Schizophrenia polygenic risk scores, clinical variables and genetic pathways as predictors of phenotypic traits of bipolar I disorder

AIM

We investigated the predictive value of polygenic risk scores (PRS) derived from the schizophrenia GWAS (Trubetskoy et al., 2022) (SCZ3) for phenotypic traits of bipolar disorder type-I (BP-I) in 1878 BP-I cases and 2751 controls from Romania and UK.

METHODS

We used PRSice-v2.3.3 and PRS-CS for computing SCZ3-PRS for testing the predictive power of SCZ3-PRS alone and in combination with clinical variables for several BP-I subphenotypes and for pathway analysis. Non-linear predictive models were also used.

RESULTS

SCZ3-PRS significantly predicted psychosis, incongruent and congruent psychosis, general age-of-onset (AO) of BP-I, AO-depression, AO-Mania, rapid cycling in univariate regressions. A negative correlation between the number of depressive episodes and psychosis, mainly incongruent and an inverse relationship between increased SCZ3-SNP loading and BP-I-rapid cycling were observed. In random forest models comparing the predictive power of SCZ3-PRS alone and in combination with nine clinical variables, the best predictions were provided by combinations of SCZ3-PRS-CS and clinical variables closely followed by models containing only clinical variables. SCZ3-PRS performed worst. Twenty-two significant pathways underlying psychosis were identified.

LIMITATIONS

The combined RO-UK sample had a certain degree of heterogeneity of the BP-I severity: only the RO sample and partially the UK sample included hospitalized BP-I cases. The hospitalization is an indicator of illness severity. Not all UK subjects had complete subphenotype information.

CONCLUSION

Our study shows that the SCZ3-PRS have a modest clinical value for predicting phenotypic traits of BP-I. For clinical use their best performance is in combination with clinical variables.

Multiple psychiatric polygenic risk scores predict associations between childhood adversity and bipolar disorder

BACKGROUND

It remains unclear how adverse childhood experiences (ACE) and increased genetic risk for bipolar disorder (BD) interact to influence BD symptom outcomes. Here we calculated multiple psychiatric polygenic risk scores (PRS) and used the measures of ACE to understand these gene-environment interactions.

METHOD

885 BD subjects were included for analyses. BD, ADHD, MDD and SCZ PRSs were calculated using the PRS-CS-auto method. ACEs were evaluated using the Children Life Event Questionnaire (CLEQ). Participants were divided into groups based on the presence of ACE and the total number of ACEs. The associations between total ACE number, PRSs and their interactions were evaluated using multiple linear and logistic regressions. Secondary analyses were performed to evaluate the influence of ACE and PRS on sub-phenotypes of BD.

RESULTS

The number of ACEs increased with the ADHD PRS. BD participants who had ACEs showed an earlier age of BD onset and higher odds of having rapid cycling. Increased BD PRS was associated with increased odds of developing psychotic symptoms. Higher ADHD PRS was associated with increased odds of having rapid cycling. No prediction effect was observed from MDD and SCZ PRS. And, we found no significant interaction between ACE numbers and any of the PRSs in predicting any selected BD sub-phenotypes.

LIMITATIONS

The study was limited by sample size, ACE definition, and cross-sectional data collection method.

CONCLUSIONS

The findings consolidate the importance of considering multiple psychiatric PRSs in predicting symptom outcomes among BD patients.

A genome-wide genomic score added to standard recommended stratification tools does not improve the identification of patients with very low bone mineral density

The role of integrating genomic scores (GSs) needs to be assessed. Adding a GS to recommended stratification tools does not improve the prediction of very low bone mineral density. However, we noticed that the GS performed equally or above individual risk factors in discrimination.

PURPOSE

We aimed to investigate whether adding a genomic score (GS) to recommended stratification tools improves the discrimination of participants with very low bone mineral density (BMD).

METHODS

BMD was measured in three thoracic vertebrae using CT. All participants provided information on standard osteoporosis risk factors. GSs and FRAX scores were calculated. Participants were grouped according to mean BMD into very low (<80 mg/cm3), low (80-120 mg/cm3), and normal (>120 mg/cm3) and according to the Bone Health and Osteoporosis Foundation recommendations for BMD testing into an "indication for BMD testing" and "no indication for BMD testing" group. Different models were assessed using the area under the receiver operating characteristics curves (AUC) and reclassification analyses.

