Self-controlled Case Series Analysis Research Articles

Unveiling unique clinical phenotypes of hip fracture patients and the temporal association with cardiovascular events

Cardiovascular events are the leading cause of death among hip fracture patients. This study aims to identify subphenotypes of hip fracture patients and investigate their association with incident cardiovascular events, all-cause mortality, and health service utilisation in Hong Kong and the United Kingdom populations. By the latent class analysis, we show three distinct clusters in the Hong Kong cohort (n = 78,417): Cluster 1 has cerebrovascular and hypertensive diseases, hyperlipidemia, and diabetes; Cluster 2 has congestive heart failure; Cluster 3 consists of relatively healthy patients. Compared to Cluster 3, higher risks of major adverse cardiovascular events are observed in Cluster 1 (hazard ratio 1.97, 95% CI 1.83 to 2.12) and Cluster 2 (hazard ratio 4.06, 95% CI 3.78 to 4.35). Clusters 1 and 2 are also associated with a higher risk of mortality, more unplanned accident and emergency visits and longer hospital stays. Self-controlled case series analysis shows a significantly elevated risk of major adverse cardiovascular events within 60 days post-hip fracture. Similar associations are observed in the United Kingdom cohort (n = 27,948). Pre-existing heart failure is identified as a unique subphenotype associated with poor prognosis after hip fractures.

Triptan use in elderly over 65 years and the risk of hospitalization for serious vascular events

BackgroundSeveral studies have focused on the use of triptan and the risk of acute vascular events but the existence of such association is still debated and has never been quantified in patients over 65 years. To assess whether triptan use among older is associated with an increased risk of hospitalization for acute vascular events.MethodsA propensity score-matched cohort study was designed using the French national health insurance database linked to hospital stays. Patients aged ≥ 65 years, newly treated by triptans between 2011 and 2014, were included… The primary event was hospitalization for an acute ischemic vascular event within de 90 days following triptan initiation. Association with triptan exposure was investigated through cox regression model, considering exposure at inclusion, and with exposure as a time-varying variable A case-crossover (CCO) and a self-controlled case series (SCCS) analyses were also conducted to address potential residual confounding.ResultsThe cohort included 24, 774 triptan users and 99 096 propensity matched controls (mean (SD) age: 71 years (5.9), 74% of women). Within 90 days after cohort entry, 163 events were observed in the triptan group, and 523 in the control group (0.66% vs. 0.53%, adjusted hazard ratio (aHR) exposed/not exposed 1.25 95%CI [1.05–1.49]; aHR time−varying 8.74 [5.21–14.66]). The association was significant (CCO) for all events (adjusted odds ratio (aOR1.63 [1.22–2.19]) with a more consistent association with cerebral events (aOR 2.14 [1.26–3.63]). The relative incidence (RI) for all events was 2.13 [1.76–2.58] in the SCCS, for cardiac (RI: 1.67 [1.23–2.27]) and for cerebral events (RI: 3.20, [2.30–4.45]).ConclusionThe incidence of acute vascular events was low among triptan users. We found that triptan use among older may be associated with a low increased risk for acute vascular events, which may be more marked for cerebral events such as stroke, than for cardiac events.

P021 Uptake, safety, and effectiveness of pneumococcal vaccination in adults with immune mediated inflammatory diseases: a UK wide study using data from the Clinical Practice Research Datalink

