Location of Vertebral Fractures is Associated with Bone Mineral Density and History of Traumatic Injury.

The upper and lower thoracolumbar spine have been associated with different biomechanical outcomes. This concept, as it applies to osteoporotic fracture risk, has not been well documented. This was a case-control study of 120 patients seen in an osteoporosis clinic. Vertebral fractures were identified from lateral radiographs using Genant's semi-quantitative assessment method. An association between bone mineral density (BMD) T-scores and vertebral fracture location was assessed. In an additional analysis, the association between a history of any traumatic injury and possible predictor variables was also explored. The median age of patients was 75 (IQR 67-80), and 84.2% of patients were female. A history of trauma was reported by 46.7% of patients. A vertebral fracture in the lower thoracolumbar spine (T11-L4) was associated with significantly higher femoral neck (p < 0.001), lumbar (p = 0.005), trochanteric (p = 0.002), intertrochanteric (p < 0.001), and total hip (p = 0.0006) BMD T-scores. The odds of having a femoral neck (OR 0.24, 95% CI 0.07-0.75, p = 0.01) or total hip (OR 0.19, 95% CI 0.06-0.65, p = 0.008) T-score less than -2.5 was also lower among patients with vertebral fractures in the lower thoracolumbar spine. A fracture in the upper thoracolumbar spine (T4-T10) decreased the odds of having a history of traumatic injury (OR 0.32, 95% CI 0.14-0.76, p = 0.01), while a non-vertebral fracture increased the odds of such an injury (OR 2.41, 95% CI 1.10-5.32, p = 0.03). Vertebral fractures in the lower thoracolumbar spine are associated with higher BMD T-scores. This should be studied further to understand possible correlations with patients' future fracture risk.

Purchasing and Using Personal Emergency Response Systems (PERS): how decisions are made by community-dwelling seniors in Canada.

BACKGROUND: As the demographic of older people continues to grow, health services that support independence among community-dwelling seniors have become increasingly important. Personal Emergency Response Systems (PERS) are medical alert systems, designed to serve as a safety net for seniors living alone. Health care professionals often recommend that seniors in danger of falls or other medical emergencies obtain a PERS. The purpose of the study was to investigate the experience of seniors living with and using a PERS in their daily lives, using a qualitative grounded theory approach. METHODS: Five focus groups and 10 semi-structured interviews, with a total of 30 participants, were completed using a grounded theory approach. All participants were PERS subscribers over the age of 80, living alone in a naturally occurring retirement community (NORC) with high health service utilization in a major urban centre in Ontario. Constant comparative analysis was used to develop themes and ultimately a model of why and how seniors obtain and use the PERS. RESULTS: Two core themes, unpredictability and decision-making around PERS activation, emerged as major features of the theoretical model. Being able to get help and the psychological value of PERS informed the context of living with a PERS. CONCLUSIONS: A number of theoretical conclusions related to unpredictability and the decision-making process around activating PERS were generated.

Clinical radiation therapy measurements with a new commercial synthetic single crystal diamond detector.