RESULTS

In the total cohort (n=1421), the AUC for the GS was 0.57 (95% CI 0.52-0.61) corresponding to AUCs for osteoporosis risk factors. In participants without indication for BMD testing, the AUC was 0.60 (95% CI 0.52-0.69) above or equal to AUCs for osteoporosis risk factors. Adding the GS to a clinical risk factor (CRF) model resulted in AUCs not statistically significant from the CRF model. Using probability cutoff values of 6, 12, and 24%, we found no improved reclassification or risk discrimination using the CRF-GS model compared to the CRF model.

CONCLUSION

Our results suggest adding a GS to a CRF model does not improve prediction. However, we noticed that the GS performed equally or above individual risk factors in discrimination. Clinical risk factors combined showed superior discrimination to individual risk factors and the GS, underlining the value of combined CRFs in routine clinics as a stratification tool.

Using national electronic health records for pandemic preparedness: validation of a parsimonious model for predicting excess deaths among those with COVID-19-a data-driven retrospective cohort study

OBJECTIVES

To use national, pre- and post-pandemic electronic health records (EHR) to develop and validate a scenario-based model incorporating baseline mortality risk, infection rate (IR) and relative risk (RR) of death for prediction of excess deaths.

DESIGN

An EHR-based, retrospective cohort study.

SETTING

Linked EHR in Clinical Practice Research Datalink (CPRD); and linked EHR and COVID-19 data in England provided in NHS Digital Trusted Research Environment (TRE).

PARTICIPANTS

In the development (CPRD) and validation (TRE) cohorts, we included 3.8 million and 35.1 million individuals aged ≥30 years, respectively.

MAIN OUTCOME MEASURES

One-year all-cause excess deaths related to COVID-19 from March 2020 to March 2021.

RESULTS

From 1 March 2020 to 1 March 2021, there were 127,020 observed excess deaths. Observed RR was 4.34% (95% CI, 4.31-4.38) and IR was 6.27% (95% CI, 6.26-6.28). In the validation cohort, predicted one-year excess deaths were 100,338 compared with the observed 127,020 deaths with a ratio of predicted to observed excess deaths of 0.79.

CONCLUSIONS

We show that a simple, parsimonious model incorporating baseline mortality risk, one-year IR and RR of the pandemic can be used for scenario-based prediction of excess deaths in the early stages of a pandemic. Our analyses show that EHR could inform pandemic planning and surveillance, despite limited use in emergency preparedness to date. Although infection dynamics are important in the prediction of mortality, future models should take greater account of underlying conditions.

POS1380 AUTOANTIBODIES ARE ASSOCIATED WITH EROSIVE DAMAGE IN THE SECOND AND THIRD METACARPOPHALANGEAL JOINTS ASSESSED BY HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

The presence of anti-citrullinated protein antibodies (ACPAs) and rheumatoid factor (RF) are prognostic for erosive severity by radiography in patients with rheumatoid arthritis (RA) [1]. However, others have shown that RF mainly acts as an enhancer for ACPAs mediated bone loss [2]. High-resolution peripheral quantitative computed tomography (HR-pQCT) has a very high resolution with a voxel size of 82 µm3, and has been proposed to monitor disease activity in patients with RA. In the current study, erosive damage was assessed by HR-pQCT according to the presence of autoantibodies. The hypothesis is that the presence of RF and especially ACPA is associated with erosive damage in two metacarpophalangeal (MCP) joints assessed by HR-pQCT; this has previously been shown using 44 joints assessment of both hands and feet by conventional radiography.

Objectives

The objective was to investigate if the presence of the autoantibodies, RF and ACPAs, was associated with a higher erosive burden in two MCP joints assessed by HR-pQCT.

Methods

Patients with RA and disease duration ≥ 5 years had their second and third MCP joints imaged by HR-pQCT. Age, sex, disease duration, ACPAs and RF status were acquired. From the Danish Clinical Quality Program – The Danish Rheumatologic Database (DANBIO) [3], the average 28-joint Disease Activity Score (DAS28-CRP) and Health Assessment Questionnaire (HAQ) from five years before inclusion were extracted. Statistical significance was investigated for the following groups, who were ordered according to the expected erosive burden: RF+/ACPA+ patients, RF-/ACPA+ patients, RF+/ACPA- patients, and autoantibodies negative patients. Analysis of variance was used to investigate the difference between the groups for age and sex. Cuzick’s Rank-sum test for trend of ordered groups was used to test for trend for disease duration, 5-year average HAQ, 5-year average DAS28, number of erosions, total erosive volume, and average erosion volume.

Results

A total number of 353 patients with RA were included in this study. 203 was RF+/ACPA+ positive, 52 was RF-/ACPA+ positive, 24 were RF+/ACPA- positives, and 74 were autoantibodies negative. The groups were comparable with respect to age, sex distribution, disease duration and mean disease activity during the last five years, according to mean DAS28-CRP and mean HAQ during the previous five years.

