Validation of the French national health insurance information system as a tool in vaccine safety assessment: Application to febrile convulsions after pediatric measles/mumps/rubella immunization

Epidemiology of congenital heart defects in France from 2013 to 2022 using the PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics) database

BACKGROUND

Congenital heart defects are common and occur in approximately 0.9% of births. In France, the registries cover approximately 20% of the population but not the entirety of France; therefore, we aimed to update the incidence data for congenital heart defects in France from 2013 to 2022 using the medico-administrative database PMSI-MCO (French Medical Information System Program in Medicine, Surgery, and Obstetrics). We aimed to compare the frequency of risk factors in a population with congenital heart defects and a reference population.

METHODS

From 2013 to 2022, we included children aged < 3 years diagnosed with congenital heart defects according to the International Classification of Diseases, 10th Revision, in the PMSI-MCO database. We compared them with a population without congenital defects on several medical data items (e.g., parity, gemellarity, and mortality rate). Bivariate and multivariate analyses compared children with congenital heart defects and children without congenital malformation.

RESULTS

We identified 83,879 children with congenital heart defects in France from 2013 to 2022 in the PMSI-MCO database and 7,739,840 children without such defects, including 7,218,952 without any congenital defects. We observed more deaths (7.49% vs. 0.68%, d = 0.59) and more twinning (8.67% vs. 1.23%, d = 0.35) among children with congenital heart defects. Multivariate analysis revealed an increased risk of congenital heart defects in male individuals (OR [odds ratio] 1.056, 95% CI [confidence interval] [1.039-1.076]) and cases of medically assisted reproduction (OR 1.115, 95% CI [1.045-1.189]) and a reduced risk in the case of multiparity (OR 0.921, 95% CI [0.905-0.938]).

CONCLUSIONS

According to the PMSI-MCO database, the incidence of congenital heart defects in France from 2013 to 2022 is 1% of births. Congenital heart defects are more frequent in cases of prematurity, twinning, primiparity, male sex, and maternal age > 40 years.

Hospitalization for physical child abuse: Associated medical factors and medical history since birth

BACKGROUND

Physical abuse often begins at a very young age and sometimes results in serious or fatal injuries. It is crucial to diagnose physical abuse as early as possible to protect this vulnerable population.

OBJECTIVE

To study the factors associated with the first hospitalization for physical abuse from birth to the infant's first birthday in France.

PARTICIPANTS AND SETTING

We included all singleton children born in a hospital setting in France between 2009 and 2013, who were identified from the French national information system database (SNDS).

METHODS

To study factors associated with the first hospitalization for physical abuse during the first year after birth, we used the Fine and Gray regression model. Factors included in the multivariate model were the infant's sex, prematurity, neonatal conditions, the number of hospitalizations (at least two), medical consultations and complementary universal health insurance (proxy for family precariousness and socio-economic vulnerability).

RESULTS

Over the 2009-2013 period, among 3,432,921 newborn singletons, 903 (0.026 %) were hospitalized for physical abuse in the year following birth. Among the factors associated with physical abuse, such as prematurity (aHR = 2.2[1.8-2.7]), male sex (aHR = 1.3[1.2-1.5]), or having had at least two hospitalizations (aHR = 1.7[1.4-2.1]), we found that complementary universal health insurance coverage was the factor most associated (aHR = 4.1[3.5-4.7]) with being hospitalized for physical abuse.

CONCLUSION

These findings could help introduce preventative measures for infant protection in certain groups, such as parents of infants born prematurely, especially if they are in a precarious situation. This study also suggests that particular attention should be paid to infants who have been hospitalized at least two times in the first year of life, whatever the reason.

Impact of COVID-19 lockdown on surgical procedures for retinal detachment in France: a national database study

BACKGROUND/AIMS

The COVID-19 crisis and the decisions made regarding population lockdown may have changed patient care. We aimed to investigate the incidence rate of rhegmatogenous retinal detachment (RRD) cases during the COVID-19 lockdown period.

METHODS

In this nationwide database study, we identified hospital and clinic admissions of French residents for a first episode of RRD in France from 2017 to the lockdown period in 2020. The monthly hospital incidence rates of RRD procedures per 100 000 inhabitants before, during and after lockdown were computed for the whole country. Finally, we assessed the influence of viral incidence on the RRD incidence rate, comparing two regions with highly contrasting viral penetration.

RESULTS

From January to July, the average monthly national hospital incidence rate of RRD decreased from a mean of 2.59/100 000 inhabitants during 2017-2019 to 1.57/100 000 inhabitants in 2020. Compared with 2019, during the 8-week lockdown period in 2020, a 41.6% decrease in the number of RRD procedures was observed (p<0.001) with the weekly incidence of RRD decreasing from 0.63/100 000 inhabitants in 2019 to 0.36/100 000 inhabitants. During the 4-month post-lockdown period, no increased activity related to postponed procedures was observed. No difference was found in the rate of RRD surgery when comparing two regions with highly contrasting viral incidence.

CONCLUSION

Containment may have been responsible for a decrease in the number of surgical procedures for RRD, without any compensating post-lockdown activity in France. These results might help increase awareness of the management of RRD emergencies.

Risk for Myocardial Infarction, Stroke, and Pulmonary Embolism Following COVID-19 Vaccines in Adults Younger Than 75 Years in France

BACKGROUND

The BNT162b2 (Pfizer-BioNTech) vaccine has been shown to be safe with regard to risk for severe cardiovascular events (such as myocardial infarction [MI], pulmonary embolism [PE], and stroke) in persons aged 75 years or older. Less is known about the safety of other COVID-19 vaccines or outcomes in younger populations.

OBJECTIVE

To assess short-term risk for severe cardiovascular events (excluding myocarditis and pericarditis) after COVID-19 vaccination in France's 46.5 million adults younger than 75 years.

DESIGN

Self-controlled case series method adapted to event-dependent exposure and high event-related mortality.

SETTING

France, 27 December 2020 to 20 July 2021.

PATIENTS

All adults younger than 75 years hospitalized for PE, acute MI, hemorrhagic stroke, or ischemic stroke (n = 73 325 total events).

MEASUREMENTS

Linkage between the French National Health Data System and COVID-19 vaccine databases enabled identification of hospitalizations for cardiovascular events (MI, PE, or stroke) and receipt of a first or second dose of the Pfizer-BioNTech, mRNA-1273 (Moderna), Ad26.COV2.S (Janssen), or ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccine. The relative incidence (RI) of each cardiovascular event was estimated in the 3 weeks after vaccination compared with other periods, with adjustment for temporality (7-day periods).