Abstract Background/Aims The safety and effectiveness of pneumococcal vaccine in people with immune mediated inflammatory diseases (IMIDs) is not known, which may contribute to suboptimal uptake. We investigated UK wide pneumococcal vaccine uptake in adults with IMIDs, the association between pneumococcal vaccination and disease flares, and the effectiveness of pneumococcal vaccine in preventing pneumonia in this at-risk population. Methods Adults with incident rheumatoid arthritis (RA), inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE) and spondyloarthritis (SpA) prior to 31st August 2018 in the Clinical Practice Research Datalink (CPRD) Gold were included. The study was approved by CPRD research data governance (Reference 21_000614). We calculated the proportion of patients vaccinated against pneumococcal pneumonia. To investigate the association between vaccination and IMID flare, we employed a self-controlled case series analysis, adjusted for season. The study period was up-to six-month before and six-month after the date of pneumococcal vaccination. This period was partitioned into induction (14 days pre-vaccination) and exposed periods (up-to 90 days post vaccination) with the remaining time considered unexposed. Incidence rate ratios (IRR) and 95% CI were calculated. We conducted a multivariable nested case-control study to assess vaccine effectiveness. Cases were patients hospitalised with pneumonia and were matched to up to ten controls for age and sex. Multivariable conditional logistic regression was used to calculate odds ratio (OR) and 95% CI. Results We included 32,277 IMID patients: 14,151 with RA, 13,631 with IBD, 3,804 with SpA and 691 with SLE. Overall uptake of pneumococcal vaccination was 50% (95% CI 49.4% -50.5%). Vaccination uptake was significantly lower in the under 45-year-olds, in patients with IBD and in those without additional indication for vaccination at 29.7%, 38.4%, 42.7% respectively. In the safety study, data for 1001, 854, 424 vaccinated patients with primary care consultations for joint pain, AIRD flare, and IBD flare respectively were included. Vaccination against pneumococcal pneumonia was not associated with AIRD flare (IRR (95% CI) 1.07 (0.93-1.22)), primary care consultations for joint pain (IRR (95% CI) 0.95 (0.83-1.10)), and IBD flare (IRR (95% CI) 0.82 (0.64-1.06)) in the 90-days post vaccination. The vaccine effectiveness study included 25,707 patients, either with (n = 2,771) or without (n = 22,936) a hospitalisation record for pneumonia after IMID diagnosis. Patients hospitalised for pneumonia compared with their matched controls, had higher odds of current smoking, deprivation, corticosteroid prescriptions, additional indication for vaccination, primary care consultations, hospital admissions and prescriptions. In the multivariable adjusted model, pneumococcal vaccination was associated with reduced odds of hospitalisation for pneumonia (OR (95% CI) 0.88 (0.78-0.98). Conclusion The uptake of pneumococcal vaccine is low in IMID patients. Pneumococcal vaccination is not associated with IMID flare and is protective against pneumonia. These findings call for promotion of pneumococcal vaccination in IMID by health professionals. Disclosure G. Nakafero: None. M.J. Grainge: None. C.D. Mallen: Grants/research support; NIHR, MRC, Versus Arthritis and BMS. T. Card: None. J.S. Nguyen Van-Tam: Consultancies; CSL Seqirus and Moderna. Royalties; AstraZeneca and Sanofi Pasteur. A. Abhishek: Consultancies; NGM Bio, Limbic and Inflazome.. Royalties; UpToDate, Springer, Cadilla Pharmaceuticals.. Grants/research support; AstraZeneca and Oxford Immunotech..

Risk of encephalitis and meningitis after COVID-19 vaccination in South Korea: a self-controlled case series analysis

BackgroundSeveral neurological manifestations shortly after a receipt of coronavirus infectious disease 2019 (COVID-19) vaccine have been described in the recent case reports. Among those, we sought to evaluate the risk of encephalitis and meningitis after COVID-19 vaccination in the entire South Korean population.MethodsWe conducted self-controlled case series (SCCS) analysis using the COVID-19 immunization record data from the Korea Disease Control Agency between February 2021 and March 2022, linked with the National Health Insurance Database between January 2021 and October 2022. We retrieved all medical claims of adults aged 18 years or older who received at least one dose of COVID-19 vaccines (BNT162b2, mRNA-1273, ChAdOx1-S, or Ad26.COV2.S), and included only those who had a diagnosis record for encephalitis or meningitis within the 240-day post-vaccination period. With day 0 defined as the date of vaccination, risk window was defined as days 1–28 and the control window as the remainder period excluding the risk windows within the 240-day period. We used conditional Poisson regression to estimate the incidence rate ratios (IRR) with 95% confidence intervals (CI), stratified by dose and vaccine type.ResultsFrom 129,956,027 COVID-19 vaccine doses administered to 44,564,345 individuals, there were 251 and 398 cases of encephalitis and meningitis during the risk window, corresponding to 1.9 and 3.1 cases per 1 million doses, respectively. Overall, there was an increased risk of encephalitis in the first 28 days of COVID-19 vaccination (IRR 1.26; 95% CI 1.08–1.47), which was only significant after a receipt of ChAdOx1-S (1.49; 1.03–2.15). For meningitis, no increased risk was observed after any dose of COVID-19 vaccine (IRR 1.03; 95% CI 0.91–1.16).ConclusionsOur findings suggest an overall increased risk of encephalitis after COVID-19 vaccination. However, the absolute risk was small and should not impede COVID-19 vaccine confidence. No significant association was found between the risk of meningitis and COVID-19 vaccination.

Uptake and safety of pneumococcal vaccination in adults with immune mediated inflammatory diseases: a UK wide observational study.