There was a statistically significant test for trend for total erosive volume (p = 0.016) and average erosion volume (p = 0.043), but not for the number of erosions (p = 0.053) (Figure 1). A significant difference between the groups was only observed between double-positive patients and patients negative for autoantibodies.

Figure 1.

Scatterplot showing the number of erosions (A), total erosive volume (B) and the average volume of erosions (C) in the second and third MCP joint per patient according to the presence of the autoantibodies, ACPAs, as well as RF. Boxes denote the median and 25th and 75th percentile of the groups.

Conclusion

In the current study, HR-pQCT scanning of only two MCP joints supports previous findings by radiography of both hands and feet, showing the accumulated erosive burden is higher in patients double-positive for RF and ACPA.

References

[1]Syversen SW, Gaarder PI, Goll GL, et al. High anti-cyclic citrullinated peptide levels and an algorithm of four variables predict radiographic progression in patients with rheumatoid arthritis: results from a 10-year longitudinal study. Ann Rheum Dis 2008;67:212–7. doi:10.1136/ARD.2006.068247

[2]Hecht C, Englbrecht M, Rech J, et al. Additive effect of anti-citrullinated protein antibodies and rheumatoid factor on bone erosions in patients with RA. Ann Rheum Dis 2015;74:2151–6. doi:10.1136/annrheumdis-2014-205428

[3]Ibfelt EH, Jensen DV, Hetland ML. The Danish nationwide clinical register for patients with rheumatoid arthritis: DANBIO. Clin Epidemiol 2016;8:737–42. doi:10.2147/CLEP.S99490

Disclosure of Interests

Rasmus Klose-Jensen: None declared, Josephine Therkildsen: None declared, Anne-Birgitte Blavnsfeldt: None declared, Bente Langdahl Speakers bureau: Amgen, UCB, Eli Lilly, Gedeon-Richter, Astellas, Consultant of: Amgen, UCB, Gedeon-Richter, Eli Lilly, Gedeon., Grant/research support from: Amgen, Novo Nordisk, Jesper Thygesen: None declared, Kresten Keller: None declared, Ellen-Margrethe Hauge Speakers bureau: AbbVie, Sanofi, Sobi, MSD, UCB, Consultant of: AbbVie, Sanofi, Sobi, MSD, UCB, Grant/research support from: Research funding to Aarhus University Hospital from Novo Nordic Foundation, Danish Rheumatism Association, Danish Regions Medicine Grants, Roche, Novartis.

Travel expenses from Celgene, MSD, Pfizer, Roche, Sobi.

POS0526 HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY AND PREDICTION OF EROSIVE PROGRESSION AS ASSESSED BY THE GOLD STANDARD CONVENTIONAL RADIOGRAPHY IN ESTABLISHED RHEUMATOID ARTHRITIS: A 1-YEAR COHORT STUDY

Background

High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) is a promising imaging technique for assessing erosive disease in rheumatoid arthritis (RA). We have shown that the diagnostic accuracy in detecting erosive disease of HR-pQCT of two joints corresponds to conventional radiography (CR) of 44 joints in established RA (1). No data assessing HR-pQCT as a tool for predicting erosive radiographic progression in a large cohort of established RA has been published.

Objectives

To assess the association between erosive disease identified using either CR or HR-pQCT at baseline and erosive progression using CR during 1-year follow-up in established RA.

Methods

This observational cohort study included 220 patients with RA (disease duration ≥ 5 yrs) at the Department of Rheumatology, Aarhus University Hospital, between Mar. 2018 and Oct. 2020. All participants had demographic information collected, together with HR-pQCT at baseline and CR made at baseline and 1-year follow-up. Erosive assessment using HR-pQCT was performed at the second and third metacarpophalangeal (MCP) joint (2). The Sharp/van der Heijde score (SHS) method was used to assess erosive status and erosive progression using CR of hands, wrists and feet (3).

Results

In total, 220 participants with RA (median age 66 yrs, interquartile range (IQR) 57-72; 71% women) were included and 212 completed their follow-up visit in Dec. 2021 (dropout n=8 (4 %)). During follow-up (median 1 yrs, range 0.7-1.4), erosive progression on CR was detected in 24 of 211 (11%) (missing baseline CR, n=1). Characteristics of the study population by erosive progression are shown in Table 1. In unadjusted regression analyses, number of erosions on HR-pQCT at baseline and erosion score (per 10) using CR at baseline were associated with erosive progression (yes/no) on CR at 1-year (Odds ratio (OR) 1.1; 95%CI 1.0-1.1; p<.05 and OR 1.1; 95%CI 1.0-1.2; p<.01). After adjusting for age and sex, erosion score remained associated with erosive progression (OR 1.1; 95%CI 1.1-1.2; p<.01), but number of erosions did not (OR 1.0; 95%CI 1.0-1.1; p=.07).