RESULTS

No association was found between the Pfizer-BioNTech or Moderna vaccine and severe cardiovascular events. The first dose of the Oxford-AstraZeneca vaccine was associated with acute MI and PE in the second week after vaccination (RI, 1.29 [95% CI, 1.11 to 1.51] and 1.41 [CI, 1.13 to 1.75], respectively). An association with MI in the second week after a single dose of the Janssen vaccine could not be ruled out (RI, 1.75 [CI, 1.16 to 2.62]).

LIMITATIONS

It was not possible to ascertain the relative timing of injection and cardiovascular events on the day of vaccination. Outpatient deaths related to cardiovascular events were not included.

CONCLUSION

In persons aged 18 to 74 years, adenoviral-based vaccines may be associated with increased incidence of MI and PE. No association between mRNA-based vaccines and the cardiovascular events studied was observed.

PRIMARY FUNDING SOURCE

None.

Safety of routine childhood vaccine coadministration versus separate vaccination

INTRODUCTION

As new vaccines are developed more vaccine coadministrations vaccines are being offered to make delivery more practical for health systems and patients. We compared the safety of coadministered vaccines with separate vaccination for 20 coadministrations by considering nine types of adverse events following immunisation (AEFI).

METHODS

Real-life immunisation and adverse event data for this observational cohort study were extracted from the Oxford-Royal College of General Practitioners Research and Surveillance Centre for children registered in the database between 2008 and 2018. We applied the self-controlled case series method to calculate relative incidence ratios (RIR) for AEFI. These RIRs compare the RI of AEFI following coadministration with the RI following separate administration of the same vaccines.

RESULTS

We assessed 3 518 047 adverse events and included 5 993 290 vaccine doses given to 958 591 children. 17% of AEFI occurred less and 11% more frequently following coadministration than would have been expected based on the RIs following separate vaccinations, while there was no significant difference for 72% of AEFI. We found amplifying interaction effects for AEFI after five coadministrations comprising three vaccines: for fever (RIR 1.93 (95% CI 1.63 to 2.29)), rash (RIR 1.49 (95% CI 1.29 to 1.74)), gastrointestinal events (RIR 1.31 (95% CI 1.14 to 1.49)) and respiratory events (RIR 1.27 (1.17-1.38)) following DTaP/IPV/Hib+MenC+ PCV; gastrointestinal events (RIR 1.65 (95% CI 1.35 to 2.02)) following DTaP/IPV/Hib+MenC+ RV; fever (RIR 1.44 (95% CI 1.09 to 1.90)) and respiratory events (RIR 1.40 (95% CI 1.25 to 1.57)) following DTaP/IPV/Hib+PCV+ RV; gastrointestinal (RIR 1.48 (95% CI 1.20 to 1.82)) and respiratory events (RIR 1.43 (95% CI 1.26 to 1.63)) following MMR+Hib/MenC+PCV; gastrointestinal events (RIR 1.68 (95% CI 1.07 to 2.64)) and general symptoms (RIR 11.83 (95% CI 1.28 to 109.01)) following MMR+MenC+PCV. Coadministration of MMR+PCV led to more fever (RIR 1.91 (95% CI 1.83 to 1.99)), neurological events (RIR 2.04 (95% CI 1.67 to 2.49)) and rash (RIR 1.06 (95% CI 1.01 to 1.11)) compared with separate administration, DTaP/IPV/Hib+MMR to more musculoskeletal events (RIR 3.56 (95% CI 1.21 to 10.50)) and MMR+MenC to more fever (RIR 1.58 (95% CI 1.37 to 1.82)). There was no indication that unscheduled coadministrations are less safe than scheduled coadministrations.

CONCLUSION

Real-life RIRs of AEFI justify coadministering routine childhood vaccines according to the immunisation schedule. Further research into the severity of AEFI following coadministration is required for a complete understanding of the burden of these AEFI.

Epidemiology of Acute Endophthalmitis after Intraocular Procedures: A National Database Study

OBJECTIVE

To describe the causes of postoperative acute endophthalmitis at the national level longitudinally.

DESIGN

Cohort study from 2009 to 2018 in France.

PARTICIPANTS

Patients diagnosed with acute endophthalmitis after intraocular procedures.

METHODS

The French medical-administrative database was used. Endophthalmitis cases and intraocular procedures were identified based on billing codes in all French hospitals and private practices.

MAIN OUTCOME MEASURES

The incidence of acute endophthalmitis within 42 days of the procedure.

RESULTS

From January 1, 2009, to October 31, 2018, 7522 cases of acute endophthalmitis occurred after 14 438 854 intraocular procedures. Most cases occurred after standalone cataract surgery (4808 cases for 7 316 077 procedures; 63.92%), followed by after intravitreal (IVT) injections (1296 cases for 5 455 631 IVT injections; 17.23%), vitreoretinal surgery (698 for 442 263 procedures; 9.28%), anterior segment surgery (245 cases; 3.26%), combined cataract and vitreoretinal surgery (191 cases; 2.54%), cornea surgery (142 cases; 1.89%), and glaucoma surgery (80 cases; 1.06%). The overall incidence of acute endophthalmitis was 1 per 1920 procedures (0.0521%; 95% confidence interval [CI], 0.0520-0.0522). The surgery with the highest incidence of endophthalmitis was scleral and globe surgery, with an incidence of 0.1827% (95% CI, 0.1757-0.1898), followed by vitreoretinal surgery combined with cataract surgery, with an incidence of 0.1685% (95% CI, 0.1663-0.1706). The incidence of endophthalmitis after IVT injections was stable over the study period, and patients receiving IVT injections were the oldest, aged 75.4 years (standard deviation, 12.0 years; P < 0.001). The onset of endophthalmitis after IVT procedures, i.e, after receiving IVT injections or undergoing vitreoretinal surgery, was earlier than that after the other procedures (P < 0.001).

CONCLUSIONS

The profile of patients referred for acute endophthalmitis has been evolving over the past decade, with a decrease in the raw number of endophthalmitis cases after cataract surgery as opposed to an increase in the number of patients presenting with endophthalmitis after IVT injections.

Enhanced recovery after posterior deep infiltrating endometriosis surgery: a national study

OBJECTIVE

To evaluate the impact of the implementation of a national enhanced recovery after surgery (ERAS) program for posterior deep infiltrating endometriosis (DIE) surgery on the length of hospital stay, the rate of postoperative complications, and readmission within 30 days.

DESIGN

Comparative exposed/nonexposed observational study.

SETTING

Study based on the French national medicoeconomic database of the Program of Medicalization of Information System.