A commercial version of a synthetic single crystal diamond detector (SCDD) in a Schottky diode configuration was recently released as the new type 60019 microDiamond detector (PTW-Freiburg, Germany). In this study we investigate the dosimetric properties of this detector to independently confirm that findings from the developing group of the SCDDs still hold true for the commercial version of the SCDDs. We further explore if the use of the microDiamond detector can be expanded to high-energy photon beams of up to 15 MV and to large field measure- ments. Measurements were performed with an Elekta Synergy linear accelerator delivering 6, 10, and 15 MV X-rays, as well as 6, 9, 12, 15, and 20 MeV electron beams. The dependence of the microdiamond detector response on absorbed dose after connecting the detector was investigated. Furthermore, the dark current of the diamond detector was observed after irradiation. Results are compared to similar results from measurements with a diamond detector type 60003. Energy dependency was investigated, as well. Photon depth-dose curves were measured for field sizes 3 × 3, 10 × 10, and 30 × 30 cm2. PDDs were measured with the Semiflex type 31010 detector, microLion type 31018 detector, P Diode type 60016, SRS Diode type 60018, and the microDiamond type 60019 detector (all PTW-Freiburg). Photon profiles were measured at a depth of 10 cm. Electron depth-dose curves normalized to the dose maximum were measured with the 14 × 14 cm2 electron cone. PDDs were measured with a Markus chamber type 23343, an E Diode type 60017 and the microDiamond type 60019 detector (all PTW-Freiburg). Profiles were measured with the E Diode and microDiamond at half of D90, D90, D70, and D50 depths and for electron cone sizes of 6 × 6 cm2, 14 × 14 cm2, and 20 × 20 cm2. Within a tol- erance of 0.5% detector response of the investigated detector was stable without any preirradiation. After preirradition with approximately 250 cGy the detector response was stable within 0.1%. A dark current after irradiation was not observed. The microDiamond detector shows no energy dependence in high energy photon or electron dosimetry. Electron PDD measurements with the E Diode and micro- Diamond are in good agreement. However, compared to E Diode measurements, dose values in the bremsstrahlungs region are about 0.5% lower when measured with the microDiamond detector. Markus detector measurements agree with E Diode measurements in the bremsstrahlungs region. For depths larger than dmax, depth-dose curves of photon beams measured with the microDiamond detector are in close agreement to those measured with the microLion detector for small fields and with those measured with a Semiflex 0.125 cc ionization chamber for large fields. Differences are in the range of 0.25% and less. For profile measurements, microDiamond detector measurements agree well with microLion and P Diode measurements in the high-dose region of the profile and the penumbra region. For areas outside the open field, P Diode measurements are about 0.5%-1.0% higher than microDiamond and microLion measurements. Thus it becomes evident that the investigated diamond detector (type 60019) is suitable for a wide range of applications in high-energy photon and electron dosimetry and is interesting for relative, as well as absolute, dosimetry. 

An exploration of risk for recurrent falls in two geriatric care settings.

BACKGROUND: Fall events were examined in two distinct geriatric populations to identify factors associated with repeat fallers, and to examine whether patients who use gait aids, specifically a walker, were more likely to experience repeat falls. Each unit already had a generic program for falls prevention in place. METHODS: Secondary data analysis was conducted on information collected during the pilot testing of a new quality assurance Incident Reporting Tool between October 2006 and September 2008. The study settings included an in-patient geriatric rehabilitation unit (GRU) and a long stay veterans' unit (LSVU) in a rehabilitation and long-stay hospital in Ontario. Participants were two hundred and twenty three individuals, aged 65 years or older on these two units, who experienced one or more fall incidents during the study period. RESULTS: Logistic regression analyses showed that on the GRU age was significantly associated with repeat falls. On the LSVU first falls in the morning or late evening were associated with repeat falling. Walker as a gait aid listed at time of first fall was not associated with repeat falls. CONCLUSIONS: This study suggests that different intervention may be necessary in different geriatric settings to identify, for secondary prevention, certain individuals for which the generic programs prove inadequate. Information collection with a specific focus on the issue of repeat falls may be necessary for greater insight.

A comparison of bone density and bone morphology between patients presenting with hip fractures, spinal fractures or a combination of the two.