Table 1.

Demographics at baseline

Progression on CRNo progression on CRP valueNo24/211 (11)187/211 (89)Age, yrs66 (57-73)66 (57-71).80Women15/24 (63)134/187 (72).35Disease Duration, yrs20 (8-28)15 (9-23).44DAS28-CRP1.7 (1.5-2.5)1.8 (1.5-2.5).53Erosive on CR24/24 (100)141/187 (75)< .01Erosive 2nd/3rdMCP on CR*17/23 (74)62/185 (34)< .001Erosive on HR-pQCT22/23 (96)153/185 (83).14Erosion score (per 10)4 (2-7)1 (0-3)< .0001Erosion number10 (5-17)3 (1-10)< .01Total erosion volume, mm3128 (19-201)26 (2-111)< .05

Data are no. (%) or median with interquartile range. P-values: Mann-Whitney U or Fisher’s exact test. Missing HR-pQCT, n=3. CR = conventional radiography, DAS28-CRP = disease activity score of 28 joints based on C-reactive protein, HR-pQCT = high-resolution peripheral quantitative computed tomography

* Same hand as HR-pQCT scanned

Conclusion

In established RA, baseline CR of 44 joints is superior to baseline HR-pQCT of two joints in identifying individuals at risk of erosive progression on CR. This underlines the need for a head-to-head comparison between progression identified by HR-pQCT and CR to fully assess the clinical utility of HR-pQCT in predicting erosive progression compared to CR.

References

[1]Klose-Jensen R, Therkildsen J, Blavnsfeldt AG, et al. Diagnostic accuracy of high-resolution peripheral quantitative computed tomography and X-ray for classifying erosive rheumatoid arthritis. Rheumatology (Oxford, England). 2021

[2]Barnabe C, Feehan L. High-resolution peripheral quantitative computed tomography imaging protocol for metacarpophalangeal joints in inflammatory arthritis: the SPECTRA collaboration. The Journal of rheumatology. 2012;39(7):1494-5

[3]van der Heijde D. How to read radiographs according to the Sharp/van der Heijde method. The Journal of rheumatology. 2000;27(1):261-3

Acknowledgements

The Danish Rheumatism Association (R179-A6365-B1668), The Health Research Foundation of Central Denmark Region (R64-A3145-B1504 and R49-A2254-B1504), The Novo Nordic Founda-tion, A.P. Møller Fonden, The Becket fund (20-2-5756), The Aase and Einar Danielsens fund (20-10-0254), The Family Hede Nielsens fund, The Grosserer L.F. Foghts fund and Aarhus University funded this project. The authors would like to thank all study participants and the clinical staff involved in this project.

Disclosure of Interests

Josephine Therkildsen: None declared, Rasmus Klose-Jensen: None declared, Anne-Birgitte Blavnsfeldt: None declared, Bente Langdahl Speakers bureau: BLL has received honorariums from Amgen, UCB, Eli Lilly, Gedeon-Richter and Astellas., Consultant of: BLL has worked as a consultant for Amgen, UCB, Gedeon-Richter, Eli Lilly and Gedeon., Grant/research support from: BLL has received financial grants from Amgen and the Novo Nordic Foundation., Anna Zejden: None declared, Jesper Thygesen: None declared, Kresten Keller: None declared, Ellen-Margrethe Hauge Speakers bureau: EMH has received honorariums and/or consulting fees from AbbVie, Sanofi, Sobi, and SynACT Pharma., Grant/research support from: EMH has received research grants to Aarhus University Hospital from Danish Regions Medicine Grants, Roche, Novartis, and the Novo Nordic Foundation.

POS1151 OPPORTUNISTIC BONE MINERAL DENSITY SCREENING IN PATIENTS UNDERGOING CARDIAC CT SCANS: EFFECT OF USING IMAGES CONTAINING INTRAVENOUS CONTRAST

Background

Osteoporosis is under-diagnosed worldwide causing increased risk of fractures and death (1). Computed tomography (CT) scans performed on other indications such as coronary artery disease harbor the potential for automatic detection of low volumetric bone mineral density (vBMD) of the vertebrae using quantitative CT (QCT); hence allowing estimation of future fracture risk (2). CT is often performed with intravenous (iv) contrast administration. In 2015, the International Society of Clinical Densitometry stated: “There is insufficient evidence to judge the effect of contrast agents on a classification of low BMD” (3); this position remains. Thus, it is important to assess the effect of contrast enhancement in order to broaden the potential of vBMD screening using routine CT scans.

