Undertaking multi-centre randomised controlled trials in primary care: learnings and recommendations from the PULsE-AI trial researchers

BACKGROUND

Conducting effective and translational research can be challenging and few trials undertake formal reflection exercises and disseminate learnings from them. Following completion of our multicentre randomised controlled trial, which was impacted by the COVID-19 pandemic, we sought to reflect on our experiences and share our thoughts on challenges, lessons learned, and recommendations for researchers undertaking or considering research in primary care.

METHODS

Researchers involved in the Prediction of Undiagnosed atriaL fibrillation using a machinE learning AlgorIthm (PULsE-AI) trial, conducted in England from June 2019 to February 2021 were invited to participate in a qualitative reflection exercise. Members of the Trial Steering Committee (TSC) were invited to attend a semi-structured focus group session, Principal Investigators and their research teams at practices involved in the trial were invited to participate in a semi-structured interview. Following transcription, reflexive thematic analysis was undertaken based on pre-specified themes of recruitment, challenges, lessons learned, and recommendations that formed the structure of the focus group/interview sessions, whilst also allowing the exploration of new themes that emerged from the data.

RESULTS

Eight of 14 members of the TSC, and one of six practices involved in the trial participated in the reflection exercise. Recruitment was highlighted as a major challenge encountered by trial researchers, even prior to disruption due to the COVID-19 pandemic. Researchers also commented on themes such as the need to consider incentivisation, and challenges associated with using technology in trials, especially in older age groups.

CONCLUSIONS

Undertaking a formal reflection exercise following the completion of the PULsE-AI trial enabled us to review experiences encountered whilst undertaking a prospective randomised trial in primary care. In sharing our learnings, we hope to support other clinicians undertaking research in primary care to ensure that future trials are of optimal value for furthering knowledge, streamlining pathways, and benefitting patients.

Prevalence of Ankle Charcot Neuroarthropathy Presenting in a Tertiary Care Center

Charcot neuroarthropathy's (CN) anatomic classification was originally formulated by the Brodsky article and the Trepman et al modification, including midfoot (type 1), rearfoot (type 2), ankle (type 3a), calcaneus (type 3b), multiarticular (type 4), and forefoot (type 5). In these classic studies, ankle joint and multijoint CN are reported as 9% and 6% to 9%, respectively, but we believe ankle CN to be more common than that in a tertiary setting. We retrospectively reviewed patients presenting initially or as referral between 2004 and 2020. Initial presentation radiographs were reviewed and classified by 3 authors based on Brodsky's model with Trepman and colleagues' modification, and any discrepancies were reviewed by the fourth author. A total of 175 patients (205 feet) were assessed. This revealed 80 cases classified as type 1 (39.0%), 23 cases type 2 (11.2%), 17 cases type 3a (8.3%), 2 cases type 3b (1.0%), and 83 cases type 4 (40.5%). After subdividing type 4, total prevalence included 150 with type 1 anatomic location (73.2%), 103 type 2 (50.2%), 44 type 3a (21.5%), and still 2 type 3b (1.0%). This study revealed a similar prevalence of isolated ankle CN (8.5%) compared to the Trepman et al article (9%), however, in total, ankle CN (21.5%) occurred 2.4-times more than the original 9%. Our study also found there to be a higher prevalence of ankle CN in the setting of multiarticular CN, which has not been evaluated in past studies. The prevalence of multiarticular CN was found to be 4.5-fold greater than the Trepman article (6%-9%).

Population estimates of obstructive and non-obstructive hypertrophic cardiomyopathy in the UK and Germany

Background

While numerous publications have estimated the prevalence of diagnosed hypertrophic cardiomyopathy (HCM), none have quantified the real-world proportion of obstructive and non-obstructive HCM using nationally representative data sources in any European countries.

Purpose

To estimate the prevalence of diagnosed HCM and its subtypes in the UK and Germany.

Methods

Patients with HCM were identified in the UK from 01 Apr 2009 to 30 Oct 2020 and Germany from 2011 to 2019. UK patients with HCM were identified using electronic health records from the Clinical Practice Research Datalink (CPRD) primary care data linked with Hospital Episode Statistics (HES) secondary care data using ICD-10 (I42.1, I42.2), Read, Medcode, SNOMED, and OPCS codes. German patients with HCM were identified using a nationally representative administrative claims data pool (WIG2 Benchmark database) from several German Statutory Health Insurance (SHI)-insurances using ICD-10 and OPS codes. Obstructive HCM was identified as any obstructive HCM diagnosis, any HCM diagnosis with septal reduction therapy, and any HCM diagnosis and left ventricular outflow tract obstruction (LVOTO; not in German claims data). Non-obstructive HCM was any non-obstructive or unspecified HCM diagnosis without evidence of any obstructive HCM. Annual prevalence was calculated for each year in the respective study periods and average annual prevalence across the study period.

Results

The average annual prevalence rate of HCM was 4.15/10,000 in the UK and 8.61/10,000 in Germany, while the average annual prevalence rate of obstructive HCM was 2.84/10,000 in the UK and 4.18/10,000 in Germany (Table). The proportion of HCM that was obstructive HCM was 68% in the UK and 49% in Germany. The prevalence rates of diagnosed HCM and obstructive HCM tended to increase over time (Figure).

Conclusion

The prevalence of HCM, obstructive HCM and the proportion of HCM that is obstructive varied between the UK and Germany. The prevalence of HCM was generally consistent with previously published estimates. Although there are limitations with coding in administrative data, it is important to differentiate obstructive HCM from non-obstructive HCM given their unique treatments and disease progression and management, especially since at least 49–68% of HCM is obstructive.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol Myers-Squibb

Real-world treatment sequencing and survival in previously treated advanced renal cell carcinoma patients receiving nivolumab monotherapy: a UK retrospective cohort study

Background

The CheckMate 025 trial established nivolumab monotherapy as one of the standards of care in previously treated advanced or metastatic renal cell carcinoma (aRCC). However, supporting real-world data is lacking. This study investigated characteristics, treatment sequences and clinical outcomes of patients who received nivolumab monotherapy for previously treated aRCC in the UK.

Methods

This was a retrospective cohort study of aRCC patients treated with nivolumab at second line or later (2L +) at 4 UK oncology centres. Eligible patients commenced nivolumab (index date) between 01 March 2016 and 30 June 2018 (index period). Study data were extracted from medical records using an electronic case report form. Data cut-off (end of follow-up) was 31 May 2019.

Results

In total, 151 patients were included with median follow-up of 15.2 months. Mean age was 66.9 years, male preponderance (72.2%), and mostly Eastern Cooperative Oncology Group performance status grade 0–1 (71.5%). Amongst 112 patients with a known International Metastatic RCC Database Consortium score, distribution between favourable, intermediate, and poor risk categories was 20.5%, 53.6%, and 25.9% respectively.

The majority of patients (n = 109; 72.2%) received nivolumab at 2L, and these patients had a median overall survival (OS) of 23.0 months [95% confidence interval: 17.2, not reached]. All patients who received nivolumab at 2L had received TKIs at 1L. Amongst the 42 patients (27.8%) who received nivolumab in third line or later (3L +) the median OS was 12.4 months [95% CI: 8.8, 23.2]. The most common reasons for nivolumab discontinuation were disease progression (2L: 61.2%; 3L: 68.8%) and adverse events (2L: 34.7%; 3L: 28.1%).

Conclusion

This study provides real-world evidence on the characteristics, treatment sequences, and outcomes of aRCC patients who received 2L + nivolumab monotherapy in the UK. Nivolumab-specific survival outcomes were similar to those achieved in the CheckMate 025 trial.

Identification of undiagnosed atrial fibrillation using a machine learning risk-prediction algorithm and diagnostic testing (PULsE-AI) in primary care: a multi-centre randomized controlled trial in England

Aims

The aim of the PULsE-AI trial was to assess the effectiveness of a machine learning risk-prediction algorithm in conjunction with diagnostic testing for identifying undiagnosed atrial fibrillation (AF) in primary care in England.

Methods and results

Eligible participants (aged ≥30 years without AF diagnosis; n = 23 745) from six general practices in England were randomized into intervention and control arms. Intervention arm participants, identified by the algorithm as high risk of undiagnosed AF (n = 944), were invited for diagnostic testing (n = 256 consented); those who did not accept the invitation, and all control arm participants, were managed routinely. The primary endpoint was the proportion of AF, atrial flutter, and fast atrial tachycardia diagnoses during the trial (June 2019-February 2021) in high-risk participants. Atrial fibrillation and related arrhythmias were diagnosed in 5.63% and 4.93% of high-risk participants in intervention and control arms, respectively {odds ratio (OR) [95% confidence interval (CI)]: 1.15 (0.77-1.73), P = 0.486}. Among intervention arm participants who underwent diagnostic testing (28.1%), 9.41% received AF and related arrhythmia diagnoses [vs. 4.93% (control); OR (95% CI): 2.24 (1.31-3.73), P = 0.003].

Conclusion

The AF risk-prediction algorithm accurately identified high-risk participants in both arms. While the proportions of AF and related arrhythmia diagnoses were not significantly different between high-risk arms, intervention arm participants who underwent diagnostic testing were twice as likely to receive arrhythmia diagnoses compared with routine care. The algorithm could be a valuable tool to select primary care groups at high risk of undiagnosed AF who may benefit from diagnostic testing.

Identification of undiagnosed atrial fibrillation using a machine learning risk prediction algorithm and diagnostic testing (PULsE-AI) in primary care: cost-effectiveness of a screening strategy evaluated in a randomized controlled trial in England

OBJECTIVE

The PULsE-AI trial sought to determine the effectiveness of a screening strategy that included a machine learning risk prediction algorithm in conjunction with diagnostic testing for identification of undiagnosed atrial fibrillation (AF) in primary care. This study aimed to evaluate the cost-effectiveness of implementing the screening strategy in a real-world setting.