The uptake and safety of pneumococcal vaccination in people with immune mediated inflammatory diseases (IMIDs) is poorly understood. We investigated the UK wide pneumococcal vaccine uptake in adults with IMIDs and explored the association between vaccination and IMID flare. Adults with IMIDs diagnosed on or before 01/09/2018, prescribed steroid-sparing drugs within the last 12 months and contributing data to the Clinical Practice Research Datalink Gold were included. Vaccine uptake was assessed using a cross-sectional study design. Self-controlled case series (SCCS) analysis investigated the association between pneumococcal vaccination and IMID flare. The SCCS observation period was up-to six-month before and after pneumococcal vaccination. This was partitioned into a 14-day pre-vaccination induction, 90-days post-vaccination exposed, and the remaining unexposed periods. We included 32 277 patients, 14 151 with RA, 13 631 with IBD, 3,804 with axial spondyloarthritis and 691 with SLE. Overall, 57% were vaccinated against pneumococcus. Vaccine uptake was lower in those younger than 45 years (32%), with IBD (42%), and without additional indication(s) for vaccination (46%). In the vaccine-safety study, data for 1,067, 935, and 451vaccinated patients with primary-care consultations for joint pain, AIRD flare and IBD flare respectively were included. Vaccination against pneumococcal pneumonia was not associated with primary-care consultations for joint pain, AIRD flare and IBD flare in the exposed period with incidence rate ratios (95% Confidence Interval) 0.95 (0.83-1.09), 1.05 (0.92-1.19), and 0.83 (0.65-1.06) respectively. Uptake of pneumococcal vaccination in UK patients with IMIDs was suboptimal. Vaccination against pneumococcal disease was not associated with IMID flare.

Rebamipide Prevents the Hemoglobin Drop Related to Mucosal-Damaging Agents at a Level Comparable to Proton Pump Inhibitors.

: The effect of proton pump inhibitors (PPIs) on the lower gastrointestinal (GI) tract is uncertain, with potential to worsen damage. This study aimed to find the best method for protecting the entire GI tract from mucosal damage. : A retrospective cohort study at Samsung Medical Center (2002-2019) included 195,817 patients prescribed GI mucosa-damaging agents. The primary goal was to assess the effectiveness of GI protective agents in preventing significant hemoglobin drops (>2 g/dL), indicating overall GI mucosal damage. Self-controlled case series and landmark analysis were used to address biases in real-world data. : The incidence rate ratios for rebamipide, PPI, and histamine-2 receptor antagonist (H2RA) were 0.34, 0.33, and 0.52, respectively. Rebamipide showed a significantly lower incidence rate than H2RA and was comparable to PPIs. Landmark analysis revealed significant reductions in hemoglobin drop risk with rebamipide and H2RA, but not with PPI. : Rebamipide, like PPIs, was highly effective in preventing blood hemoglobin level decreases, as shown in real-world data. Rebamipide could be a comprehensive strategy for protecting the entire GI tract, especially when considering PPIs' potential side effects on the lower GI tract.

Estimation and reduction of bias in self-controlled case series with non-rare event dependent outcomes and heterogeneous populations.

The self-controlled case series (SCCS) is a commonly adopted study design in the assessment of vaccine and drug safety. Recurrent event data collected from SCCS studies are typically analyzed using the conditional Poisson model which assumes event times are independent within-cases. This assumption is violated in the presence of event dependence, where the occurrence of an event influences the probability and timing of subsequent events. When event dependence is suspected in an SCCS study, the standard recommendation is to include only the first event from each case in the analysis. However, first event analysis can still yield biased estimates of the exposure relative incidence if the outcome event is not rare. We first demonstrate that the bias in first event analysis can be even higher than previously assumed when subpopulations with different baseline incidence rates are present and describe an improved method for estimating this bias. Subsequently, we propose a novel partitioned analysis method and demonstrate how it can reduce this bias. We provide a recommendation to guide the number of partitions to use with the partitioned analysis, illustrate this recommendation with an example SCCS study of the association between beta-blockers and acute myocardial infarction, and compare the partitioned analysis against other SCCS analysis methods by simulation.

Post-marketing surveillance of intussusception after Rotarix administration in Afghanistan, 2018–2022

