An artificial intelligence-generated model predicts 90-day survival in alcohol-associated hepatitis: A global cohort study

BACKGROUND AIMS

Alcohol-associated hepatitis (AH) poses significant short-term mortality. Existing prognostic models lack precision for 90-day mortality. Utilizing artificial intelligence (AI) in a global cohort, we sought to derive and validate an enhanced prognostic model.

APPROACH AND RESULTS

The Global AlcHep initiative, a retrospective study across 23 centers in 12 countries, enrolled AH patients per NIAAA criteria. Centers were partitioned into derivation (11 centers, 860 patients) and validation cohorts (12 centers, 859 patients). Focusing on 30 and 90-day post-admission mortality, three AI algorithms (Random Forest, Gradient Boosting Machines, and eXtreme Gradient Boosting) informed an ensemble model, subsequently refined via Bayesian updating, integrating the derivation cohort's average 90-day mortality with each center's approximate mortality rate to produce post-test probabilities. The ALCoholic Hepatitis Artificial INtelligence (ALCHAIN) Ensemble score integrated age, gender, cirrhosis, and 9 laboratory values, with center-specific mortality rates. Mortality was 18.7% (30-day) and 27.9% (90-day) in the derivation cohort, versus 21.7% and 32.5% in the validation cohort. Validation cohort 30 and 90-day AUCs were 0.811 (0.779 - 0.844) and 0.799 (0.769 - 0.830), significantly surpassing legacy models like Maddrey's Discriminant Function, MELD variations, ABIC, Glasgow, and modified Glasgow Scores (p<0.001). ALCHAIN Ensemble score also showcased superior calibration against MELD and its variants. Steroid use improved 30-day survival for those with an ALCHAIN Ensemble score>0.20 in both derivation and validation cohorts.

CONCLUSIONS

Harnessing AI within a global consortium, we pioneered a scoring system excelling over traditional models for 30 and 90-day AH mortality predictions. Beneficial for clinical trials, steroid therapy, and transplant indications, it's accessible at: https://aihepatology.shinyapps.io/ALCHAIN/.

Regional impacts of warming on biodiversity and biomass in high latitude stream ecosystems across the Northern Hemisphere

Warming can have profound impacts on ecological communities. However, explorations of how differences in biogeography and productivity might reshape the effect of warming have been limited to theoretical or proxy-based approaches: for instance, studies of latitudinal temperature gradients are often conflated with other drivers (e.g., species richness). Here, we overcome these limitations by using local geothermal temperature gradients across multiple high-latitude stream ecosystems. Each suite of streams (6-11 warmed by 1-15°C above ambient) is set within one of five regions (37 streams total); because the heating comes from the bedrock and is not confounded by changes in chemistry, we can isolate the effect of temperature. We found a negative overall relationship between diatom and invertebrate species richness and temperature, but the strength of the relationship varied regionally, declining more strongly in regions with low terrestrial productivity. Total invertebrate biomass increased with temperature in all regions. The latter pattern combined with the former suggests that the increased biomass of tolerant species might compensate for the loss of sensitive species. Our results show that the impact of warming can be dependent on regional conditions, demonstrating that local variation should be included in future climate projections rather than simply assuming universal relationships.

AB0433 ANTI-RITUXIMAB ANTIBODIES DEMONSTRATE NEUTRALISING CAPACITY, ASSOCIATE WITH LOWER CIRCULATING DRUG LEVELS AND EARLY RELAPSE IN PATIENTS UNDERGOING TREATMENT FOR SYSTEMIC LUPUS ERYTHEMATOSUS

Background

A major limitation of biologic therapy is formation of anti-drug antibodies (ADA). We previously found ADA to rituximab (RTX) are more prevalent in patients undergoing treatment for systemic lupus erythematosus (SLE) than rheumatoid arthritis and vasculitis (1). In addition, we demonstrated that ADA to RTX predict subsequent infusion related reactions (2). However, little is known regarding the long-term dynamics of ADA to RTX in patients undergoing treatment for SLE.

Objectives

In this study we evaluated the longitudinal impact of ADA positivity with particular focus on; 1) Risk factors for development of ADA. 2) Impact of ADA on treatment response. 3) Influence of ADA on RTX drug kinetics over time. 4) The capacity of ADA to neutralise RTX.

Methods

Patients with SLE undergoing treatment with RTX were recruited to this study (n=35). Serum samples were collected at the following intervals post-treatment; 1-3 months (defined as ‘early’ post-treatment), 6 months, 12 months, 36 months (n=114).