METHODS

Data from the PULsE-AI trial - a prospective, randomized, controlled trial conducted across six general practices in England from June 2019 to February 2021 - were used to inform a cost-effectiveness analysis that included a hybrid screening decision tree and Markov AF disease progression model. Model outcomes were reported at both individual- and population-level (estimated UK population ≥30 years of age at high-risk of undiagnosed AF) and included number of patients screened, number of AF cases identified, mean total and incremental costs (screening, events, treatment), quality-adjusted-life-years (QALYs), and incremental cost-effectiveness ratio (ICER).

RESULTS

The screening strategy was estimated to result in 45,493 new diagnoses of AF across the high-risk population in the UK (3.3 million), and an estimated additional 14,004 lifetime diagnoses compared with routine care only. Per-patient costs for high-risk individuals who underwent the screening strategy were estimated at £1,985 (vs £1,888 for individuals receiving routine care only). At a population-level, the screening strategy was associated with a cost increase of approximately £322 million and an increase of 81,000 QALYs. The screening strategy demonstrated cost-effectiveness versus routine care only at an accepted ICER threshold of £20,000 per QALY-gained, with an ICER of £3,994/QALY.

CONCLUSIONS

Compared with routine care only, it is cost-effective to target individuals at high risk of undiagnosed AF, through an AF risk prediction algorithm, who should then undergo diagnostic testing. This AF risk prediction algorithm can reduce the number of patients needed to be screened to identify undiagnosed AF, thus alleviating primary care burden.

Real-world treatment patterns and overall survival in previously treated advanced renal cell carcinoma patients receiving nivolumab in the UK

e16561

Background: CheckMate 025 demonstrated favorable efficacy and safety results for nivolumab monotherapy in previously treated advanced or metastatic renal cell carcinoma (aRCC). However, real-world evidence on treatment patterns and clinical outcomes is limited. Methods: This multi-centre, retrospective cohort study examined treatment patterns and overall survival (OS) in aRCC patients treated with nivolumab monotherapy. Eligible patients who initiated nivolumab at second-line (2L) or beyond (index) between 01 March 2016 and 30 June 2018 were sampled from four UK centers. Data were extracted using an electronic case report form from index to earliest of: most recent visit; death; end of follow up (31 May 2019). Results: Overall , 151 patients were included in analyses (mean age at index 66.9 years, 72.2% male, median follow-up from index 15.2 months), with 109 (72.2%) and 42 (27.8%) receiving nivolumab at 2L and ≥ third-line (3L+), respectively. Key clinical characteristics are outlined in Table 1. All 2L nivolumab patients had received first-line (1L) tyrosine kinase inhibitors (TKI), pazopanib (57.8%), sunitinib (30.3%), or both in sequence (10.1%). After 2L nivolumab, 3L cabozantinib (36/52, 69.2%) was most common. Most 3L nivolumab patients received 2L TKI (31/36, 86.1%) - commonly axitinib (70.9%). After 3L nivolumab, most patients received fourth-line cabozantinib (8/12, 66.7%). Median time on line of therapy (LOT) decreased with LOT progression: from 7.8 months at 1L to 4.6 months at fifth-line (5L). The proportion of patients who discontinued treatment due to adverse events decreased by LOT, (28.6%, 22.7%, 16.0% and 0%, and 34.7%, 28.1%, 0% and 0% from 2L to 5L, overall and for nivolumab treatment, respectively). Overall, median OS from nivolumab initiation was 19.2 months [95% CI, 16.9-27.0]. Patients who received 2L nivolumab had longest median OS (23.0 months [95% CI, 17.2, not reached]), comparable to CheckMate 025 (25.8 months [95% CI, 22.2-29.8]). Median OS for 3L+ nivolumab patients was 12.4 months [95% CI, 8.8, 23.2]. Among 2L nivolumab patients, 73.9%, 46.2%, and 33.6% survived 12, 24, and 36 months, respectively. For the same respective timeframes, 52.4%, 24.7%, and 18.6% of 3L+ nivolumab patients survived. Conclusions: This study provides real-world evidence on the characteristics, treatment patterns and effectiveness of 2L or ≥ 3L nivolumab monotherapy in previously treated aRCC patients. OS results from UK routine clinical care were comparable to those found in CheckMate 025.[Table: see text]

Bronchiectasis is associated with delayed diagnosis and adverse outcomes in the New Zealand Common Variable Immunodeficiency Disorders cohort study

Common variable immunodeficiency disorders (CVID) are multi-system disorders where target organ damage is mediated by infective, autoimmune and inflammatory processes. Bronchiectasis is probably the most common disabling complication of CVID. The risk factors for bronchiectasis in CVID patients are incompletely understood. The New Zealand CVID study (NZCS) is a nationwide longitudinal observational study of adults, which commenced in 2006. In this analysis, the prevalence and risk factors for bronchiectasis were examined in the NZCS. After informed consent, clinical and demographic data were obtained with an interviewer-assisted questionnaire. Linked electronic clinical records and laboratory results were also reviewed. Statistical methods were applied to determine if variables such as early-onset disease, delay in diagnosis and increased numbers of infections were associated with greater risk of bronchiectasis. One hundred and seven adult patients with a diagnosis of CVID are currently enrolled in the NZCS, comprising approximately 70% of patients known to have CVID in New Zealand. Fifty patients (46·7%) had radiologically proven bronchiectasis. This study has shown that patients with compared to those without bronchiectasis have an increased mortality at a younger age. CVID patients with bronchiectasis had a greater number of severe infections consequent to early-onset disease and delayed diagnosis. Indigenous Māori have a high prevalence of CVID and a much greater burden of bronchiectasis compared to New Zealand Europeans. Diagnostic latency has not improved during the study period. Exposure to large numbers of infections because of early-onset disease and delayed diagnosis was associated with an increased risk of bronchiectasis. Earlier diagnosis and treatment of CVID may reduce the risk of bronchiectasis and premature death in some patients.

Risk factors associated with the incidence and recurrence of hyperkalaemia in patients with cardiorenal conditions

INTRODUCTION

Hyperkalaemia (HK) is associated with increased mortality risk. Prior studies suggest that the causes of HK are multifactorial. This study aimed to examine risk factors for incident and recurrent HK in six large real-world cohorts of UK patients that could be considered at elevated HK risk because of underlying disease pathology and/or medication use.

METHODS

This retrospective, observational cohort study utilised UK primary and secondary care data from Clinical Practice Research Datalink (CPRD) and linked Hospital Episode Statistics (HES), respectively. Patients were included if they were aged ≥18 years and had a record of ≥1 condition of interest (chronic kidney disease [CKD] stage 3+, heart failure, resistant hypertension [RHTN], dialysis, diabetes) and/or renin-angiotensin-aldosterone system inhibitors (RAASi) use between 01 January 2003 and 30 June 2018. Based on their diagnosis/ RAASi prescription record, patients were assigned to overlapping cohorts. The outcomes assessed were HK and recurrent HK, the latter defined as second or subsequent HK episode during follow-up. HK was defined as a serum K⁺ measurement ≥5.0 mmol/L; thresholds of ≥5.5 and ≥ 6.0 mmol/L were also explored.

RESULTS

Of 931 460 meeting the eligibility criteria, 310 535 (33.3%) patients experienced ≥1 HK event and 187 719 (20.2%) experienced HK recurrence. The probability of subsequent HK events increased with event number from 60.5% for the second event to 76.5% for the sixth and the corresponding time to the next HK event decreased from 15.8 months to 6.1 months. Amongst the key risk factors, serum creatinine, serum phosphorus, systolic blood pressure, and white cell count demonstrated direct relationships with incidence and recurrence of HK, while inverse relationships were observed for estimated glomerular filtration rate (eGFR), haemoglobin and diastolic blood pressure. The relationship for Charlson's Comorbidity Index was mixed. The use of RAASi and anti-hyperglycaemic agents was associated with an increased risk of HK, while the use of diuretics (non-K⁺ -sparing) was protective against HK.

CONCLUSION

Several risk factors for HK that are easily measured in routine clinical practice were identified, facilitating the identification of patients who are at the highest risk of experiencing HK, including recurrent HK.

Outcomes in rheumatoid arthritis patients treated with abatacept: a UK multi-centre observational study

BACKGROUND

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease that causes chronic synovitis, resulting in progressive joint destruction and functional disability and affects approximately 400,000 people in the UK. This real-world study aimed to describe the characteristics, treatment patterns and clinical outcomes of patients who received abatacept in UK clinical practice.

METHODS

This was a multi-centre, retrospective, observational study of patients with RA treated with abatacept at four UK centres between 01 January 2013 and 31 December 2017. Data were collected from medical records of each patient from the index date (date of first bDMARD initiation) until the most recent visit, death or end of study (31 December 2017).

RESULTS

In total, 213 patients were included in the study. Patients received up to eight lines of therapy (LOTs). Treatment with abatacept, or any other bDMARD, was associated with reductions in DAS28-ESR and DAS28-CRP scores at 6 and 12 months. The distribution of EULAR responses (good/moderate/no response) tended to be more favourable for patients when receiving abatacept than when receiving other bDMARDs (22.8%/41.3%/35.9% versus 16.6%/41.4%/42.1% at 6 months, and 27.9%/36.1%/36.1% versus 21.2%/34.5%/44.2% at 12 months). Patients receiving abatacept at LOT1 (n = 68) spent significantly longer on treatment compared with patients receiving other bDMARDs (53.4 vs. 17.4 months; p< 0.01); a similar trend was observed for LOT2. Among patients who discontinued after 6 months, a greater proportion experienced infection requiring antibiotics when receiving other bDMARDs compared to those receiving abatacept.