BACKGROUND: Currently it is uncertain how to define osteoporosis and who to treat after a hip fracture. There is little to support the universal treatment of all such patients but how to select those most in need of treatment is not clear. In this study we have compared cortical and trabecular bone status between patients with spinal fractures and those with hip fracture with or without spinal fracture with the aim to begin to identify, by a simple clinical method (spine x-ray), a group of hip fracture patients likely to be more responsive to treatment with current antiresorptive agents. METHODS: Comparison of convenience samples of three groups of 50 patients, one with spinal fractures, one with a hip fracture, and one with both. Measurements consist of bone mineral density at the lumbar spine, at the four standard hip sites, number, distribution and severity of spinal fractures by the method of Genant, cortical bone thickness at the infero-medial femoral neck site, femoral neck and axis length and femoral neck width. RESULTS: Patients with spinal fractures alone have the most deficient bones at both trabecular and cortical sites: those with hip fracture and no spinal fractures the best at trabecular bone and most cortical bone sites: and those with both hip and spinal fractures intermediate in most measurements. Hip axis length and neck width did not differ between groups. CONCLUSION: The presence of the spinal fracture indicates poor trabecular bone status in hip fracture patients. Hip fracture patients without spinal fractures have a bone mass similar to the reference range for their age and gender. Poor trabecular bone in hip fracture patients may point to a category of patient more likely to benefit from therapy and may be indicated by the presence of spinal fractures.

Underrepresentation of individuals 80 years of age and older in chronic disease clinical practice guidelines.

OBJECTIVE: To determine whether Canadian clinical practice guidelines (CPGs), and the evidence used to create CPGs, include individuals 80 years of age and older. DESIGN: Descriptive analysis of 14 CPGs for 5 dominant chronic conditions (diabetes, hypertension, heart failure, osteoporosis, stroke) and descriptive analysis of all research-based references with human participants in the 14 guidelines. MAIN OUTCOME MEASURES: To identify recommendations for individuals 65 years of age and older or 80 years of age and older and for those with multiple chronic conditions. RESULTS: Although 12 of 14 guidelines provided specific recommendations for individuals 65 years of age and older, only 5 provided recommendations for frail older individuals (≥ 80 years). A total of 2559 studies were used as evidence to support the recommendations in the 14 CPGs; 2272 studies provided the mean age of participants, of which only 31 (1.4%) reported a mean age of 80 years of age and older. CONCLUSION: There is very low representation of individuals in advanced old age in CPGs and in the studies upon which these guidelines are based, calling into question the applicability of current chronic disease CPGs to older individuals. The variety of medical and functional issues occurring in the elderly raises the concern of whether or not evidence-based disease-specific CPGs are appropriate for such a diverse population.

QA for helical tomotherapy: report of the AAPM Task Group 148.

Helical tomotherapy is a relatively new modality with integrated treatment planning and delivery hardware for radiation therapy treatments. In view of the uniqueness of the hardware design of the helical tomotherapy unit and its implications in routine quality assurance, the Therapy Physics Committee of the American Association of Physicists in Medicine commissioned Task Group 148 to review this modality and make recommendations for quality assurance related methodologies. The specific objectives of this Task Group are: (a) To discuss quality assurance techniques, frequencies, and tolerances and (b) discuss dosimetric verification techniques applicable to this unit. This report summarizes the findings of the Task Group and aims to provide the practicing clinical medical physicist with the insight into the technology that is necessary to establish an independent and comprehensive quality assurance program for a helical tomotherapy unit. The emphasis of the report is to describe the rationale for the proposed QA program and to provide example tests that can be performed, drawing from the collective experience of the task group members and the published literature. It is expected that as technology continues to evolve, so will the test procedures that may be used in the future to perform comprehensive quality assurance for helical tomotherapy units.

Hip fracture types in men and women change differently with age.