Clinical and laboratory data was collected pre-treatment and at each follow-up time point. Response to treatment was assessed by improvement in SLEDAI-2K score from baseline and also according to BILAG as previously described (3).

ADA were detected using an electrochemiluminescent immunoassay. Serum RTX levels were measured by ELISA. ADA status was defined according to the following patterns over time; persistently negative, persistently positive (0-15 AU/ml) and persistently high positive (≥16 AU/ml, upper quartile). A complement dependent cytotoxic assay was used to determine neutralising capability of ADA in a subgroup of positive samples (n=38).

Results

ADA to RTX were found to be persistently positive in 64.3% of patients over the 36-month follow-up period and there was no significant difference in baseline disease activity (BILAG / SLEDAI-2K) between those who were subsequently ADA positive vs negative. ADA positive patients had a younger age at diagnosis of SLE when compared with ADA negative (mean 22.50 ± 9.10 vs 37.29 ± 11.31 years, p=0.002, Figure 1 A). Multivariate logistic regression found a 22% decrease in risk of ADA positivity for each addition year after diagnosis (p=0.03).

Figure 1.

ADA positive patients had a significantly lower C3 level at baseline (mean 0.61 ± 0.23 g/L vs 0.87 ± 0.30 g/L, p=0.026), which remained lower at each subsequent time point post-treatment up to 12 months post-treatment (Figure 1B).

At 1-3 months post-RTX, patients who were ADA positive had a significantly lower circulating drug level than ADA negative (p<0.001, Figure 1 C).

In terms of clinical response, ADA positive patients had an initial significant improvement in disease activity (SLEDAI-2K) by 3 months (p<0.001). However, response was not maintained at 12 months (Figure 1 D). In comparison, ADA negative patients showed a significant improvement in SLEDAI-2K at 6 months and this was maintained across the 36-month follow-up period (Figure 1 E).

BILAG defined relapse was more common at six months post-treatment in ADA positive patients (22%) and ADA highly positive patients (33%) than those who were ADA negative (in which there were no cases of relapse within the first six months, Figure 1 F). At 12-months post-RTX, a higher rate of BILAG defined Major Response was seen in those who were ADA negative (80%) when compared with ADA positive (44%) and high positive (36%) as shown in Figure 1 G.

Finally, antibodies derived from all ADA positive samples (38/38) were found to neutralise RTX in vitro.

Conclusion

ADA to RTX were common and persisted over the 36-month period of this study. ADA associated with earlier serum drug elimination, increased relapse rates and demonstrated neutralising capacity suggesting that ADA could be a significant limitation to sustained response to treatment in clinical practice.

References

[1]Faustini F et al. Arthritis research & therapy. 2021;23(1):211

[2]Wincup C et al. Annals of the rheumatic diseases. 2019;78(8):1140-2

[3]Md Yusof MY et al Annals of the rheumatic diseases. 2017;76(11):1829-36

Disclosure of Interests

None declared

Practical considerations for quantitative clinical SPECT/CT imaging of alpha particle emitting radioisotopes

Rationale: Alpha particle emitting radiopharmaceuticals are generating considerable interest for the treatment of disseminated metastatic disease. Molecular imaging of the distribution of these agents is critical to safely and effectively maximize the clinical potential of this emerging drug class. The present studies aim to investigate the feasibility and limitations of quantitative SPECT for 223Ra, 225Ac and 227Th. Methods: Three state-of-the-art SPECT/CT systems were investigated: the GE Discovery NM/CT 670, the GE Optima NM/CT 640, and the Siemens Symbia T6. A series of phantoms, including the NEMA IEC Body phantom, were used to compare and calibrate each camera. Additionally, anthropomorphic physical tumor and vertebrae phantoms were developed and imaged to evaluate the quantitative imaging protocol. Results: This work describes and validates a methodology to calibrate each clinical system. The efficiency of each gamma camera was analyzed and compared. Using the calibration factors obtained with the NEMA phantom, we were able to quantify the activity in 3D-printed tissue phantoms with an error of 2.1%, 3.5% and 11.8% for 223Ra, 225Ac, and 227Th, respectively. Conclusion: The present study validates that quantitative SPECT/CT imaging of 223Ra, 225Ac, and 227Th is achievable but that careful considerations for camera configuration are required. These results will aid in future implementation of SPECT-based patient studies and will help to identify the limiting factors for accurate image-based quantification with alpha particle emitting radionuclides.

