Anita McGrogan

The epidemiology of Guillain-Barré syndrome worldwide. A systematic literature review

Background: This systematic literature review of the epidemiology of Guillain-Barré syndrome (GBS) identifies trends in incidence rates by age, study method and cause of disease. It is important to have a reliable estimate of incidence to determine and investigate any changes: no previous systematic reviews of GBS have been found. Methods: After critical assessment of the reliability of the reported data, incidence rates were extracted from all relevant papers published between 1980 and 2008, identified through searches of Medline, Embase and Science Direct. Results: Sixty-three papers were included in this review; these studies were prospective, retrospective reviews of medical records or retrospective database studies. Ten studies reported on the incidence in children (0–15 years old), and found the annual incidence to be between 0.34 and 1.34/100,000. Most studies investigated populations in Europe and North America and reported similar annual incidence rates, i.e. between 0.84 and 1.91/100,000. A decrease in incidence over the time between the 1980s and 1990s was found. Up to 70% of cases of GBS were caused by antecedent infections. Conclusions: Our best estimate of the overall incidence of GBS was between 1.1/100,000/year and 1.8/100,000/year. The incidence of GBS increased with age after 50 years from 1.7/100,000/year to 3.3/100,000/year.

The incidence of primary glomerulonephritis worldwide: a systematic review of the literature

BACKGROUND Little is known about the worldwide variation in incidence of primary glomerulonephritis (GN). The objective of this review was to critically appraise studies of incidence published in 1980-2010 so that an overall view of trends of these diseases can be found. This would provide important information for determining changes in rates and understanding variations between countries. METHODS All relevant papers found through searches of Medline, Embase and ScienceDirect were critically appraised and an assessment was made of the reliability of the reported incidence data. RESULTS This review includes 40 studies of incidence of primary GN from Europe, North and South America, Canada, Australasia and the Middle East. Rates for the individual types of disease were found to be in adults, 0.2/100,000/year for membrano-proliferative GN, 0.2/100,000/year for mesangio-proliferative GN, 0.6/100,000/year for minimal change disease, 0.8/100,000/year for focal segmental glomerulosclerosis, 1.2/100,000/year for membranous nephropathy and 2.5/100,000/year for IgA nephropathy. Rates were lower in children at around 0.1/100,000/year with the exception of minimal change disease where incidence was reported to be 2.0/100,000/year in Caucasian children with higher rates in Arabian children (9.2/100,000/year) and Asian children (6.2-15.6/100,000/year). CONCLUSIONS This study found that incidence rates of primary GN vary between 0.2/100,000/year and 2.5/100,000/year. The incidence of IgA nephropathy is at least 2.5/100,000/year in adults; this disease can exist subclinically and is therefore only detected by chance in some patients. In addition, referral policies for diagnostic biopsy vary between countries. This will affect the incidence rates found.

The Incidence of Myasthenia Gravis: A Systematic Literature Review

Background: A systematic review of literature published between 1980 and 2007, on the incidence of myasthenia gravis, was undertaken. Methods: All relevant papers found through searches of Medline, Embase and Science Direct were critically appraised and an assessment was made of the reliability of the reported incidence data. Results: Thirty-one studies were included in the review, the majority of which investigated populations in Europe. The incidence rates reported were between 3.0 and 30.0/1,000,000/year. However, it is thought that the rates at the upper end of this range, reported by the prospective studies, provided the most accurate estimates. Overall, incidence rates have increased over time owing to a greater awareness of the disease and improved methods of diagnosis. Conclusions: The most accurate estimate of incidence of myasthenia gravis was around 30/ 1,000,000/year. The incidence in children and adolescents aged 0–19 years was found to be between 1.0 and 5.0/ 1,000,000/year. The rates presented in this review are likely to be an underestimate of the true incidence rates, as mild cases will have been missed and cases in the elderly will have been misdiagnosed.

The incidence of autoimmune thyroid disease: a systematic review of the literature

Objective  To undertake a systematic review of literature published between 1980 and 2008 on the incidence of autoimmune thyroid disease.