Objectives

We aimed to compare thoracic vBMD measurements from CT scans with and without iv contrast enhancement.

Methods

This cross-sectional multicenter sub-study is based on a larger clinical trial, Dan-NICAD-1, from which we randomly selected a cohort of 136 participants. First, a non-contrast scan was performed followed by a contrast-enhanced scan during which 60-90mL of iv contrast was administered (Iomeron, 350 mgI/mL). Mindways QCT Pro software was used to measure BMD values (mg/cm3) and the mean estimate was calculated for each participant (4). American College of Radiology quantitative CT cut-off values for lumbar spine were used to categorize patients into very low (<80mg/cm3), low (80-120mg/cm3), or normal BMD (>120mg/cm3).

Results

In 136 participants undergoing cardiac CT (Table 1), we found a different mean vBMD before vs. after contrast; 117.5 mg/cm3 [95%CI: 111.6–123.4] vs. 132.1 mg/cm3 [95%CI: 125.1–139.1], p<.0001. The absolute difference was 14.7mg/cm3 [95%CI: 12.3–17.0]; the relative difference, was 12.5% [95% CI: 10.5–14.5]. In total, 8/15 (53%) participants changed from very low BMD to low BMD after contrast administration, and 21 participants (21/63, 33%) changed from low to normal BMD (Figure 1). No participants changed from very low BMD to normal BMD.

Table 1.

Demographics by vBMD*

CharacteristicsAll (n=136)Very low BMD (n=15)Low BMD (n=63)Normal BMD (n=58)Gender M:F89:478:749:1432:26Age, yrs (range)57±9 (40-73)64±6 (48-72)59±8 (44-73)54±8 (40-72)Mean vBMD before contrast, mg/cm92.2±16.168.0±10.598.0±10.1151.5±21.9Mean vBMD after contrast, mg/cm95.2±16.068.6±10.5100.8±10.3159.6±31.6Risk factorsDiabetes mellitus**16079Smoking status**Never6541744Former181710Active5252423Bone dataDXA performed previously**7232Osteoporosis diagnosed previously**1010Family history of osteoporosis**22589Anti-osteoporotic medication**152310

* Classifications defined by American College of Radiology and grouped using the non-enhanced CT. Data: number of participants, (range) and mean with standard deviations.

** Self-reported

Figure 1.

Participants with change in BMD category after contrast administration Figure 1. vBMD measurements before and after contrast administration. 33/136 participants changed BMD category illustrated by the dotted lines (80 mg/cm3; 120 mg/cm3). Black lines: increase in vBMD after contrast (n=29); blue lines: decrease in vBMD after contrast (n=4).

Conclusion

Our data suggest a significant effect of contrast on clinical vBMD measurements; thus, this should be adjusted for before using contrast-enhanced cardiac CT for opportunistic vBMD screening. This urges further studies on the effect of scan protocols on the contrast-enhanced increase in BMD.

References

[1]M. S. Nanes et al., Seminars in nuclear medicine44, 439-450 (2014).

[2]J. Therkildsen et al., Radiology296, 499-508 (2020).

[3]K. Engelke et al., Journal of clinical densitometry18, 393-407 (2015).

[4]J. Therkildsen et al., Journal of Clinical Densitometry23, (2018).

Acknowledgements

The Danish Osteoporosis Foundation, The Danish Council for Independent Research (DFF–7025–00103), the Danish Heart foundation (15-R99-A5837–22920), the Hede Nielsen Foundation, Acarix A/S (unrestricted grant) and Mrs. Lily Benthine Lunds Foundation of 1.6. 1978 supported this project. The authors would like to thank all study participants and the clinical staff involved in this project.

Disclosure of Interests

Andia Cheneymann: None declared, Josephine Therkildsen: None declared, Simon Winther Grant/research support from: Disclosed an unrestricted grant from Acarix A/S., Louise Nissen: None declared, Jesper Thygesen: None declared, Bente Langdahl Consultant of: Worked as a consultant for Amgen, UCB, Gedeon-Richter, Eli Lilly and Gedeon., Grant/research support from: Received honorariums from Amgen, UCB, Eli Lilly, Gedeon-Richter and Astellas. Received financial grants from Amgen and the Novo Nordic Foundation., Ellen-Margrethe Hauge Consultant of: Received honorariums and/or consulting fees from AbbVie, Sanofi, Sobi, and SynACT Pharma., Grant/research support from: Research grants to Aarhus University Hospital from Danish Regions Medicine Grants, Danish Rheumatism Association, Roche, Novartis, and Novo Nordic Foundation., Morten Böttcher Consultant of: Advisory board participation for NOVO Nordisk, Astra-Zeneca, Pfizer, Boeringer Ingelheim, Bayer, Sanofi, Novartis and Acarix.