Conservation genetics of native and European-introduced Chinese water deer (Hydropotes inermis)

Sufficient genetic variation is vital for the long-term survival of a population. The adaptive potential and reproductive fitness of a population is generally enhanced by greater levels of genetic diversity, while loss of genetic variation in small populations may increase extinction risk due to disease susceptibility and decreased reproductive fitness. Determining levels of genetic diversity in threatened species can, therefore, help inform conservation strategies. The Chinese water deer (Hydropotes inermis) is classified as Vulnerable in its native range on the IUCN Red List, and populations in Korea and mainland China have declined drastically in recent years. However, the species was introduced to Europe about a century ago and populations there now make up over 40% of global numbers. To infer the population genetic structure and genetic diversity of Chinese water deer both in their native China and in populations introduced to the UK and France, variation in mitochondrial DNA was investigated for over 100 individuals (92 cytochrome b and 106 control region sequences). Our results reveal lower levels of genetic diversity in the British populations, differentiation between native and introduced populations, and that the source population of British deer is likely to be extinct. Recommendations are made for the conservation of populations.

Mitochondrial genome of the Silvertip shark, Carcharhinus albimarginatus, from the British Indian Ocean Territory

The Chagos archipelago in the British Indian Ocean Territory (BIOT) has been lacking in detailed genetic studies of its chondrichthyan populations. Chondrichthyes in Chagos continue to be endangered through illegal fishing operations, necessitating species distribution and abundance studies to facilitate urgent monitoring and conservation of the species. Here, we present a complete mitochondrial genome of the Silvertip Shark, Carcharhinus albimarginatus sampled in the Chagos archipelago. The mitochondrial genome of C. albimarginatus was 16,706 bp in length and consisted of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, a replication origin and a D-loop region. GC content was at 38.7% and the control region was 1,065 bp in length. We expect that mitogenomes presented here will aid development of molecular assays for species distribution studies. Overall these studies will promote effective conservation of marine ecosystemes in the BIOT.

Complete mitochondrial genome of the gray reef shark, Carcharhinus amblyrhynchos (Carcharhiniformes: Carcharhinidae)

We report the first mitochondrial genome sequences for the gray reef shark, Carcharhinus amblyrhynchos. Two specimens from the British Indian Ocean Territory were sequenced independently using two different next generation sequencing methods, namely short read sequencing on the Illumina HiSeq and long read sequencing on the Oxford Nanopore Technologies’ MinION sequencer. The two sequences are 99.9% identical and are 16,705 base pairs (bp) and 16,706 bp in length. The mitogenome contains 22 tRNA genes, two rRNA genes, 13 protein-coding genes and two non-coding regions; the control region and the origin of light-strand replication (OL).

Behavior and season affect crayfish detection and density inference using environmental DNA

Although the presence/absence of aquatic invertebrates using environmental DNA (eDNA) has been established for several species, inferring population densities has remained problematic. The invasive American signal crayfish, Pacifastacus leniusculus (Dana), is the leading cause of decline in the UK's only native crayfish species, Austropotamobius pallipes (Lereboullet). Methods to detect species at low abundances offer the opportunity for the early detection, and potential eradication, of P. leniusculus before population densities reach threatening levels in areas occupied by A. pallipes. Using a factorial experimental design with aquaria, we investigated the impacts of biomass, sex ratio, and fighting behavior on the amount of eDNA released by P. leniusculus, with the aim to infer density per aquarium depending on treatments. The amount of target eDNA in water samples from each aquarium was measured using the quantitative Polymerase Chain Reaction. We show that the presence of eggs significantly increases the concentration of crayfish eDNA per unit of mass, and that there is a significant relationship between eDNA concentration and biomass when females are egg‐bearing. However, the relationship between crayfish biomass and eDNA concentration is lost in aquaria without ovigerous females. Female‐specific tanks had significantly higher eDNA concentrations than male‐specific tanks, and the prevention of fighting did not impact the amount of eDNA in the water. These results indicate that detection and estimate of crayfish abundance using eDNA may be more effective while females are ovigerous. This information should guide further research for an accurate estimation of crayfish biomass in the field depending on the season. Our results indicate that detection and quantification of egg‐laying aquatic invertebrate species using eDNA could be most successful during periods when eggs are developing in the water. We recommend that practitioners consider the reproductive cycle of target species when attempting to study or detect aquatic species using eDNA in the field.

