Classification of patients with osteoarthritis through clusters of comorbidities using 633 330 individuals from Spain

OBJECTIVES

To explore clustering of comorbidities among patients with a new diagnosis of OA and estimate the 10-year mortality risk for each identified cluster.

METHODS

This is a population-based cohort study of individuals with first incident diagnosis of OA of the hip, knee, ankle/foot, wrist/hand or 'unspecified' site between 2006 and 2020, using SIDIAP (a primary care database representative of Catalonia, Spain). At the time of OA diagnosis, conditions associated with OA in the literature that were found in ≥1% of the individuals (n = 35) were fitted into two cluster algorithms, k-means and latent class analysis. Models were assessed using a range of internal and external evaluation procedures. Mortality risk of the obtained clusters was assessed by survival analysis using Cox proportional hazards.

RESULTS

We identified 633 330 patients with a diagnosis of OA. Our proposed best solution used latent class analysis to identify four clusters: 'low-morbidity' (relatively low number of comorbidities), 'back/neck pain plus mental health', 'metabolic syndrome' and 'multimorbidity' (higher prevalence of all studied comorbidities). Compared with the 'low-morbidity' cluster, the 'multimorbidity' cluster had the highest risk of 10-year mortality (adjusted hazard ratio [HR]: 2.19 [95% CI: 2.15, 2.23]), followed by the 'metabolic syndrome' cluster (adjusted HR: 1.24 [95% CI: 1.22, 1.27]) and the 'back/neck pain plus mental health' cluster (adjusted HR: 1.12 [95% CI: 1.09, 1.15]).

CONCLUSION

Patients with a new diagnosis of OA can be clustered into groups based on their comorbidity profile, with significant differences in 10-year mortality risk. Further research is required to understand the interplay between OA and particular comorbidity groups, and the clinical significance of such results.

Drug utilization analysis of osteoporosis medications in seven European electronic health databases

We studied the characteristics of patients prescribed osteoporosis medication and patterns of use in European databases. Patients were mostly female, older, had hypertension. There was suboptimal persistence particularly for oral medications. Our findings would be useful to healthcare providers to focus their resources on improving persistence to specific osteoporosis treatments.

PURPOSE

To characterise the patients prescribed osteoporosis therapy and describe the drug utilization patterns.

METHODS

We investigated the treatment patterns of bisphosphonates, denosumab, teriparatide, and selective estrogen receptor modulators (SERMs) in seven European databases in the United Kingdom, Italy, the Netherlands, Denmark, Spain, and Germany. In this cohort study, we included adults aged ≥ 18 years, with ≥ 1 year of registration in the respective databases, who were new users of the osteoporosis medications. The study period was between 01 January 2018 to 31 January 2022.

RESULTS

Overall, patients were most commonly initiated on alendronate. Persistence decreased over time across all medications and databases, ranging from 52-73% at 6 months to 29-53% at 12 months for alendronate. For other oral bisphosphonates, the proportion of persistent users was 50-66% at 6 months and decreased to 30-44% at 12 months. For SERMs, the proportion of persistent users at 6 months was 40-73% and decreased to 25-59% at 12 months. For parenteral treatment groups, the proportions of persistence with denosumab were 50-85% (6 month), 30-63% (12 month) and with teriparatide 40-75% (6 month) decreasing to 21-54% (12 month). Switching occurred most frequently in the alendronate group (2.8-5.8%) and in the teriparatide group (7.1-14%). Switching typically occurred in the first 6 months and decreased over time. Patients in the alendronate group most often switched to other oral or intravenous bisphosphonates and denosumab.

CONCLUSION

Our results show suboptimal persistence to medications that varied across different databases and treatment switching was relatively rare.

Risk of adverse events following the initiation of antihypertensives in older people with complex health needs: a self-controlled case series in the United Kingdom

BACKGROUND

We assessed the risk of adverse events-severe acute kidney injury (AKI), falls and fractures-associated with use of antihypertensives in older patients with complex health needs (CHN).

SETTING

UK primary care linked to inpatient and mortality records.

METHODS

The source population comprised patients aged >65, with ≥1 year of registration and unexposed to antihypertensives in the year before study start. We identified three cohorts of patients with CHN, namely, unplanned hospitalisations, frailty (electronic frailty index deficit count ≥3) and polypharmacy (prescription of ≥10 medicines). Patients in any of these cohorts were included in the CHN cohort. We conducted self-controlled case series for each cohort and outcome (AKI, falls, fractures). Incidence rate ratios (IRRs) were estimated by dividing event rates (i) during overall antihypertensive exposed patient-time over unexposed patient-time; and (ii) in the first 30 days after treatment initiation over unexposed patient-time.

RESULTS

Among 42,483 patients in the CHN cohort, 7,240, 5,164 and 450 individuals had falls, fractures or AKI, respectively. We observed an increased risk for AKI associated with exposure to antihypertensives across all cohorts (CHN: IRR 2.36 [95% CI: 1.68-3.31]). In the 30 days post-antihypertensive treatment initiation, a 35-50% increased risk for falls was found across all cohorts and increased fracture risk in the frailty cohort (IRR 1.38 [1.03-1.84]). No increased risk for falls/fractures was associated with continuation of antihypertensive treatment or overall use.

CONCLUSION

Treatment with antihypertensives in older patients was associated with increased risk of AKI and transiently elevated risk of falls in the 30 days after starting antihypertensive therapy.

Characterising complex health needs and the use of preventive therapies in the older population: a population-based cohort analysis of UK primary care and hospital linked data

BACKGROUND

While several definitions exist for multimorbidity, frailty or polypharmacy, it is yet unclear to what extent single healthcare markers capture the complexity of health-related needs in older people in the community. We aimed to identify and characterise older people with complex health needs based on healthcare resource use (unplanned hospitalisations or polypharmacy) or frailty using large population-based linked records.

METHODS

In this cohort study, data was extracted from UK primary care records (CPRD GOLD), with linked Hospital Episode Statistics inpatient data. People aged > 65 on 1st January 2010, registered in CPRD for ≥ 1 year were included. We identified complex health needs as the top quintile of unplanned hospitalisations, number of prescribed medicines, and electronic frailty index. We characterised all three cohorts, and quantified point-prevalence and incidence rates of preventive medicines use.

RESULTS

Overall, 90,597, 110,225 and 116,076 individuals were included in the hospitalisation, frailty, and polypharmacy cohorts respectively; 28,259 (5.9%) were in all three cohorts, while 277,332 (58.3%) were not in any (background population). Frailty and polypharmacy cohorts had the highest bi-directional overlap. Most comorbidities such as diabetes and chronic kidney disease were more common in the frailty and polypharmacy cohorts compared to the hospitalisation cohort. Generally, prevalence of preventive medicines use was highest in the polypharmacy cohort compared to the other two cohorts: For instance, one-year point-prevalence of statins was 64.2% in the polypharmacy cohort vs. 60.5% in the frailty cohort.

CONCLUSIONS

Three distinct groups of older people with complex health needs were identified. Compared to the hospitalisation cohort, frailty and polypharmacy cohorts had more comorbidities and higher preventive therapies use. Research is needed into the benefit-risk of different definitions of complex health needs and use of preventive therapies in the older population.

Oral Bisphosphonates Are Associated With Increased Risk of Severe Acute Kidney Injury in Elderly Patients With Complex Health Needs: A Self-Controlled Case Series in the United Kingdom

Although oral bisphosphonates (BP) are commonly used, there is conflicting evidence for their safety in the elderly. Safety concerns might trump BP use in older patients with complex health needs. Our study evaluated the safety of BP, focusing on severe acute kidney injury (AKI), gastrointestinal ulcer (GI ulcer), osteonecrosis of the jaw (ONJ), and femur fractures. We used UK primary care data (Clinical Practice Research Datalink [CPRD GOLD]), linked to hospital (Hospital Episode Statistics [HES] inpatient) and ONS mortality data. We included all patients aged >65 with complex health needs and no BP use in the year before study start (January 1, 2010). Complex health needs were defined in three cohorts: an electronic frailty index score ≥3 (frailty cohort), one or more unplanned hospitalization/s (hospitalization cohort); and prescription of ≥10 different medicines in 2009 (polypharmacy cohort). Incidence rates were calculated for all outcomes. Subsequently, all individuals who experienced AKI or GI ulcer anytime during follow-up were included for Self-Controlled Case Series (SCCS) analyses. Incidence rate ratios (IRRs) were estimated separately for AKI and GI ulcer, comparing event rates between BP-exposed and unexposed time windows. No SCCS were conducted for ONJ and femur fractures. We identified 94,364 individuals in the frailty cohort, as well as 78,184 and 95,621 persons in the hospitalization and polypharmacy cohorts. Of those, 3023, 1950, and 2992 individuals experienced AKI and 1403, 1019, and 1453 had GI ulcer/s during follow-up, respectively. Age-adjusted SCCS models found evidence of increased risk of AKI associated with BP use (frailty cohort: IRR 1.65; 95% confidence interval [CI], 1.25-2.19), but no association with GI ulcers (frailty cohort: IRR 1.24; 95% CI, 0.86-1.78). Similar results were obtained for the hospitalization and polypharmacy cohorts. Our study found a 50% to 65% increased risk of AKI associated with BP use in elderly patients with complex health needs. Future studies should further investigate the risk-benefit of BP use in these patients. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

What influences patients' opinion of remission and low disease activity in psoriatic arthritis? Principal component analysis of an international study

OBJECTIVE

In PsA, the treatment objective is remission or low disease activity (LDA), but patients' perception of remission is poorly studied. This analysis aimed to identify factors associated with patient-defined remission.