BackgroundIn January 2018, Afghanistan introduced the monovalent oral rotavirus vaccine (Rotarix) nationwide, administered as a 2-dose series at six and ten weeks of age. We describe characteristics of intussusception cases and assess potential intussusception risk associated with Rotarix vaccination in Afghan infants. MethodsMulti-center prospective active hospital-based surveillance for intussusception was conducted from May 2018 to March 2022 in four sentinel sites in Afghanistan. We applied the Brighton Level 1 criteria for intussusception and verified vaccination status by reviewing vaccine cards. We used the self-controlled case series (SCCS) methodology to compare intussusception incidence in the 1 to 21 days after each dose of Rotarix vaccination against non-risk periods. ResultsA total of 468 intussusception cases were identified in infants under 12 months, with 264 cases aged between 28 and 245 days having confirmed vaccination status contributing to the SCCS analysis. Most case-patients (98 %) required surgery for treatment, and over half (59 %) of those who underwent surgery required intestinal resection. Nineteen (7 %) case-patients died. Eighty-six percent of case-patients received the first dose of Rotarix, and 69 % received the second dose before intussusception symptom onset. There was no increased risk of intussusception in the 1–7 days (relative incidence: 0.9, 95 % CI: 0.1, 7.5), 8–21 days (1.3, 95 % CI: 0.4, 4.2), or 1–21 days (1.1, 95 % CI: 0.4, 3.4) following receipt of the first dose or in the 1–7 days (0.2, 95 % CI: 0.3, 1.8), 8–21 days (0.7, 95 % CI: 0.3, 1.5), or 1–21 days (0.6, 95 % CI: 0.3, 1.2) following the second dose. ConclusionRotarix vaccination was not associated with an increased intussusception risk, supporting its continued use in Afghanistan's immunization program. However, there was a high level of death and resection due to intussusception among Afghan infants.

Audiovestibular adverse events following COVID-19 vaccinations

IntroductionEvidence regarding audiovestibular adverse events post COVID-19 vaccination to date has been inconclusive regarding a potential association. This study aimed to determine if there was an increase in audiovestibular events following COVID-19 vaccination in South-eastern Australia during January 2021–March 2023. MethodsA multi-data source approach was applied. First, a retrospective observational analysis of spontaneous reports of audiovestibular events to a statewide vaccine safety surveillance service, SAEFVIC. Second, a self-controlled case series analysis using general practice data collected via the POpulation Level Analysis and Reporting (POLAR) tool. Results and conclusionsThis study is the first to demonstrate an increase in general practice presentations of vertigo following mRNA vaccines (RI = 1.40, P <.001), and tinnitus following both the Vaxzevria® adenovirus vector and mRNA vaccines (RI = 2.25, P <.001 and 1.53, P <.001 respectively). There was no increase in hearing loss following any COVID-19 vaccinations. Our study, however, was unable to account for the potential of concurrent COVID-19 infections, which literature has indicated to be associated with audiovestibular events.Healthcare providers and vaccinees should be alert to potential audiovestibular complaints after COVID-19 vaccination. Our analysis highlights the importance of using large real-world datasets to gather reliable evidence for public health decision making.

Acute disseminated encephalomyelitis and transverse myelitis following COVID-19 vaccination – A self-controlled case series analysis

Acute Disseminated Encephalomyelitis (ADEM) and Transverse Myelitis (TM) are within the group of immune mediated disorders of acquired demyelinating syndromes. Both have been described in temporal association following various vaccinations in case reports and case series and have been evaluated in observational studies. A recent analysis conducted by The Global Vaccine Data Network (GVDN) observed an excess of ADEM and TM cases following the adenoviral vectored ChAdOx1 nCoV-19 (AZD1222) and mRNA-1273 vaccines, compared with historically expected background rates from prior to the pandemic. Further epidemiologic studies were recommended to explore these potential associations.We utilized an Australian vaccine datalink, Vaccine Safety Health-Link (VSHL), to perform a self-controlled case series analysis for this purpose. VSHL was selected for this analysis as while VSHL data are utilised for GVDN association studies, they were not included in the GVDN observed expected analyses. The VSHL dataset contains vaccination records sourced from the Australian Immunisation Register, and hospital admission records from the Victorian Admitted Episodes Dataset for 6.7 million people. These datasets were used to determine the relative incidence (RI) of G040 (ADEM) and G373 (TM) ICD-10-AM coded admissions in the 42-day risk window following COVID-19 vaccinations as compared to control periods either side of the risk window.We observed associations between ChAdOx1 adenovirus vector COVID-19 vaccination and ADEM (all dose RI: 3.74 [95 %CI 1.02,13.70]) and TM (dose 1 RI: 2.49 [95 %CI: 1.07,5.79]) incident admissions. No associations were observed between mRNA COVID-19 vaccines and ADEM or TM. These findings translate to an extremely small absolute risk of ADEM (0.78 per million doses) and TM (1.82 per million doses) following vaccination; any potential risk of ADEM or TM should be weighed against the well-established protective benefits of vaccination against COVID-19 disease and its complications.This study demonstrates the value of the GVDN collaboration leveraging large population sizes to examine important vaccine safety questions regarding rare outcomes, as well as the value of linked population level datasets, such as VSHL, to rapidly explore associations that are identified.