The origin of efficient triplet state population in sulfur-substituted nucleobases

Elucidating the photophysical mechanisms in sulfur-substituted nucleobases (thiobases) is essential for designing prospective drugs for photo- and chemotherapeutic applications. Although it has long been established that the phototherapeutic activity of thiobases is intimately linked to efficient intersystem crossing into reactive triplet states, the molecular factors underlying this efficiency are poorly understood. Herein we combine femtosecond transient absorption experiments with quantum chemistry and nonadiabatic dynamics simulations to investigate 2-thiocytosine as a necessary step to unravel the electronic and structural elements that lead to ultrafast and near-unity triplet-state population in thiobases in general. We show that different parts of the potential energy surfaces are stabilized to different extents via thionation, quenching the intrinsic photostability of canonical DNA and RNA nucleobases. These findings satisfactorily explain why thiobases exhibit the fastest intersystem crossing lifetimes measured to date among bio-organic molecules and have near-unity triplet yields, whereas the triplet yields of canonical nucleobases are nearly zero.

Cardiovascular magnetic resonance of cardiomyopathy in limb girdle muscular dystrophy 2B and 2I

BACKGROUND

Limb girdle muscular dystrophies (LGMD) are inclusive of 7 autosomal dominant and 14 autosomal recessive disorders featuring progressive muscle weakness and atrophy. Studies of cardiac function have not yet been well-defined in deficiencies of dysferlin (LGMD2B) and fukutin related protein (LGMD2I). In this study of patients with these two forms of limb girdle muscular dystrophy, cardiovascular magnetic resonance (CMR) was used to more specifically define markers of cardiomyopathy including systolic dysfunction, myocardial fibrosis, and diastolic dysfunction.

METHODS

Consecutive patients with genetically-proven LGMD types 2I (n = 7) and 2B (n = 9) and 8 control subjects were enrolled. All subjects underwent cardiac magnetic resonance (CMR) on a standard 1.5 Tesla clinical scanner with cine imaging for left ventricular (LV) volume and ejection fraction (EF) measurement, vector velocity analysis of cine data to calculate myocardial strain, and late post-gadolinium enhancement imaging (LGE) to assess for myocardial fibrosis.

RESULTS

Sixteen LGMD patients (7 LGMD2I, 9 LGMD2B), and 8 control subjects completed CMR. All but one patient had normal LV size and systolic function; one (type 2I) had severe dilated cardiomyopathy. Of 15 LGMD patients with normal systolic function, LGE imaging revealed focal myocardial fibrosis in 7 (47%). Peak systolic circumferential strain rates were similar in patients vs. controls: εendo was -23.8 ± 8.5vs. -23.9 ± 4.2%, εepi was -11.5 ± 1.7% vs. -10.1 ± 4.2% (p = NS for all). Five of 7 LGE-positive patients had grade I diastolic dysfunction [2I (n = 2), 2B (n = 3)]. that was not present in any LGE-negative patients or controls.

CONCLUSIONS

LGMD2I and LGMD2B generally result in mild structural and functional cardiac abnormalities, though severe dilated cardiomyopathy may occur. Long-term studies are warranted to evaluate the prognostic significance of subclinical fibrosis detected by CMR in these patients.

A longitudinal study of blood folate levels and depressive symptoms among young women in the Southampton Women's Survey

BACKGROUND

Lower blood folate levels have been associated with depression in cross-sectional surveys, but no studies have examined the relationship prospectively to determine whether the relationship is causal. A follow-up study was designed to examine whether lower blood folate levels predict incident depressive symptoms.

METHOD

Women aged 20-34 years registered in general practices in Southampton, UK, were asked to participate. Baseline assessment included the general health questionnaire (GHQ-12) measure of anxiety and depression, and socioeconomic factors, diet, smoking and alcohol intake. Two years later, participants' general practice (GP) records were examined for evidence of incident symptoms of depression.

RESULTS

At baseline, 5051 women completed the GHQ-12 and had red cell folate levels measured, of whom 1588 (31.4%) scored above the threshold for case level symptoms of anxiety and depression on the GHQ-12. Two years later, GP records for 3996 (79.1%) were examined, but 1264 with baseline evidence of depression were excluded from follow-up analysis. Incident depressive symptoms were recorded for 307 (11.2%) of the remaining 2732. Lower red cell folate levels were associated with caseness on the GHQ-12 (adjusted prevalence ratio 0.99 per 100 nmol/l red cell folate, 95% CI 0.98 to 1.00). No relationship was found between red cell folate levels and incident depressive symptoms over 2 years (adjusted hazard ratio 1.00, 95% CI 0.97 to 1.03).

CONCLUSIONS

Low folate levels were not associated with subsequent depressive symptoms. This suggests that lower blood folate levels may be a consequence rather than a cause of depressive symptoms.