METHODS

This analysis uses ReFlaP data, an international PsA study, with remission defined as 'At this time, is your psoriatic arthritis in remission, if this means: you feel your disease is as good as gone?'. Variables associated with, first, patient-defined remission and, second, LDA were identified using multivariable logistic regression and principal component analysis (PCA) to explore correlated variables.

RESULTS

Of 424 patients (50.2% male, mean age 52 years) with established disease, 94 (22.2%) reported themselves as being in remission and 191 (45.0%) as LDA alone. In multivariable analysis pain, psoriasis, impact of disease, physician opinion of symptoms from joint damage and Groll comorbidity index were independent predictors of remission. For LDA, results were similar. Using PCA, variance explained was 74% by five components for men and 80% by six components for women. The key component from PCA for remission was, for both sex, disease impact (Psoriatic Arthritis Impact of Disease, pain and HAQ) explaining 22.2-27.5% of variance. Other factors included musculoskeletal disease activity, chronicity/joint damage, psoriasis, enthesitis and CRP. For LDA, similar factors were identified but the variance explained was lower (64-68%).

CONCLUSION

Many factors impact on patients' opinion of remission, dominated by disease impact. Disease activity in multiple domains, chronicity/age, comorbidities and symptoms due to other conditions contribute to a robust model highlighting that patient-defined remission is multifaceted.

TRIALS REGISTRATION

Clinicaltrials.gov, http://clinicaltrials.gov, NCT03119805.

Bariatric surgery increases the rate of major fracture: self-controlled case series study in UK Clinical Practice Research Datalink

Conflicting results exist about the relationship between bariatric surgery and fracture risk. Also, prediction of who is at increased risk of fracture after bariatric surgery is not currently available. Hence, we used a combination of a self-controlled case series (SCCS) study to establish the association between bariatric surgery and fracture, and develop a prediction model for postoperative fracture risk estimation using a cohort study. Patients from UK Primary care records from the Clinical Practice Research Datalink GOLD linked to Hospital Episode Statistics undergoing bariatric surgery with body mass index (BMI) ≥30 kg/m2 between 1997 and 2018 were included in the cohort. Those sustaining one or more fractures in the 5 years before or after surgery were included in the SCCS. Fractures were considered in three categories: (i) any except skull and digits (primary outcome); (ii) major (hip, vertebrae, wrist/forearm, and humerus); and (iii) peripheral (forearm and lower leg). Of 5487 participants, 252 (4.6%) experienced 272 fractures (of which 80 were major and 135 peripheral) and were included in the SCCS analyses. Major fracture risk increased after surgery, incidence rate ratios (IRRs) and 95% confidence intervals (CIs): 2.77 (95% CI, 1.34-5.75) and 3.78 (95% CI, 1.42-10.08) at ≤3 years and 3.1 to 5 years postsurgery when compared to 5 years prior to surgery, respectively. Any fracture risk was higher only in the 2.1 to 5 years following surgery (IRR 1.73; 95% CI, 1.08-2.77) when compared to 5 years prior to surgery. No excess risk of peripheral fracture after surgery was identified. A prediction tool for major fracture was developed using 5487 participants included in the cohort study. It was also internally validated (area under the receiver-operating characteristic curve [AUC ROC] 0.70) with use of anxiolytics/sedatives/hypnotics and female as major predictors. Hence, major fractures are nearly threefold more likely after bariatric surgery. A simple prediction tool with five variables identifies high risk patients for major fracture. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Estimating the population health burden of musculoskeletal conditions using primary care electronic health records

OBJECTIVES

Better indicators from affordable, sustainable data sources are needed to monitor population burden of musculoskeletal conditions. We propose five indicators of musculoskeletal health and assessed if routinely available primary care electronic health records (EHR) can estimate population levels in musculoskeletal consulters.

METHODS

We collected validated patient-reported measures of pain experience, function and health status through a local survey of adults (≥35 years) presenting to English general practices over 12 months for low back pain, shoulder pain, osteoarthritis and other regional musculoskeletal disorders. Using EHR data we derived and validated models for estimating population levels of five self-reported indicators: prevalence of high impact chronic pain, overall musculoskeletal health (based on Musculoskeletal Health Questionnaire), quality of life (based on EuroQoL health utility measure), and prevalence of moderate-to-severe low back pain and moderate-to-severe shoulder pain. We applied models to a national EHR database (Clinical Practice Research Datalink) to obtain national estimates of each indicator for three successive years.

RESULTS

The optimal models included recorded demographics, deprivation, consultation frequency, analgesic and antidepressant prescriptions, and multimorbidity. Applying models to national EHR, we estimated that 31.9% of adults (≥35 years) presenting with non-inflammatory musculoskeletal disorders in England in 2016/17 experienced high impact chronic pain. Estimated population health levels were worse in women, older aged and those in the most deprived neighbourhoods, and changed little over 3 years.

CONCLUSION

National and subnational estimates for a range of subjective indicators of non-inflammatory musculoskeletal health conditions can be obtained using information from routine electronic health records.

Safety of Oral Bisphosphonates in Moderate-to-Severe Chronic Kidney Disease: A Binational Cohort Analysis

Bisphosphonates are the first-line treatment for preventing fractures in osteoporosis patients. However, their use is contraindicated or to be used with caution in chronic kidney disease (CKD) patients, primarily because of a lack of information about their safety and effectiveness. We aimed to investigate the safety of oral bisphosphonates in patients with moderate to severe CKD, using primary-care electronic records from two cohorts, CPRD GOLD (1997-2016) and SIDIAP (2007-2015) in the UK and Catalonia, respectively. Both databases were linked to hospital records. SIDIAP was also linked to end-stage renal disease registry data. Patients with CKD stages 3b to 5, based on two or more estimated glomerular filtration rate measurements less than 45 mL/min/1.73 m² , aged 40 years or older were identified. New bisphosphonate users were propensity score-matched with up to five non-users to minimize confounding within this population. Our primary outcome was CKD stage worsening (estimated glomerular filtration rate [eGFR] decline or renal replacement therapy). Secondary outcomes were acute kidney injury, gastrointestinal bleeding/ulcers, and severe hypocalcemia. Hazard ratios (HRs) were estimated using Cox regression and Fine and Gray sub-HRs were calculated for competing risks. We matched 2447 bisphosphonate users with 8931 non-users from CPRD and 1399 users with 6547 non-users from SIDIAP. Bisphosphonate use was associated with greater risk of CKD progression in CPRD (sub-HR [95% CI]: 1.14 [1.04, 1.26]) and SIDIAP (sub-HR: 1.15 [1.04, 1.27]). No risk differences were found for acute kidney injury, gastrointestinal bleeding/ulcers, or hypocalcemia. Hence, we can conclude a modest (15%) increased risk of CKD progression was identified in association with bisphosphonate use. No other safety concerns were identified. Our findings should be considered before prescribing bisphosphonates to patients with moderate to severe CKD. © 2020 American Society for Bone and Mineral Research (ASBMR).

Bisphosphonates to reduce bone fractures in stage 3B+ chronic kidney disease: a propensity score-matched cohort study

BACKGROUND

Bisphosphonates are contraindicated in patients with stage 4+ chronic kidney disease. However, they are widely used to prevent fragility fractures in stage 3 chronic kidney disease, despite a lack of good-quality data on their effects.

OBJECTIVES

The aims of each work package were as follows. Work package 1: to study the relationship between bisphosphonate use and chronic kidney disease progression. Work package 2: to study the association between using bisphosphonates and fracture risk. Work package 3: to determine the risks of hypocalcaemia, hypophosphataemia, acute kidney injury and upper gastrointestinal events associated with using bisphosphonates. Work package 4: to investigate the association between using bisphosphonates and changes in bone mineral density over time.

DESIGN

This was a new-user cohort study design with propensity score matching.

SETTING AND DATA SOURCES

Data were obtained from UK NHS primary care (Clinical Practice Research Datalink GOLD database) and linked hospital inpatient records (Hospital Episode Statistics) for work packages 1-3 and from the Danish Odense University Hospital Databases for work package 4.

PARTICIPANTS

Patients registered in the data sources who had at least one measurement of estimated glomerular filtration rate of < 45 ml/minute/1.73 m2 were eligible. A second estimated glomerular filtration rate value of < 45 ml/minute/1.73 m2 within 1 year after the first was requested for work packages 1 and 3. Patients with no Hospital Episode Statistics linkage were excluded from work packages 1-3. Patients with < 1 year of run-in data before index estimated glomerular filtration rate and previous users of anti-osteoporosis medications were excluded from work packages 1-4.

INTERVENTIONS/EXPOSURE

Bisphosphonate use, identified from primary care prescriptions (for work packages 1-3) or pharmacy dispensations (for work package 4), was the main exposure.