Evaluating the Hazard of Foetal Death following H1N1 Influenza Vaccination; A Population Based Cohort Study in the UK GPRD

Background To evaluate the risk of foetal loss associated with pandemic influenza vaccination in pregnancy. Retrospective cohort study. UK General Practice Research Database Pregnancies ending in delivery or spontaneous foetal death after 21 October 2009 and starting before 01 January 2010. Methodology/Principal Findings Hazard ratios of foetal death for vaccinated compared to unvaccinated pregnancies were estimated for gestational weeks 9 to 12, 13 to 24 and 25 to 43 using discrete-time survival analysis. Separate models were specified to evaluate whether the potential effect of vaccination on foetal loss might be transient (for ∼4 weeks post vaccination only) or more permanent (for the duration of the pregnancy). 39,863 pregnancies meeting our inclusion criteria contributed a total of 969,322 gestational weeks during the study period. 9,445 of the women were vaccinated before or during pregnancy. When the potential effect of vaccination was assumed to be transient, the hazard of foetal death during gestational weeks 9 through 12 (HRunadj 0.56; CI95 0.43 to 0.73) and 13 through 24 (HRunadj 0.45; CI95 0.28 to 0.73) was lower in the 4 weeks after vaccination than in other weeks. Where the more permanent exposure definition was specified, vaccinated pregnancies also had a lower hazard of foetal loss than unvaccinated pregnancies in gestational weeks 9 through 12 (HRunadj 0.74; CI95 0.62 to 0.88) and 13 through 24 (HRunadj 0.59; CI95 0.45 to 0.77). There was no difference in the hazard of foetal loss during weeks 25 to 43 in either model. Sensitivity analyses suggest the strong protective associations observed may be due in part to unmeasured confounding. Conclusions/Significance Influenza vaccination during pregnancy does not appear to increase the risk of foetal death. This study therefore supports the continued recommendation of influenza vaccination of pregnant women.

Use of laser speckle contrast imaging to assess digital microvascular function in primary Raynaud phenomenon and systemic sclerosis: a comparison using the Raynaud condition score diary

Objective. Evaluate objective assessment of digital microvascular function using laser speckle contrast imaging (LSCI) in a cross-sectional study of patients with primary Raynaud phenomenon (RP) and systemic sclerosis (SSc), comparing LSCI with both infrared thermography (IRT) and subjective assessment using the Raynaud Condition Score (RCS) diary. Methods. Patients with SSc (n = 25) and primary RP (n = 18) underwent simultaneous assessment of digital perfusion using LSCI and IRT with a cold challenge on 2 occasions, 2 weeks apart. The RCS diary was completed between assessments. The relationship between objective and subjective assessments of RP was evaluated. Reproducibility of LSCI/IRT was assessed, along with differences between primary RP and SSc, and the effect of sex. Results. There was moderate-to-good correlation between LSCI and IRT (Spearman rho 0.58–0.84, p < 0.01), but poor correlation between objective assessments and the RCS diary (p > 0.05 for all analyses). Reproducibility of IRT and LSCI was moderate at baseline (ICC 0.51–0.63) and immediately following cold challenge (ICC 0.56–0.86), but lower during reperfusion (ICC 0.3–0.7). Neither subjective nor objective assessments differentiated between primary RP and SSc. Men reported lower median daily frequency of RP attacks (0.82 vs 1.93, p = 0.03). Perfusion using LSCI/IRT was higher in men for the majority of assessments. Conclusion. Objective and subjective methods provide differing information on microvascular function in RP. There is good convergent validity of LSCI with IRT and acceptable reproducibility of both modalities. Neither subjective nor objective assessments could differentiate between primary RP and SSc. Influence of sex on subjective and objective assessment of RP warrants further evaluation.

Factors associated with uptake of seasonal and pandemic influenza vaccine among clinical risk groups in the UK: an analysis using the General Practice Research Database.

BACKGROUND Influenza vaccine uptake rates are low compared with uptake rates of many other vaccines. It is unclear how this differs between risk groups in the population and between pandemic and non-pandemic influenza vaccines. AIM This study sought to estimate uptake rates of pandemic and seasonal influenza vaccines among clinical risk groups in the UK during the 2009/2010 influenza season and to identify predictors of vaccine uptake in this cohort. METHODS Uptake rates were calculated using data from the UK General Practice Research Database (GPRD). Predictors of vaccination were identified using a modified Poisson regression with robust standard error estimates. RESULTS Uptake of pandemic influenza vaccine in clinical risk groups was 40.3% and uptake of seasonal influenza vaccine was 61.3%. Factors found to be predictive of seasonal and pandemic influenza vaccination included age and the total number of underlying health conditions an individual had. At risk individuals in those age groups in which universal vaccination of the general population was recommended were more likely to have been vaccinated than individuals in age groups in which only clinical risk groups were recommended for vaccination; hence children in clinical risk groups were more likely to receive pandemic than seasonal influenza vaccine. In older people, having a history of Guillain Barré syndrome was associated with a reduced likelihood of receipt of both seasonal (IRR(adj) 0.83, CI(95) 0.77-0.90) and pandemic influenza vaccines (IRR(adj) 0.82, CI(95) 0.73-0.92). DISCUSSION Uptake of pandemic influenza vaccine was lower than that of seasonal influenza vaccine among those at a clinically high risk of influenza related morbidity. This suggests that vaccination strategies may need to be altered during future pandemics. Recommending universal vaccination within age categories in which there is a large proportion of high risk individuals could be considered as this may result in higher uptake among clinical risk groups.