Association between dementia and infectious disease: evidence from a case-control study

Inflammation plays a part in the etiology of dementia. Whether this is the primary pathogenesis, or a secondary reaction is unclear. We postulate that since systemic infection can provoke the enhanced synthesis of inflammatory mediators in the brain, such diseases may promote the onset of dementia. We carried out a nested case-control study using the General Practice Research Database. Cases were patients with incident dementia, and controls without such a diagnosis. Infectious episodes in the four years preceding diagnosis were counted using diagnostic codes, or prescription codes for anti-infective drugs. We considered age, sex, smoking, diabetes mellitus, and frequency of consultation as potential confounders. There were 9954 valid cases, and 9374 valid controls. Cases were on average older, more likely to be female, to smoke and to have diabetes, than the controls. There was an increased risk of diagnosis of dementia in those patients older than 84 with infections (OR for 2 or more infections compared with 0 or 1 = 1.4, 95% CI 1.2 to 1.7). Smoking and diabetes mellitus were also shown to markedly increase the risk of diagnosis of dementia. We have shown a positive association between episodes of infection and increased likelihood of diagnosis of dementia in the very elderly. Smoking and diabetes mellitus are associated with onset of dementia in the elderly. The evidence from this study may represent cause and effect, since there is a credible biologic explanation.

Lactococcal 936-Species Phage Attachment to Surface of Lactococcus lactis

The interactions of the 936-species phages sk1, jj50, and 64 with the cell surface of Lactococcus lactis LM0230 were analyzed. Cell envelopes (walls + plasma membrane), cell wall, or plasma membrane from L. lactis ssp. lactis LM0230 each inactivated the phages in vitro. However, other 936-species phages kh and P008, which do not infect strain LM0230, were not inactivated by any of the subcellular fractions. Treating cell walls or plasma membrane with the cell wall hydrolase mutanolysin eliminated inactivation of phage sk1. This suggested that intact cell wall fragments were required for inactivation. A role for plasma membrane in phage sk1 inactivation was further investigated. Boiling, washing in 2 M KCl, 8 M urea, or 0.1 M Na(2)CO(3)/pH 11, or treating the plasma membrane with proteases did not reduce adsorption or inactivation of phage. Adding lipoteichoic acid or antibodies to lipoteichoic acid did not reduce inactivation of phage in a mixture with membrane, suggesting that lipoteichoic acid was not involved. Inactivation by envelopes or cell wall correlated with ejection of DNA from the phage sk1 capsid. Although calcium is required for plaque formation, it was not required for adsorption, inactivation, or ejection of phage DNA by envelopes or cell wall. The results suggest that at least for phages sk1, jj50, and 64, adsorption and phage DNA injection into the host does not require a host membrane protein or lipoteichoic acid, and that cell wall components are sufficient for these initial steps of phage infection.

Acute and long-term management of patients with vertebral fractures

Symptomatic vertebral fractures are associated with significant morbidity, excess mortality and health and social service expenditure. Up to 20% of patients with an incident vertebral fracture experience a further vertebral fracture within one year. It is therefore important that vertebral fractures are detected early, and treatment considered as soon as possible. Only a third of vertebral fractures come to medical attention, where they typically present with acute back pain, but other presentations include loss of height and increasing kyphosis. Spine X-rays should then be performed to confirm the diagnosis and exclude other pathology. Bone density measurements are not essential before starting treatment for osteoporosis in patients with low-trauma vertebral fractures, but may be useful to confirm osteoporosis when there is uncertainty about previous trauma. They may also aid in selecting the most appropriate therapy and monitoring response to treatment. Up to 30% of women and 55% of men with symptomatic vertebral crush fractures have underlying secondary osteoporosis, where treatment may lead to large increases in bone density. These conditions should therefore be sought by medical history, physical examination and appropriate investigations. The management of patients with acute vertebral fractures should include measures to reduce pain and improve mobility, as well as starting treatment for osteoporosis. Treatments have now been shown in randomized controlled trials to improve bone density and reduce the incidence of vertebral and non-vertebral fractures in patients with osteoporosis. Choice of treatment will depend on the underlying causes of bone loss, efficacy in any particular situation, cost, patient preference and the potential non-skeletal advantages and disadvantages.

The clinical and cost-effectiveness of patient education models for diabetes: a systematic review and economic evaluation

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of educational interventions for patients with diabetes, compared with usual care or other educational interventions.

DATA SOURCES

Electronic databases, reference lists and experts were all consulted in this study. Sponsor submissions to the National Institute of Clinical Excellence were also reviewed.