BACKGROUND: Hip fractures are expensive and a frequent cause of morbidity and mortality in the elderly. In most studies hip fractures have been viewed as a unitary fracture but recently the two main types of fracture (intertrochanteric and subcapital) have been viewed as two fractures with a different etiology and requiring a different approach to prevention. The relative proportion of intertrochanteric fractures increases with age in women. In previous studies no particular pattern in men has been noted. In this study, we explored changes in the relative proportion of the two fracture types with age in the two genders. METHODS: Patients of 50 years and older, with a diagnosis of hip fracture, discharged from two local acute care hospitals over a 5 year period (n = 2150) were analyzed as a function of age and gender to explore the relative proportions of intertrochanteric and subcapital fractures, and the change in relative proportion in the two genders with age. RESULTS: Overall, for the genders combined, the proportion of intertrochanteric fractures increases with age (p = .007). In women this increase is significant (p < .001), but in men the opposite pattern is observed, with the proportion of intertrochanteric fractures falling significantly with age (p = .025). CONCLUSIONS: The pattern of hip fractures is different in men and women with aging. It is likely that the pattern difference reflects differences in type and rate of bone loss in the genders, but it is conjectured that the changing rate and pattern of falling with increasing age may also be important. The two main hip fracture types should be considered distinct and different and be studied separately in studies of cause and prevention.

Longitudinal Detection of Radiation-Induced Peripapillary and Macular Retinal Capillary Ischemia Using OCT Angiography.

PURPOSE: To study longitudinal changes in retinal capillary circulation in eyes treated with iodine 125 (I125) plaque brachytherapy for uveal melanoma using OCT angiography (OCTA). DESIGN: Longitudinal prospective study of 21 patients undergoing treatment for uveal melanoma with I125 plaque brachytherapy. Eyes with melanoma were imaged with OCTA before treatment and at 12-month intervals until 2 years after brachytherapy. PARTICIPANTS: After institutional review board approval, participants were enrolled prospectively from an academic ocular oncology clinic. METHODS: Peripapillary (4.5 × 4.5-mm) and macular (3 × 3-mm) OCTA scans were acquired with AngioVue (Optovue, Inc, Fremont, CA). MAIN OUTCOME MEASURES: The peripapillary nerve fiber layer plexus capillary density (NFLP_CD), macular superficial vascular complex vessel density (mSVC_VD), and foveal avascular zone (FAZ) area were calculated. RESULTS: Before treatment, no significant difference was found in the NFLP_CD, mSVC_VD, or FAZ area between eyes with melanoma and normal fellow eyes. By 24 months, 11 eyes had developed clinical signs of radiation retinopathy, radiation optic neuropathy, or both. In treated eyes, the NFLP_CD (48.4±4.1%) was reduced at 12 months (46.7±5.0%; P = 0.04, Wilcoxon signed-rank test) and 24 months (44.5±6.1%; P < 0.001). Similarly, the mSVC_VD (48.4 2±3.6%) was reduced in treated eyes at 12 months (43.5±5.9%; P = 0.01) and 24 months (37.4±9.1%; P < 0.001). The FAZ area (0.26±0.11 mm2) increased in treated eyes at 12 months (0.35±0.22 mm2; P = 0.009) and 24 months (0.81±1.03 mm2; P = 0.001). When only eyes with clinically evident radiation changes were evaluated, the changes in NFLP_CD, mSVC_VD, and FAZ area were more pronounced. OCT angiography measurements correlated with both radiation dose and visual acuity. The mSVC_VD measured at 12 months was found to predict the development of clinically apparent radiation retinopathy within 1 year. CONCLUSIONS: OCT angiography demonstrated early emergence of peripapillary and macular capillary vasculature changes after I125 plaque brachytherapy. OCT angiography provided a quantitative measurement of retinal capillary changes associated with ischemia that correlated with visual acuity and radiation dose and may predict future development of radiation-induced retinal toxicity.

Practice Patterns for the Treatment of Uveal Melanoma with Iodine-125 Plaque Brachytherapy: Ocular Oncology Study Consortium Report 5.