PATIENTS

Seven hundred and sixty-four women who underwent DIE surgery were involved and matched (1:3 ratio) into two groups: ERAS group for the year 2019 and non-ERAS group for the year 2015.

INTERVENTIONS

Surgical management for posterior DIE.

MAIN OUTCOME MEASURES

The length of hospital stay, the rate of postoperative complications during the initial hospital stay, and readmission within 30 days.

RESULTS

The ERAS group included 191 women, and the non-ERAS group included 573 women. The mean length of hospital stay was shorter in the ERAS group than in the non-ERAS group (4.28 ± 3.80 days vs. 5.42 ± 4.04 days, respectively). The rate of postoperative abdominal or pelvic pain syndromes was lower in the ERAS group than in the non-ERAS group (5/191 (2.62%) vs. 48/573 (8.38%), respectively; relative risk, 0.31 [0.125-0.7969]). The rate of postoperative complication and the rate of readmission within 30 days were not different between the two groups.

CONCLUSIONS

The implementation of ERAS has a significant positive impact on patient outcomes after DIE surgery. The length of hospital stay and abdominal or pelvic pain syndromes were reduced without increasing complications or readmission within 30 days.

Early exposure of pregnant women to non-steroidal anti-inflammatory drugs delivered outside hospitals and preterm birth risk: nationwide cohort study

OBJECTIVE

To assess the risk of preterm birth associated with nonsteroidal anti-inflammatory drugs (NSAIDs), focusing on early exposure in the period from conception to 22 weeks of gestation (WG).

DESIGN

National population-based retrospective cohort study.

SETTING

The French National Health Insurance Database that includes hospital discharge data and health claims data.

POPULATION

Singleton pregnancies (2012-2014) with a live birth occurring after 22WG from women between 15 and 45 years old and insured the year before the first day of gestation and during pregnancy were included. We excluded pregnancies for which anti-inflammatory medications were dispensed after 22WG.

METHODS

The association between exposure and risk of preterm birth was evaluated with GEE models, adjusting on a large number of covariables, socio-demographic variables, maternal comorbidities, prescription drugs and pregnancy complications.

MAIN OUTCOME MEASURES

Prematurity, defined as a birth that occurred before 37WG.

RESULTS

Among our 1 598 330 singleton pregnancies, early exposure to non-selective NSAIDs was associated with a significantly increased risk of preterm birth, regardless of the severity of prematurity: adjusted odds ratio (aOR) = 1.76 (95% CI 1.54-2.00) for extreme prematurity (95% CI 22-27WG), 1.28 (95% CI 1.17-1.40) for moderate prematurity (28-31WG) and 1.08 (95% CI 1.05-1.11) for late prematurity (32-36WG), with non-overlapping confidence intervals. We identified five NSAIDs for which the risk of premature birth was significantly increased: ketoprofen, flurbiprofen, nabumetone, etodolac and indomethacin: for the latter, aOR = 1.92 (95% CI 1.37-2.70) with aOR = 9.33 (95% CI 3.75-23.22) for extreme prematurity.

CONCLUSION

Overall, non-selective NSAID use (delivered outside hospitals) during the first 22WG was found to be associated with an increased risk of prematurity. However, the association differs among NSAIDs.

TWEETABLE ABSTRACT

French study for which early exposure to non-selective NSAIDs was associated with increased risk of prematurity.

Could venous thromboembolism and major bleeding be indicators of lung cancer mortality? A nationwide database study

Background

Venous thromboembolism (VTE) is highly prevalent in cancer patients and can cause severe morbidity. VTE treatment is essential, but anticoagulation increases the risk of major bleeding. The purpose was to evaluate the impact of VTE and major bleeding on survival and to identify significant risk factors for these events in lung cancer patients.

Methods

Data were extracted from a permanent sample of the French national health information system (including hospital and out-of-hospital care) from 2009 to 2016. All episodes of VTE and major bleeding events within one year after cancer diagnosis were identified. A Cox model was used to analyse the effect of VTE and major bleeding on the patients’ one-year survival. VTE and major bleeding risk factors were analysed with a Fine and Gray survival model.

Results

Among the 2553 included patients with lung cancer, 208 (8%) had a VTE episode in the year following diagnosis and 341 (13%) had major bleeding. Almost half of the patients died during follow-up. Fifty-six (60%) of the patients presenting with pulmonary embolism (PE) died, 48 (42%) of the patients presenting with deep vein thrombosis (DVT) alone died and 186 (55%) of those presenting with a major bleeding event died. The risk of death was significantly increased following PE and major bleeding events. VTE concomitant with cancer diagnosis was associated with an increased risk of VTE recurrence beyond 6 months after the first VTE event (sHR = 4.07 95% CI: 1.57–10.52). Most major bleeding events did not appear to be related to treatment.

Conclusion

VTE is frequent after a diagnosis of lung cancer, but so are major bleeding events. Both PE and major bleeding are associated with an increased risk of death and could be indicators of lung cancer mortality.

Validation study: evaluation of the metrological quality of French hospital data for perinatal algorithms

OBJECTIVE

The aim of our validation study was to assess the metrological quality of hospital data for perinatal algorithms on a national level.

DESIGN

Validation study.

SETTING

This was a multicentre study of the French medicoadministrative database on perinatal indicators.

PARTICIPANTS

In each hospital, we selected 150 discharge abstracts for delivery (after 22 weeks of gestation), in 2014, and their corresponding medical records. Overall, 22 hospitals were included.

INTERVENTIONS

A single investigator performed blind data collection from medical records in order to compare data from discharge abstracts with data from medical records. Finally, 3246 discharge abstracts were studied.

PRIMARY AND SECONDARY OUTCOME MEASURES

Seventy items, including maternal and delivery characteristics and maternal morbidity, were collected for each delivery stay.

RESULTS

The concordance rate of maternal age at delivery was 94.8% (95% CI 93.8 to 95.4). Combining the two forms of pre-existing diabetes, the algorithm presented a PPV of 65.9% and a sensitivity of 75.7%. The concordance rate of gestational age at delivery was 91.8% (90.9 to 92.7). Regarding gestational diabetes, the PPV was 80.8% (79.4 to 82.2) and the sensitivity was 79.5% (78.1 to 80.9). Regardless of the algorithm explored, the PPV for vaginal delivery was over 99%. For the diagnosis codes corresponding to immediate postpartum haemorrhage, the PPV was 77.7% (76.3 to 79.1) and the sensitivity was 75.5% (74.0 to 77.0). The algorithm for stillbirth presented a PPV of 89.4% (88.3 to 90.5) and a sensitivity of 95.4% (94.7 to 96.1).