REVIEW METHODS

Electronic databases were searched, references of all retrieved articles were checked for relevant studies, and experts were contacted for advice and peer review and to identify additional published and unpublished references. Randomised clinical trials (RCTs) and controlled clinical trials (CCTs) were included if they fulfilled pre-specified criteria, among which was follow-up from inception for 12 months or longer. Data were synthesised through a narrative review because the diversity of studies prevented a meta-analysis.

RESULTS

Twenty-four studies (18 RCTs and six CCTs) that compared education with either a control group or with another educational intervention were included. The quality of reporting and methodology was generally found to be poor by today's standards. As part of treatment intensification, education in Type 1 diabetes (four studies) resulted in significant and long-lasting improvements in metabolic control and reductions in complications. In Type 2 diabetes (16 studies) a diversity of educational programmes did not yield consistent results on measures of metabolic control. Inconsistent results on metabolic control were also found in studies of diabetes of either type (four studies), with studies of lower quality producing significant effects. Few studies evaluated quality of life. Economic evaluations comparing education with usual care or other educational interventions were not identified.

CONCLUSIONS

Education as part of intensification of treatment produces improvement in diabetic control in Type 1 diabetes. Mixed results in Type 2 diabetes mean that no clear characterisation is possible as to what features of education may be beneficial. Cost analysis and information from sponsor submissions indicated that where costs associated with patient education were in the region of 500-600 pounds sterling per patients, the benefits over time would have to be very modest to offer an attractive cost-effectiveness profile. Further research should focus on RCTs with clear designs based on explicit hypotheses and with a range of outcomes evaluated after long follow-up intervals.

Sedation with "non-sedating" antihistamines: four prescription-event monitoring studies in general practice

OBJECTIVES

To investigate the frequency with which sedation was reported in post-marketing surveillance studies of four second generation antihistamines: loratadine, cetirizine, fexofenadine, and acrivastine.

DESIGN

Prescription-event monitoring studies.

SETTING

Prescriptions were obtained for each cohort in the immediate post-marketing period.

SUBJECTS

Event data were obtained for a total of 43 363 patients.

MAIN OUTCOME MEASURES

Reporting of sedation or drowsiness.

RESULTS

The odds ratios (adjusted for age and sex) for the incidence of sedation were 0.63 (95% confidence interval 0.36 to 1.11; P=0.1) for fexofenadine; 2.79 (1.69 to 4.58; P<0.0001) for acrivastine, and 3.53 (2.07 to 5.42; P<0.0001) for cetirizine compared with loratadine. No increased risk of accident or injury was evident with any of the four drugs.

CONCLUSIONS

Although the risk of sedation was low with all four drugs, fexofenadine and loratadine may be more appropriate for people working in safety critical jobs.

Prescription-event and other forms of epidemiological monitoring of side-effects in the UK

The post-marketing surveillance (PMS) of drugs is necessary because of the limited size of the clinical safety database at the time of marketing. The principal hypothesis-generating methods of PMS are spontaneous reporting (e.g. the yellow card) and Prescription Event Monitoring. These methods are discussed in this chapter and certain basic pharmacoepidemiological issues that are relevant are briefly reviewed.

Oral contraceptives and myocardial infarction: results of the MICA case-control study

OBJECTIVES

To determine the association between myocardial infarction and use of different types of oral contraception in young women.

DESIGN

Community based case-control study. Data from interviews and general practice records.

SETTING

England, Scotland, and Wales.

PARTICIPANTS

Cases (n=448) were recruited from women aged between 16 and 44 who had suffered an incident myocardial infarction between 1 October 1993 and 16 October 1995. Controls (n=1728) were women without a diagnosis of myocardial infarction matched for age and general practice.

MAIN OUTCOME MEASURES

Odds ratios for myocardial infarction in current users of all combined oral contraceptives stratified by their progestagen content compared with non-users; current users of third generation versus second generation oral contraceptives.

RESULTS

The adjusted odds ratio for myocardial infarction was 1.40 (95% confidence interval 0.78 to 2. 52) for all combined oral contraceptive users, 1.10 (0.52 to 2.30) for second generation users, and 1.96 (0.87 to 4.39) for third generation users. Subgroup analysis by progestagen content did not show any significant difference from 1, and there was no effect of duration of use. The adjusted odds ratio for third generation users versus second generation users was 1.78 (0.66 to 4.83). 87% of cases were not exposed to an oral contraceptive, and 88% had clinical cardiovascular risk factors or were smokers, or both. Smoking was strongly associated with myocardial infarction: adjusted odds ratio 12.5 (7.29 to 21.5) for smoking 20 or more cigarettes a day.