MAIN OUTCOME MEASURES

Work package 1: chronic kidney disease progression, defined as stage worsening or starting renal replacement. Work package 2: hip fracture. Work package 3: acute kidney injury, hypocalcaemia and hypophosphataemia identified from Hospital Episode Statistics, and gastrointestinal events identified from Clinical Practice Research Datalink or Hospital Episode Statistics. Work package 4: annualised femoral neck bone mineral density percentage change.

RESULTS

Bisphosphonate use was associated with an excess risk of chronic kidney disease progression (subdistribution hazard ratio 1.12, 95% confidence interval 1.02 to 1.24) in work package 1, but did not increase the probability of other safety outcomes in work package 3. The results from work package 2 suggested that bisphosphonate use increased fracture risk (hazard ratio 1.25, 95% confidence interval 1.13 to 1.39) for hip fractures, but sensitivity analyses suggested that this was related to unresolved confounding. Conversely, work package 4 suggested that bisphosphonates improved bone mineral density, with an average 2.65% (95% confidence interval 1.32% to 3.99%) greater gain in femoral neck bone mineral density per year in bisphosphonate users than in matched non-users.

LIMITATIONS

Confounding by indication was a concern for the clinical effectiveness (i.e. work package 2) data. Bias analyses suggested that these findings were due to inappropriate adjustment for pre-treatment risk. work packages 3 and 4 were based on small numbers of events and participants, respectively.

CONCLUSIONS

Bisphosphonates were associated with a 12% excess risk of chronic kidney disease progression in participants with stage 3B+ chronic kidney disease. No other safety concerns were identified. Bisphosphonate therapy increased bone mineral density, but the research team failed to demonstrate antifracture effectiveness.

FUTURE WORK

Randomised controlled trial data are needed to demonstrate antifracture efficacy in patients with stage 3B+ chronic kidney disease. More safety analyses are needed to characterise the renal toxicity of bisphosphonates in stage 3A chronic kidney disease, possibly using observational data.

STUDY REGISTRATION

This study is registered as EUPAS10029.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 17. See the NIHR Journals Library website for further project information. The project was also supported by the National Institute for Health Research Biomedical Research Centre, Oxford.

Serious complications and risk of re-operation after Dupuytren's disease surgery: a population-based cohort study of 121,488 patients in England

Dupuytren’s disease (DD) is a common fibro-proliferative disorder of the palm. We estimated the risk of serious local and systemic complications and re-operation after DD surgery. We queried England’s Hospital Episode Statistics database and included all adult DD patients who were surgically treated. A longitudinal cohort study and self-controlled case series were conducted. Between 1 April 2007 and 31 March 2017, 121,488 adults underwent 158,119 operations for DD. The cumulative incidence of 90-day serious local complications was low at 1.2% (95% CI 1.1–1.2). However, the amputation rate for re-operation by limited fasciectomy following dermofasciectomy was 8%. 90-day systemic complications were also uncommon at 0.78% (95% CI 0.74–0.83), however operations routinely performed under general or regional anaesthesia carried an increased risk of serious systemic complications such as myocardial infarction. Re-operation was lower than previous reports (33.7% for percutaneous needle fasciotomy, 19.5% for limited fasciectomy, and 18.2% for dermofasciectomy). Overall, DD surgery performed in England was safe; however, re-operation by after dermofasciectomy carries a high risk of amputation. Furthermore, whilst serious systemic complications were unusual, the data suggest that high-risk patients should undergo treatment under local anaesthesia. These data will inform better shared decision-making regarding this common condition.

Alendronate use and bone mineral density gains in women with moderate-severe (stages 3B-5) chronic kidney disease: an open cohort multivariable and propensity score analysis from Funen, Denmark

Bisphosphonates are contraindicated in moderate-to-severe chronic kidney disease patients. However, they are used to prevent fragility fractures in patients with impaired kidney function, despite a lack of evidence on their effects on bone density in these patients. We demonstrated that Alendronate had a positive effect on bone in these patients.

PURPOSE

This study aimed to assess the association between alendronate use and bone mineral density (BMD) change in subjects with moderate-severe chronic kidney disease (CKD).

METHODS

We created a cohort of CKD stage 3B-5 patients by linking all DXA-based measurements in the Funen area, Denmark, to biochemistry, national health registries and filled prescriptions. Exposure was dispensation of alendronate and the outcome was annualized percentage change in BMD at the femoral neck, total hip and lumbar spine. Individuals were followed from first BMD to the latest of subsequent DXA measurements. Alendronate non-users were identified using incidence density sampling and matched groups were created using propensity scores. Linear regression was used to estimate average differences in the annualized BMD.

RESULTS

Use of alendronate was rare in this group of patients: propensity score matching (PSM) resulted in 71 alendronate users and 142 non-users with stage 3B-5 CKD (as in the 1 year before DXA). Whilst alendronate users gained an average 1.07% femoral neck BMD per year, non-users lost an average of 1.59% per annum. The PSM mean differences in annualized BMD were + 2.65% (1.32%, 3.99%), + 3.01% (1.74%, 4.28%) and + 2.12% (0.98%, 3.25%) at the femoral neck, total hip and spine BMD, respectively, all in favour of alendronate users.

CONCLUSION

In a real-world cohort of women with stage 3B-5 CKD, use of alendronate appears associated with a significant improvement of 2-3% per year in the femoral neck, total hip and spine BMD. More data are needed on the anti-fracture effectiveness and safety of bisphosphonate therapy in moderate-severe CKD.

Opioid use, postoperative complications, and implant survival after unicompartmental versus total knee replacement: a population-based network study

BACKGROUND

There is uncertainty around whether to use unicompartmental knee replacement (UKR) or total knee replacement (TKR) for individuals with osteoarthritis confined to a single compartment of the knee. We aimed to emulate the design of the Total or Partial Knee Arthroplasty Trial (TOPKAT) using routinely collected data to assess whether the efficacy results reported in the trial translate into effectiveness in routine practice, and to assess comparative safety.

METHODS

We did a population-based network study using data from four US and one UK health-care database, part of the Observational Health Data Sciences and Informatics network. The inclusion criteria were the same as those for TOPKAT; briefly, we identified patients aged at least 40 years with osteoarthritis who had undergone UKR or TKR and who had available data for at least one year prior to surgery. Patients were excluded if they had evidence of previous knee arthroplasty, knee fracture, knee surgery (except diagnostic), rheumatoid arthritis, infammatory arthropathies, or septic arthritis. Opioid use from 91-365 days after surgery, as a proxy for persistent pain, was assessed for all participants in all databases. Postoperative complications (ie, venous thromboembolism, infection, readmission, and mortality) were assessed over the 60 days after surgery and implant survival (as measured by revision procedures) was assessed over the 5 years after surgery. Outcomes were assessed in all databases, except for readmission, which was assessed in three of the databases, and mortality, which was assessed in two of the databases. Propensity score matched Cox proportional hazards models were fitted for each outcome. Calibrated hazard ratios (cHRs) were generated for each database to account for observed differences in control outcomes, and cHRs were then combined using meta-analysis.

FINDINGS

33 867 individuals who received UKR and 557 831 individuals who received TKR between Jan 1, 2005, and April 30, 2018, were eligible for matching. 32 379 with UKR and 250 377 with TKR were propensity score matched and informed the analyses. UKR was associated with a reduced risk of postoperative opioid use (cHR from meta-analysis 0·81, 95% CI 0·73-0·90) and a reduced risk of venous thromboembolism (0·62, 0·36-0·95), whereas no difference was seen for infection (0·85, 0·51-1·37) and readmission (0·79, 0·47-1·25). Evidence was insufficient to conclude whether there was a reduction in risk of mortality. UKR was also associated with an increased risk of revision (1·64, 1·40-1·94).

INTERPRETATION

UKR was associated with a reduced risk of postoperative opioid use compared with TKR, which might indicate a reduced risk of persistent pain after surgery. UKR was associated with a lower risk of venous thromboembolism but an increased risk of revision compared with TKR. These findings can help to inform shared decision making for individuals eligible for knee replacement surgery.

FUNDING

EU/European Federation of Pharmaceutical Industries and Associations Innovative Medicines Initiative (2) Joint Undertaking (EHDEN).

Treatment of first-time traumatic anterior shoulder dislocation: the UK TASH-D cohort study

BACKGROUND

Shoulder dislocations are the most common joint dislocations seen in emergency departments. Most traumatic cases are anterior and cause recurrent dislocations. Management options include surgical and conservative treatments. There is a lack of evidence about which method is most effective after the first traumatic anterior shoulder dislocation (TASD).

OBJECTIVES

To produce UK age- and sex-specific incidence rates for TASD. To assess whether or not surgery within 6 months of a first-time TASD decreases re-dislocation rates compared with no surgery. To identify clinical predictors of recurrent dislocation.

DESIGN

A population-based cohort study of first-time TASD patients in the UK. An initial validation study and subsequent propensity-score-matched analysis to compare re-dislocation rates between surgery and no surgery after a first-time TASD. Prediction modelling was used to identify potential predictors of recurrent dislocation.

SETTING

UK primary and secondary care data.