CONCLUSIONS

This first national validation study of many perinatal algorithms suggests that the French national hospital database is an appropriate data source for epidemiological studies, except for some indicators which presented low PPV and/or sensitivity.

Oral health treatment habits of people with schizophrenia in France: A retrospective cohort study

OBJECTIVE

To identify the differences between persons with schizophrenia (PWS) and general population in France in terms of oral health treatment (tooth scaling, dental treatment and tooth extraction) and the factors associated with these differences.

METHODS

This retrospective cohort study included PWS identified from a representative sample of 1/97th of the French population (general sample of beneficiaries). PWS were identified from 2014 data by an algorithm that included: F2 diagnostic codes in the register of long-term diseases in 2014 AND {(at least three deliveries of antipsychotics in 2014) OR (F20 diagnostic codes as a main or associated diagnosis in hospital discharge abstracts in 2012 or 2013 (hospital data for medicine, surgery and obstetrics)}. Follow-up dental care was explored for all people over a period of 3 years (2014 to 2017).

RESULTS

In 2014, 580,219 persons older than 15 years were identified from the 96 metropolitan departments in France; 2,213 were PWS (0.4%). Fewer PWS were found along a diagonal line from north-east to south-west France, and the highest numbers were located in urban departments. PWS were more often male (58.6% vs 48.7%, p<0.001). They were less likely to have had tooth scaling but more likely to have undergone a dental extraction. In one third of departments, more than 50% of PWS had at least one tooth scaling over a three-year period; the rate of dental extraction in these departments ranged from 6 to 23%. Then, a quarter of the departments in which 40 to 100% of PWS had had at least one dental extraction (2/8) presented a rate of tooth scaling ranging from 0 to 28% over the study period.

CONCLUSIONS

Compared with the general population, PWS were less likely to have had tooth scaling and dental treatment but more likely to have undergone dental extraction.

Seasonal influenza vaccine and Guillain-Barré syndrome: A self-controlled case series study

OBJECTIVE

To evaluate the risk of Guillain-Barré syndrome (GBS) following seasonal influenza vaccination based on French nationwide data.

METHODS

All cases of GBS occurring in metropolitan France between September 1 and March 31 from 2010 to 2014 were identified from the French national health data system. Data were analyzed according to the self-controlled case series method. The risk period started 1 day after the patient received vaccine (D1) until 42 days after vaccination (D42). The incidence of GBS during this risk period was compared to that of the control period (D43-March 31). The incidence rate ratio (IRR) was estimated after adjusting for seasonality and presence or not of acute infections.

RESULTS

Between September and March, of the 2010/2011 to 2013/2014 influenza vaccination seasons, 3,523 cases of GBS occurred in metropolitan France and were included in the study. Among them, 15% (527 patients) had received influenza vaccination. A total of 140 patients developed GBS during the 42 days following influenza vaccination. The crude risk of developing GBS was not significantly increased during the 42 days following influenza vaccination (IRR, 1.02; 95% confidence interval [CI], 0.83-1.25; p = 0.85). This result remained nonsignificant after adjustment for calendar months and the incidence of acute gastrointestinal and respiratory tract infections (IRR, 1.10; 95% CI, 0.89-1.37; p = 0.38). In contrast, the risk of GBS was fourfold higher after acute respiratory tract infection (IRR, 3.89; 95% CI, 3.52-4.30; p < 0.0001) or gastrointestinal infection (IRR, 3.64; 95% CI, 3.01-4.40; p < 0.0001).

CONCLUSIONS

No association between seasonal influenza vaccination and GBS was shown during the 42 days following vaccination.

Safety of first year vaccination in children born to mothers with inflammatory bowel disease and exposed in utero to anti-TNFα agents: a French nationwide population-based cohort

BACKGROUND

Children born to mothers with IBD may be exposed to anti-TNFα agents antenatally. Current European guidelines recommend postponing live vaccines until after 6 months of life in this population. Data on the safety of live vaccines administration in the first year of life of these children are sparse with one reported fatality following bacillus Calmette-Guerin (BCG) administration.

AIMS

To describe the use and safety of vaccines administered in children born to mothers with IBD and exposed antenatally to anti-TNFα agents METHODS: Data from children born to mothers with IBD between 2013 and 2014 were collected retrospectively from the French Health Insurance Database. Vaccines recommended before or at 1 year of age were considered.

RESULTS

Among 4741 children, 670 (14.1%) were exposed to anti-TNFα agents antenatally, with concomitant thiopurines in 16.0% (n = 107) and steroids in 19.3% (n = 214). Among these 670 children, 315 (47%) were exposed up to delivery. Exposed children were less likely than non-exposed to receive BCG (88/670, 13.1% vs 780/4071, 19.2% respectively, P < .05) and received it later in life (months, mean ± SD, 4.3 ± 3.9 and 2.4 ± 2.9 respectively, P < .001). In exposed children, 64/88 (73%) received BCG vaccination before 6 months of age, but with no BCG-related severe adverse event observed during the first year. Uptake of other vaccines recommended before 6 months was above 85% in both groups.

CONCLUSION

In children exposed antenatally to anti-TNFα agents, vaccinations are often not postponed in keeping with the recommendations, but no BCG-related severe adverse events were reported in children vaccinated before 6 months of life.

Postvaccination Febrile Seizure Severity and Outcome

BACKGROUND

Febrile seizures (FSs) are a common pediatric condition caused by a sudden rise in temperature, affecting 3% to 5% of children aged ≤6 years. Although vaccination can cause FSs, little is known on whether FSs occurring in the time soon after vaccination (vaccine-proximate febrile seizures [VP-FSs] differ clinically from non-vaccine-proximate febrile seizures [NVP-FSs]). We compared the clinical profile and outcomes of VP-FS to NVP-FS.

METHODS

Prospective cohort study of children aged ≤6 years presenting with their first FS at 1 of 5 Australian pediatric hospitals between May 2013 and June 2014. Clinical features, management, and outcomes were compared between VP-FS and NVP-FS.

RESULTS

Of 1022 first FS cases (median age 19.8 months; interquartile range 13.6-27.6), 67 (6%) were VP-FSs. When comparing VP-FS to NVP-FS, there was no increased risk of prolonged (>1 day) hospitalization (odds ratio [OR] 1.61; 95% confidence interval [95% CI] 0.84-3.10), ICU admission (OR 0.72; 95% CI 0.10-5.48), seizure duration >15 minutes (OR 1.47; 95% CI 0.73-2.98), repeat FS within 24 hours (OR 0.80; 95% CI 0.34-1.89), or requirement for antiepileptic treatment on discharge (OR 1.81; 95% CI 0.41-8.02). VP-FS patients with a laboratory-confirmed infection (12%) were more likely to have a prolonged admission compared with those without.