CONCLUSIONS

RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. When receiving abatacept as first or second line of therapy, patients persisted with treatment significantly longer than those receiving other bDMARDs.

The relationship between duration of heart failure, serum potassium concentration and adverse clinical outcomes

Background

Hyper- and hypokalaemia are frequent complications in patients with heart failure (HF). The association between all-cause mortality (ACM), major adverse cardiovascular events (MACE) and serum potassium (K+) has previously been characterised in a UK incident HF population, with hypo- and hyperkalaemic patients being at increased risk of adverse clinical outcomes.

Purpose

This study aimed to assess the generalisability and findings of previously published risk equations in a broader HF population, spanning both incident and prevalent HF cases regardless of chronic kidney disease (CKD), and to explore the relationship between duration of HF and elevated risk associated with hypo- or hyperkalaemia.

Methods

A retrospective cohort study was conducted using linked UK Clinical Practice Research Datalink (CPRD) GOLD and Hospital Episode Statistics (HES) data. Eligible patients included individuals ≥18 years with HF (identified using READ codes) during the study period (January 2008 to June 2018) or five-year lookback period (2003 to 2007). Patients' index date was set to 1st January 2008 for prevalent patients or date of HF diagnosis for incident patients. Adverse clinical outcomes included ACM and MACE, a composite of arrhythmia, HF, myocardial infarction and stroke. Published risk equations for ACM and MACE for incident HF without CKD were refitted to this broader study population using original covariates and model forms. Coefficient values were adjusted for the inclusion of HF duration (≤5 and &gt;5 years). Incidence rate ratios (IRRs) were recalculated with K+ concentration 4.5 to &lt;5.0 mmol/L as the reference category.

Results

The HF cohort consisted of 84,210 patients with a mean follow-up of 5.01 years. The cohort was predominantly male (53.0%), with a mean age of 77.3 years at index. Ischaemic heart disease, hypertension, atrial fibrillation and type 2 diabetes were present in 42.24%, 61.39%, 40.89% and 20.38% of the population, respectively. CKD stage 3+ was present in 39.13% of patients, with a cohort mean estimated glomerular filtration rate of 56.9 mL/min/1.73m2 at index. Crude ACM and MACE event rates were 159.5 (95% confidence interval (CI): 157.9–161.0) and 575.8 (95% CI: 572.8–578.7) per 1,000 patient years, respectively. Hypo- and hyperkalaemia were generally associated with increased risk of ACM and MACE in comparison with patients with K+ concentrations of 4.5 to &lt;5.0 mmol/L (figure 1); these associations were maintained irrespective of the duration of HF.

Conclusion

A real-world analysis of UK patients suggests that previously published associations between hypo- and hyperkalaemia and increased risk of adverse clinical outcomes in an incident HF population are generalisable to a cohort of incident and prevalent HF patients, irrespective of HF duration and the presence of comorbid CKD. Improved monitoring and management of K+ may have the potential to improve outcomes in these patients.

Figure 1. IRRs of ACM and MACE

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): AstraZeneca

Assessing the relationship between serum potassium variability and the risk of hyperkalaemia and adverse clinical outcomes

Background

Serum potassium (SK+) is a vital electrolyte, which level is maintained by adjusting renal K+ excretion. Variability in SK+ has been linked to increased risk of mortality and other adverse clinical events in patients in intensive care and/or receiving haemodialysis, prompting a similar investigation in cardiovascular patients.

Purpose

To examine the effect of SK+ variability on all-cause mortality (ACM) and the incidence of major adverse cardiovascular events (MACE), comprising arrhythmia, [subsequent records of] HF, myocardial infarction, or stroke, in patients with heart failure (HF) or resistant hypertension (RHTN).

Methods

Patients aged ≥18 years with HF or RHTN were identified from the UK Clinical Practice Research Datalink (CPRD, primary care data) and linked Hospital Episode Statistics (HES, secondary care data). HF and RHTN were defined through READ codes recorded during the study period (2008-June 2018) or the five-year look-back period (2003–2007). Index date was set to 1st January 2008 or initial diagnosis; whichever occurred later. Mean SK+ and variability of measurements (quantified as standard deviation [SD] and each patient categorised as low or highly variable based on the median SD of the cohort), and crude incidence rates of ACM and MACE were estimated over a follow-up period from index date to event or end of follow-up (death, loss to follow-up or end of study, whichever was earlier).

Results

The eligible population included 317,135 RHTN patients and 84,210 HF patients with a mean follow-up of 6.37 (SD 3.06) and 5.01 (SD 3.20) years, respectively. In both cohorts, higher mean SK+ ≥5.0 mmol/L was associated with increased rates of ACM and MACE relative to a mean SK+ of 3.5–5 mmol/L (Table 1). High SK+ variability was associated with increased incidence of adverse outcomes, with rates consistently higher in the high SK+ variability group compared to low-variability patients with the same diagnosis and mean SK+ category (Table 1); all comparisons were statistically significant except for ACM in HF patients with mean SK+ ≥5 mmol/L.

Conclusion

Independently of mean SK+, increased variability in SK+ levels was associated with an increased rate of mortality and MACE in patients with RHTN or HF. Careful SK+ monitoring and management to maintain SK+ concentrations may improve the outcomes of patients with RHTN and HF.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): AstraZeneca

Estimating the burden of hyperkalaemia in the UK in high-risk patient populations

Background

Patients with chronic kidney disease (CKD), heart failure (HF), resistant hypertension (RHTN) and diabetes are at an increased risk of hyperkalaemia (HK) which can be potentially life-threatening, as a result of cardiac arrhythmias, cardiac arrest leading to sudden death. In these patients, renin-angiotensin-aldosterone system inhibitors (RAASi), are used to manage several cardiovascular and renal conditions, and are associated with an increased risk of HK. Assessing the burden of HK in real-world clinical practice may concentrate relevant care on those patients most in need, potentially improving patient outcomes and efficiency of the healthcare system.

Purpose

To assess the burden of HK in a real-world population of UK patients with at least one of: RHTN, Type I or II diabetes, CKD stage 3+, dialysis, HF, or in receipt of a prescription for RAASi.

Methods

Primary and secondary care data for this retrospective study were obtained from the UK Clinical Practice Research Datalink (CPRD) and linked Hospital Episode Statistics (HES). Eligible patients were identified using READ codes defining the relevant diagnosis, receipt of indication-specific medication, or, in the case of CKD, an estimated glomerular filtration rate (eGFR) ≤60 ml/min/1.73m2 within the study period (01 January 2008 to 30 June 2018) or in the five-year lookback period (2003–2007). The index date was defined as 01 January 2008 or first diagnosis of an eligible condition or RAASi prescription, whichever occurred latest. HK was defined as K+ ≥5.0 mmol/L; thresholds of ≥5.5 mmol/L and ≥6.0 mmol/L were explored as sensitivity analyses. Incidence rates of HK were calculated with 95% confidence intervals (CI).

Results

The total eligible population across all cohorts was 931,460 patients. RHTN was the most prevalent comorbidity (n=317,135; 34.0%) and dialysis the least prevalent (n=4,415; 0.5%). The majority of the eligible population were prescribed RAASi during follow-up (n=754,523; 81.0%). At a K+ threshold of ≥5.0 mmol/L, the dialysis cohort had the highest rate of HK (501.0 events per 1,000 patient-years), followed by HF (490.9), CKD (410.9), diabetes (355.0), RHTN (261.4) and the RAASi cohort (211.2) (Figure 1). This pattern was still observed at alternative threshold definitions of HK.

Conclusion

This large real-world study of UK patients demonstrates the burden of hyperkalaemia in high-risk patient populations from the UK. There is a need for effective prevention and treatment of HK, particularly in patients with CKD, dialysis or HF where increased incidence rates are observed which in turn will improve patient outcomes and healthcare resource usage.

Figure 1. Rates of HK by condition

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): AstraZeneca

Serum Potassium As A Predictor Of Adverse Clinical Outcomes In Patients With Increasing Comorbidity Burden

Aims

The aim of this study was to establish whether patients with multiple comorbidities may be at elevated risk of hyperkalaemia (HK), a potentially life-threatening electrolyte imbalance, and the associated adverse clinical outcomes.

Methods and results

This was a retrospective, observational cohort study using UK primary and secondary care data. Adult patients with at least one of: resistant hypertension, chronic kidney disease stage 3+, dialysis, heart failure (HF), and diabetes, were eligible for inclusion. According to their diagnoses, patients were grouped into overlapping cohorts that were updated as multimorbidity progressed. Outcomes of interest were incident HK, all-cause mortality (ACM), and major adverse cardiovascular events (MACE). A total of 673 686 patients met the eligibility criteria, 36.3% of whom developed multimorbidity during the study period. A consistent U-shaped association was observed between serum K⁺ level and adjusted incidence of ACM and MACE. Hyperkalaemia was progressively more common with increasing Charlson Comorbidity Index (CCI). Relative to a CCI <3, scores of ≥3 to <6, and ≥6 were associated with 2.9- and 6.2-fold increases, respectively, in crude HK (serum K⁺ ≥5.0 mmol/L) incidence rate. In all condition-based cohorts except for HF, there was a clear correlation between increasing CCI and the risk of ACM and MACE associated with hypokalaemia and HK.

Conclusion

Patients with a higher CCI are at an increased risk of developing HK and appear more prone to adverse clinical outcomes associated with abnormal serum K⁺ levels, warranting additional routine clinical monitoring.