PARTICIPANTS

Patients with a first-time TASD between 1997 and 2015.

INTERVENTIONS

Stabilisation surgery within 6 months of a first-time TASD (compared with no surgery). Stabilisation surgery within 12 months of a first-time TASD was also carried out as a sensitivity analysis.

MAIN OUTCOME MEASURE

Re-dislocation rate up to 2 years after the first TASD.

METHODS

Eligible patients were identified from the Clinical Practice Research Datalink (CPRD) (1997-2015). Accuracy of shoulder dislocation coding was internally validated using the CPRD General Practitioner questionnaire service. UK age- and sex-specific incidence rates for TASD were externally validated against rates from the USA and Canada. A propensity-score-matched analysis using linked CPRD and Hospital Episode Statistics (HES) data compared re-dislocation rates for patients aged 16-35 years, comparing surgery with no surgery. Multivariable Cox regression models for predicting re-dislocation were developed for the surgical and non-surgical cohorts.

RESULTS

Shoulder dislocation was coded correctly for 89% of cases in the CPRD [95% confidence interval (CI) 83% to 95%], with a 'primary' dislocation confirmed for 76% of cases (95% CI 67% to 85%). Far fewer patients than expected received stabilisation surgery within 6 months of a first TASD, leading to an underpowered study. Around 20% of re-dislocation rates were observed for both surgical and non-surgical patients. The sensitivity analysis at 12 months also showed little difference in re-dislocation rates. Missing data on risk factors limited the value of the prediction modelling; however, younger age, epilepsy and sex (male) were identified as statistically significant predictors of re-dislocation.

LIMITATIONS

Far fewer than the expected number of patients had surgery after a first-time TASD, resulting in an underpowered study. This and residual confounding from missing risk factors mean that it is not possible to draw valid conclusions.

CONCLUSIONS

This study provides, for the first time, UK data on the age- and sex-specific incidence rates for TASD. Most TASD occurs in men, but an unexpected increased incidence was observed in women aged > 50 years. Surgery after a first-time TASD is uncommon in the NHS. Re-dislocation rates for patients receiving surgery after their first TASD are higher than previously expected; however, important residual confounding risk factors were not recorded in NHS primary and secondary care databases, thus preventing useful recommendations.

FUTURE WORK

The high incidence of TASD justifies investigation into preventative measures for young men participating in contact sports, as well as investigating the risk factors in women aged > 50 years. A randomised controlled trial would account for key confounders missing from CPRD and HES data. A national TASD registry would allow for a more relevant data capture for this patient group.

STUDY REGISTRATION

Independent Scientific Advisory Committee (ISAC) for the Medicines and Healthcare Products Regulatory Agency (ISAC protocol 15_0260).

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The limitations of using simple definitions of glucocorticoid exposure to predict fracture risk: A cohort study

PURPOSE

To evaluate the effects of different definitions of glucocorticoid (GC) exposure on the magnitude and pattern of fracture risk using the same dataset.

METHODS

Data from patients with rheumatoid arthritis (RA) were extracted from the Clinical Practice Research Datalink, a primary care database with electronic health records in the United Kingdom. Patients exposed to oral GCs were matched to up to two unexposed patients by age, gender and location. The first osteoporotic fracture was identified and adjusted and unadjusted cox proportional hazard ratios (HR) and 95% confidence intervals (CI) produced for fracture risk following GC therapy using different models of risk attribution. These include models demonstrating the effect of dose, duration and recency of GC exposure.

RESULTS

There were 16,507 patients included. Exposed patients were older and had more comorbidities. GC therapy was associated with an increased risk of fracture, with the effect size influenced by risk attribution model. The risk of fracture decreased with less recent exposure from HR (95% CI) 1.66 (1.27, 2.16) during the first month of stopping GCs to 1.11 (0.79, 1.57) for between 1 and 3 months. The risk of fracture increased with current daily dose, HR 1.44 (1.17, 1.77) for 5-9.9 mg prednisolone equivalent dose (PEQ) to 3.02 (1.77, 5.15) for 15-19.9 mg PEQ. Risk of fracture increased with cumulative dose, a function of dose and duration, from HR 1.22 (1.03, 1.44) for <1 g to 1.83 (1.35, 2.48) for 7.5-10 g.

CONCLUSION

GC exposure was associated with excess fracture risk, with effect size differing according to definition of exposure. This highlights the need to incorporate all exposure dimensions (dose, duration and recency) in these patient's fracture risk assessments.

Bone Phenotype Assessed by HRpQCT and Associations with Fracture Risk in the GLOW Study

The epidemiology and pathogenesis of fractures in postmenopausal women has previously been investigated in the Global Longitudinal study of Osteoporosis in Women (GLOW). To date, however, relationships between bone imaging outcomes and fracture have not been studied in this cohort. We examined relationships between high-resolution peripheral quantitative computed tomography (HRpQCT) parameters and fracture in the UK arm of GLOW, performing a cluster analysis to assess if our findings were similar to observations reported from older participants of the Hertfordshire Cohort Study (HCS), and extended the analysis to include tibial measurements. We recorded fracture events and performed HRpQCT of the distal radius and tibia and dual-energy X-ray absorptiometry (DXA) of the hip in 321 women, mean age 70.6 (SD 5.4) years, identifying four clusters at each site. We saw differing relationships at the radius and tibia. Two radial clusters (3 and 4) had a significantly lower hip areal bone mineral density (p < 0.001) compared to Cluster 1; only individuals in Cluster 4 had a significantly higher risk of fracture (p = 0.005). At the tibia, clusters 1, 3 and 4 had lower hip areal bone mineral density (p < 0.001) compared to Cluster 2; individuals in Cluster 3 had a significantly higher risk of fracture (p = 0.009). In GLOW our findings at the radius were very similar to those previously reported in the HCS, suggesting that combining variables derived from HRpQCT may give useful information regarding fracture risk in populations where this modality is available. Further data relating to tibial HRpQCT-phenotype and fractures are provided in this paper, and would benefit from validation in other studies. Differences observed may reflect age differences in the two cohorts.

A review of the methods used to define glucocorticoid exposure and risk attribution when investigating the risk of fracture in a rheumatoid arthritis population

BACKGROUND

Glucocorticoid therapy is used widely in patients with rheumatoid arthritis (RA) with good efficacy but concerns about safety including fractures. Estimates of fracture risk for any given patient are complicated by the dynamic pattern of glucocorticoid use, where patients vary in their dose, duration and timing of glucocorticoid use.

OBJECTIVE

To investigate which methods are currently used to attribute fractures to glucocorticoid exposure and investigate whether such methods can consider individual treatment patterns.

RESULTS

Thirty-eight studies used five common definitions of risk attribution to glucocorticoid exposure: "current use", "ever use", "daily dose", "cumulative dose" and "time variant". One study attempted to combine multiple definitions where "cumulative dose" was nested within "daily dose", covering the effects of dose and duration but not timing. The majority of results demonstrated an equivocal or increased risk of fracture with increased exposure, although there was wide variation, with odds ratios, hazard ratios and relative risks ranging from 0.16 to 8.16. Within definitions there was also variability in the results with the smallest range for "time variant", 1.07 to 2.8, and the largest for "cumulative dose", ranging from risk estimates of 0.88 to 8.12.

CONCLUSION

Many studies have looked into the effect of glucocorticoids on fracture risk in patients with RA. Despite this, there is no clear consensus about the magnitude of risk. This is a consequence of the varied analysis models and their different assumptions. Moreover, no current analysis method allows consideration of dose, duration and timing of glucocorticoid therapy, preventing a clear understanding of fracture risk for patients and their individual treatment patterns.

Cluster analysis of bone microarchitecture from high resolution peripheral quantitative computed tomography demonstrates two separate phenotypes associated with high fracture risk in men and women

Osteoporosis is a major healthcare problem which is conventionally assessed by dual energy X-ray absorptiometry (DXA). New technologies such as high resolution peripheral quantitative computed tomography (HRpQCT) also predict fracture risk. HRpQCT measures a number of bone characteristics that may inform specific patterns of bone deficits. We used cluster analysis to define different bone phenotypes and their relationships to fracture prevalence and areal bone mineral density (BMD). 177 men and 159 women, in whom fracture history was determined by self-report and vertebral fracture assessment, underwent HRpQCT of the distal radius and femoral neck DXA. Five clusters were derived with two clusters associated with elevated fracture risk. "Cluster 1" contained 26 women (50.0% fractured) and 30 men (50.0% fractured) with a lower mean cortical thickness and cortical volumetric BMD, and in men only, a mean total and trabecular area more than the sex-specific cohort mean. "Cluster 2" contained 20 women (50.0% fractured) and 14 men (35.7% fractured) with a lower mean trabecular density and trabecular number than the sex-specific cohort mean. Logistic regression showed fracture rates in these clusters to be significantly higher than the lowest fracture risk cluster [5] (p<0.05). Mean femoral neck areal BMD was significantly lower than cluster 5 in women in cluster 1 and 2 (p<0.001 for both), and in men, in cluster 2 (p<0.001) but not 1 (p=0.220). In conclusion, this study demonstrates two distinct high risk clusters in both men and women which may differ in etiology and response to treatment. As cluster 1 in men does not have low areal BMD, these men may not be identified as high risk by conventional DXA alone.