CONCLUSIONS

VP-FS accounted for a small proportion of all FS hospital presentations. There was no difference in outcomes of VP-FS compared with NVP-FS. This is reassuring data for clinicians and parents of children who experience FS after vaccination and can help guide decisions on revaccination.

Continuous Anti-TNFα Use Throughout Pregnancy: Possible Complications For the Mother But Not for the Fetus. A Retrospective Cohort on the French National Health Insurance Database (EVASION)

OBJECTIVES

Inflammatory bowel diseases (IBD) need long-term treatment, which can influence pregnancies in young women. Uncontrolled IBD is associated with poor pregnancy outcomes. Despite the labeling of Anti-tumor necrosis factor (TNF) antibodies (anti-TNFα) which indicates that their use is not recommended during pregnancy, anti-TNFα are increasingly being used during pregnancy and may expose women and their fetuses to treatment-related complications. Existing recommendations on the timing of treatment during pregnancy are inconsistent. We aimed to assess the safety of anti-TNFα treatment in pregnant women with IBD, and up to the first year of life for their children.

METHODS

An exposed/non exposed retrospective cohort was conducted on the French national health system database SNIIRAM (Système National d'Information Inter-Régimes de l'Assurance Maladie). All IBD women who became pregnant between 2011 and 2014 were included. Women with concomitant diseases potentially treated with anti-TNFα were excluded. Anti-TNFα exposure (infliximab, adalimumab, golimumab or certolizumab pegol) during pregnancy was retrieved from the exhaustive prescription database in SNIIRAM. The main judgment criterion was a composite outcome of disease-, treatment- and pregnancy-related complications during pregnancy for the mother, and infections during the first year of life for children.

RESULTS

We analyzed data from 11,275 pregnancies (8726 women with IBD), among which 1457 (12.9%) pregnancies were exposed to anti-TNFα, mainly infliximab or adalimumab, with 1313/7722 (17.0%) suffering from Crohn's disease and 144/3553 (4.1%) from ulcerative colitis. After adjusting for disease severity, steroid use, age, IBD type, and duration and concomitant 6-mercaptopurine use, anti-TNFα treatment was associated with a higher risk of overall maternal complications (adjusted Odds Ratio (aOR) = 1.49; 95% confidence interval (CI): 1.31-1.67) and infections (aOR = 1.31; 95% CI: 1.16-1.47). Maintaining anti-TNFα after 24 weeks did not increase the risk of maternal complication, but interrupting the anti-TNFα increased relapse risk. No increased risk for infection was found in children (aOR = 0.89; 95% CI: 0.76-1.05) born to mother exposed to anti-TNFα during pregnancy.

CONCLUSIONS

Anti-TNFα treatment during pregnancy increased the risk of maternal complications compared to unexposed; however, discontinuation before week 24 increased the risk of disease flare. There was no increased risk for children exposed to anti-TNFα up to 1 year of life.

Self-controlled case series studies: Just how rare does a rare non-recurrent outcome need to be?

The self-controlled case series method assumes that adverse outcomes arise according to a non-homogeneous Poisson process. This implies that it is applicable to independent recurrent outcomes. However, the self-controlled case series method may also be applied to unique, non-recurrent outcomes or first outcomes only, in the limit where these become rare. We investigate this rare outcome assumption when the self-controlled case series method is applied to non-recurrent outcomes. We study this requirement analytically and by simulation, and quantify what is meant by 'rare' in this context. In simulations we also apply the self-controlled risk interval design, a special case of the self-controlled case series design. To illustrate, we extract data on the incidence rate of some recurrent and non-recurrent outcomes within a defined study population to check whether outcomes are sufficiently rare for the rare outcome assumption to hold when applying the self-controlled case series method to first or unique outcomes. The main findings are that the relative bias should be no more than 5% when the cumulative incidence over total time observed is less than 0.1 per individual. Inclusion of age (or calendar time) effects will further reduce bias. Designs that begin observation with exposure maximise bias, whereas little or no bias will be apparent when there is no time trend in the distribution of exposures, or when exposure is central within time observed.

Thirty-day rehospitalizations among elderly patients with acute myocardial infarction: Impact of postdischarge ambulatory care

Rehospitalization after acute myocardial infarction (AMI) is common in elderly patients. It increases morbimortality and health care expenditures. The association between ambulatory care after discharge for AMI and rehospitalization has never been studied in France. We analyzed the impact of ambulatory care on rehospitalization of elderly patients (≥65 years) within 30 days after hospital discharge.We conducted a nationwide population-based study of elderly patients hospitalized with a main diagnosis of AMI in France between 2011 and 2013. We excluded patients hospitalized for AMI in the previous year and those who died during the index hospitalization or within 30 days after discharge. The primary outcome was the first all-cause 30-day rehospitalization in an acute care hospital. Individual and neighborhood-level variables were compared among rehospitalized and nonrehospitalized patients. Determinants of 30-day rehospitalization were identified using logistic regression models.Among the 624 eligible patients, 137 (22.0%) were rehospitalized within 30 days after discharge. In multivariate analyses, chronic kidney failure (odds ratio [OR] 1.88; 95% confidence interval [CI], 1.01-3.53) was an independent predictor of 30-day rehospitalization. We found no association among deprivation and spatial accessibility measures and 30-day rehospitalization. The purchase of lipid-lowering drugs prescription within 7 days after discharge was associated with a reduced risk of 30-day rehospitalization (OR 0.53; 95% CI, 0.36-0.79).This study highlights the role of coordination among hospital and primary care physicians in post-AMI discharge and follow-up among elderly patients. Specifically, targeted interventions to reduce 30-day rehospitalizations should focus on patients with comorbidities and use of prescription drugs after hospital discharge.

The French prospective multisite registry on sudden unexpected infant death (OMIN): rationale and study protocol

INTRODUCTION

Even after 'back-to-sleep' campaigns, sudden unexpected infant death (SUID) continues to be the leading cause of death for infants 1 month to 1 year old in developed countries, with devastating social, psychological and legal implications for families. To sustainably tackle this problem and decrease the number of SUIDs, a French SUID registry was initiated in 2015 to (1) inform prevention with standardised data, (2) understand the mechanisms leading to SUID and the contribution of the already known or newly suggested risk factors and (3) gather a multidisciplinary group of experts to coordinate and develop innovative and urgent research in the SUID area.