Identification of undiagnosed atrial fibrillation patients using a machine learning risk prediction algorithm and diagnostic testing (PULsE-AI): Study protocol for a randomised controlled trial

Atrial fibrillation (AF) is associated with an increased risk of stroke, enhanced stroke severity, and other comorbidities. However, AF is often asymptomatic, and frequently remains undiagnosed until complications occur. Current screening approaches for AF lack either cost-effectiveness or diagnostic sensitivity; thus, there is interest in tools that could be used for population screening. An AF risk prediction algorithm, developed using machine learning from a UK dataset of 2,994,837 patients, was found to be more effective than existing models at identifying patients at risk of AF. Therefore, the aim of the trial is to assess the effectiveness of this risk prediction algorithm combined with diagnostic testing for the identification of AF in a real-world primary care setting. Eligible participants (aged ≥30 years and without an existing AF diagnosis) registered at participating UK general practices will be randomised into intervention and control arms. Intervention arm participants identified at highest risk of developing AF (algorithm risk score ≥ 7.4%) will be invited for a 12‑lead electrocardiogram (ECG) followed by two-weeks of home-based ECG monitoring with a KardiaMobile device. Control arm participants will be used for comparison and will be managed routinely. The primary outcome is the number of AF diagnoses in the intervention arm compared with the control arm during the research window. If the trial is successful, there is potential for the risk prediction algorithm to be implemented throughout primary care for narrowing the population considered at highest risk for AF who could benefit from more intensive screening for AF. Trial Registration: NCT04045639.

Treatment patterns and health outcomes in metastatic renal cell carcinoma patients treated with targeted systemic therapies in the UK

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) treated with targeted systemic therapies have demonstrated favourable outcomes in randomised controlled trials, however real-world evidence is limited. Thus, this study aimed to determine the effectiveness of targeted systemic therapies for patients with mRCC in routine clinical practice in the UK.

METHODS

A retrospective, observational, longitudinal study based on chart review of newly diagnosed adult mRCC patients treated at two UK hospitals from 2008 to 2015 was conducted. Targeted systemic therapies recommended for use in mRCC patients were evaluated across first to third lines of therapy (1LOT-3LOT). Important exclusions were treatment with cytokine therapy and within non-standard of care clinical trials. Primary outcome measure was overall survival (OS); data were analysed descriptively and using Kaplan-Meyer analysis.

RESULTS

652 patients (65.3% male, 35.0% ≥70 years) were included. In 1LOT, 98.5% of patients received sunitinib or pazopanib. In 2LOT and 3LOT, 99.0 and 94.4% received axitinib or everolimus. Median OS was 12.9, 6.5 and 5.9 months at 1LOT, 2LOT and 3LOT respectively. Estimated OS at 1-year was 52.4% (95% CI: 48.6-56.4%) in 1LOT, 31.5% (25.2-39.5%) in 2LOT and 23.8% (10.1-55.9%) in 3LOT. Median OS from 1LOT in favourable, intermediate and poor MSKCC were 39.7, 15.8 and 6.1 months respectively.

CONCLUSIONS

In this study, treatment was consistent with current National Institute for Health and Care Excellence (NICE) guidelines for mRCC patients. Although the study population favoured poorer prognosis patients, outcomes were more favourable than those for England at the same time. However, overall survival in this 'real-world' population remains poor and indicates significant unmet need for effective and safe treatment options to improve survival among mRCC patients.

AB0295 CHANGE IN DISEASE ACTIVITY AND TREATMENT RESPONSE AFTER ABATACEPT TREATMENT FOR RHEUMATOID ARTHRITIS: REAL-WORLD EVIDENCE FROM THE UK

Background:

Patients with moderate to severe active rheumatoid arthritis (RA) may be treated with biological disease-modifying antirheumatic drugs (bDMARDs), such as abatacept, after treatment failure with conventional synthetic DMARDs (csDMARDs). Abatacept has shown equivalent efficiency with other targeted therapies for RA in clinical trials and network meta-analyses. However, there is limited real-world evidence on patient outcomes associated with abatacept treatment in UK routine clinical practice.

Objectives:

To describe the clinical outcomes of RA patients treated with abatacept in UK real-world clinical practice.

Methods:

A multi-centre, retrospective observational study was undertaken in RA patients treated with abatacept at any line of therapy (LOT). Data were extracted from medical records at four UK hospitals. Patients aged 18 years or older who received abatacept between 1 January 2013 and 31 December 2017 were included. The index date was the date of first bDMARD initiation, with follow-up from index date to latest RA clinic visit, death or 31 December 2017, whichever occurred first.

Clinical outcomes (disease activity and response to treatment) were measured using the 28-joint Disease Activity Score based on erythrocyte sedimentation rate (DAS28-ESR) and European League Against Rheumatism (EULAR) response criteria1-3.

Results:

The study included 213 patients (mean age 55.2 years, 71.4% female, 7.0 years mean duration of RA at index date). Where ACPA and RF status were recorded, 66.1% of patients were anti-citrullinated protein antibodies (ACPA) and rheumatoid factor (RF) positive at index. Mean DAS28-ESR at index was 6.2 (SD 1.0) and 80.9% of patients were categorised with high disease activity.

Irrespective of LOT, changes in DAS28-ESR (where recorded) from LOT initiation among patients treated with abatacept versus other bDMARDs were -1.59 vs -1.56 (LS mean (SE): -0.04; 95% CI: -0.45,0.38; p=0.86) at 6 months and -1.98 vs -1.42 (LS mean (SE): -0.56; 95% CI: -1.04,-0.07; p=0.03) at 12 months, respectively. Table 1 shows that compared with other bDMARDs, patients treated with abatacept at any LOT experienced good response to treatment at 6 months (22.8%, n= 21/92 vs 15.9%, n= 24/151) and 12 months (27.9%, n= 17/61 vs 20.5%, n= 24/117) according to EULAR criteria.

Table1.

Treatment response at 6 and 12 months after initiation of any LOT*

EULAR response6 months12 monthsAbatacept,n = 92Other bDMARDs,n = 151Abatacept,n = 61Other bDMARDs,n = 117Good21 (22.8%)24 (15.9%)17 (27.9%)24 (20.5%)Moderate38 (41.3%)60 (39.7%)22 (36.1%)40 (34.2%)None33 (35.9%)67 (44.4%)22 (36.1%)53 (45.3%)

n = number of unique LOTs in which a patient has both a DAS28-ESR collected at initiation and 6 and/or 12 months (a patient may be included in this analysis multiple times)

Patients who received abatacept remained on treatment for significantly longer than patients who received other bDMARDs at LOT1 (median 53.4 vs 17.4 months; p<0.01) (Figure 1) and at LOT2 (median 40.1 vs 17.1 months; p<0.01).

Figure 1.

Time on treatment from first LOT initiation, abatacept versus other bDMARDs

Conclusion:

RA patients who received bDMARDs, including abatacept, experienced reduced disease activity. These findings are comparable with those from a European, multicentre, observational study on patients receiving abatacept4. The mechanisms associated with such clinical benefit should be elucidated in future research.

References:

[1]Prevoo et al. Arthritis Rheum 1995;38:44–8.

[2]Fransen & van Riel. Clin Exp Rheumatol 2005;23:S93–9.

[3]van Gestel et al. Arthritis Rheum 1998;41:1845–50.

[4]Alten et al. Clin Rheumatol (2019) 38: 1413.

Acknowledgments:

Yusuf Patel

Srinivasan Venkatachalam

James Maxwell

Usman Farooqui

Kevin Pollock

Disclosure of Interests:

Sadie Henning Shareholder of: Sadie Henning is a shareholder for Bristol-Myers Squibb Pharmaceuticals Ltd., Employee of: Sadie Henning is employed by Bristol-Myers Squibb Pharmaceuticals Ltd., Lara Groves Grant/research support from: Lara Groves is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Michael Hurst Grant/research support from: Michael Hurst is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Daniel Sugrue Grant/research support from: Daniel Sugrue is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Jason Gordon Grant/research support from: Jason Gordon is an employee of Health Economics and Outcomes Research Ltd., Cardiff, UK, who received fees from Bristol-Myers Squibb Pharmaceuticals Ltd in relation to this study., Ernest Choy Grant/research support from: Amgen, Bio-Cancer, Chugai Pharma, Ferring Pharmaceuticals, Novimmune, Pfizer, Roche, UCB, Consultant of: AbbVie, Amgen, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Chelsea Therapeutics, Chugai Pharma, Daiichi Sankyo, Eli Lilly, Ferring Pharmaceuticals, GlaxoSmithKline, Hospita, Ionis, Janssen, Jazz Pharmaceuticals, MedImmune, Merck Sharp & Dohme, Merrimack Pharmaceutical, Napp, Novartis, Novimmune, ObsEva, Pfizer, R-Pharm, Regeneron Pharmaceuticals, Inc., Roche, SynAct Pharma, Sanofi Genzyme, Tonix, UCB, Speakers bureau: Amgen, Boehringer Ingelheim, Bristol-Myers Squibb, Chugai Pharma, Eli Lilly, Hospira, Merck Sharp & Dohme, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc., Roche, Sanofi-Aventis, UCB

P0671THE ASSOCIATION BETWEEN HYPERKALAEMIA RISK AND CARDIOVASCULAR AND RENAL COMORBIDITIES IN A LARGE REAL-WORLD COHORT OF CKD PATIENTS

Background and Aims

Approximately 275.9 million people globally and 5.6 million people in the UK are living with chronic kidney disease (CKD). The risk of hyperkalaemia (HK) is elevated in CKD due to renal impairment and may increase further upon treatment with renin-angiotensin-aldosterone system inhibitors, which are commonly used in many cardiovascular and renal conditions. This study aimed to assess the relationship between comorbidity burden and HK risk in a large cohort of UK CKD patients.