The risk of acute disseminated encephalomyelitis (ADEM) following covid-19 vaccination in England: A self-controlled case-series analysis

ABSTRACT Acute disseminated encephalomyelitis (ADEM) has been identified as an Adverse Event of Special Interest in the COVID-19 vaccine programme due to its long-standing temporal association with a wide range of other vaccines. Case reports of ADEM shortly following COVID−19 vaccination have now been documented. There were 217 ADEM admissions in 215 individuals in the period 8th December 2020 to 31st March 2023. An increased risk of ADEM following the first dose of ChAdOx1 vaccine was observed (relative incidence (RI) = 3.13, 95% Confidence Interval (CI) [1.56–6.25]) with a vaccine attributable risk of 0.39 per million doses. When doses 1 and 2 were combined this increased risk remained just significant (1.96 [95%CI 1.01–3.82]). No significant increased risk was observed with any other vaccine or dose. This small, elevated risk after the first dose of ChAdOx1-S vaccine demonstrates how large national electronic datasets can be used to identify very rare risks and provides reassurance that any risk of ADEM following the ChAdOx1-S COVID-19 vaccination is extremely small. Given the rarity of this risk, further studies in settings with access to data on large populations should be carried out to verify these findings.

Limaprost and the Risk of Bleeding: A Self-Controlled Case Series Study.

To investigate the association between the use of limaprost and the risk of bleeding. A self-controlled case series analysis was conducted using the National Health Insurance Service-National Sample Cohort database in South Korea. We identified patients aged 18 years or older who had at least one prescription of limaprost and were diagnosed with at least one case of bleeding between 2003 and 2019. The incidence rate ratio (IRR) of bleeding was calculated by dividing the incidence rate in the exposed period to limaprost by that in the unexposed period and adjusted for age using conditional Poisson regression model. Among 72,860 patients with limaprost prescriptions and bleeding diagnoses, there were 184,732 events of bleeding. After adjusting for age, the IRR was 1.47 (95% confidence interval [CI], 1.43-1.50), wherein the IRR was the highest during the 0-7 days after limaprost initiation (IRR, 2.11; 95% CI, 2.03-2.18). Risk of bleeding was higher when limaprost was concomitantly used with antithrombotics or other drugs for spinal stenosis treatment, and when higher daily doses of limaprost were administered. Our findings suggest that the risk of bleeding increased by 1.5-fold in periods of limaprost exposure compared to unexposed periods, with particularly higher risks observed during the first week after limaprost initiation, with concomitant drugs related to bleeding, and with a higher daily dose. A careful risk-benefit assessment is warranted when initiating limaprost, especially when administered with other medications or in higher daily doses.

Nationwide safety surveillance of COVID-19 mRNA vaccines following primary series and first booster vaccination in Singapore

BackgroundThe real-world safety profile ofCOVID-19 mRNA vaccines remains incompletely elucidated. MethodsWe performed a nationwide post-market safety surveillance analysis in Singapore, on vacinees aged 5 years and older, through mid-September 2022. Observed-over-expected (O/E) analyses were performed to identify potential safety signals among eight shortlisted adverse events of special interest (AESIs): strokes, cerebral venous thrombosis (CVT), acute myocardial infarction, myocarditis/pericarditis, pulmonary embolism, immune thrombocytopenia, convulsions and appendicitis. Self-controlled case series analyses (SCCS) were performed to validate signals of concern, occurring within 42 days of vaccination. FindingsElevated risks were observed on O/E analyses for the following AESIs: myocarditis/pericarditis, [rate ratio (RR): 3.66, 95 % confidence interval (95 % CI): 2.71 to 4.94], appendicitis [RR: 1.14 (1.02 to 1.27)] and CVT [RR: 2.11 (1.18 to 3.77)]. SCCS analyses generated corroborative findings: myocarditis/pericarditis, [relative incidence (RI): 6.96 (3.95 to 12.27) at 1 to 7 days post-dose 2], CVT [RI: 4.30 (1.30 to 14.20) at 22 to 42 days post-dose 1] and appendicitis [RI: 1.31 (1.03 to 1.67) at 1 to 7 days post-dose 1]. Booster dose 1 continued to be associated with higher rates of myocarditis/pericarditis on O/E analysis [RR: 2.30, (1.39 to 3.80) and 1.69, (1.11 to 2.59)] at 21- and 42-days post-booster dose 1, respectively. Males aged 12 to 17 exhibited highest risks of both myocarditis/pericarditis [RI: 6.31 (1.36 to 29.3)] and appendicitis [RI: 2.01 (1.12 to 3.64)] after primary vaccination. Similarly, CVT was also predominantly observed in males aged above 50 (11 out of 16 cases), within 42-days of vaccination. InterpretationOur data suggest that myocarditis/pericarditis, appendicitis and CVT are associated with primary vaccination using COVID-19 mRNA vaccines. Males at specific ages exhibit higher risks for all three AEs identified. The risk of myocarditis/pericarditis continues to be elevated after booster dose 1.