Ankle arthrodesis and its relationship to ipsilateral arthritis of the hind- and mid-foot

It has been suggested that arthrodesis of the ankle leads to osteoarthritis of the joints of the ipsilateral hind- and midfoot. We believe these studies overlooked the presence of osteoarthritic changes in these joints before the arthrodesis.

We reviewed the pre-operative radiographs of 70 patients with osteoarthritis of the ankle who underwent 71 ankle arthrodeses (one was bilateral). The talonavicular, calcaneocuboid, subtalar and naviculocuneiform joints were given an osteoarthritis score according to Kellgren and Lawrence. The mean age at operation was 54.9 years and the most common indication was for post-traumatic osteoarthritis (52 cases). A total of 68 patients showed pre-existing arthritis in either the hind- or mid-foot, with the subtalar joint the most commonly affected.

Ipsilateral hind- and mid-foot arthritis is almost universally present in patients with arthritis of the ankle requiring arthrodesis. The presence of such changes may not be a consequence of this arthrodesis.

Arthroscopic ankle arthrodesis

We reviewed 116 patients who underwent 118 arthroscopic ankle arthrodeses. The mean age at operation was 57 years, 2 months (20 to 86 years). The indication for operation was post-traumatic osteoarthritis in 67, primary osteoarthritis in 36, inflammatory arthropathy in 13 and avascular necrosis in two. The mean follow-up was 65 months (18 to 144). Nine patients (10 ankles) died before final review and three were lost to follow-up, leaving 104 patients (105 ankles) who were assessed by a standard telephone interview. The preoperative talocrural deformity was between 22 degrees valgus and 28 degrees varus, 94 cases were within 10 degrees varus/valgus. The mean time to union was 12 weeks (6 to 20). Nonunion occurred in nine cases (7.6%). Other complications included 22 cases requiring removal of a screw for prominence, three superficial infections, two deep vein thromboses/pulmonary emboli, one revision of fixation, one stress fracture and one deep infection. Six patients had a subtalar fusion at a mean of 48 months after ankle fusion. There were 48 patients with excellent, 35 with good, 10 with fair and 11 with poor clinical results.

Arthroscopic treatment of osteochondral lesions of the talus

We reviewed, retrospectively, 65 patients who had undergone arthroscopic treatment for osteochondral lesions of the talus. The 46 men and 19 women with a mean age at operation of 34.25 years, were followed up for a mean of 3.5 years. The medial aspect was affected in 45 patients and the lateral aspect in 20. All the lateral lesions and 35 (75%) of the medial lesions were traumatic in origin. Medial lesions presented later than lateral lesions (3 v 1.5 years) and had a much greater incidence of cystic change (46% v 8%). At follow-up, 34 patients had achieved a good result, and 17 and 14 fair and poor results, respectively. Of the 14 poor results, 13 involved medial lesions. Cystic lesions had a poor outcome in 53% of patients. Excision and curettage led to better results than excision and drilling of the base. Further arthroscopic surgery for patients with a poor result was disappointing. There was no association between outcome and the patient's age.

Toxicity, bioaccumulation and tissue partitioning of dieldrin by the shrimp, Macrobrachium faustinum de Sassure, in fresh and brackish waters of Jamaica

The 2-week no observed effect (NOEC) and lowest observed effect (LOEC) concentrations of dieldrin were determined for Macrobrachium faustinum de Sassure in fresh and brackish waters. LOEC1,10,50,95 values in fresh water were 0.001, 0.003, 0.011 and 0.058 microg l(-1), respectively, and in brackish water, 0.00006, 0.00027, 0.00165, and 0.0172 microg l(-1), respectively. The 96-hr LC10, LC50 and LC95 values were 0.029, 0.123 and 0.771 microg l(-1), respectively. It is proposed that NOEC and LOEC be redefined to take into account the percentage of individuals affected, the severity of symptoms and the recovery of poisoned individuals. Two new terms are proposed--Median Observable Effect Concentration (MOEC) for pronounced toxic symptoms in most individuals but mortality in <50%, and Pronounced Observed Effect Concentration (POEC), which inflicts mortality in >50% individuals. Bioaccumulation of dieldrin by M. faustinum from surrounding fresh and brackish waters were rapid and fairly uniform for the first 48 h when the bioconcentration equilibrium (14.4 +/- 0.42 ng g(-1) at 0.001 microg l(-1) and 42.5 +/- 1.72 ng g(-1) at 0.01 phi g l(-1)) was achieved. Relative partitioning of residues (ng g(-1) wet wt.), after 24h exposure to 0.001 microg l(-1) of dieldrin in fresh water, in the different tissues was hepatopancreas > gonads > gills > large claws > muscle and exoskeleton. Shrimp which had accumulated 10.5 +/- 0.52 ng g(-1) dieldrin in fresh and brackish water, eliminated only about 52% of the residues after eight days in uncontaminated water.

Femoral impaction grafting in revision hip arthroplasty with irradiated bone

We evaluated the results of femoral impaction grafting with the Exeter stem (Stryker Howmedica Osteonics, Newbury, UK) and irradiated bone-graft. We followed 57 hips for an average of 27 months. Endo-Klinik grading showed 8 grade 1, 22 grade 2, and 27 grade 3 hips. Radiographic analysis revealed cortical repair in 34% and graft incorporation in 39% but no evidence of trabecular remodeling. Moderate subsidence (5-10 mm) occurred in 7 patients (12.5%), and massive subsidence (>10 mm) occurred in 4 patients (7%). Complications included 6 dislocations, 3 periprosthetic fractures, and 2 stem revisions. Impaction grafting with the Exeter system produces satisfactory results for most patients, but a few hips perform poorly, and the reasons for this are unclear. We have concerns about irradiated bone-graft because the characteristic changes of graft remodeling are not seen.

Background and framework for ILSI's collaborative evaluation program on alternative models for carcinogenicity assessment. International Life Sciences Institute

The willingness of the agencies involved in the regulation of pharmaceuticals to accept data from newly proposed models for carcinogenicity testing (eg, transgenic animals, neonatal rodent models, initiation-promotion models) has stimulated international interest in gaining experience and a greater understanding of the strengths and limitations of the specific models. Over a 4-year period, the International Life Sciences Institute (ILSI) Health and Environmental Science Institute (HESI) has coordinated a large-scale collaborative research program to help to better characterize the responsiveness of several models proposed for use in carcinogenicity assessment. The overall objective of this partnership among industry, government, and academic scientists was to evaluate the ability of these new models to provide useful information for human cancer risk assessment. This research program reflected a commitment of nearly US$35 million by over 50 industrial, govemment, and academic laboratories from the United States, Europe, and Japan. Evaluation of the models required the development of standardized protocols to allow reproducibility and comparability of data obtained across multiple laboratories. Test compounds were selected on the basis of mechanistically meaningful carcinogenic activity or noncarcinogenicity in the rodent bioassay as well as humans. Criteria were established for dose selection, pathology review, quality control, and for evaluation of study outcome. The database from these studies represents an important contribution to the future application of new models for human cancer risk assessment. Beyond the data, the collaborative process by which the models were evaluated may also represent a prototype for assessing new methods in the future.

Femoral impaction bone grafting with the Elite Plus stem

This study evaluates the results of impaction grafting of the femoral stem with the Elite Plus system (DePuy, Leeds, UK) in revision hip arthroplasty with irradiated allograft. Nineteen hips in 19 patients (12 men and 7 women), at an average age of 59 years were followed for an average of 33 months. Endo-Klinik grading of bone stock loss was 5 grade 1, 6 grade 2, 8 grade 3 and no grade 4. Radiographic analysis revealed evidence of graft incorporation in 32% but no evidence of trabecular remodelling or cortical repair. Four patients have undergone revision of the femoral stem, one patient died while awaiting revision and one patient is unfit for revision. Most complications occurred in patients classified as Endo-Klinik grade 3. We found that impaction grafting with the Elite Plus system was associated with a high failure rate, especially in those cases with more severe bone stock loss. (Hip International 2002; 1: 11-6).

Inactivation of protein farnesyltransferase by active-site-targeted dicarbonyl compounds

Upon farnesylation by protein farnesyltransferase (FTase), key proteins become compartmentalized in cells. For example, cell membrane localization is essential for the mitogenic role of mutant Ras protein, which acts as a switch for cancer cell proliferation. We report that alpha-dicarbonyl compounds derived from the isoprenoid skeleton or other hydrophobic groups potently obstruct farnesylation of a Ras model peptide by human recombinant FTase in vitro. A geranyl-derived isoprenoid diketone, 5,9-dimethyl-8-decene-2,3-dione, at 17 microM caused a 62% reduction in FTase activity after 30 minutes. A farnesyl-derived isoprenoid diketone, 5,9,13-trimethyl-8,12-tetradecadiene-2,3-dione, at 93 microM caused a 94% reduction after 30 minutes. Other dicarbonyl compounds found to be effective against FTase in vitro were (+/-)-6-(camphorquinone-10-sulfonamido)-hexanoic acid, 4,4'-biphenyldiglyoxaldehyde, dehydroascorbic acid 6-palmitate, 2-oxododecanal, and phenylglyoxal. Higher concentrations of the alpha-dicarbonyl compound resulted in more rapid and more extensive inactivation. These findings demonstrate that alpha-dicarbonyl compounds targeted to FTase interfere with protein farnesylation in vitro and may lead to derivatives that have utility as chemotherapeutic agents.