Method

Primary and secondary care data from the UK Clinical Practice Research Datalink (CPRD) and linked Hospital Episode Statistics (HES) were used to identify patients aged ≥18 years who had a diagnosis of stage 3+ CKD (identified as either a READ code for non-dialysis CKD stage 3+ or an estimated glomerular filtration rate (eGFR) &lt;60 mL/min/1.73m2 without a prior READ code for dialysis) during the study period (2008–June 2018) or the five-year look-back period (2003–2007). Patient’s index date was 1st January 2008 or the first date of CKD diagnosis, whichever occurred later. Diagnoses based on the presence of READ codes were used to define the accumulation of further cardiovascular or renal comorbidities of interest (resistant hypertension, heart failure, diabetes or dialysis-dependent CKD). The incidence of HK was defined as serum potassium (K+) thresholds of ≥5.0, ≥5.5 and ≥6.0 mmol/L.

Results

In total, 297,702 eligible patients had a CKD diagnosis during the study or look back periods and their mean follow-up was 5.6 (SD 3.2) years from index date. At baseline, mean age was 74.7 (11.3) years, mean body mass index was 28.3 (5.9) kg/m2, and 58.6% of patients were female.

CKD was the first diagnosis in 169,532 patients (56.9% of all CKD diagnoses), second diagnosis in 92,651 patients (31.1%), third in 32,606 patients (11.0%) and fourth or fifth in 2,913 patients (1.0%); however, only 11,129 CKD patients (3.74%) developed four or more comorbidities of interest. In total, 1.5% of the cohort (4,544 patients) progressed to dialysis and 29.6% (88,245 patients) died during the study period.

In general, the incidence of HK increased with the number of comorbidities of interest (Figure 1). At a K+ threshold of ≥5.0 mmol/L, crude incidence rate of HK was 286.5 (95% CI: 285.2–287.8) per 1,000 patient-years in patients with CKD only; this increased 2.8-fold to 806.8 (741.5–876.4) in patients with five comorbidities of interest. A similar trend was observed at K+ thresholds of ≥5.5 mmol/L and ≥6.0 mmol/L. A 5.9 fold increase was observed in crude incidence rate of HK (from 59.7 [59.1–60.3] with CKD only, to 350.3 [307.7–397.1] with all five comorbidities) at a threshold of ≥5.5 mmol/L and a 10.6-fold increase (from 9.1 [8.9–9.4] to 96.2 [74.6–122.2]) at the ≥6.0 mmol/L threshold.

Conclusion

This assessment of a large real-world patient cohort showed that the risk of HK in patients with CKD increases with the number of cardiovascular or renal comorbidities. Emphasis should be put on effective prevention and treatment of HK in CKD, especially in patients with high comorbidity burden.

What Next After Metformin in Type 2 Diabetes? Selecting the Right Drug for the Right Patient

INTRODUCTION

Metformin is the recommended initial treatment in type 2 diabetes mellitus (T2DM), but when this does not give adequate glucose control the choice of which second-line drug to use is uncertain as none have been found to have a better overall glycaemic response. In this real-world study dipeptidyl peptidase 4 inhibitors (DPP4i), sulphonylureas (SU), thiazolidinediones (TZD) and sodium glucose co-transporter 2 inhibitors (SGLT2i) were compared for their effectiveness in lowering glycated haemoglobin (HbA1c) levels for a particular individual based on their clinical characteristics.

METHODS

A retrospective analysis was undertaken of electronic health records of people with T2DM prescribed metformin alongside a DPP4i, SU, TZD or SGLT2i at second-line. Regression modelling was used to model the changes in HbA1c from baseline at month 6 and month 12 for the individual therapies, adjusting for demographic and clinical characteristics.

RESULTS

There were 7170 people included in the study. Treatment at second-line with SUs, DPP4i, TZDs and SGLT2i resulted in similar percentages of people achieving the recommended HbA1c target of < 7.5% (58 mmol/mol) at both 6 and 12 months. For those receiving SGLT2i and SUs, the greatest improvement in HbA1c was observed in relatively younger and older people, respectively. Trends were detected between other baseline characteristics and HbA1c improvement by drug class, but they were not statistically significant. Non-adherence rates were low for all drug classes. People with a higher medication possession ratio (≥ 80%) also had greater improvements in HbA1c at 12 months.

CONCLUSION

This study identified patients' phenotypic characteristics that may have the potential to influence individual treatment response. Accounting for these characteristics in clinical treatment decisions may facilitate individualised prescribing by being able to select the right drug for the right patient.

P0683PATTERNS OF HYPERKALAEMIA RECURRENCE AMONG CHRONIC KIDNEY DISEASE PATIENTS IN UK CLINICAL PRACTICE

Background and Aims

Patients with chronic kidney disease (CKD) are at increased risk of hyperkalaemia, HK (high serum potassium concentration) due to impaired renal function. This medical condition is potentially life threatening if untreated or poorly managed. This study describes the characteristics of CKD patients in the UK who experience HK and assessed the frequency of recurrent HK and time between first (index) and subsequent events.

Method

A retrospective cohort study was conducted using linked Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) data from 01 January 2008 to 30 June 2018, with a five-year lookback period (2003-2007).

Patients were included if they were diagnosed with CKD stage 3+ (READ code or eGFR &lt;60 mL/min/1.73m2 without prior dialysis) during the study or lookback periods and aged &gt;18 years at diagnosis (index).

Patient demographics, clinical history and baseline medication use were described. HK was defined as serum K+ ≥5.0 mmol/L. HK events occurring during the study period, but after diagnosis of CKD, were assessed. Recurrent HK was defined as any event subsequent to the first event. Time to recurrence was calculated using Kaplan-Meier.

Results

In total, 297,702 CKD patients (mean age 74.7 years [standard deviation: 11.3], male [41.4%]) met eligibility criteria. At time of CKD diagnosis, 30.6% of the population had resistant hypertension. Other prominent comorbidities included diabetes (22.24%), CKD (7.9%) and cancer (7.8%). Approximately half of patients were in receipt of diuretics at baseline (49.2%), while 32.5% and 32.0% were in receipt of beta blockers and calcium channel blockers, respectively. During follow up, 67.0% of patients received a renin-angiotensin aldosterone system inhibitor (RAASi).

147,215 patients (49.5%) experienced at least one HK event, of which 53,695 (36.5%) had only one HK event, 93,250 (63.5%) had two or more HK events and 29,413 (20.0%) had six or more events. HK event incidence was predictive of subsequent events, with the probability of experiencing a HK event increasing from 49.5% to 63.5%, 70.7%, 74.1%, 76.5% and 78.6% for patients experiencing 2-6 events, respectively. There was an inverse relationship between the number of recurrent events and time to next event, with less time between the next event for those experiencing multiple events (Figure 1).

Conclusion

This study shows that approximately half of CKD patients experienced a HK event. Furthermore, patients who experienced a HK event were at increased risk of subsequent events. Frequent monitoring of serum potassium may help reduce the burden of HK in patients with CKD.

Brentuximab vedotin for the treatment of patients with relapsed or refractory Hodgkin lymphoma after autologous stem cell transplantation

Brentuximab vedotin (BV) is the first approved novel agent for salvage treatment of relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) after autologous stem cell transplantation (ASCT). In this study, a literature-based analysis was undertaken to assess, via an indirect treatment comparison, the comparative efficacy of BV to salvage chemotherapy as treatment for R/R cHL patients following ASCT. This comparative effectiveness research was undertaken to support a reimbursement submission for BV to the Australian Pharmaceutical Benefits Advisory Committee. Retrospective analysis of individual patient data from four data sources demonstrated that the use of BV as first salvage treatment in cHL patients relapsing or progressing post-ASCT achieved improvements in both clinical response and overall survival. More specifically, BV was associated with an incremental improvement of 22% in overall response rate compared to salvage chemotherapy. Five-year overall survival and progression-free survival rates were 92·2% [95% confidence interval (CI): 85·5-99·3%] and 32·2% (95% CI: 19·1-54·6%) respectively for BV, compared to 30·5% (95% CI: 22·2-42·0%) and 3·2% (95% CI: 1·1-8·9%) respectively for salvage chemotherapy. The encouraging results from this conservative analysis have the potential to support informed clinical management and funding decisions for the first salvage of cHL patients demonstrating recurrence after ASCT.

Evolution of the burden of active hepatitis C virus infection in England from September 2015 to September 2016: a repeated cross-sectional analysis

OBJECTIVE

To evaluate the impact of treatment with new direct-acting antivirals (DAAs) on the prevalent hepatitis C virus (HCV) population in England.

DESIGN

A repeated cross-sectional analysis.

SETTING

Four secondary care hospitals in England.

PARTICIPANTS

Patients who, in 2015 and/or 2016, had chronic HCV infection and were alive were eligible, regardless of the type of HCV intervention received.

OUTCOME MEASURES

Data including intravenous drug use (IVDU) status, HCV genotype, cirrhosis status, HCV treatment history, vital status and treatment outcomes were collected at two time points in 2015 and 2016 using electronic case report forms.

RESULTS

There were 1605 and 1355 patients with active chronic HCV in 2015 and 2016, respectively. Between 2015 and 2016, the proportion of patients with current IVDU increased (10.3% vs 14.5%, respectively), while that of patients with cirrhosis (28.2% vs 22.4%) and treatment-experienced patients (31.2% vs 27.1%) decreased. Among patients whose treatment outcome was known by 2016, high cure rates were observed, with an overall sustained virological response rate of 93.2%. From 2015 to 2016, there was a progressive increase in the proportion of treated patients who were non-cirrhotic, with current IVDU and non-liver transplant recipients.

CONCLUSIONS

The characteristics of patients with HCV remaining in contact with specialised care evolved with a changing landscape of treatment and related health policy. With increasing access to DAAs in UK, high cure rates were achieved in the study cohort.