Risk of cardiac arrhythmia and cardiac arrest after primary and booster COVID-19 vaccination in England: A self-controlled case series analysis

BackgroundVarious cardiac arrhythmias have been reported after COVID-19 infection and vaccination. We assessed the risk after primary immunisation with the ChAdOx1 adenovirus vectored vaccine, and primary and booster immunisation with an mRNA vaccine in 40 million vaccinated adults with 121 million doses (33.9% ChAdOx1 and 66.1% mRNA) in England. MethodsHospital admissions for a cardiac arrhythmia and emergency care attendance for a cardiac arrest in individuals aged 18 years and older on the 31st March 2021 were linked to the national COVID-19 immunisation register. The incidence of events 1–14 and 15–28 days after vaccination relative to a post-vaccination control period was estimated using the self-controlled case series method modified for fatal events. Outcomes were stratified by arrhythmia type, vaccine type, age group and dose number (up to five). Elevated relative incidence (RI) estimates with p < 0.001 were considered strong evidence of an association. FindingsThere was an increased risk of admission for arrhythmia events that were largely palpitations without myocarditis within 14 days of a second priming dose of an mRNA vaccine in 18–49 year olds with an RI of 1.66 (95 % confidence interval 1.47,1.86) for BNT162b2 and 3.75 (2.52,5.57) for mRNA-1273 (p < 0.001) and also after a first booster dose, 1.34 (1.17,1.53) and 1.75 (1.43,2.15) respectively (p < 0.001). No other cardiac arrhythmia, including cardiac arrest, showed an elevated incidence within 28 days of vaccination for any dose, age group or vaccine type. In contrast the risk of a cardiac arrhythmia of all types, including a cardiac arrest, was consistently elevated in those testing positive for SARS-CoV-2 infection. InterpretationOur study provides reassuring evidence of the safety of the ChAdOx1 and mRNA COVID-19 vaccines with respect to serious cardiac arrhythmias and of the favourable risk benefit of mRNA booster vaccination.

Risk of lymphadenopathy from SARS-CoV-2 vaccination in Korea: a self-controlled case series analysis.

To assess the risk of lymphadenopathy following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. A self-controlled case series design was used to determine whether the risk of lymphadenopathy was higher in the 1-day to 42-day risk interval after coronavirus disease 2019 (COVID-19) vaccination compared to the control period. In addition, subgroup analyses were conducted according to baseline characteristics, time since vaccination, and sensitivity analyses adjusted for the length of the risk interval. The risk of developing lymphadenopathy in the risk interval (1-42 days) after COVID-19 vaccination compared to the control period was significantly increased, with a relative incidence (RI) of 1.17 (95% confidence interval [CI], 1.17 to 1.18) when the first, second, and third doses were combined. The RI was greater on the day of vaccination (1.47; 95% CI, 1.44 to 1.50). In subgroup analyses by baseline characteristics, a significantly increased risk or trend toward increased risk was observed in most subgroups except for those aged 70 years and older, with a significant increase in risk in younger individuals, those with a Charlson's comorbidity index <5, and those who received mRNA vaccines (mRNA-1273>BNT162b2). Within the 1-day to 42-day post-dose risk period, the relative risk was highest during the 1-day to 7-day post-dose period (1.59; 95% CI, 1.57 to 1.60) compared to the control period, and then the risk declined. In the sensitivity analysis, we found that the longer the risk window, the smaller the RI. SARS-CoV-2 vaccination is associated with a statistically significant increase in the risk of lymphadenopathy, and this risk was observed only with mRNA vaccines.

Safety and Health Care Utilization following COVID-19 Vaccination among Adults with Rheumatoid Arthritis - A population-based self-controlled case series analysis.