CONCLUSIONS

There was no significant association between the use of oral contraceptives and myocardial infarction. The modest and non-significant point estimates for this association have wide confidence intervals. There was no significant difference between second and third generation products.

Safety profile of nicorandil—prescription-event monitoring (PEM) study

PURPOSE

A PEM study of nicorandil (Ikorel) was undertaken to assess the drug's overall safety in everyday clinical practice.

METHODS

The prescription data used covered the period December 1994 to October 1996. The event data, which were based on a minimum observation period of 6 months, came from questionnaires returned by the prescribing general practitioners. Incidence densities (IDs) were calculated for all events occurring during month 1, months 2-6, and the overall treatment period. Selected events were followed up.

RESULTS

The study was based on a cohort of 13,260 patients and 86,760 patient-months of nicorandil treatment. Major indications for use were angina (8744) and ischaemic heart disease (846). Adverse reactions (258) were reported in 175 (1.3%) of patients--the most frequent being headache (58; 0.4%) and unspecified side effects (36; 0.3%). The most common reasons for stopping treatment (excluding those confounded by indication) were headache (477; 3.5%), dizziness (88; 0.65%) and 'not effective' (491; 3.6%). The number of patients still being prescribed nicorandil after 6 months was 74.3%. In those cases where an opinion on effectiveness was given, nicorandil was reported to be effective in 80% (8713) of patients. The event of headache/migraine had the highest ID in the first month of treatment (49.4 per 1000 patient-months) and was not confounded by indication. Follow-up of selected events was reassuring overall; rare side effects included angioneurotic oedema and photosensitivity (3 cases each).

CONCLUSION

This PEM study provides information on the 'real-world' use of nicorandil and shows generally that the drug is safe when used in the recommended dosage.

Nicorandil and diabetes: a nested case-control study to examine a signal generated by prescription-event monitoring

OBJECTIVE

To investigate a signal generated by an observational cohort study that treatment with the potassium channel opener drug, nicorandil, is associated with an increased incidence of diabetes mellitus (DM).

METHODS

Nested case-control study within cohorts used for prescription-event monitoring.

RESULTS

The cohort study of nicorandil showed that there was a significant difference between the event rate for DM in the first month after starting nicorandil, compared to months 2-6 (difference in rates 1.93, 99% CI 0.7-3.1, per 1000 patient months of treatment). However, the adjusted odds ratio from the case-control study was 1.42 (95% CI 0.66-3.07) for incidence of newly diagnosed DM in nicorandil versus four comparator drugs.

CONCLUSIONS

The nested case-control study was used as a hypothesis-testing instrument for following up a signal of a possible drug reaction to nicorandil. It showed no evidence that nicorandil is associated with increased incidence of newly diagnosed DM.

Psychiatric aspects of alcohol misuse

Alcohol and psychiatric disorder have a complicated relationship. Certain important psychiatric syndromes arise from the toxic effects of alcohol and thiamine deficiency. Liver disease and hypoglycaemia are also associated with their own psychiatric syndromes. Many psychiatric patients also turn to alcohol as an easily available 'medication'.

Does good practice organization improve the outcome of care for diabetic patients?

BACKGROUND

Audit of diabetic care is becoming common in general practice. Most of this audit is concerned with structure and process; outcome audit is much more difficult to achieve.

AIM

To determine whether the structure of general practice diabetic care influenced the process or outcome and whether efficiency of process predicted improved outcome.

METHOD

Cross-sectional survey, by questionnaire and review of notes, among general practices in the East Dorset district, involving diabetic patients identified from general practitioner (GP) disease registers or from a hospital diabetic register. The main outcome measures were the proportion of process and outcome measurements, related to selected structure criteria and the proportion of outcome measurements, related to appropriate process measurements. All associations were tested using the practice as the unit of analysis.

RESULTS

Practices with a detailed diabetic register showed a positive association with a higher proportion of some process, but no outcome, measurements compared to those practices without such a registrar. A high proportion of process measurements did not correlate with improved outcome.

CONCLUSION

Assessment of the follow-up of diabetic patients in general practice by measurement of the structure or process of care does not allow the prediction of an improved outcome for those patients when summarized on a practice basis. There is no shortcut to the collection of data on outcome as a measure of the benefit of follow-up for diabetic patients.