BACKGROUND: Treatment planning for I-125 plaque therapy for uveal melanoma has advanced significantly since the Collaborative Ocular Melanoma Study trial, with more widely available image-guided planning and improved dosimetry. OBJECTIVE: We evaluated real-world practice patterns for I-125 plaque brachytherapy in the United States by studying practice patterns at centers that comprise the Ocular Oncology Study Consortium (OOSC). METHODS: The OOSC database and responses to a treatment practice survey were evaluated. The database contains treatment information from 9 institutions. Patients included in the database were treated between 2010 and 2014. The survey was conducted in 2018 and current treatment planning methods and prescriptions were queried. RESULTS: Examination of the OOSC database revealed that average doses to critical structures were highly consistent, with the exception of one institution. Survey responses indicated that most centers followed published guidelines regarding dose and prescription point. Dose rate ranged from 51 to 118 cGy/h. As of 2018, most institutions use pre-loaded plaques and fundus photographs and/or computed tomography or magnetic resonance imaging in planning. CONCLUSIONS: While there were differences in dosimetric practices, overall agreement in plaque brachytherapy practices was high among OOSC institutions. Clinical margins and planning systems were similar among institutions, while prescription dose, dose rates, and dosimetry varied.

Evaluation of a care pathway in the initiation of calcium and vitamin D treatment of patients after hip fracture.

Hip fractures, fragility fractures, indicate an increased risk for further fragility fractures. Although the way to define osteoporosis, requiring antiresorptive therapy, is not clear, all patients who have had hip fractures should be prescribed calcium and vitamin D at a minimum. In a retrospective chart review, we have explored the effectiveness of incorporating a standing recommendation (but not a standing order) for calcium and vitamin D treatment in a hip fracture care pathway, comparing units where the pathway had been implemented with those where it had not yet been started. The pathway resulted in significantly more initiation of calcium and vitamin D compared to patients not on the pathway (72% vs. 13.5%, p < 0.01). However, a follow-up study after four years showed a marked decline in the frequency of the initiation of calcium and vitamin D, suggesting the need for ongoing encouragement for the intervention to continue to be successful.

Quantitative OCT Angiography Evaluation of Peripapillary Retinal Circulation after Plaque Brachytherapy.

OBJECTIVE: To study peripapillary retinal capillary circulation in eyes treated with I-125 plaque brachytherapy for uveal melanoma using optical coherence tomography angiography (OCTA). DESIGN: Cross-sectional study of 10 subjects imaged with OCTA prior to uveal melanoma treatment and 15 subjects imaged after development of radiation retinopathy and/or optic neuropathy. PARTICIPANTS: Following IRB approval, subjects were enrolled from an academic ocular oncology clinical practice. All subjects had uveal melanoma in one eye and treatment with I-125 plaque brachytherapy was planned or had previously taken place. Patients with low vision at baseline and uncontrolled hypertension were excluded. In the post-treatment group, seven subjects were male and eight were female; age range 38 to 81 years. Visual acuities in the irradiated eyes ranged from 20/20 to counting fingers. Visual acuities in the untreated fellow eyes were 20/25 or better. METHODS: Peripapillary retinal capillary circulation was measured by OCTA (Optovue, Inc). 4.5×4.5 mm optic disc scans were obtained. 10 subjects were imaged prior to brachytherapy treatment and 15 subjects were imaged after development of clinically apparent radiation retinopathy and/or radiation optic neuropathy post-brachytherapy. MAIN OUTCOME MEASURES: The relationship of the peripapillary retinal capillary density (PPCD) as measured by OCTA to the calculated dose to the optic nerve (D50, the dose to 50% of the disc) and the LogMAR vision was evaluated. RESULTS: No significant difference was seen in the PPCD as measured by OCTA when comparing the eye with melanoma to the fellow eye prior to brachytherapy; however the PPCD was significantly lower in treated eyes (52.9% +/- 22.4%) than in fellow eyes that did not receive radiation (73.3% +/- 13.7%, p = 0.004). There was an inverse linear correlation between D50 and the PPCD (Pearson's; r= -0.528, P=0.043) and between visual acuity and the PPCD (Pearson's; r= -0.564, P=0.028). CONCLUSIONS: Among patients with clinically apparent radiation retinopathy and/or radiation optic neuropathy, PPCD was lower in the treated eye and correlated with the radiation dose to the optic nerve and the visual acuity. OCTA provides a measure of capillary changes following radiation, and may serve as a quantitative endpoint to address visual prognosis.