Iliopsoas hematoma with femoral neuropathy presenting a diagnostic dilemma after spinal decompression

STUDY DESIGN

Case report of an iliopsoas hematoma with femoral neuropathy appearing 8 weeks after a posterior spinal decompression procedure.

OBJECTIVES

To describe a potential complication and differential diagnosis for nerve root symptoms following spinal decompression.

SUMMARY OF BACKGROUND DATA

Iliopsoas hematoma is usually a complication of anticoagulation, hemophilia, or trauma. It has not been described previously as a complication of posterior spinal decompression. Femoral neuropathy results from compression within the iliopsoas compartment.

METHODS

A 53-year-old woman reported pain in the right side of her groin and an increasing fixed flexion deformity of the right hip 8 weeks after a posterior, midline, spinal decompression. A femoral neuropathy later developed. Magnetic resonance imaging and computed tomography were performed.

RESULTS

Imaging studies demonstrated a diffusely enlarged iliopsoas. Exploration revealed a large hematoma, which was evacuated. The compartment was fully decompressed with resolution of the nerve root symptoms within 48 hours.

CONCLUSIONS

Iliopsoas pathology is a rare cause of nerve root symptoms and presented diagnostic difficulties after an apparently successful spinal decompression.

Convenient preparation of O-linked polymer-bound N-substituted hydroxylamines, intermediates for synthesis of N-substituted hydroxamic acids

[reaction: see text] An efficient procedure for preparation of O-linked polymer-bound N-substituted hydroxylamines by reduction of resin-bound oximes with borane.pyridine complex in the presence of dichloroacetic acid is reported. Other reducing systems commonly used for imine or oxime reduction were ineffective, including borane.pyridine in the presence of acetic acid. Oximes derived from a variety of aromatic and aliphatic aldehydes and ketones were successfully reduced. The N-substituted products were acylated and cleaved from resin to afford N-substituted hydroxamic acids.

Elastography--the movement begins

The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting very small tissue motions, using natural stimuli. The method could also be applied in the lag (autocorrelation) domain to directly measure the amount of deformation to high accuracy. This method was also applied to measuring the amount of dilatation of blood vessels using both conventional and intravascular ultrasound. A basic limitation of these techniques was the poor spatial resolution, and quasistatic methods soon replaced this method of measuring tissue deformation. However, a new way of assessing the health of tissues had been established.

Lessons learned in applying the U.S. EPA proposed cancer guidelines to specific compounds

An expert panel was convened to evaluate the U.S. Environmental Protection Agency's "Proposed Guidelines for Carcinogen Risk Assessment" through their application to data sets for chloroform (CHCl3) and dichloroacetic acid (DCA). The panel also commented on perceived strengths and limitations encountered in applying the guidelines to these specific compounds. This latter aspect of the panel's activities is the focus of this perspective. The panel was very enthusiastic about the evolution of these proposed guidelines, which represent a major step forward from earlier EPA guidance on cancer-risk assessment. These new guidelines provide the latitude to consider diverse scientific data and allow considerable flexibility in dose-response assessments, depending on the chemical's mode of action. They serve as a very useful template for incorporating state-of-the-art science into carcinogen risk assessments. In addition, the new guidelines promote harmonization of methodologies for cancer- and noncancer-risk assessments. While new guidance on the qualitative decisions ensuing from the determination of mode of action is relatively straightforward, the description of the quantitative implementation of various risk-assessment options requires additional development. Specific areas needing clarification include: (1) the decision criteria for judging the adequacy of the weight of evidence for any particular mode of action; (2) the role of mode of action in guiding development of toxicokinetic, biologically based or case-specific models; (3) the manner in which mode of action and other technical considerations provide guidance on margin-of-exposure calculations; (4) the relative roles of the risk manager versus the risk assessor in evaluating the margin of exposure; and (5 ) the influence of mode of action in harmonizing cancer and noncancer risk assessment methodologies. These points are elaborated as recommendations for improvements to any revisions. In general, the incorporation of examples of quantitative assessments for specific chemicals would strengthen the guidelines. Clearly, any revisions should retain the emphasis present in these draft guidelines on flexibility in the use of scientific information with individual compounds, while simultaneously improving the description of the processes by which these mode-of-action data are organized and interpreted.

Fate and transport of ethoprophos in the Jamaican environment

The hydrolytic half lives of ethoprophos in distilled, river, brackish and open sea water were 25, 133, 65 and 81 days, respectively. Under laboratory conditions, volatilisation of the residues after 12 h was 1.4-3.6, 2.3-4.5 and 6.5-20.2% from a sandy loam soil with 1, 10 and 20% moisture levels, respectively. Photolysis in soil was significantly faster (P < 0.05) in direct sunlight (T1/2 of 4.7 days) than in the shade (T1/2 of 12.3 days). The microbial degradation of ethoprophos was more than two-fold faster in unsterile soil (T1/2 of 10.9 days) than in sterile soil (T1/2 of 28.8 days). The runoff of ethoprophos from unweeded plantation soil at 23 degrees slope was significantly (P = 0.015) less than at 38 degrees slope; the amounts lost after 9 weeks and 27.5 mm of rainfall were 89.4 and 91.2%, respectively, of the applied amount from the two respective slopes. In the weeded plots, 93.6 and 92.4% of the applied insecticide were lost from 23 degrees and 38 degrees slopes, respectively. Under laboratory conditions, between 67.0 and 85.1% of ethoprophos leached through the soil columns. Under field conditions, after 9 weeks and 25 mm of rainfall, only 2.8 and 2.0% residues were recovered at a depth of 10-15 cm from unweeded and weeded slopes, respectively at 23 degrees slope, and 2.2 and 1.9% from the two respective plots at 38 degrees slope.

Mmu and D2 receptor antisense oligonucleotides injected in nucleus accumbens suppress high alcohol intake in genetic drinking HEP rats

Numerous pharmacological and other studies have implicated both Mmu and dopamine receptor subtypes in alcohol consumption. In the genetic drinking rat as well as those chemically induced to drink, evidence has accrued that the abnormal intake of alcohol is underpined by these receptors in the brain. The purpose of this investigation was to demonstrate unequivocally that a biological impairment by antisense oligodeoxynucleotide (ODN) targeted specifically to these two receptor subtypes would disrupt ongoing alcohol drinking. In this project, a new strain of female and male high-ethanol preferring (HEP) rats was used that had free access to preferred concentrations of alcohol over water in a two choice paradigm. A guide cannula for a microinjection needle was first implanted bilaterally above the nucleus accumbens (NAC) of each rat. Following recovery, a dose of either 250 or 500 ng of the Mmu ODN or 500 ng D2ODN was microinjected into the NAC of the rat in a volume of 0.8-1.0 microl. A standard temporal sequence was used in which microinjections were given four times at successive 12-h intervals over a 2-day interval. The control mismatch ODNs corresponding to both the Mmu or D2 receptor antisense were microinjected identically at homologous sites in the NAC. Following the experiments, the brain of each rat was removed and sectioned in the coronal plane for histological analysis so that each microinjection site was identified. The results showed that the Mmu receptor antisense caused a significant dose dependent fall in free access alcohol drinking within 12 to 24 h following the initial microinjection. This decline often persisted for 1 to 2 days in terms of both g/kg intake and proportion of alcohol to water consumed. Similarly, the D2 receptor ODN likewise induced an intense and significant decline in both g/kg and proportion measures of alcohol intake. Since the corresponding mismatch ODN for both Mmu and D2 receptors exerted no effect on either of these measures of alcohol consumption, the specificity of molecular action of the respective antisense molecules on drinking behavior of the HEP rats was confirmed. Thus, these results provide the first unequivocal evidence that the genes for D2 and Mmu receptors are fundamentally involved in abnormal alcohol drinking in the genetically predisposed individual. Finally, important new anatomical evidence is introduced for the critical role of the NAC in the genetic basis of aberrant drinking of alcohol.