The role of prescribing and referral bias in studies of the association between third generation oral contraceptives and increased risk of thromboembolism

Recently published papers have shown a slightly increased risk for venous thromboembolism (VTE) among users of third generation oral contraceptive pills (OC) as compared with users of second generation OC. The extra risk is small (about twofold) and could be explained possibly by biases introduced into the original case-control studies. This paper examines the possible role of prescribing bias (i.e. that doctors would prescribe third generation OC preferentially to women whom they knew to be at risk of VTE) and referral bias (i.e. that doctors would preferentially refer women on third generation OC to hospital for investigations of symptoms suggestive of VTE). A cross-sectional survey was carried out of 106 physicians, to record their attitude to the prescription of OC in certain risk situations. Each doctor then extracted data on OC prescription from approximately 12 patients under his care. A total of 1192 patients were included. Data collected related to known risk factors to which the patient was prone, and the type of OC that the woman was taking. The results from the doctors' attitudinal survey showed that third generation oral contraceptives seemed to be very popular among doctors in England and that they would prefer to prescribe third generation to second generation oral contraceptives in virtually all risk situations, and also in situations where there was no particular risk of VTE. The results from the patients' survey, however, did not correspond with the attitudinal survey, and there was no evidence of a systematic bias running through this sample of patients, associating third generation OC prescription with particular risk factors. The results from the doctors' attitudinal survey on referral did not show any evidence of potential bias towards referring patients on third generation OC to hospitals. Comparison of this survey with an equivalent survey done in Germany suggests that there may be different factors governing doctors' behaviour in Germany and England, with reference to choice of OC prescription.

The application of molecular biology to the development of novel vaccines

In summary, we have shown that yeast is the preferred host for the expression of recombinant-derived hepatitis B vaccines, and that a yeast expression system which is productive, stable and scaleable can be developed for each of the three HBV envelope proteins. The versatility of regulated and integrated yeast expression systems in the production of foreign polypeptides with biomedical utility also has been highlighted. We also have shown that careful attention to the development of recombinant clones helps to optimize the entire production process leading to highly purified products which share many biochemical properties with the plasma-derived vaccine. Furthermore, immunization with PreS2 sequences is capable of protecting chimpanzees from HBV infection. The availability of PreS2 + S and PreS1 + PreS2 + S proteins expressed in yeast now provides the opportunity for establishing the relevance of such candidate vaccines in preventing human disease, thereby highlighting the utility of molecular biology in modern vaccine development.

A candidate vaccine for hepatitis B containing the complete viral surface protein

The entire surface protein of hepatitis B virus serotype ayw containing the preS (preS1+preS2) and S domains has been expressed in the yeast Saccharomyces cerevisiae. Yeast containing a recombinant plasmid utilizing a constitutive promoter did not express this gene successfully due to the toxicity of the protein. A plasmid using a regulatable promoter directed expression which initiated late in the exponential phase of growth and resulted in the accumulation of high intracellular levels of the complete surface protein. The purified polypeptide aggregates into a form which, although not comprised of typical 20 nm particles, displays antigenic determinants encoded by the preS1, preS2 and S domains. Immunization of rabbits elicited the formation of antibodies directed against all three domains. This candidate vaccine will be useful for studying the contributions to viral immunity of the host response to the preS1 and preS2 domains.

Unexplained acute backache in longstanding ankylosing spondylitis

Patients with longstanding ankylosing spondylitis who develop untypical severe backache may have spinal lesions.

Human acute myelogenous leukemia antigens defined by simian antisera: evidence for leukemia-associated antigens distinct from immune response-associated alloantigens

Leukemic blasts from a patient with acute myelogenous leukemia (AML) and peripheral blood T- and B-lymphocyte subpopulations from his genetically identical normal twin were analyzed with the use of the simian antiserum-defining AML antigens and a rabbit antiserum to immune response-associated (la)-like antigens. Blast cells from the patient consistently reacted with both reagents, whereas the B-lymphocyte populations from the patient's normal identical twin reacted only with the rabbit anti-la serum and in no instances reacted with the antiserum to AML cell antigens. Blast cells from the AML patient significantly stimulated the lymphocytes of his normal twin and his own remission leukocytes, whereas the cells from the normal twin failed to stimulate the cells of the patient. These results suggested the existence on AML cells of tumor-associated antigens that are distinct from various other well-characterized normal human alloantigens and differentiation antigens including B-cell antigens. Changes were reported in the expression of leukemia-associated antigens and Ia-like antigens on the cells of an AML patient undergoing chemotherapy as well as in the ability of the simian antisera to distinguish antigens specific for myeloid leukemias from lymphocytic types of leukemias.