Improving the diagnosis and treatment of osteoporosis using a senior-friendly peer-led community education and mentoring model: a randomized controlled trial.

BACKGROUND: This randomized controlled trial (RCT) evaluated a 6-month peer-led community education and mentorship program to improve the diagnosis and management of osteoporosis. METHODS: Ten seniors (74-90 years of age) were trained to become peer educators and mentors and deliver the intervention. In the subsequent RCT, 105 seniors (mean age =80.5±6.9; 89% female) were randomly assigned to the peer-led education and mentorship program (n=53) or control group (n=52). Knowledge was assessed at baseline and 6 months. Success was defined as discussing osteoporosis risk with their family physician, obtaining a bone mineral density assessment, and returning to review their risk profile and receive advice and/or treatment. RESULTS: Knowledge of osteoporosis did not change significantly. There was no difference in knowledge change between the two groups (mean difference =1.3, 95% confidence interval [CI] of difference -0.76 to 3.36). More participants in the intervention group achieved a successful outcome (odds ratio 0.16, 95% CI 0.06-0.42, P<0.001). CONCLUSION: Peer-led education and mentorship can promote positive health behavior in seniors. This model was effective for improving osteoporosis risk assessment, diagnosis, and treatment in a community setting.

Involving the community elderly in the planning and provision of health services: predictors of volunteerism and leadership.

A rapidly growing older population has led to changes in health care, including a community health movement with an emphasis on community collaboration, self-help, and capacity building. This study examined factors in the lives of older individuals that influenced their ability and willingness to participate in a health-related community-capacity-building project to help their frail, older neighbours. Using cross-sectional survey methodology, 107 volunteers who lived in a high density seniors' apartment complex known for its high health service utilization were compared with a random sample of 74 non-volunteers from the same community. Factors associated with volunteer involvement included age, activity level, functional ability, life satisfaction and certain personality characteristics. The study suggests that, within a community, the ''younger-old'' may be able to support their frail, older neighbours so that they can remain living in the community.

Hip Fracture Types in Canadian Men and Women Change Differently with Age: A Population-Level Analysis.

BACKGROUND: We have previously reported a gender difference in the occurrence of hip fracture type with age in our local population. In the current report, we have explored this phenomenon in a Canadian population using five years of data from a national administrative database. We have compared community-dwelling and institutionalized individuals to determine if frailty is important and has a differential effect on the type of hip fracture experienced. METHODS: Hospitalization records from 2005 to 2009, in which the most responsible diagnosis, that is the diagnosis causing the admission to hospital, was a hip fracture, were obtained from the Discharge Abstract Database of the Canadian Institute for Health Information. Hip fracture type was identified using the Canadian Classification of Health Interventions and the International Classification of Diseases 10th Revision, Canada (ICD-10-CA). Hip fracture proportions were calculated for the study period and stratified by age group and sex. RESULTS: The relative proportion of intertrochanteric fractures in women rose from 35% in the youngest group (55-59 years) to 51% in the oldest group (84+ years; P < 0.0001). In men, the proportions remain relatively stable (47% and 44%, respectively). Community and institutionalized patients showed the same pattern. CONCLUSIONS: The change in the proportion of the two hip fracture types that occur in women but not men may point to differences in the etiology and consequently the approaches to prevention for the two fracture types. Level of frailty did not seem to be important.

Patient outcomes after discharge from a geriatric day hospital.

Evidence suggests that frailer older patients benefit from a continuum of care rather than the admit/discharge model of our health system. This study examined patient outcomes after discharge from a geriatric day hospital (GDH) to determine what proportion continues to do well, what proportion declines, how the two groups differ, and if factors predictive of deterioration can be identified. Using telephone survey and Goal Attainment Scaling methodologies, the goals of 151 patients discharged from a GDH between 6 and 18 months previously were examined to determine whether GDH achievements were maintained or lost. All but 5 patients improved between GDH admission and discharge; after discharge, 39 per cent deteriorated. The need for more support in the community was predictive of deterioration, probably reflecting patient frailty. Number of medical diagnoses or medications were not predictive. Frailer older patients tend not to maintain goals achieved in a GDH after discharge and may benefit from ongoing maintenance.