METHODS AND ANALYSIS

This observational multisite prospective observatory includes all cases of sudden unexpected deaths in children younger than 2 years occurring in the French territory covered by the 35 participating French referral centres. From these cases, various data concerning sociodemographic conditions, death scene, personal and family medical history, parental behaviours, sleep environment, clinical examinations, biological and imagery investigations and autopsy are systematically collected. These data will be complemented as of 2018 with a biobank of diverse biological samples (blood, hair, urine, faeces and cerebrospinal fluid), with other administrative health-related data (health claim reimbursements and hospital admissions) and socioenvironmental data. Insights from exploratory descriptive statistics and thematic analysis will be combined for the design of targeted strategies to effectively reduce preventable infant deaths.

ETHICS AND DISSEMINATION

The French sudden unexpected infant death registry (Observatoire National des Morts Inattendues du Nourrisson registry;OMIN) was approved in 2015 by the French Data Protection Authority in clinical research (Commission Nationale de l'Informatique et des Libertés: number 915273) and by an independent ethics committee (Groupe Nantais d'Ethique dans le Domaine de la Santé: number 2015-01-27). Results will be discussed with associations of families affected by SUID, caregivers, funders of the registry, medical societies and researchers and will be submitted to international peer-reviewed journals and presented at international conferences.

Exchangeable Femoral Neck (Dual-Modular) THA Prostheses Have Poorer Survivorship Than Other Designs: A Nationwide Cohort of 324,108 Patients

BACKGROUND

Exchangeable neck stems, defined as those with a dual taper (that is, a modular junction between the femoral head and the femoral neck and an additional junction between the neck and the stem body), were introduced in THA to improve restoration of joint biomechanics (restoring anteversion, offset, and limb length) and reduce the risk of dislocation. However exchangeable necks have been reported to result in adverse effects such as stem fractures and acute local tissue reaction. Whether they result in a net improvement to or impairment of reconstructive survivorship remains controversial.

QUESTIONS/PURPOSES

(1) To compare the prosthetic survivorship and all-cause revision risk of exchangeable femoral neck THAs versus fixed neck THAs, taking known prosthetic revision risk factors into account; and (2) to compare the cause-specific revision risk of exchangeable femoral neck THAs versus fixed neck THAs, adjusting for known prosthetic risk factors.

METHODS

Using French national health-insurance databases, we identified all French patients older than 40 years who underwent primary THA from 2009 through 2012. To ensure accuracy of the data, we considered only beneficiaries of the general insurance scheme (approximately 77% of the population). Characteristics of the prosthesis and the patients receiving an exchangeable femoral neck THA were compared with those receiving a fixed femoral neck THA (defined as femoral stem with only the head being exchangeable). Revision was the event of interest. Followup started on the date the THA was performed, until the patient experienced revision, died, was lost to followup, or until the followup period ended (December 31, 2014), whichever came first. Competing risk THA survivorship was calculated and compared (purpose 1), as were cause-specific Cox regression models (purpose 2). The study cohort included 324,108 individuals with a mean age of 77 years. A total of 24% underwent THA for acute trauma, and 3% of the group received an exchangeable neck THA. During the median 45-month followup (mean, 42 months; minimum, 1 day; maximum, 6 years), 11,968 individuals underwent prosthetic revision.

RESULTS

The cumulative revision incidence was 6.5% (95% CI, 5.8%-7.3%) for exchangeable neck THAs versus 4.7% (95% CI, 4.6%-4.8%) for fixed neck THAs (p < 0.001). After controlling for potential confounding variables including age, sex, comorbidities, indication for THA, cementation, bearing surface, and the characteristics of the center where the implantation was performed, we found that the exchangeable femoral neck THA was associated with an increased hazard ratio (HR) of revision of 1.26 (95% CI, 1.14-1.38; p < 0.001) compared with the fixed neck THA. When dealing with cause-specific revision, exchangeable neck THAs had a higher incidence of revision for implant failure or periprosthetic fracture, and for mechanical complications; adjusted HRs were, respectively, 1.68 (95% CI, 1.24-2.27; p < 0.001) and 1.27 (95% CI, 1.13-1.43; p < 0.001), for exchangeable neck THAs compared with fixed ones.

CONCLUSIONS

Exchangeable neck THAs had poorer survivorship independent of other prosthetic revision risk factors. Accordingly, expected anatomic and functional benefits should be carefully assessed before choosing this design.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Human papillomavirus vaccination and risk of autoimmune diseases: A large cohort study of over 2million young girls in France

BACKGROUND

Whether human papillomavirus (HPV) vaccination could induce or trigger autoimmune diseases (AID) has been questioned, and potentially contributes to low immunization coverage in France. This study evaluated the association between HPV vaccination and the risk of AID using routinely collected data sources.

METHODS

All girls aged 13-16years between 2008 and 2012, covered by the general health insurance scheme and without history of HPV vaccination or AID, were included and followed using French nationwide databases. Fourteen neurological, rheumatological, haematological, gastrointestinal or endocrine AID, were identified from ICD-10 codes allocated to hospital stays and long-term illnesses or by marker drugs. Their incidence was compared between girls exposed and non-exposed to HPV vaccination, using a Cox model adjusted for inclusion year, geographic area, socio-economic indicators, healthcare use level and other immunizations.

RESULTS

Among 2,252,716 girls, 37% received HPV vaccine and 4,096 AID occurred during a mean follow-up time of 33months. The incidence of AID was not increased after exposure to HPV vaccination, except for Guillain-Barré syndrome (GBS) (incidence rate of 1.4 among exposed [20 cases] versus 0.4 per 100,000 PY among unexposed [23 cases]; adjusted HR: 3.78 [1.79-7.98]). This association persisted across numerous sensitivity analyses and was particularly marked in the first months following vaccination. Under the hypothesis of a causal relationship, this would result in 1-2 GBS cases attributable to HPV vaccine per 100,000 girls vaccinated.

CONCLUSIONS

Our study provides reassuring results regarding the risk of AID after HPV vaccination, but an apparently increased risk of GBS was detected. Further studies are warranted to confirm this finding.

Relative impact of hospital and surgeon procedure volumes on primary total hip arthroplasty revision: a nationwide cohort study in France

BACKGROUND

Both surgeon and hospital procedure volumes have been found to be associated with total hip arthroplasty (THA) outcomes. However, little research has been conducted on the relative influence. We studied the association between THA survivorship and both hospital and surgeon procedure volumes, considering their relative impact.

METHODS

A population-based cohort included all patients aged ≥40 years having received a unilateral primary THA from 2010 to 2011, from the French National Health Insurance Database. Patients were followed up until the end of 2014. The outcome was THA revision. Exposures of interest were procedure volumes, divided into tertiles: <1.5, 1.5-4, >4 and <7, 7-15, >15 procedures per month defined as low, medium, and high volumes for surgeon and hospital, respectively.