The Cost-Effectiveness of Alogliptin Versus Sulfonylurea as Add-on Therapy to Metformin in Patients with Uncontrolled Type 2 Diabetes Mellitus

INTRODUCTION

ENDURE (ClinicalTrials.gov identifier, NCT00856284), a multicenter, double-blind, active-controlled study of 2639 patients with uncontrolled type 2 diabetes mellitus (T2DM), found that metformin in combination with alogliptin (12.5 and 25 mg doses), when compared to standard add-on therapy (sulfonylurea, SU), exerted sustained antihyperglycemic effects over 2 years. This economic analysis of ENDURE aimed to quantify the relationship between increased glycemic durability and cost-effectiveness of alogliptin in the UK clinical setting, and communicate its sustained glycemic benefit in economic terms.

METHODS

Using baseline characteristics and treatment effects from the ENDURE trial population, between-group cost-effectiveness analyses compared the combined use of metformin and alogliptin (MET + ALO_12.5/25) in patients with inadequately controlled T2DM, as an alternative to metformin and SU (MET + SU). In scenario analyses, an intragroup cost-effectiveness analysis compared MET + ALO_12.5/25 with MET + SU; a between-group cost-effectiveness analysis also compared MET + ALO_12.5/25 versus MET + SU within a subpopulation of patients who achieved HbA1c control (<7.5%) at 2 years on study drug.

RESULTS

Compared with baseline profiles of patients, combination therapies with alogliptin or SU were associated with improvements in length and quality of life and were cost-effective at established norms. Despite increased drug acquisition costs, alogliptin at 12.5 mg and 25 mg doses resulted in greater predicted lifetime quality-adjusted life year (QALY) gains with associated incremental cost-effectiveness ratios (ICERs) of £10,959/QALY and £7217/QALY compared to SU, respectively.

CONCLUSION

The ENDURE trial and the present cost-effectiveness analysis found that the glycemic durability of alogliptin therapy was associated with improved long-term patient outcomes, QALY gains, and ICERs that were cost-effective when evaluated against standard threshold values. Alogliptin therefore represents a cost-effective treatment alternative to SU as add-on therapy to metformin in patients with poorly managed T2DM.

FUNDING

Takeda Development Centre Europe Ltd.

Incidence of hypoglycemia with tight glycemic control protocols: a comparative study

BACKGROUND

Comparison of hypoglycemia incidence among tight glycemic control (TGC) protocols is a crucial aspect that has not been done in previous trials. This study compared the incidence of hypoglycemia using three TGC protocols in critically ill patients.

METHODOLOGY

This was a prospective study of 420 patients over 18 months. Patients were divided into three groups by TGC protocol: A (modified Leuven protocol), B (Georgia Hospital Association protocol, target blood glucose [BG] 80-110 mg/dL), and C (modified Georgia Hospital Association protocol, target BG 90-140 mg/dL). End points included differences in the incidence of first-degree hypoglycemia (BG <or= 60 mg/dL), second-degree hypoglycemia (BG <or= 40 mg/dL), and hyperglycemia (BG >or= 180 mg/dL).

RESULTS

A total of 34,497 BG samples were analyzed: group A, 11,202 (32.47%); group B, 9,627 (27.91%); and group C, 13,668 (39.62%). First-degree hypoglycemia was more frequent in group A (348 episodes [3.11%]) compared to group B (209 episodes [2.17%] [odds ratio (OR) 1.45, 95% confidence interval (CI) 1.25-1.172, P = 0.001]) and group C (266 episodes [1.95%] [OR 1.66, 95% CI 1.37-1.89, P = 0.001]). Second-degree hypoglycemia was more frequent in group A (131 episodes [1.17%]) compared to group B (62 episodes [0.64%] [OR 1.83, 95% CI 1.22-1.72, P = 0.001]) and group C (58 episodes [0.42%] [OR 2.77, 95% CI 2.04-3.79, P = 0.001]). No significant difference was found when groups B and C were compared (P = 0.10 and P = 0.06, respectively). Hyperglycemia was significantly more common in group A (2,175 episodes [19.42%]) compared to group B (1,333 episodes [13.83%] [OR 1.49, 95% CI 1.39-1.62, P = 0.001], but there was no significant difference compared to group C (2,560 episodes [18.73%] [P = 0.17]).

CONCLUSIONS

TGC protocols vary in their risk of inducing hypoglycemia. Whether this translates into differences in clinical outcomes such as mortality and adverse effects is still to be determined by future studies.

Leptospira in slaughtered fattening pigs in southern Vietnam: presence of the bacteria in the kidneys and association with morphological findings

One kidney was collected from each of 32 fattening pigs at an abattoir in southern Vietnam in 2001 in order to demonstrate infecting Leptospira serovar and to associate renal macro- and microscopic findings with the presence of renal leptospires. Leptospires were demonstrated in 22 (69%) of the investigated kidneys by immunofluorescence. Multifocal interstitial nephritis (MFIN) and gross renal lesions (white spots) were each demonstrated in 24 (75%) kidneys. Leptospira interrogans serovar bratislava was isolated from one kidney. There was no association between presence of leptospires and MFIN (P=0.19), respectively and white spots (P=0.98), respectively. These data suggest that Leptospira infection is common among fattening pigs in the study area and that these animals may be considered as an occupational human health hazard. It is also suggested that the presence of white spots is an unreliable indicator of the presence of renal leptospires.

Perindopril: an updated review of its use in hypertension

Perindopril erbumine (perindopril) is a prodrug ester of perindoprilat, an angiotensin converting enzyme (ACE) inhibitor. Perindopril 4 to 8 mg once daily significantly reduces supine systolic blood pressure (SBP) and diastolic blood pressure (DBP) from baseline values in hypertensive patients. These reductions are maintained for at least 24 hours, as evidenced by trough/peak ratios of >50%. Vascular abnormalities associated with hypertension were improved or normalised during perindopril treatment. Perindopril 4 to 8 mg once daily significantly decreased carotid-femoral aortic pulse wave velocity (PWV), improved arterial compliance, reduced left ventricular mass index and, in patients with recent cerebral ischaemia and/or stroke, preserved cerebral blood flow despite significantly reducing SBP and DBP. Further research is needed to establish the significance of promising results showing that reductions in aortic PWV were associated with reduced mortality in patients with end-stage renal failure, a third of whom received perindopril. Response rates (numbers of patients with supine DBP < or = 90 mm Hg) were significantly higher with perindopril 4 to 8 mg once daily (67 to 80%) than with captopril 25 to 50 mg twice daily (44 to 57%) in 3 randomised double-blind trials. In other clinical trials, the antihypertensive effects of perindopril were similar to those of other ACE inhibitors (including enalapril) and calcium-channel antagonists. Combination treatment with perindopril and an antihypertensive agent from another treatment class provided additional benefits, either as first-line treatment or in patients failing to respond to monotherapy. Perindopril monotherapy was also effective in the elderly and in patients with hypertension and concomitant disease. Perindopril has a similar adverse event profile to that of other ACE inhibitors; cough is the most common event reported during treatment, and is also the most common adverse event responsible for treatment withdrawal.

CONCLUSIONS

Perindopril is a well tolerated ACE inhibitor that is significantly better than captopril (in terms of response rates) in the treatment of hypertension, and as effective as other ACE inhibitors. Perindopril appears to reverse some of the vascular abnormalities associated with hypertension, including arterial stiffness and left ventricular hypertrophy, although further research is needed to confirm promising results regarding its ability to decrease associated cardiovascular morbidity and mortality. Results from ongoing studies will help confirm the place of perindopril in the treatment of hypertension; currently, it is an effective and well tolerated treatment for patients with mild to moderate essential hypertension.

Oestrogens and oestrogenic activity in raw and treated water in Severn Trent Water

Sewage effluent discharged to surface water has been shown to contain human hormones, particularly oestrogens, and synthetic chemicals which may be able to disrupt the endocrine system. Since many surface waters which receive sewage effluent are subsequently used as drinking water sources, it is important to demonstrate that treated drinking water is not contaminated. Oestrogenic activity in rivers and drinking water in the region of Severn Trent Water was studied using a combination of bioassay, to integrate exposure over time, and advanced chemical analysis. There was little or no evidence of substances that were oestrogenic, even in waters receiving significant amounts of sewage effluent. Oestrogenic activity, as measured in the rainbow trout vitellogenin assay, was seen at the Tame/Trent confluence but this activity was relatively weak. There was no activity detected at raw water intakes and no hormones or substances that are oestrogenic were detected in the final drinking water.

Paclitaxel: a pharmacoeconomic review of its use in non-small cell lung cancer

A number of first-line chemotherapy options for patients with advanced non-small cell lung cancer (NSCLC) are advocated in treatment guidelines and/or by various clinical investigators. Platinum-based chemotherapy has clearly demonstrated efficacy in patients with advanced NSCLC and is generally recommended as first-line therapy, although there is increasing interest in the use of non-platinum chemotherapy regimens. Among the platinum-based combinations currently used in clinical practice are regimens such as cisplatin or carboplatin combined with paclitaxel, vinorelbine, gemcitabine, docetaxel or irinotecan. The particular combinations employed may vary between institutions and geographical regions. Several pharmacoeconomic analyses have been conducted on paclitaxel in NSCLC and most have focused on its use in combination with cisplatin. In terms of clinical efficacy, paclitaxel-cisplatin combinations achieved significantly higher response rates than teniposide plus cisplatin or etoposide plus cisplatin (previously thought to be among the more effective regimens available) in two large randomised trials. One of these studies showed a survival advantage for paclitaxel plus cisplatin [with or without a granulocyte colony-stimulating factor (G-CSF)] compared with etoposide plus cisplatin. A Canadian cost-effectiveness analysis incorporated data from one of the large randomised comparative trials and showed that the incremental cost per life-year saved for outpatient administration of paclitaxel plus cisplatin versus etoposide plus cisplatin was $US 22181 (30619 Canadian dollars; $Can) [1997 costs]. A European analysis incorporated data from the other large randomised study and showed slightly higher costs per responder for paclitaxel plus cisplatin than for teniposide plus cisplatin in The Netherlands ($US 30769 vs $US 29592) and Spain ($US 19 923 vs $US 19724) but lower costs per responder in Belgium ($US 22852 vs $US 25000) and France ($US28 080 vs $US 34747) [1995/96 costs]. In other cost-effectiveness analyses, paclitaxel plus cisplatin was associated with a cost per life-year saved relative to best supportive care of approximately $US 10000 in a US study (year of costing not reported) or $US 11200 in a Canadian analysis ($Can 15400; 1995 costs). Results were less favourable when combining paclitaxel with carboplatin instead of cisplatin and particularly when G-CSF was added to paclitaxel plus cisplatin. The Canadian study incorporated the concept of extended dominance in a threshold analysis and ranked paclitaxel plus cisplatin first among several comparator regimens (including vinorelbine plus cisplatin) when the threshold level was $Can 75000 ($US 54526) per life-year saved or per quality-adjusted life-year gained (1995 values).

