Utilization of inpatient care before and after hip fracture: a population-based study

Delayed fracture healing and increased callus adiposity in a C57BL/6J murine model of obesity-associated type 2 diabetes mellitus

Introduction

Impaired healing and non-union of skeletal fractures is a major public health problem, with morbidity exacerbated in patients with diabetes mellitus (DM). DM is prevalent worldwide and affects approximately 25.8 million US adults, with >90% having obesity-related type 2 DM (T2DM). While fracture healing in type 1 DM (T1DM) has been studied using animal models, an investigation into delayed healing in an animal model of T2DM has not yet been performed.

Methods

Male C57BL/6J mice at 5 weeks of age were placed on either a control lean diet or an experimental high-fat diet (HFD) for 12 weeks. A mid-diaphyseal open tibia fracture was induced at 17 weeks of age and a spinal needle was used for intra-medullary fixation. Mice were sacrificed at days 7, 10, 14, 21, 28, and 35 for micro-computed tomography (μCT), histology-based histomorphometry and molecular analyses, and biomechanical testing.

Results

HFD-fed mice displayed increased body weight and impaired glucose tolerance, both characteristic of T2DM. Compared to control mice, HFD-fed mice with tibia fractures showed significantly (p<0.001) decreased woven bone at day 28 by histomorphometry and significantly (p<0.01) decreased callus bone volume at day 21 by μCT. Interestingly, fracture calluses contained markedly increased adiposity in HFD-fed mice at days 21, 28, and 35. HFD-fed mice also showed increased PPARγ immunohistochemical staining at day 14. Finally, calluses from HFD-fed mice at day 35 showed significantly (p<0.01) reduced torsional rigidity compared to controls.

Discussion

Our murine model of T2DM demonstrated delayed fracture healing and weakened biomechanical properties, and was distinctly characterized by increased callus adiposity. This suggests altered mesenchymal stem cell fate determination with a shift to the adipocyte lineage at the expense of the osteoblast lineage. The up-regulation of PPARγ in fracture calluses of HFD-fed mice is likely involved in the proposed fate switching.

A systematic review of osteoporosis medication adherence and osteoporosis-related fracture costs in men

BACKGROUND AND OBJECTIVE

Male osteoporosis is an increasingly important public health concern. Although several medications are approved for the treatment of osteoporosis, medication non-adherence and the associated consequences are not well documented in male populations. Our objective was to identify and summarize the current knowledge related to osteoporotic medication adherence, the potential implications of non-adherence to the medication, and the cost of osteoporosis-related fractures and health-resource utilization in men.

METHODS

Two separate systematic searches were conducted concurrently: one to identify literature reporting male-specific adherence to anti-osteoporotic medication and the clinical consequence of non-adherence in men, and the other to identify literature reporting the cost and resource burden of osteoporosis-related fractures in men. The PubMed, MEDLINE, EMBASE, and Cochrane databases were searched using a date range of 1 January 1998 to 30 June 2012, and citations were screened based on pre-defined criteria.

RESULTS

The percentage of males adherent to bisphosphonates [medication possession ratio (MPR) >0.8] over a 1-year period ranged from 32% to 64%. The data imply worse clinical outcomes with treatment non-adherence. Costs and resource use associated with osteoporosis-related fractures in men are high, with hip fractures generating the most cost.

CONCLUSIONS

One-third to two-thirds of men are not adherent to bisphosphonates. Non-adherence is associated with increased fracture risk. Estimates of direct and indirect osteoporosis-related fracture costs are also substantial in men, and may even be more costly than in women. More robust data would better inform disease management initiatives that could improve adherence to medication and outcomes in men with osteoporosis.

Impaired angiogenesis during fracture healing in GPCR kinase 2 interacting protein-1 (GIT1) knock out mice

G protein coupled receptor kinase 2 (GRK2) interacting protein-1 (GIT1), is a scaffold protein that plays an important role in angiogenesis and osteoclast activity. We have previously demonstrated that GIT1 knockout (GIT1 KO) mice have impaired angiogenesis and dysregulated osteoclast podosome formation leading to a reduction in the bone resorbing ability of these cells. Since both angiogenesis and osteoclast-mediated bone remodeling are involved in the fracture healing process, we hypothesized that GIT1 participates in the normal progression of repair following bone injury. In the present study, comparison of fracture healing in wild type (WT) and GIT1 KO mice revealed altered healing in mice with loss of GIT1 function. Alcian blue staining of fracture callus indicated a persistence of cartilagenous matrix in day 21 callus samples from GIT1 KO mice which was temporally correlated with increased type 2 collagen immunostaining. GIT1 KO mice also showed a decrease in chondrocyte proliferation and apoptosis at days 7 and 14, as determined by PCNA and TUNEL staining. Vascular microcomputed tomography analysis of callus samples at days 7, 14 and 21 revealed decreased blood vessel volume, number, and connection density in GIT1 KO mice compared to WT controls. Correlating with this, VEGF-A, phospho-VEGFR2 and PECAM1 (CD31) were decreased in GIT1 KO mice, indicating reduced angiogenesis with loss of GIT1. Finally, calluses from GIT1 KO mice displayed a reduced number of tartrate resistant acid phosphatase-positive osteoclasts at days 14 and 21. Collectively, these results indicate that GIT1 is an important signaling participant in fracture healing, with gene ablation leading to reduced callus vascularity and reduced osteoclast number in the healing callus.