RESULTS

The cohort had 62,906 patients, with mean age 69 years and women 57%. Mean surgeon and hospital volumes were 8 and 23 procedures per month, respectively, and 5%, 72%, 22% and 7%, 28%, 65% of THAs were implanted by a low-, medium-, and high-volume surgeon or in a low-, medium-, and high-volume hospital, respectively. Median follow-up was 45 months (range, 0-57 months). In multivariate analysis, adjusted for both surgeon and hospital volumes, for patient and THA characteristics, a lower surgeon volume was associated with poorer THA survivorship (adjusted hazard ratio [aHR] = 1.19; 95% confidence interval [CI], 1.07-1.34 and aHR = 1.70; 95% CI, 1.40-2.05, for medium- and low-volume surgeon, respectively, compared with that of high volume), whereas hospital volume was not.

CONCLUSIONS

This study brings evidence to support the notion that THAs performed by high-volume surgeons in French private hospitals have higher survivorship in the first 4 years.

Assessment of the French National Health Insurance Information System as a tool for epidemiological surveillance of malaria

OBJECTIVE

Epidemiological surveillance of malaria in France is based on a hospital laboratory sentinel surveillance network. There is no comprehensive population surveillance. The objective of this study was to assess the ability of the French National Health Insurance Information System to support nationwide malaria surveillance in continental France.

MATERIALS AND METHODS

A case identification algorithm was built in a 2-step process. First, inclusion rules giving priority to sensitivity were defined. Then, based on data description, exclusion rules to increase specificity were applied. To validate our results, we compared them to data from the French National Reference Center for Malaria on case counts, distribution within subgroups, and disease onset date trends.

RESULTS

We built a reusable automatized tool. From July 1, 2013, to June 30, 2014, we identified 4077 incident malaria cases that occurred in continental France. Our algorithm provided data for hospitalized patients, patients treated by private physicians, and outpatients for the entire population. Our results were similar to those of the National Reference Center for Malaria for each of the outcome criteria.

DISCUSSION

We provided a reliable algorithm for implementing epidemiological surveillance of malaria based on the French National Health Insurance Information System. Our method allowed us to work on the entire population living in continental France, including subpopulations poorly covered by existing surveillance methods.

CONCLUSION

Traditional epidemiological surveillance and the approach presented in this paper are complementary, but a formal validation framework for case identification algorithms is necessary.

Epidemiology of Endometriosis in France: A Large, Nation-Wide Study Based on Hospital Discharge Data

We aimed to assess the prevalence of hospitalization for endometriosis in the general population in France and in each French region and to describe temporal trends, rehospitalization rates, and prevalence of the different types of endometriosis. The analyses were carried out on French hospital discharge data and covered the period 2008–2012 and a population of 14,239,197 women of childbearing age. In this population, the prevalence of hospitalization for endometriosis was 0.9%, ranging from 0.4% to 1.6% between regions. Endometriosis affected 1.5% of hospitalized women of childbearing age, ranging from 1.0% to 2.4% between regions. The number of patients hospitalized for endometriosis significantly increased over the study period (p < 0.01). Of these, 4.2% were rehospitalized at least once at one year: ranging from 2.7% to 6.3% between regions. The cumulative rehospitalization rate at 3 years was 6.9%. The types of endometriosis according to the procedures performed were as follows: ovarian (40–50%), peritoneal (20–30%), intestinal (10–20%), and ureteral or bladder (<10%), with significant differences between regions. This is the first detailed epidemiological study of endometriosis in France. Further studies are needed to assess the reasons for the increasing prevalence of endometriosis and for the significant differences in regional prevalence of this disease.

Incidence of Acute Postoperative Endophthalmitis after Cataract Surgery: A Nationwide Study in France from 2005 to 2014

PURPOSE

To report the incidence of acute postoperative endophthalmitis (POE) after cataract surgery from 2005 to 2014 in France.

DESIGN

Cohort study.

PARTICIPANTS

Patients undergoing operation for cataract surgery by phacoemulsification and presenting acute POE.

METHODS

We identified acute POE occurring within 6 weeks after phacoemulsification cataract surgery and the use of intracameral antibiotic injection during the surgical procedure by means of billing codes from a national database.

MAIN OUTCOME MEASURES

Incidence of acute POE.

RESULTS

From January 2005 to December 2014, 6 371 242 eyes in 3 983 525 patients underwent phacoemulsification cataract surgery. The incidence of acute POE after phacoemulsification decreased from 0.145% to 0.053% during this 10-year period; the unadjusted incidence rate ratio (IRR) (95% confidence interval) was 0.37 (0.32-0.42; P < 0.001). In multivariate analysis, intracameral antibiotic injection was associated with a lower risk of acute POE 0.53 (0.50-0.57; P < 0.001), whereas intraoperative posterior capsule rupture, combined surgery, and gender (male) were associated with a higher risk of acute POE: 5.24 (4.11-6.68), 1.77 (1.53-2.05), and 1.48 (1.40-1.56) (P < 0.001), respectively.

CONCLUSIONS

Access to a national database allowed us to observe a decrease in acute POE after phacoemulsification cataract surgery from 2005 to 2014. Within the same period, the use of intracameral antibiotics during the surgical procedures increased.

Haemoptysis in adults: a 5-year study using the French nationwide hospital administrative database

Haemoptysis is a serious symptom with various aetiologies. Our aim was to define the aetiologies, outcomes and associations with lung cancer in the entire population of a high-income country.

This retrospective multicentre study was based on the French nationwide hospital medical information database collected over 5 years (2008–2012). We analysed haemoptysis incidence, aetiologies, geographical and seasonal distribution and mortality. We studied recurrence, association with lung cancer and mortality in a 3-year follow-up analysis.

Each year, ∼15 000 adult patients (mean age 62 years, male/female ratio 2/1) were admitted for haemoptysis or had haemoptysis as a complication of their hospital stay, representing 0.2% of all hospitalised patients. Haemoptysis was cryptogenic in 50% of cases. The main aetiologies were respiratory infections (22%), lung cancer (17.4%), bronchiectasis (6.8%), pulmonary oedema (4.2%), anticoagulants (3.5%), tuberculosis (2.7%), pulmonary embolism (2.6%) and aspergillosis (1.1%). Among incident cases, the 3-year recurrence rate was 16.3%. Of the initial cryptogenic haemoptysis patients, 4% were diagnosed with lung cancer within 3 years. Mortality rates during the first stay and at 1 and 3 years were 9.2%, 21.6% and 27%, respectively.