CONCLUSION

Current treatment guidelines for advanced NSCLC recognise paclitaxel-platinum combinations as one of the first-line chemotherapy treatment options. In two large head-to-head comparative clinical trials, paclitaxel plus cisplatin was associated with significantly greater response rates than cisplatin in combination with either teniposide or etoposide, and a survival advantage was shown for paclitaxel plus cisplatin (with or without G-CSF) over etoposide plus cisplatin. There are limitations to the currently available pharmacoeconomic data and further economic analyses of paclitaxel-carboplatin regimens are warranted, as this combination is widely used in NSCLC and appears to have some clinical advantages over paclitaxel plus cisplatin in terms of ease of administration and tolerability profile. Nevertheless, results of various cost-effectiveness studies support the use of paclitaxel-platinum combinations, particularly paclitaxel plus cisplatin, as a first-line chemotherapy treatment option in patients with advanced NSCLC.

Magnetic resonance imaging as the primary imaging modality in children presenting with acute non-traumatic hip pain

The role of magnetic resonance imaging (MRI) in children presenting with acute non-traumatic hip pain was evaluated prospectively. Hip MRI was performed in addition to standard investigations (arthrosonography +/- hip radiographs) in 50 children presenting to the accident and emergency department of a paediatric hospital. MRI was performed on an open 0.23T system and comprised gradient echo T1 weighted coronal, fast spin echo T2 weighted coronal and inversion recovery spin echo (IRSE) axial sequences. Diagnostic quality MRI examinations were obtained in 94% of children. The IRSE sequence was the most reliable at determining underlying disorder (p<0.002). Interobserver agreement on the MRI examinations was very good with unweighted kappa value of 0.89, 95% confidence intervals 0.79, 0.99. Sensitivity of MRI was 0.79 (0.68, 0.90, specificity 1.00 (0.89, 1.00), accuracy 0.81 (0.70, 0.92), PPV 1.00 (0.89, 1), NPV 0.36 (0.25, 0.47). Sensitivity of standard imaging was 0.70 (0.54-0.86), specificity 0.57 (0.41, 0.73), accuracy 0.72 (0.56, 0.88), PPV 0.91 (0.75, 1.00), NPV 0.24 (0.08, 0.40). MRI correctly identified all seven children with serious underlying disorder whereas conventional imaging correctly diagnosed only two. Pelvic musculoskeletal infection was associated with the combination of marked alteration in signal in tissues adjacent to a symptomatic hip and an erythrocyte sedimentation rate of >20 mm 1st h (p<0.0001). In conclusion, MRI is a practical, well accepted and accurate non-invasive imaging technique in children presenting with acute non-traumatic hip pain. Combined with inflammatory markers MRI can be used to determine those children who require aggressive management. Where it is available, MRI is the imaging modality of choice in this condition.

Lopinavir

Lopinavir is a protease inhibitor with high specificity for HIV-1 protease. Ritonavir strongly inhibits lopinavir metabolism; coadministration of lopinavir and ritonavir in healthy volunteers increased the area under the lopinavir plasma concentration-time curve >100-fold. Trough plasma concentration: antiviral 50% effective concentration ratio for lopinavir was >75 for wild-type HIV at the dose used in clinical trials, compared to values of < or = 4 for other commonly used protease inhibitors. Coformulated lopinavir and ritonavir (lopinavir/ ritonavir) 400/100mg twice daily for 48 weeks suppressed HIV replication in significantly more antiretroviral-naive patients than nelfinavir 750mg 3 times daily (all patients also received stavudine and lamivudine). Suppression of viral replication was observed in most protease inhibitor-experienced patients with lopinavir/ ritonavir (400/100, 400/200 or 533/133mg twice daily for 48 or 96 weeks) in combination with > or = 2 nucleoside reverse transcriptase inhibitors (NRTIs) and either efavirenz or nevirapine. 48 weeks of treatment with twice daily lopinavir/ ritonavir (230/57.5 or 300/75 mg/m2 for the first 12 weeks and then 300/75 mg/m2) in combination with 1 or2 NRTIs, with or without nevirapine, suppressed viral replication in the majority of antiretroviral-naive and -experienced paediatric patients (aged 6 months to 12 years). Diarrhoea, nausea and asthenia were the most frequently reported adverse effects in patients receiving lopinavir/ritonavir-based regimens. Elevated total cholesterol, triglyceride and hepatic enzyme levels were also reported.

Ebastine: an update of its use in allergic disorders

Ebastine is a second-generation antihistamine which undergoes transformation to its active metabolite, carebastine. Its antihistaminic and antiallergic effects have been demonstrated in in vitro and in vivo studies, in addition to data obtained from clinical trials. Patients with allergic rhinitis or chronic idiopathic urticaria experienced significant improvement in their symptoms with ebastine 10 or 20 mg once daily. Some studies in patients with seasonal allergic rhinitis (SAR) have indicated trends towards greater efficacy with the 20 mg than the 10 mg dose, although only 1 study has shown statistically significant benefits. In comparative trials in patients with SAR, ebastine 10 mg was as effective as most other second-generation antihistamines, including astemizole, azelastine, cetirizine, loratadine and terfenadine. Ebastine 20 mg/day was significantly superior to loratadine 10 mg/day in patients with SAR according to effects on secondary efficacy variables in comparative studies; 1 study found significantly greater changes from baseline in mean total symptom score with ebastine 20 mg (-43 vs -36% with loratadine, p = 0.045). In patients with perennial allergic rhinitis, ebastine 10 or 20 mg daily was significantly more effective than loratadine in reducing total symptom scores from baseline 1 comparative study. There have been no reports of serious adverse cardiac effects during ebastine therapy. Increases in corrected QT interval have been observed during clinical trials; however, these have not been considered clinically significant and were generally of similar magnitude to those seen with loratadine. The normal diurnal variation in QTc interval and the problems associated in correcting for changes in heart rate also complicate assessment of this issue. The incidence of adverse events during ebastine treatment is not significantly greater than that observed with placebo or other second-generation antihistamines.

CONCLUSIONS

Ebastine 10 mg daily is a well tolerated and effective treatment for allergic rhinitis and chronic idiopathic urticaria. At this dosage, it is as effective as the other second-generation antihistamines against which it has been compared. Ebastine 20 mg has similar tolerability to the 10 mg dose, and trends towards greater efficacy with the higher dose have been shown in some studies. Ebastine does not appear to be associated with any significant cardiac adverse events. Ebastine is a useful treatment option for patients with allergic rhinitis or chronic idiopathic urticaria.

Meropenem: a review of its use in patients in intensive care

Meropenem is a carbapenem antibacterial agent that has antimicrobial activity against gram-negative, gram-positive and anaerobic micro-organisms. In vitro studies involving isolates from patients in intensive care units (ICUs) indicate that meropenem is more active against most gram-negative pathogens than other comparators (including imipenem), although, compared with imipenem, meropenem is less active against most gram-positive organisms. Resistance to meropenem is uncommon in most bacteria. Treatment with meropenem as initial empirical monotherapy was effective in a range of serious infections in adult and paediatric ICU patients. Meropenem monotherapy was as effective as imipenem/cilastatin in 4 comparative trials in terms of satisfactory clinical and bacteriological responses. Meropenem monotherapy was significantly more effective than ceftazidime-based combination treatments in 2 trials in patients with nosocomial lower respiratory tract infections (LRTIs) in terms of both clinical and bacteriological responses. Meropenem was also more active than ceftazidime-based treatments against both gram-positive and gram-negative organisms. However, 2 studies in patients with a range of serious infections found no significant differences between meropenem and cephalosporin-based treatments in terms of clinical or bacteriological response. Meropenem was also as effective as cephalosporin-based treatments in comparative trials in children with serious infections. Meropenem is well tolerated as either a bolus or an infusion, and clinical trials have shown similar incidences of adverse events to those observed with cephalosporin-based treatments. It is well tolerated by the CNS, with seizures reported infrequently, and can therefore be used at high doses and in patients with meningitis. The incidence of drug-related nausea and vomiting is low and, in contrast to imipenem/cilastatin, does not increase with dose or speed of administration.

CONCLUSIONS

Meropenem is a well tolerated broad spectrum antibacterial agent that, when used as initial empirical monotherapy, is as effective as imipenem/cilastatin in the treatment of a range of serious infections (including nosocomial) in adults and children in ICUs. Compared with cephalosporin-based combination treatments, meropenem monotherapy may be more effective in the treatment of nosocomial LRTIs and can be used as monotherapy. Meropenem has an important role in the empirical treatment of serious infections in adults and children in ICUs.