Trends in the utilization and outcomes of Medicare patients hospitalized for hip fracture, 2000-2008

OBJECTIVE

This study examines temporal trends in hip fracture related utilization and outcomes among elderly fee-for-service Medicare beneficiaries.

METHOD

The study uses claims data for a 5% sample of Medicare beneficiaries with an incident hip fracture hospitalization between 2000 and 2008. We present annual mean patient characteristics, health services utilization, and outcomes and use ordinary least squares regressions to examine adjusted trends in utilization and outcomes after controlling for changes in patient characteristics.

RESULTS

We observe a statistically significant temporal decline in inpatient acute days and a statistically significant increase in inpatient post-acute days following hip fractures. In models that control for patient characteristics, we observe statistically significant declines in 1-year hip fracture readmission and mortality rates. Rates of nursing home residence 1-year following fracture were unchanged and remain high.

DISCUSSION

Hip fractures remain highly debilitating events and pose significant challenges for the financing of public health insurance programs.

Drug Burden Index and hospitalization among community-dwelling older people

BACKGROUND

Medications with anticholinergic and sedative effects carry significant risks in older people. Adverse events arising from the use of these medications may also lead to hospitalization and contribute to length of stay. The Drug Burden Index (DBI) is a tool that measures a person's total exposure to medications with anticholinergic and sedative properties, using the principles of dose response and maximal effect. Cumulative anticholinergic and sedative drug burden measured using the DBI has been associated with clinically important outcomes in older people. The association between the DBI and hospitalization still remains relatively unknown.

OBJECTIVE

The main aim of this study was to evaluate the relationship between DBI and hospitalization in a population-based sample of community-dwelling older Finns over a 1-year period.

METHODS

The health status and medication use of 339 community-dwelling ≥75-year-old Finns were assessed in 2004. Data on hospitalizations over the following year were obtained from the national discharge register. Two different measures were used to assess hospitalizations in the study sample: (i) the proportion of hospitalized participants; and (ii) the number of hospital days per person-year. Estimates for the number of hospital days per person-year and rate ratios (RRs) with 95% confidence intervals (CIs) were calculated using Poisson or negative binomial regression analysis.

RESULTS

A total of 127 participants (38%) were exposed to DBI medications; 27% had a low DBI (>0 to <1), and 11% had a high DBI (≥1). The number of hospital days per person-year was 7.9 (95% CI 7.6, 8.3) for the unexposed participants (DBI = 0) and 13.4 (95% CI 12.8, 14.1) for the exposed participants (DBI >1); the age, gender and co-morbidity adjusted RR of hospital days per person-year between the exposed and unexposed participants was 1.26 (95% CI 1.18, 1.35). Between the low and high DBI groups, the difference in the number of hospital days per person-year was insignificant (p = 0.42). In multivariate analyses, the number of regularly used medications (RR = 1.12 [95% CI 1.00, 1.26] per additional medication) and the measure of basic activities of daily living Barthel Index (RR = 0.94 [95% CI 0.88, 0.99] per increase) were independently associated with the use of hospital days.

CONCLUSION

Exposure to DBI medications was associated with a greater use of hospital days, but a cumulative dose-response relationship between DBI and hospitalization was not observed. The number of regularly used medications and functioning in the basic activities of daily living predicted hospital care utilization.

Direct costs of fractures in Canada and trends 1996-2006: a population-based cost-of-illness analysis

Cost-of-illness (COI) analysis is used to evaluate the economic burden of illness in terms of health care resource (HCR) consumption. We used the Population Health Research Data Repository for Manitoba, Canada, to identify HCR costs associated with 33,887 fracture cases (22,953 women and 10,934 men) aged 50 years and older that occurred over a 10-year period (1996-2006) and 101,661 matched control individuals (68,859 women and 32,802 men). Costs (in 2006 Canadian dollars) were estimated for the year before and after fracture, and the change (incremental cost) was modeled using quantile regression analysis to adjust for baseline covariates and to study temporal trends. The greatest total incremental costs were associated with hip fractures (median $16,171 in women and $13,111 for men), followed by spine fractures ($8,345 in women and $6,267 in men). The lowest costs were associated with wrist fractures ($663 in women and $764 in men). Costs for all fracture types were greater in older individuals (p < 0.001). Similar results were obtained with regression-based adjustment for baseline factors. Some costs showed a slight increase over the 10 years. The largest temporal increase in women was for hip fracture ($13 per year, 95% CI $6-$21, p < 0.001) and in men was for humerus fracture ($11 per year, 95% CI $3-$19, p = 0.007). At the population level, hip fractures were responsible for the largest proportion of the costs after age 80, but the other fractures were more important prior to age 80. We found that there are large incremental health care costs associated with incident fractures in Canada. Identifying COI from HCR use offers a cost baseline for measuring the effects of evidence-based guidelines implementation.