This is the first epidemiological study analysing haemoptysis and its outcomes in an entire population. Haemoptysis is a life-threatening symptom unveiling potentially life-threatening underlying conditions.

Mining care trajectories using health administrative information systems: the use of state sequence analysis to assess disparities in prenatal care consumption

Background

Pregnant women are a vulnerable population. Although regular follow-ups are recommended during pregnancy, not all pregnant women seek care. This pilot study wanted to assess whether the integration of data from administrative health information systems and socio-economic features allows identifying disparities in prenatal care trajectories.

Methods

Prenatal care trajectories were extracted from the permanent sample of the French health insurance information system linked to the hospital discharge information system. The records of 2518 women who gave birth without complications in France in 2009 were analyzed. State sequence data analysis was performed to identify homogeneous groups of prenatal care trajectories. Socio-economic data were used to characterize their living environment.

Results

We identified three groups of homogeneous prenatal care trajectories: (i) women with relatively high prenatal care consumption (~11 %), (ii) women with no prenatal care (~21 %), and (iii) women with an intermediate level of prenatal care (~66 %). Analysis of the socio-economic data demonstrated the association between disparities in prenatal care trajectories and the women’s living environment. Women with relatively high care consumption generally lived in socio-economically privileged areas (better education levels, employment status and housing conditions) compared with women with few or no prenatal care.

Conclusions

Although ecological, our approach demonstrates that data from health administrative information systems could be used to describe prenatal care. However, more individual variables and an improvement of the data quality are needed to efficiently monitor the content and timing of prenatal care. Moreover, state sequence analysis, which was used in this context for the first time, proves to be an interesting approach to explore care trajectories. Finally, the integration of heterogeneous sources of data, including contextual information, might help identifying areas that require health promotion actions toward vulnerable populations, such as pregnant women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-015-0857-5) contains supplementary material, which is available to authorized users.

Febrile seizures following measles and varicella vaccines in young children in Australia

BACKGROUND

Febrile seizures (FS) are common in childhood with incidence peaking in the second year of life when measles and varicella-containing vaccines are administered. This study aimed to examine the vaccine-attributable risk of FS following separate administration of MMR and monovalent varicella vaccines (VV) prior to a planned change to MMRV as the second dose of measles-containing vaccine at 18 months of age.

METHODS

All FS cases in children aged <5 years from 1st January 2012 to 30th April 2013 were identified from emergency department (ED) and inpatient databases at five Australian tertiary paediatric hospitals participating in PAEDS (Paediatric Active Enhanced Disease Surveillance). Immunization records were obtained from the Australian Childhood Immunization Register (ACIR). The relative incidence (RI) of FS following MMR dose 1 (MMR1) and VV in children aged 11-23 months was determined using the self-controlled case series (SCCS) method and used to calculate attributable risk.

RESULTS

There were 2013 FS episodes in 1761 children. The peak age at FS was 18 months. The risk of FS was significantly increased 5-12 days post receipt of MMR1 at 12 months (RI=1.9 [95% CI: 1.3-2.9]), but not after VV at 18 months (RI=0.6 [95% CI: 0.3-1.2]. The estimated excess annual number of FS post MMR1 was 24 per 100,000 vaccinated children aged 11-23 months (95% CI=7-49 cases per 100,000) or 1 per 4167 doses.

CONCLUSIONS

Our study detected the expected increased FS risk post MMR1 vaccine at 12 months, but monovalent varicella vaccine at age 18 months was not associated with increased risk of FS. This provides baseline data to assess the risk of FS post MMRV, introduced in Australia as the second dose of measles-containing vaccine at 18 months of age in July 2013.

Hospital and ambulatory management, and compliance to treatment in HIV infection: regional health insurance agency analysis

OBJECTIVE

We had for objective to study HIV management (hospital, ambulatory, and mixed) and assess compliance with health insurance database.

METHOD

We conducted a retrospective study using the French Social Security (CPAM) database. The inclusion criteria were: age>18years of age, at least 2 prescriptions of antiretroviral therapy.

RESULTS

Five hundred and seventy-five patients were included: extra-hospital (12), hospital (162), mixed (401). The prescriptions were exclusively hospital issued for 76.2% of the patients. Among the mixed group patients, 91% of treatments were delivered at least once in the community, and 45.6% of biological tests were performed in private laboratories at least once. The sex ratio (2.1 vs. 1.3), the number of patients having switched antiretroviral therapy (36.7% vs. 27.8%), and the frequency of biological tests (3.1 vs. 2.6) were significantly higher in the mixed group compared to the hospital group. The mean compliance was 90% in the hospital group and 91.8% in the mixed group. The compliance was<80% for 104 patients (21.8%). Patients with≥80% compliance were older (46.1years of age vs. 42.7years of age), with more frequent biological tests (3 per year vs. 2.5 per year), and more frequent switches in treatment (35.4% vs. 26.0%).

CONCLUSION

Prescriptions of ARV were almost exclusively hospital issued. Their dispensation and biological tests were split between hospital and extra-hospital settings. Most patients demonstrated an optimal compliance. The CPAM database allows describing HIV management and assessing compliance.

Risk of febrile seizures after first dose of measles-mumps-rubella-varicella vaccine: a population-based cohort study

BACKGROUND

The combination measles-mumps-rubella-varicella (MMRV) vaccine currently used in Canada (Priorix-Tetra) may increase the risk of febrile seizures relative to the separate vaccines (MMR and varicella) previously administered. We determined the risk of febrile seizure after the first dose of MMRV, as well as any additional risk for children at high risk for seizures because of pre-existing medical conditions.

METHODS

In this retrospective, population-based cohort study, we compared the risk of seizures after the first dose of MMRV with the risk after same-day administration of separate MMR and varicella vaccines (MMR+V) in children 12 to 23 months of age in the province of Alberta. We deterministically linked vaccination data to health service utilization data for seizures. We used Poisson regression, with adjustment for age and calendar year, to determine the risk for the full cohort and for high-risk children.

RESULTS

The risk of seizures 7 to 10 days after vaccination was twice as high with MMRV as with MMR+V (relative risk [RR] 1.99, 95% confidence interval [CI] 1.30-3.05). The excess absolute risk of seizures was 3.52 seizures per 10 000 doses of MMRV relative to MMR+V. In high-risk children, the risk was not differentially higher for MMRV (RR 1.30, 95% CI 0.60-2.79).

INTERPRETATION

Despite an increased risk of febrile seizures following MMRV (compared with MMR+V), the absolute level of risk was small. Policy-makers need to balance these findings with the potential benefits of administering the combination vaccine or determine whether the choice of vaccine rests with clinicians and/or parents.