A European Perspective on Costs and Cost Effectiveness of Ophthalmic Combinations in the Treatment of Open-Angle Glaucoma

Purpose

Efficacy, safety, and cost implications are important considerations when choosing an ophthalmic treatment. Fixed-combination glaucoma medications containing brimonidine 0.2% and timolol 0.5%, or dorzolamide 2% and timolol 0.5%, were compared with brimonidine 0.2% and dorzolamide 2% that were used as adjunctive therapy to timolol 0.5%.

Methods

A literature review was conducted to determine the outcome parameters of intraocular pressure reduction and tolerability after 3 months of use of brimonidine or dorzolamide, each together with timolol as a fixed-combination or in concomitant therapy. Modelled cost-minimization and cost-effectiveness analyses were performed to investigate the economic consequences of ophthalmic therapy with brimonidine, dorzolamide, and timolol from a societal perspective.

Results

The literature review found that brimonidine and dorzolamide used as fixed combinations with timolol as well as in adjunctive therapy to timolol were equally effective and safe. Furthermore, in the European countries studied, the fixed combination of brimonidine/timolol represented a less costly option when compared to the fixed combination of dorzolamide/timolol evaluated over both a 3-month and a 12-month horizon.

Conclusions

Brimonidine used as a fixed-combination therapy with timolol provided better cost value than dorzolamide/timolol in all the countries studied. For most countries, the fixed combination of brimonidine and timolol also provided better cost value than adjunctive therapy with brimonidine, which was more cost effective than adjunctive therapy with dorzolamide.

First experiences with model based iterative reconstructions influence on quantitative plaque volume and intensity measurements in coronary computed tomography angiography

PURPOSE

Investigate the influence of adaptive statistical iterative reconstruction (ASIR) and the model-based IR (Veo) reconstruction algorithm in coronary computed tomography angiography (CCTA) images on quantitative measurements in coronary arteries for plaque volumes and intensities.

METHODS

Three patients had three independent dose reduced CCTA performed and reconstructed with 30% ASIR (CTDI_vol at 6.7 mGy), 60% ASIR (CTDI_vol 4.3 mGy) and Veo (CTDI_vol at 1.9 mGy). Coronary plaque analysis was performed for each measured CCTA volumes, plaque burden and intensities.

RESULTS

Plaque volume and plaque burden show a decreasing tendency from ASIR to Veo as median volume for ASIR is 314 mm³ and 337 mm³-252 mm³ for Veo and plaque burden is 42% and 44% for ASIR to 39% for Veo. The lumen and vessel volume decrease slightly from 30% ASIR to 60% ASIR with 498 mm³-391 mm³ for lumen volume and vessel volume from 939 mm³ to 830 mm³. The intensities did not change overall between the different reconstructions for either lumen or plaque.

CONCLUSION

We found a tendency of decreasing plaque volumes and plaque burden but no change in intensities with the use of low dose Veo CCTA (1.9 mGy) compared to dose reduced ASIR CCTA (6.7 mGy & 4.3 mGy), although more studies are warranted.

Dynamic contrast-enhanced CT in suspected lung cancer: quantitative results

OBJECTIVES

To examine whether dynamic contrast-enhanced CT (DCE-CT) could be used to characterise and safely distinguish between malignant and benign lung tumours in patients with suspected lung cancer.

METHODS

Using a quantitative approach to DCE-CT, two separate sets of regions of interest (ROIs) in tissues were placed in each tumour: large ROIs over the entire tumour and small ROIs over the maximally perfused parts of the tumour. Using mathematical modelling techniques and dedicated perfusion software, this yielded a plethora of results.

RESULTS

First, because of their non-normal distribution, DCE-CT measurements must be analysed using log scale data transformation. Second, there were highly significant differences between large ROI and small ROI measurements (p<0.001). Thus, the ROI method used in a given study should always be specified in advance. Third, neither quantitative parameters (blood flow and blood volume) nor semi-quantitative parameters (peak enhancement) could be used to distinguish between malignant and benign tumours. This was irrespective of the method of quantification used for large ROIs (0.13<p<0.76) and small ROIs (0.084<p<0.31). Fourth, although there were no indications of systematic reproducibility bias, the 95% limits of agreement were so broad that the risk of disagreement between the measurements could affect the clinical use of the measurements. This lack of reproducibility should be addressed. CONCLUSION AND ADVANCES IN KNOWLEDGE: A quantitative approach to DCE-CT is not a clinically usable method for characterising lung tumours.

