Medicare random sample denominator, inpatient, outpatient (2003-2011), and prescription (2006-2011) claims, we studied patients age 68 and older with osteoporosis and/or oral bisphosphonate use. Inverse propensity weighting estimated marginal structural models for the effect of bisphosphonate intensity (pills per month) and cumulative bisphosphonate pills received on upper gastrointestinal cancer risk. Secondary analyses of sub-cohorts without past bisphosphonates or upper endoscopy assessed bisphosphonate initiation and risk of (1) upper endoscopy, (2) incident Barrett's esophagus, and (3) prescription antacid initiation.

RESULTS

The cohort included 1.64 million beneficiaries: 87.9% women, mean age, 76.8 (standard deviation (SD) 9.3); mean follow-up, 39.6 months; 38.1% received oral bisphosphonates. Cumulative bisphosphonate receipt, among users, ranged from 4 to 252 pills (5th to 95th percentile). We identified 2,308 upper gastrointestinal cancers (0.43/1000 person years). We found no association between cumulative bisphosphonate pills and cancer, odds ratio (OR) for each additional pill 1.00 (95% confidence interval (CI) 1.00, 1.00). In sub-cohorts, compared to none, lowest cumulative bisphosphonate use (one to nine pills) was associated with higher risk of endoscopy (OR 1.11, 95% CI 1.08-1.14) and antacid initiation (OR 1.13, 95% CI 1.10-1.16); higher intensity conferred no increased risk. Higher intensity and higher cumulative bisphosphonate category were associated with lower Barrett's risk.

CONCLUSIONS

We found no bisphosphonate-cancer association and negative bisphosphonate-Barrett's association. Bisphosphonate initiation appears to identify patients susceptible to early irritating effects; clinicians might offer alternatives and delay endoscopy or antacids.