Tetrahydropapaveroline injected in the ventral tegmental area shifts dopamine efflux differentially in the shell and core of nucleus accumbens in high-ethanol-preferring (HEP) rats

Since the 1970s tetrahydropapaveroline (THP) and other tetrahydroisoquinoline alkaloids have been implicated in the etiology of alcoholism. When injected into the cerebral ventricle or at specific sites in the mesolimbic system such as the ventral tegmental area (VTA), THP evokes spontaneous and intense intake of alcohol in the nondrinking animal. Further, THP evokes the extracellular efflux of dopamine in the nucleus accumbens (NAC), which comprises, in part, the postulated alcohol drinking "circuit" of neurons. The purpose of this study was to characterize the action of a THP reactive structure, the VTA, on the activity of dopamine and its metabolism in the NAC. In the anesthetized high-ethanol-preferring (HEP) rat, artificial CSF was perfused for 10 min at a rate of 10 microl per min specifically in either the core or shell of the NAC. A microbore push-pull cannula system was selected over a microdialysis probe because of its superior recovery of neurotransmitters and tip exposure of less than 1.0 mm. After a series of 5-min perfusions, a single microinjection of 5.0 microg/microl of THP was made in the ipsilateral VTA while the NAC was perfused simultaneously. Sequential samples of the NAC perfusate were assayed by an HPLC coulometric system to quantitate the concentrations of dopamine and its metabolites, DOPAC and HVA, as well as the 5-HT metabolite, 5-HIAA. The results showed that THP injected in the VTA caused a significant increase by 94 +/- 23% in the efflux of dopamine from the core of the NAC. Conversely, the THP injected identically in the VTA suppressed the efflux of dopamine within the shell of the NAC by 51 +/- 10%. The levels of DOPAC, HVA and 5-HIAA within the core and shell of the NAC generally paralleled the increase and decrease in efflux, respectively, of dopamine. CSF control injections in the VTA as well as injections outside of the VTA failed to alter dopamine or metabolite activity in the NAC. These results demonstrate that the presence of THP in the VTA alters directly the function of the pathway of mesolimbic neurons generally and the dopaminergic system specifically. That such a perturbation could account for the induction of alcohol preference is proposed in relation to a reinforcing mechanism involving opioidergic and dopaminergic elements.

The role of certification in the buyer/planner position: a case study at Harley-Davidson Motor Company

The use of buyer/planners may becoming more popular. If they are, the reason is probably that many companies are integrating materiel management skill sets as a way of increasing the effectiveness of their supply chains. Harley-Davidson recently created a supply management function composed of buyer/planners. This article describes the method it used to achieve the transition, the training plan it implemented to support the process, and the role management played in achieving success.

Genetics of alcoholism: rapid development of a new high-ethanol-preferring (HEP) strain of female and male rats

A genetically based animal model of alcoholism has been developed in a relatively short period of 3 years. The new strain is characterized by an intense preference for ethanol over water as well as unique behavioral, neurochemical and other attributes. This new strain, termed high-ethanol-preferring (HEP) rats, was derived initially from selective cross-breeding of a variant strain of female Harlan Sprague-Dawley (SD) rats with the outbred Wistar line of male ethanol-preferring (P) rats. In this study, drinking patterns of both genders were obtained over 10 days by presenting water and ethanol in concentrations ranging from 3% to 30%. To expedite the development of the new strain, only three to five female and male rats served as breeders, which were chosen from all litters on the basis of their maximum g/kg intake integrated with proportion of ethanol to total fluid values. Profiles of intake of preferred concentrations of ethanol were obtained over 24 h of unlimited access as well as during 2-h intervals of limited access to ethanol. Levels of blood ethanol were measured in both female and male HEP animals during bouts of ethanol drinking in the limited access paradigm. By the sixth generation of HEP rats, ethanol consumption of the females often exceeded that of any other rat genetically bred to drink ethanol (e.g., at a concentration of 15.7%, 10.3 g/kg per day). Seven additional characteristics are notable: 1) the HEP rats prefer ethanol in the presence of a nutritious chocolate drink or nonnutrient sweetened solution (aspartame); 2) high levels of blood ethanol are associated with their drinking; 3) females drink significantly greater g/kg amounts of ethanol than HEP males and prefer a higher percent concentration of ethanol; 4) the drinking of ethanol by the female HEP animals does not fluctuate during the estrous cycle; 5) neurochemical assays show differential profiles of 5-HT, dopamine, and their metabolites in different regions of the brain; 6) measures of activity using the elevated plus maze, open field, and cork gnawing reveal differences between genders of HEP rats and SD rats; and 7) the HEP animals are without phenotypically expressed abnormalities. Finally, one cardinal principle derived from this study revealed that the breeding strategy to develop high-ethanol-drinking rats centers on the use of multiple solutions of ethanol whereby the intakes of ethanol in concentration of 9% through 20% dictate the ultimate selection of breeding pairs over successive F generations. Further, it is concluded that because of an intense rise in ethanol drinking of the F1 generation of female HEP rats well above that of the parental SD female breeders, the complex genotypic characteristic of the male P rat is predominantly responsible for evoking ethanol drinking in female offspring.

Do peroxisome proliferating compounds pose a hepatocarcinogenic hazard to humans?

The purpose of the workshop "Do Peroxisome Proliferating Compounds Pose a Hepatocarcinogenic Hazard to Humans?" was to provide a review of the current state of the science on the relationship between peroxisome proliferation and hepatocarcinogenesis. There has been much debate regarding the mechanism by which peroxisome proliferators may induce liver tumors in rats and mice and whether these events occur in humans. A primary goal of the workshop was to determine where consensus might be reached regarding the interpretation of these data relative to the assessment of potential human risks. A core set of biochemical and cellular events has been identified in the rodent strains that are susceptible to the hepatocarcinogenic effects of peroxisome proliferators, including peroxisome proliferation, increases in fatty acyl-CoA oxidase levels, microsomal fatty acid oxidation, excess production of hydrogen peroxide, increases in rates of cell proliferation, and expression and activation of the alpha subtype of the peroxisome proliferator-activated receptor (PPAR-alpha). Such effects have not been identified clinically in liver biopsies from humans exposed to peroxisome proliferators or in in vitro studies with human hepatocytes, although PPAR-alpha is expressed at a very low level in human liver. Consensus was reached regarding the significant intermediary roles of cell proliferation and PPAR-alpha receptor expression and activation in tumor formation. Information considered necessary for characterizing a compound as a peroxisome proliferating hepatocarcinogen include hepatomegaly, enhanced cell proliferation, and an increase in hepatic acyl-CoA oxidase and/or palmitoyl-CoA oxidation levels. Given the lack of genotoxic potential of most peroxisome proliferating agents, and since humans appear likely to be refractive or insensitive to the tumorigenic response, risk assessments based on tumor data may not be appropriate. However, nontumor data on intermediate endpoints would provide appropriate toxicological endpoints to determine a point of departure such as the LED10 or NOAEL which would be the basis for a margin-of-exposure (MOE) risk assessment approach. Pertinent factors to be considered in the MOE evaluation would include the slope of the dose-response curve at the point of departure, the background exposure levels, and variability in the human response. Copyright 1998 Academic Press.

Do peroxisome proliferating compounds pose a hepatocarcinogenic hazard to humans?

The purpose of the workshop "Do Peroxisome Proliferating Compounds Pose a Hepatocarcinogenic Hazard to Humans?" was to provide a review of the current state of the science on the relationship between peroxisome proliferation and hepatocarcinogenesis. There has been much debate regarding the mechanism by which peroxisome proliferators may induce liver tumors in rats and mice and whether these events occur in humans. A primary goal of the workshop was to determine where consensus might be reached regarding the interpretation of these data relative to the assessment of potential human risks. A core set of biochemical and cellular events has been identified in the rodent strains that are susceptible to the hepatocarcinogenic effects of peroxisome proliferators, including peroxisome proliferation, increases in fatty acyl-CoA oxidase levels, microsomal fatty acid oxidation, excess production of hydrogen peroxide, increases in rates of cell proliferation, and expression and activation of the alpha subtype of the peroxisome proliferator-activated receptor (PPAR-alpha). Such effects have not been identified clinically in liver biopsies from humans exposed to peroxisome proliferators or in in vitro studies with human hepatocytes, although PPAR-alpha is expressed at a very low level in human liver. Consensus was reached regarding the significant intermediary roles of cell proliferation and PPAR-alpha receptor expression and activation in tumor formation. Information considered necessary for characterizing a compound as a peroxisome proliferating hepatocarcinogen include hepatomegaly, enhanced cell proliferation, and an increase in hepatic acyl-CoA oxidase and/or palmitoyl-CoA oxidation levels. Given the lack of genotoxic potential of most peroxisome proliferating agents, and since humans appear likely to be refractive or insensitive to the tumorigenic response, risk assessments based on tumor data may not be appropriate. However, nontumor data on intermediate endpoints would provide appropriate toxicological endpoints to determine a point of departure such as the LED10 or NOAEL which would be the basis for a margin-of-exposure (MOE) risk assessment approach. Pertinent factors to be considered in the MOE evaluation would include the slope of the dose-response curve at the point of departure, the background exposure levels, and variability in the human response.