Risk factors for falling among community-dwelling veterans and their caregivers.

PURPOSE: To assess the prevalence and strength of association of risk factors for falling in Canadian veterans of World War II and Korea and their caregivers. METHODS: Questionnaires were sent to addresses of 3,000 Canadian veterans (response rate(1/4)70%). Risk factors for falls and the frequency of falls and injurious falls in the past 12 months were collected. RESULTS: Veterans had more risk factors than did caregivers, and more had fallen in the past year (39.8% vs. 29.7%). Risk factors in the logistic model for veterans included lower extremity disability (odds ratio 1.98, 95% confidence interval 1.5-2.6); lower extremity weakness (OR 1.75, 95% CI 1.3-2.3); worse memory than peers (OR 1.67, 95% CI 1.1-2.5); one or more visits to the family doctor in the past month (OR 1.53, 95% CI 1.2-2.0); and worse memory than 5 years ago (OR 1.36, 95% CI 1.0-1.8). CONCLUSIONS: Veterans appear more frail and prone to falling than their caregivers.

Successful knowledge translation intervention in long-term care: final results from the vitamin D and osteoporosis study (ViDOS) pilot cluster randomized controlled trial.

BACKGROUND: Few studies have systematically examined whether knowledge translation (KT) strategies can be successfully implemented within the long-term care (LTC) setting. In this study, we examined the effectiveness of a multifaceted, interdisciplinary KT intervention for improving the prescribing of vitamin D, calcium and osteoporosis medications over 12-months. METHODS: We conducted a pilot, cluster randomized controlled trial in 40 LTC homes (21 control; 19 intervention) in Ontario, Canada. LTC homes were eligible if they had more than one prescribing physician and received services from a large pharmacy provider. Participants were interdisciplinary care teams (physicians, nurses, consultant pharmacists, and other staff) who met quarterly. Intervention homes participated in three educational meetings over 12 months, including a standardized presentation led by expert opinion leaders, action planning for quality improvement, and audit and feedback review. Control homes did not receive any additional intervention. Resident-level prescribing and clinical outcomes were collected from the pharmacy database; data collectors and analysts were blinded. In addition to feasibility measures, study outcomes were the proportion of residents taking vitamin D (≥800 IU/daily; primary), calcium ≥500 mg/day and osteoporosis medications (high-risk residents) over 12 months. Data were analyzed using the generalized estimating equations technique accounting for clustering within the LTC homes. RESULTS: At baseline, 5,478 residents, mean age 84.4 (standard deviation (SD) 10.9), 71% female, resided in 40 LTC homes, mean size = 137 beds (SD 76.7). In the intention-to-treat analysis (21 control; 19 intervention clusters), the intervention resulted in a significantly greater increase in prescribing from baseline to 12 months between intervention versus control arms for vitamin D (odds ratio (OR) 1.82, 95% confidence interval (CI): 1.12, 2.96) and calcium (OR 1.33, 95% CI: 1.01, 1.74), but not for osteoporosis medications (OR 1.17, 95% CI: 0.91, 1.51). In secondary analyses, excluding seven nonparticipating intervention homes, ORs were 3.06 (95% CI: 2.18, 4.29), 1.57 (95% CI: 1.12, 2.21), 1.20 (95% CI: 0.90, 1.60) for vitamin D, calcium and osteoporosis medications, respectively. CONCLUSIONS: Our KT intervention significantly improved the prescribing of vitamin D and calcium and is a model that could potentially be applied to other areas requiring quality improvement. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01398527 . Registered: 19 July 2011.