Late-stage, primary open-angle glaucoma in Europe: social and health care maintenance costs and quality of life of patients from 4 countries

OBJECTIVE

The purpose of this study was to estimate costs and quality of life (QoL) of late-stage glaucoma patients in 4 European countries.

METHODS

Retrospective review of medical charts of patients with POAG who were followed in a low-vision or vision rehabilitation center in one of 4 countries for at least 1 year was used to determine patient characteristics, health status, and health care resource use. Visual impairment was measured by best-corrected visual acuity (Snellen score). Patients were also interviewed over the telephone in order to assess their health-related QoL (using EuroQol EQ-5D) and use of resources including: the number of visits to rehabilitation centers, visits to hospital and non-hospital specialists, the use of low-vision devices, medication, tests, and the use of hired home help. The costs associated with resource use were calculated from the perspective of a third-party payer of health and social care based on resource usage and unit costs in each country.

RESULTS

Patients undergoing visual rehabilitation in France (n=21), Denmark (n=59), Germany (n=60), and the United Kingdom (n=22) were identified, interviewed and had their medical charts reviewed. Annual maintenance costs of late-stage glaucoma amounted to euro830 (+/-445) on average. Average home help costs were more than 3 times higher. QoL, on average, was 0.65 (+/-0.28). QoL was positively correlated with the level of visual acuity in the patients' best eye. On the other hand, visual acuity was also positively correlated to health care costs, but negatively correlated to costs of home help.

CONCLUSIONS

The study was limited by its observational, uncontrolled design. The finding that late-stage glaucoma is associated with higher home help costs than health care maintenance costs suggests that potential savings from a better preventive treatment are to be found for social care payers rather than health care payers.

A cost-effectiveness analysis of fixed-combination therapies in patients with open-angle glaucoma: a European perspective

OBJECTIVE

To compare the efficacy and cost implications of the use of the intraocular pressure-lowering prostaglandin analogues bimatoprost, travoprost, and latanoprost as fixed-combination therapies with timolol, a beta-adrenergic receptor antagonist.

METHODS

A decision analytic cost-effectiveness model was constructed. Since no head-to-head studies comparing the three treatment options exist, the analysis was based on an indirect comparison. Hence, the model was based on efficacy data from five randomized, controlled, clinical studies. The studies were comparable with respect to study design, time horizon, patient population and type of end point presented. The measure of effectiveness was the percentage reduction of the intraocular pressure level from baseline. The cost evaluated was the cost of medication and clinical visits to the ophthalmologist. All drug costs were market prices inclusive of value-added tax, and visit costs were priced using official physician fees. Cost-effectiveness analyses were carried out in five European countries: Spain, Italy, United Kingdom, Norway and Sweden. The time horizon for the analyses was 3 months.

RESULTS

The analysis showed that fixed-combination bimatoprost/timolol was more effective and less costly than fixed-combination travoprost/timolol and fixed-combination latanoprost/timolol in three out of the five countries analyzed. In two countries, bimatoprost/timolol was less costly than latanoprost/timolol, and cost the same as travoprost/timolol.

CONCLUSIONS

This cost-effectiveness analysis showed that the fixed combination of bimatoprost 0.03%/timolol 0.5% administered once daily was a cost-effective treatment option for patients with primary open-angle glaucoma. This study was limited by available clinical data: without a head-to-head trial, indirect comparisons were necessary. In the United Kingdom, Sweden, Norway, Italy, and Spain, from a health service viewpoint, bimatoprost/timolol was a slightly more effective as well as less costly treatment strategy when compared to both travoprost/timolol and latanoprost/timolol.

[Glaucoma patients treated by practicing ophthalmologists in Denmark. Estimated number of patients and the extent of visual field defects]

A test survey based on a questionnaire was carried out among Danish eye practitioners. The response rate was 72%. The purpose was to estimate the minimum number of patients suffering from glaucoma (prevalence). Survey results show a prevalence of 0.65%. Further, the survey shows a clear correlation between glaucoma diagnosis and age. The number of glaucoma patients increase from approximately 0.5% for persons 50 years of age to approximately 5% for persons 80 years of age. Seventy-two percent of the diagnosed glaucoma patients have visual field defects at different stages. Six percent have central islands on both eyes, the equivalent of a prevalence for social blindness of 0.04%. Ninety-three percent of the diagnosed glaucoma patients receive anti-glaucomatous treatment, of these 42% combination therapy. Eighty percent of glaucoma patients in combination therapy received three or more drugs.