Stavudine: an update of its use in the treatment of HIV infection

Stavudine is a thymidine nucleoside analogue which is phosphorylated intracellularly to an active metabolite, stavudine 5'-triphosphate. This metabolite inhibits HIV replication, either by competing with thymidine 5'-triphosphate for incorporation into viral DNA by reverse transcriptase or by causing premature termination of the viral chain after incorporation. Resistance to stavudine, either alone or as part of resistance to multiple nucleoside reverse transcriptase inhibitors, has been reported; however, high-level resistance is uncommon even after long periods of treatment. Initial treatment with stavudine-containing triple therapies reduced HIV RNA levels to below the limit of detection (LOD; 500 copies/ml) in 68 to 100% of antiretroviral-naive patients after at least 20 weeks of treatment. Effects on clinical outcomes have not yet been established, although earlier trials showed significant improvements with stavudine (alone or with 1 other drug) in patients who had previously received zidovudine. Results from 2 randomised nonblind clinical trials indicated that the efficacy of stavudine-containing triple therapy was similar to that of zidovudine-containing triple therapy (when used in combination with the same drugs), although there were no statistical comparisons. Improvements in surrogate end-points have also been seen in trials in antiretroviral-experienced patients receiving stavudine and 2 or 3 other antiretroviral agents. Stavudine-containing combination therapies have also been effective in reducing viral load and increasing CD4+ lymphocyte count in children, although data are limited. Like other nucleoside analogues, stavudine treatment can cause mitochondrial toxicity. The major adverse effect from this observed with stavudine therapy is peripheral neuropathy, which is both dosage- and treatment duration-dependent. Most cases respond to short term cessation of treatment and reintroduction of stavudine at half the previous dosage.

CONCLUSION

Stavudine-containing triple therapies are effective in the treatment of antiretroviral-naive adults with HIV infection as assessed by surrogate end-points; earlier trials involving 1 or 2-drug therapy showed that stavudine can significantly improve clinical end-points. Stavudine has also been beneficial as part of combination regimens in antiretroviral-experienced patients and children with HIV infection, although data are limited and more studies are needed. High-level resistance to stavudine is uncommon. The major adverse event associated with treatment is peripheral neuropathy, which may limit its use in some patients. Currently, stavudine has a valuable role as part of initial triple therapy in antiretroviral-naive adults with HIV/AIDS.

Clodronate: a review of its use in breast cancer

Like other members of its class, the bisphosphonate clodronate (clodronic acid) inhibits bone resorption. The efficacy of oral clodronate 1600 mg/day in reducing the incidence of skeletal complications and metastasis development has been assessed in several clinical trials in patients with breast cancer. Long term use of oral clodronate significantly reduced the total cumulative incidence of skeletal events (including fractures, hypercalcaemia, and the need for radiotherapy for bone pain) compared with that in placebo recipients in 2 randomised double-blind placebo-controlled studies, each involving >100 patients. Significant differences in favour of clodronate were also seen in the frequency of some individual skeletal events in 1 trial. A nonblind trial in 302 patients considered to be at high risk of developing metastases found that, at a 3-year follow-up, significantly fewer patients who received clodronate for 2 years developed skeletal metastases than those in a control group. Clodronate recipients were also significantly less likely than controls to develop visceral metastases, and had significantly higher survival rates. A smaller double-blind placebo-controlled study in women with recurrent breast cancer found that clodronate significantly decreased the total number of new skeletal metastases, but not the number of patients who developed them. In a nonblind trial in 299 patients with node-positive breast cancer, however, the incidence of skeletal metastases did not differ significantly between patients who received clodronate for 3 years and those in a control group. In addition, clodronate recipients had a significantly greater incidence of nonskeletal metastases (local and visceral), and significantly lower survival rates. Intravenous or oral clodronate has been well tolerated in clinical trials. The most common adverse effects reported were mild gastrointestinal disturbances such as nausea, vomiting and diarrhoea. All these events were transient, and usually resolved without stopping treatment.

CONCLUSIONS

Clodronate is a well tolerated bisphosphonate, available in both oral and intravenous forms, that significantly reduces the incidence of skeletal complications associated with breast cancer. Further research is needed to establish more clearly its efficacy in reducing metastasis development, to assess its efficacy compared with other bisphosphonates, and to determine which patients will benefit most from treatment. Currently, clodronate is probably most effective in the treatment and prevention of general skeletal complications in patients with breast cancer.

Gender differences on Internet cancer support groups

The role of community-based cancer support groups (CSGs) in helping people cope with cancer is well known. Recently, online CSGs have become a viable alternative to traditional CSGs. The purposes of this study were to determine if categories of responses on Internet cancer support groups (ICSGs) differ when the majority of the participants were of a single gender, and whether response categories seen on gender-specific ICSGs were different than those on ICSGs used equally by men and women. A line-by-line analysis of postings on prostate, breast, and mixed ICSGs were analyzed and responses categorized. Four categories (information giving/seeking; encouragement/support; personal opinion; and personal experience) accounted for approximately 80% of responses across the groups. Information giving/seeking was ranked first in the prostate group, and personal experience took priority in the breast group. Men were more than twice as likely to give information and women more than twice as likely to give encouragement and support. One category (prayer), identified in the mixed group, was lacking in the prostate and breast groups, and an activism category was added to the prostate group. Categorical responses differed by gender (chi 2 = 79.40, P < .0001). Attention should be given to facilitating the entry of underserved groups into ICSGs. Future research should explore the relationship between ICSG membership and variables such as depression, survival time, and quality of life.

Schistosoma japonicum in the pig: the host-parasite relationship as influenced by the intensity and duration of experimental infection

Parasitologic, clinicopathologic, and pathologic aspects of Schistosoma japonicum infections of varying durations and intensities were studied in growing pigs injected intramuscularly with a dose of either 0, 100, 500, or 2,000 cercariae and killed at 4, 11, 17, or 24 weeks postinfection (PI). The number of viable worm pairs decreased significantly in the high dose group after 11 weeks PI but not in the lower dose groups; however, a stable population of immature worms persisted throughout the study in all dose groups. Liver egg counts also tended to decrease in the high dose group after 11 weeks but not in the other groups. Fecal egg excretion began at six weeks PI, was highest at eight weeks PI with a pronounced peak occurring only in the high dose group, and then decreased to low levels by 14 weeks PI in all groups. Egg counts from the feces as well as the liver correlated strongly with worm pair numbers during the acute phase of infection. The only clinicopathologic abnormality observed was an increase in circulating eosinophils corresponding to cercarial dose in all infected pigs by week six with peak counts occurring between six and eight weeks PI. The pigs exhibited no clinical signs of disease aside from diarrhea at the onset of patency. However, lesions were present throughout the large intestine of all infected pigs from 11 weeks PI, gradually decreasing with time. Severe liver fibrosis occurred in the 500 and 2,000 dose groups mainly at 11 weeks PI and then decreased in severity. In the liver, but not in the intestine, the severity of lesions at all time points was proportional to the cercarial dose given. The results indicate that after several weeks of patency, pigs with high intensities of S. japonicum infection are able to effectively eliminate the majority of adult worms while maintaining a stable population of immature schistosomes.

Optimal temporal frequencies in oscillatory movement hyperacuity measurements of visual function in cataract patients

Hyperacuity tasks have been suggested for the assessment of potential visual function in the presence of cataracts. To test this suggestion, hyperacuity thresholds for an oscillating bar were measured in 30 subjects with idiopathic cataract and in 24 age-matched normals over a range of oscillation frequencies. Each subject's cataract was categorized using the Oxford Clinical Cataract Classification and Grading System. Cataract was found to have a significant effect on thresholds, although a differential morphological effect on thresholds was equivocal. Thresholds at higher temporal frequencies were significantly raised when compared to the normal group. The main conclusion to be drawn from this study is that motion hyperacuity thresholds appear unaffected by cataract at low oscillation frequencies and should be used in preference to higher frequencies in the assessment of such patients.

Immunohistochemical localization of platelet-derived growth factor receptors in the porcine uterus during the oestrous cycle and pregnancy

The distribution of alpha- and beta-type receptors for PDGF was studied immunohistochemically in the uterus of cycling and pregnant pigs with well-documented hormonal status in order to determine a possible steroid hormone-dependence of its expression. Peroxidase-antiperoxidase (PAP) labelling at light microscopical level was done with rabbit polyclonal antisera recognizing either both alpha- and beta-type receptors (PDGFR-1), or selectively beta-type (PDGFR-3). Immunoreactivity to the PDGF-receptors of alpha- and beta-type (PDGFR-1) was present in all endometrial samples examined, being located principally on subepithelial stromal and endothelial cells, the wall of endometrial blood vessels and in the fetal placenta (trophoblast and adjoining blood capillaries). In the myometrium, the major reactive cells were the non-vascular smooth muscle cells, and to some extent, also those of the tunica media of major uterine vessels. No dramatic variations in the intensity of the reaction were noticed during the oestrous cycle. A very intense immunoreactivity was present at early pregnancy and at term, i.e. under major oestrogenic influence. The immunoreactivity to the PDGF-receptor antiserum R-3 (against beta-type) was similarly localized as that showed for R-1 antiserum, while of a weaker intensity. The results indicate the presence of PDGF receptors (alpha- and beta-type) in the endo- and myometrium of cycling and pregnant pigs, and that their expression seems to be accentuated under oestrogenic influence.

Embryonic development of the porcine indifferent gonad and testis

The early gonadal development in the pig from day 18 to day 36 post conception, when distinct testes were present in male embryos, has been studied. The development of the porcine gonad followed the general mammalian pattern. During testicular differentiation, the germ cells and the relevant somatic cells, the Sertoli cells, became enclosed in testicular cords, thus creating an intracordal germ cell compartment and an extracordal compartment. The development of conspicuous cell junctions and the production of a basal lamina were evident in the Sertoli cells during the early testis development. Their origin in this species remains unclear.