Pandemic influenza vaccination during pregnancy: An investigation of vaccine uptake during the 2009/10 pandemic vaccination campaign in Great Britain

Background: Pregnant women in Great Britain were recommended to receive influenza A(H1N1)pdm09 vaccines during the 2009/10 influenza pandemic, however uptake of the vaccines by pregnant women was reported to have been very low. Aim: We sought to estimate uptake of influenza A(H1N1)pdm09 vaccines and to investigate predictors of vaccine uptake in pregnant women in Great Britain during the 2009/10 pandemic. Methods: Uptake rates were calculated using data from the UK General Practice Research Database (GPRD). Predictors of vaccination were identified using a Cox proportional hazards model. Results: Uptake of influenza A(H1N1)pdm09 vaccines by pregnant women was 21.6%. Pregnant women with an underlying health condition increasing the risk of influenza-related complications had a higher vaccination rate than pregnant women without such conditions. The hazard ratio comparing these two groups decreased logarithmically throughout pregnancy from 9.3 in the first week to 1.3 by the end of pregnancy. Increasing maternal age (HR 1.01, CI95 1.01–1.01), having a previous delivery recorded (HR 1.21, CI95 1.16–1.27) and living in Scotland (HR 2.58, CI95 2.34–2.85) or Wales (HR 1.37, CI95 1.20–1.57) as opposed to England were all also associated with an increase in vaccination uptake rates throughout pregnancy. Discussion: Uptake of influenza A(H1N1)pdm09 vaccines by pregnant women was low. None of the potential predictors evaluated in this study were strong enough to account for this, however information on health beliefs and GP recommendation were not available. If the low rates reported here are to be improved new strategies to increase uptake of influenza vaccine in pregnant women need to be identified, evaluated and implemented.

Pregnancy losses in women with type 1 or type 2 diabetes in the UK: an investigation using primary care records

This study aims to investigate pregnancy losses in women with Type 1 or Type 2 diabetes and compare this with the general population.

Prescribing of Antidiabetic Medicines before, during and after Pregnancy: A Study in Seven European Regions

Aim To explore antidiabetic medicine prescribing to women before, during and after pregnancy in different regions of Europe. Methods A common protocol was implemented across seven databases in Denmark, Norway, The Netherlands, Italy (Emilia Romagna/Tuscany), Wales and the rest of the UK. Women with a pregnancy starting and ending between 2004 and 2010, (Denmark, 2004–2009; Norway, 2005–2010; Emilia Romagna, 2008–2010), which ended in a live or stillbirth, were identified. Prescriptions for antidiabetic medicines issued (UK) or dispensed (non-UK) during pregnancy and/or the year before or year after pregnancy were identified. Prescribing patterns were compared across databases and over calendar time. Results 1,082,673 live/stillbirths were identified. Pregestational insulin prescribing during the year before pregnancy ranged from 0.27% (CI95 0.25–0.30) in Tuscany to 0.45% (CI95 0.43–0.47) in Norway, and increased between 2004 and 2009 in all countries. During pregnancy, insulin prescribing peaked during the third trimester and increased over time; third trimester prescribing was highest in Tuscany (2.2%) and lowest in Denmark (0.5%). Of those prescribed an insulin during pregnancy, between 50.5% in Denmark and 88.8% in the Netherlands received an insulin analogue alone or in combination with human insulin, this proportion increasing over time. Oral products were mainly metformin and prescribing was highest in the 3 months before pregnancy. Metformin use during pregnancy increased in some countries. Conclusion Pregestational diabetes is increasing in many areas of Europe. There is considerable variation between and within countries in the choice of medication for treating pregestational diabetes in pregnancy, including choice of insulin analogues and oral antidiabetics, and very large variation in the treatment of gestational diabetes despite international guidelines.