Short-term effect of latanoprost and timolol eye drops on tear fluid and the ocular surface in patients with primary open-angle glaucoma and ocular hypertension

PURPOSE

To investigate and compare the short term effects of topical latanoprost and timolol on the tear fluid and ocular surface condition in patients with bilateral primary open angle glaucoma or ocular hypertension.

METHODS

Thirty-seven patients were included in this randomized, double-masked, parallel group study. Patients received either latanoprost 0.005% (n= 18) or timolol 0.5% (n= 19) instilled once daily in the morning for a treatment period of 27 days. Routine ophthalmic examinations, including intraocular pressure measurement, as well as tests to evaluate tear fluid and the ocular surface were performed.

RESULTS

After one drop of medication, tear secretion was significantly reduced by timolol, but not by latanoprost. At the end of the study the break-up time (BUT) was significantly decreased in the timolol group but not in the latanoprost group. The BUT still remained in the normal range in both groups, although it is important to note that timolol was administered at half the clinical dose. Both latanoprost and timolol tended to increase Rose-Bengal staining of the cornea and conjunctiva after one month of treatment but no statistically significant difference was found between the groups. Corneal sensitivity was within the normal range for all patients during the study.

CONCLUSION

Regarding ocular surface effects, no clinically important differences between latanoprost and timolol were observed as all the effects remained in the normal range.

[Two cases of severe eye and cranial injuries due to firework explosions]

Two patients who sustained serious facial, cranial and eye trauma secondary to recreational fireworks injuries are reported. Initial assessment included axial and coronary computerized tomography, control of haemorrhage, debridement of wound and brain, and in one patient bilateral excenteration of the globe. Both patients suffered from intracranial haemorrhage, but both recovered without severe neurological sequelae.

A milestone in ribosomal crystallography: the construction of preliminary electron density maps at intermediate resolution

Preliminary electron density maps of the large and the small ribosomal particles from halophilic and thermophilic sources, phased by the isomorphous replacement method, have been constructed at intermediate resolution. These maps contain features comparable in size with what is expected for the corresponding particles, and their packing arrangements are in accord with the schemes obtained by ab-initio procedures as well as with the motifs observed in thin sections of the crystals by electron microscopy. To phase higher resolution data, procedures are being developed for derivatization by specific labeling of the ribosomal particles at selected locations with rather small and dense clusters. Potential binding sites are being inserted either by site directed mutagenesis or by chemical modifications to facilitate cluster binding on the surface of the halophilic large and the thermophilic small ribosomal particles, which yield the crystals diffracting to highest resolution (2.9 and 7.3 A (1 A = 0.1 nm), respectively). For this purpose, the surface of these ribosomal particles is being characterized and procedures are being developed for quantitative detachment of selected ribosomal proteins and for their incorporation into core particles. The genes of these proteins are being cloned, sequenced, mutated to introduce reactive side groups, mainly cysteines, and overexpressed. In parallel, two in situ small and stable complexes were isolated from the halophilic ribosome. Procedures for their crystal production in large quantities are currently being developed. Models, reconstructed at low resolution from crystalline arrays of ribosomes and their large subunits, are being used for initial low-resolution phasing of the X-ray amplitudes. The interpretation of these models stimulated the design and the crystallization of complexes mimicking defined functional states of a higher quality than those obtained for isolated ribosomes. These models also inspired modelling experiments according to results of functional studies, performed elsewhere, focusing on the progression of nascent proteins.

Corneal astigmatism after cataract extraction. A comparison of corneal and corneoscleral incisions

Corneal astigmatism after cataract surgery by way of corneal incision (C, n = 62) and corneo-scleral incision (CS, n = 61) was followed for six months. Corneal incisions were closed by continuous nylon 10--0 (7--25 loops, median 14). Corneo-scleral incisions were sutured with single knots (2--10, median value 5). Keratometric results in the C and CS groups are compared. Concerning the degree of astigmatism, pre-operative median values were 0.5 and 0.7 D, respectively. After one week they were 4.5 and 3.0 D; after two weeks 3.3 and 3.0 D; after four months 3.0 and 2.0 D; after six months (final status) 1.5 and 1.7 D, respectively. The differences between C and CS were not significant. For both, astigmatism after cataract surgery did not quite return to pre-operative levels. Concerning the axis (weaker meridian) of corneal astigmatism, the C cases retained their pre-operative distribution, while the CS cases showed the classical shift towards against-rule astigmatism. Final corrected visual acuity was of the same order in the C and CS group. Due to frequent shifts, also of the axis, it is recommended by early (preliminary) glass prescription not to correct the astigmatism, but to give only the best spherical correction.