To determine if COVID-19 vaccines were associated with adverse events of special interest (AESIs) and health care use among adults with rheumatoid arthritis (RA). Among adults with RA who received at least 1 COVID-19 vaccine, a self-controlled case series (SCCS) analysis was conducted to evaluate relative incidence (RI) rates of AESIs (Bell's Palsy, Idiopathic Thrombocytopenia, Acute Disseminated Encephalomyelitis, Pericarditis/Myocarditis, Guillain-Barre syndrome, Transverse Myelitis, Myocardial Infarction, Anaphylaxis, Stroke, Deep Vein Thrombosis, Pulmonary Embolism, Narcolepsy, Appendicitis, and Disseminated Intravascular Coagulation) in any 21-day period following vaccination compared to control periods. Secondary outcomes included emergency department (ED) visits, hospitalizations, and rheumatology visits. A matched non-RA comparator group was created and a separate SCCS analysis was conducted. Relative incidence ratios (RIR) were used to compare between RA and non-RA groups. Among 123,466 RA patients and 493,864 comparators, the majority received mRNA vaccines. For RA patients, relative to control periods, AESIs were not increased. ED visits increased after dose 2 [RI:1.06 (95%CI:1.03-1.10)] and decreased after dose 3 [RI:0.93 (95%CI:0.89-0.96)]. Hospitalizations were lower after the first [RI:0.83 (95%CI:0.78-0.88)], second [RI:0.86 (95%CI:0.81-0.92)], and third [RI:0.89 (95%CI:0.83-0.95)] doses. Rheumatology visits increased after dose 1 [RI:1.08 (95%CI:1.07-1.10)], and decreased after doses 2 and 3. Relative to comparators, RA patients had a higher AESI risk after dose 3 [RIR:1.28 (95%CI:1.1- 1.6)]. RA patients experienced fewer ED visits [RIR:0.73 (95%CI:0.58-0.90)] and hospitalizations [RIR:0.52 (95%CI:0.36-0.75)] after dose 4. COVID-19 vaccines in RA patients was not associated with an increase in AESI risk or health care utilization after every dose.

A transient positive association between direct-acting antiviral therapy for hepatitis C infection and drug-related hospitalization among people who inject drugs: Self-controlled case-series analysis of national data.

Direct-acting antiviral (DAA) treatment has an established positive effect on liver outcomes in people with hepatitis C infection; however, there is insufficient evidence regarding its effects on the 'extra-hepatic' outcomes of drug-related hospitalization and mortality (DRM) among people who inject drugs (PWID). We investigated associations between these outcomes and DAA treatment by comparing post-treatment to baseline periods using a within-subjects design to minimize selection bias concerns with cohort or case-control designs. This was a self-controlled case-series study. Scotland, 1 January 2015-30 November 2020. The study population of non-cirrhotic, DAA-treated PWID was identified using a data set linking Scotland's hepatitis C diagnosis, HCV clinical databases, national inpatient/day-case hospital records and the national deaths register. Three principal outcomes (drug overdose admission, non-viral injecting related admission and drug-related mortality) were defined using ICD codes. Self-controlled case-series methodology was used to estimate the relative incidence (RI) of each outcome associated with time on treatment and up to six 90-day exposure risk periods thereafter. A total of 6050 PWID were treated with DAAs in the sampling time-frame. Compared with the baseline period, there was a significantly lowered risk of a drug overdose hospital admission in the second to fifth exposure risk periods only [relative incidence (RI) = 0.86, 95% confidence interval (CI) = 0.80-0.99; 0.89, 95% CI = 0.80-0.99; 0.86, 95% CI = 0.77-0.96; 0.88, 95% CI = 0.78-0.99, respectively]. For non-viral injecting-related admission, there was a reduced risk in the first, third and fourth exposure risk periods (RI = 0.76, 95% CI = 0.64-0.90; 0.75, 95% CI = 0.62-0.90; 0.79, 95% CI = 0.66-0.96, respectively). There was no evidence for reduced DRM risk in any period following treatment end. Among people who inject drugs in Scotland, direct-acting antiviral treatment appears to be associated with a small, non-durable reduction in the risk of drug-related hospital admission, but not drug-related mortality. Direct-acting antiviral therapy, despite high effectiveness against liver disease, does not appear to offer a panacea for reducing other drug-related health harms.

Use of hypnotic-sedative medication and risk of falls and fractures in adults: A self-controlled case series study.

To evaluate the risk of falls and fractures in users of benzodiazepines, Z-drugs, or melatonin. We followed 699,335 adults with a purchase of benzodiazepines, Z-drugs, or melatonin in the Danish National Prescription Registry between 2003 and 2016 for falls and fractures in the Danish National Patient Registry between 2000 and 2018. A self-controlled case-series analysis and conditional Poisson regression were used to derive incidence rate ratios (IRR) of falls and fractures during six predefined periods. In total 62,105 and 36,808 adults, respectively, experienced a fall or fracture. For older adults, the risk of falls was highest during the 3-month pre-treatment period (IRRmen+70 , 4.22 (95% confidence interval, 3.53-5.05), IRRwomen + 70 , 3.03 (2.59-3.55)) compared to the baseline (>1 year before initiation). The risk continued to be higher in the later treatment periods. Contrarily, in men and women aged 40-69 years, the risk was only higher in the 3-month pre-treatment period. The incidence of falls among young men and women was slightly lower after initiation of sedating medication (treatment period, IRRmen15-39 , 0.66 (0.50-0.86), IRRwomen15-39 , 0.65 (0.51-0.83)). Analyses with fractures as outcome yielded similar results. Although falls and fractures occur more often in persons using sedative-hypnotic medication, the higher risk of falls and fractures in the pre-treatment period relative to the period directly after treatment, suggests that this association is better explained by other factors that elicited the prescription of this medication rather than the adverse effects of the sedative-hypnotic medication.