Chloroform mode of action: implications for cancer risk assessment

Risk assessment methodology, particularly pertaining to potential human carcinogenic risks from exposures to environmental chemicals, is undergoing intense scrutiny from scientists, regulators, and legislators. The current practice of estimating human cancer risk is based almost exclusively on extrapolating the results of chronic, high-dose studies in rodents to estimate potential risk in humans. However, many scientists are questioning whether the logic used in this current risk assessment methodology is the best way to safeguard public health. A major tool of human cancer risk assessment is the linearized multistage (LMS) model. The LMS model has been identified as an aspect of risk assessment that could be improved. One way to facilitate this improvement is by developing a way to incorporate a carefully derived, more biologically relevant mechanism of action data on carcinogenesis. Recent data on chloroform indicate that the dose-response relationship for chloroform-induced tumors in rats and mice is nonlinear, based upon events secondary to cell necrosis and subsequent regeneration as the likely mode of action for the carcinogenic effects of chloroform. In light of these data, there is a sound scientific basis for removing some of the uncertainty that accompanies current cancer risk assessments of chloroform. The following points summarize the critical data: (1) a substantial body of data demonstrates a lack of direct in vivo or in vitro genotoxicity of chloroform; (2) chloroform induces liver and kidney tumors in long-term rodent cancer bioassays only at doses that induce frank toxicity at these target sites; (3) the chloroform doses required to produce tumors in susceptible species exceed the MTD, often by a considerable margin; (4) cytotoxicity and compensatory cell proliferation are associated with the chloroform doses required to induce liver or kidney tumors in susceptible rodent species; (5) there are no instances of chloroform-induced tumors that are not preceded by this pattern of dose-dependent toxic responses; (6) it is biologically plausible that cytolethality leads to chronically stimulated cell proliferation and related events such as inflammation and growth stimulation which act to initiate and promote the carcinogenic process; and (7) the consistently linked cellular events of cytolethality and subsequent cell proliferation, for which doses of no adverse effect have been clearly shown to exist, are one of the biological prerequisites for chloroform-induced tumors in animals. Based on these data, it is inappropriate to extrapolate cancer risk from high doses that produce necrosis and regenerative cell proliferation to low doses that do not with a model that presumes genotoxicity and a linear dose-response relationship. The weight of the scientific evidence concerning chloroform-induced tumors in rodents is consistent with and supports a cancer risk assessment methodology based on mode of action as the basis for establishing regulatory standards for this compound.

A parallelogram approach for safety evaluation of ingested acetaldehyde

Route-specific carcinogenicity data are often lacking for compounds of regulatory importance. Acetaldehyde (AA), for example, a natural constituent in foods, is a rodent carcinogen via the inhalation route, but oral carcinogenicity data are not available. In the absence of such data, a parallelogram approach can be used to estimate the oral carcinogenic potency of this chemical. The relative potency of AA to the structurally related compound formaldehyde (FA) in the nose and the relative potency of FA in the nose and stomach serve as the basis for estimating the potency of AA in the stomach. On a dosimetric basis, inhaled AA is 14- to 35-fold less potent than FA in producing nasal DNA-protein crosslinks (DPX), subchronic tissue injury, and tumors. Ingested AA is also considerably ( approximately 5-fold) less potent than FA in producing gastric injury and DPX. Compared to the nose, the stomach is 10- to 60-fold less sensitive to both AA- and FA-induced DPX and subchronic tissue injury. The parallelogram approach will not supplant long-term oral carcinogenicity studies with AA; however, the consistent pattern of decreased sensitivity of acetaldehyde compared to formaldehyde, lower sensitivity of the stomach to the nose, and the lack of gastric tumorigenicity of orally ingested formaldehyde strongly suggests that ingested acetaldehyde is not likely to be carcinogenic. Successful estimation of the carcinogenic potency of ingested glutaraldehyde, for which chronic oral and inhalation data are available, provides further support that the parallelogram approach can provide a reasonable estimate of the carcinogenic potency of closely related aldehydes, such as AA.

The absorption of oral micronized progesterone: the effect of food, dose proportionality, and comparison with intramuscular progesterone

OBJECTIVES

To examine the effects of food ingestion and administered dose on the absorption of oral micronized P (Utrogestan; Besins-Iscovesco, Paris, France) and to compare the bioavailability of intramuscular versus oral routes of administration.

DESIGN

Prospective, randomized, open label crossover protocol with 7 days between dosages.

SETTING

Academic institution.

PARTICIPANTS

Fifteen normal postmenopausal women.

INTERVENTIONS

All subjects participated in three separate protocols: [1] micronized P (200 mg) or placebo under fasting or nonfasting conditions once daily for 5 days; [2] micronized P (100, 200, or 300 mg) once daily under fasting conditions for 5 days; and [3] micronized P (200 mg) or intramuscular P (50 mg in oil) administered once daily for 2 days.

MAIN OUTCOME MEASURES

Serum P concentrations were measured in all groups.

RESULTS

Concomitant food ingestion increased the area under the serum P concentration versus time curve (AUC0 to 24) and the maximum serum P concentration (Cmax) without affecting time to maximum serum concentration (Tmax) (P < 0.05). Micronized P absorption and elimination were first-order processes and exhibited dose-independent pharmacokinetics between 100 and 300 mg. After intramuscular P, Cmax was higher and Tmax occurred later compared with the oral P preparation. Oral P had lower relative bioavailability (8.6%) than intramuscular P.

CONCLUSIONS

Absorption of micronized P was enhanced twofold in the presence of food. Both absorption and elimination were dose-independent, dose proportionality being confirmed. Bioavailability of the oral P was approximately 10% compared with intramuscular P.

A physiologically based pharmacokinetic model for nicotine and cotinine in man

Physiologically based pharmacokinetic (PBPK) models have been developed describing the disposition kinetics of nicotine and its major metabolite, cotinine, in man. Separate 9-compartment, flow-limited PBPK models were initially created for nicotine and cotinine. The physiological basis for compartment designation and parameter selection has been provided; chemical-specific tissue-to-blood partition coefficients and elimination rates were derived from published human and animal data. The individual models were tested through simulations of published studies of nicotine and cotinine infusions in man using similar dosing protocols to those reported. Each model adequately predicted the time course of nicotine or cotinine concentrations in the blood and urine following the administration of nicotine or cotinine. These individual models were then linked through the liver compartments to form a nicotine-cotinine model capable of predicting the metabolic production and disposition of cotinine from administered nicotine. The potential for integrating this functional PBPK model with an appropriate pharmacodynamic model for the characterization of nicotine's physiological effects is discussed.

The Mental Health Review Board: A New Concept for Difficult Clients

1. The Mental Health Review Board concept is a hospital systems approach to the difficult client. Board membership varies with each case and includes representation from all areas of the hospital. 2. The Review Board deals with clients who have exhausted the system, are threatening or abusive to staff, and noncompliant with treatment recommendations. 3. The Review Board contract is the "final offer" for treatment and is without input from the client. Terms of the contract are nonegotiable. Noncompliance results in discharge and referral elsewhere.

Effects of vehicle supplementation on total estradiol absorption from a transdermal estradiol delivery system

OBJECTIVE

To evaluate the effects of vehicle supplementation on serum estradiol (E2) delivery pharmacokinetics from the Ciba-Geigy (Summit, NJ) 0.1-mg Estraderm Patch.

DESIGN

Postmenopausal women were randomized to a 28-day crossover treatment protocol separated by a 14-day wash out period.

SETTING

Normal human volunteers were studied in an academic research environment.

PATIENTS, PARTICIPANTS

The subject pool included eight healthy postmenopausal women between 32 and 60 years of age.

INTERVENTIONS

In treatment A, a 0.1-mg Estraderm Patch was worn for 7 days; in treatment B, and identical patch was worn into which 0.6 mL of ethanol was injected on day 3 of use.

MAIN OUTCOME MEASURES

Serum E2 levels were measured in both groups.

RESULTS

Although E2 absorption showed characteristic interpatient variability, addition of ethanol significantly extended the mean time for serum E2 levels to return to baseline, without increasing peak absorption. The mean extension was 50 hours.

CONCLUSION

The addition of ethanol to the Estraderm Patch increased the duration of elevated serum E2 levels measured in menopausal women, thus potentially increasing the effective life span of the transdermal therapeutic system.

Pulse-echo ultrasound speed measurements: progress and prospects

The data on the relationship of sound speed to tissue condition, and the development of methods for measurement of sound speed in vivo, are outlined. The methods developed by the authors are discussed. These include methods which use the spatial shift in images of targets viewed from different directions, time-of-flight measurements along incrementally tracked beams and echo tracking during transaxial compression of tissue. The reported sound-speed values are discussed, discrepancies noted and suggestions made on the potential clinical applications of in vivo sound-speed estimation.

Effects of acute administration of diazepam and d-amphetamine on aggressive and escape responding of normal male subjects

Normal males participated in sessions providing two operant response options and were administered either diazepam (study I and II) or d-amphetamine (study II). The acute effects of diazepam on human aggressive responding, which ostensibly subtracted points from another person, were determined in study I. Study II was conducted to determine the extent to which social context and response consequence influenced diazepam (study I) and d-amphetamine (previous research) effects on aggressive responding. In study II, the other response option was escape responding which protected the subject's counter from point losses. Aggressive and escape responding were engendered by subtracting points from the subject's counter, and maintained by initiation of intervals free of point loss. Point subtractions were attributed to the other person (study I) or to a machine (study II). Responding to accumulate points exchangeable for money was available in both studies. Acute diazepam administration decreased aggressive responding in most subjects (study I), slightly increased escape responding (study II), and decreased responding to accumulate points. In study II, d-amphetamine increased both escape responding and responding to accumulate points. The effects of d-amphetamine and diazepam were altered by the instructed source of point loss.

Ultrasound in diagnosis--an Australian perspective

The paper is a personal perspective of the development of diagnostic ultrasound in Australia, outlining some of the contributions from the Ultrasonics Institute. The present status of current technology and applications are briefly described, with some comments on the potential and directions for further development of ultrasonic techniques.