Service use and costs of incident femoral fractures in nursing home residents in Germany: the Bavarian Fall and Fracture Prevention Project (BF2P2)

OBJECTIVES

Hip fractures are one of the most costly consequences of falls in the elderly. Despite their increased risk of falls and fractures, nursing home residents are often neglected in service utilization and costing studies. The purpose of this study was to determine service use, initial and long-term direct costs of incident femoral fractures in nursing home residents 65 years or older in Germany.

DESIGN

An incidence-based, bottom-up cost-of-illness study aiming at measuring fracture-related direct costs from a payer perspective was conducted.

SETTING

Nursing homes

PARTICIPANTS

The retrospective dataset included all insurants of a sickness fund (Allgemeine Ortskrankenkasse Bavaria), who were 65 years or older, resided in a nursing home, and had a level of care of at least one in the statutory long-term care insurance (n = 60,091).

MEASUREMENTS

Incident femoral fractures (ICD-10, S72) in 2006 were followed until the end of 2008, incorporating service use and costs of inpatient care (up to 12 months after the initial hospitalization episode), nursing home care (until death or the end of 2008), and ambulatory care (pharmaceuticals, nonphysician providers, and medical supply within 3 months after the initial hospitalization episode). Additional costs for nursing home and ambulatory care were determined with a before/after design. Costs beyond the year 2006 were discounted with a rate of 5%. Sensitivity analyses on key parameters were performed.

RESULTS

Overall mean direct costs of 9488 USD (SD ± 4453 USD, 2006) occurred for incident femoral fractures (n = 1525). This included inpatient care (90.2%), additional costs for nursing home care (7.1%), and ambulatory care (2.7%). Eighty-seven percent of the costs occurred for the initial hospitalization episode and 13% for long-term costs. After the index admission, 12.1% were admitted to a rehabilitation facility, 4.1% were rehospitalized within a year, and in 17.7% the level of care increased within 90 days after the end of the initial hospital episode. The share of residents with incident femoral fractures rehospitalized was significantly higher and costs for nonphysician providers were significantly lower for male residents.

CONCLUSION

Residents with femoral fractures used a wide range of health services. Our study underestimates the true costs to society in Germany. Efforts should be directed to economic evaluations of fall-prevention programs aiming at reducing fall-related fractures including femoral fractures.

Burden of hip fracture on inpatient care: a before and after population-based study

SUMMARY

We estimated the excess hospital expenditure attributable to osteoporotic hip fracture (HF) within a population of 6,019 patients. Post-fracture excess of hospital days was 23.1, including 22.7 days in rehabilitation care. HF might result from a patient's pre-fracture poor health status rather than predispose to a worsening of such pre-existing conditions.

INTRODUCTION

Hip fracture represents a large burden on hospital services. It is unclear whether the post-fracture expenditure is linked to a worsening of pre-fracture comorbid conditions. We estimated the excess hospital expenditure attributable to osteoporotic HF following the initial hospitalization for acute care (index stay).

METHODS

We identified 6,019 patients (> or = 50 years) who experienced HF in 2005 and compared their hospitalizations 1 year before and 1 year after the index stay. Excess expenditure was estimated by subtracting the utilization of hospital days or costs (Euros 2005) before the index stay from those after the index stay. Factors associated with hospitalization during the pre-fracture and post-fracture years were identified using multivariate logistic regressions.

RESULTS

Beside the index stay, post-fracture excess of hospital days was 23.1 (95% Confidence Interval (CI) [21.8-24.3]), including 22.7 days (95% CI [21.7-23.7]) in rehabilitation care and 0.3 days (95% CI [0-0.9]) in acute care. Estimated excess cost per patient was <euro>5,986 (95% CI [5,638-6,335]) after the index stay, including <euro>5,673 (95% CI [5,419-5,928]) in rehabilitation care. Male and elderly patients were at higher risk to be hospitalized in acute care during the year preceding and succeeding HF.

CONCLUSIONS

Osteoporotic HF represents a pronounced excess expenditure in hospital, which is mostly linked to rehabilitation care. Considering that utilization of inpatient acute care was quite similar before and after the index stay, HF might result from a patient's pre-fracture poor health status, rather than predispose to a worsening of such pre-existing conditions.

The societal burden of osteoporosis

Osteoporosis currently affects 10 million Americans and is responsible for more than 1.5 million fractures annually. The financial burden of osteoporosis is substantial, with annual direct medical costs estimated at 17 to 20 billion dollars. Most of these costs are related to the acute and rehabilitative care following osteoporotic fractures, particularly hip fractures. The societal burden of osteoporosis includes these direct medical costs and the monetary (eg, caregiver time) and nonmonetary costs of poor health. The aging of the US population is expected to increase the prevalence of osteoporosis and the number of osteoporotic fractures. Growth of the older adult population will pose significant challenges to Medicare and Medicaid, which bear most of the cost of osteoporosis. Efforts to address the looming financial burden must focus on reducing the prevalence of osteoporosis and the incidence of costly fragility fractures.