Thrombocytopenic, thromboembolic and haemorrhagic events following second dose with BNT162b2 and ChAdOx1: self-controlled case series analysis of the English national sentinel cohort.

Thrombosis associated with thrombocytopenia was a matter of concern post first and second doses of BNT162b2 and ChAdOx1 COVID-19 vaccines. Therefore, it is important to investigate the risk of thrombocytopenic, thromboembolic and haemorrhagic events following a second dose of BNT162b2 and ChAdOx1 COVID-19 vaccines. We conducted a large-scale self-controlled case series analysis, using routine primary care data linked to hospital data, among 12.3 million individuals (16 years old and above) in England. We used the nationally representative Oxford-Royal College of General Practitioners (RCGP) sentinel network database with baseline and risk periods between 8th December 2020 and 11th June 2022. We included individuals who received two vaccine (primary) doses of the BNT162b2 mRNA (Pfizer-BioNTech) and two vaccine doses of ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines in our analyses. We carried out a self-controlled case series (SCCS) analysis for each outcome using a conditional Poisson regression model with an offset for the length of risk period. We reported the incidence rate ratios (IRRs) and 95% confidence intervals (CI) of thrombocytopenic, thromboembolic (including arterial and venous events) and haemorrhagic events, in the period of 0-27 days after receiving a second dose of BNT162b2 or ChAdOx1 vaccines compared to the baseline period (14 or more days prior to first dose, 28 or more days after the second dose and the time between 28 or more days after the first and 14 or more days prior to the second dose). We adjusted for a range of potential confounders, including age, sex, comorbidities and deprivation. Between December 8, 2020 and February 11, 2022, 6,306,306 individuals were vaccinated with two doses of BNT162b2 and 6,046,785 individuals were vaccinated with two doses of ChAdOx1. Compared to the baseline, our analysis show no increased risk of venous thromboembolic events (VTE) for both BNT162b2 (IRR 0.71, 95% CI: 0.65-0.770) and ChAdOx1 (IRR 0.91, 95% CI: 0.84-0.98); and similarly there was no increased risk for cerebral venous sinus thrombosis (CVST) for both BNT162b2 (IRR 0.87, 95% CI: 0.41-1.85) and ChAdOx1 (IRR 1.73, 95% CI: 0.82-3.68). We additionally report no difference in IRR for pulmonary embolus, and deep vein thrombosis, thrombocytopenia, including idiopathic thrombocytopenic purpura (ITP), and haemorrhagic events post second dose for both BNT162b2. Reassuringly, we found no associations between increased risk of thrombocytopenic, thromboembolic and haemorrhagic events post vaccination with second dose for either of these vaccines. Data and Connectivity: COVID-19 Vaccines Pharmacovigilance study.

Risk of Thrombosis Following the First Dose of ChAdOx1 nCoV-19 Vaccine in Patients Undergoing Maintenance Hemodialysis: A Self-Controlled Case Series Study.

The ChAdOx1 nCoV-19 vaccine is associated with vaccine-induced thrombosis and thrombocytopenia (VITT). Patients with end-stage renal disease (ESRD) under hemodialysis are at elevated risk of heparin-induced thrombocytopenia, which shares similar mechanisms with VITT. We aimed to examine the risk of VITT after the first dose of ChAdOx1 nCoV-19 vaccine using a self-controlled case series analysis (SCCS) in the hemodialyzed ESRD population. Drawing from the largest multi-center electronic medical records database in Taiwan, we identified adult patients, with or without hemodialysis, between 1st December, 2020, and 31st December, 2021, who received a first dose of ChAdOx1 nCoV-19 vaccine and had an outcome of thrombocytopenia, venous thrombosis, or arterial thrombosis. We calculated the incident rate ratios (IRRs) of outcomes in different periods at risk, compared to periods not at risk. We identified 59 hemodialysis patients and 41 non-dialysis patients with an outcome. The SCCS analyses showed, for the hemodialysis group, a significantly increased risk of outcomes during the period 31 to 60 days post-exposure to ChAdOx1 nCoV-19 vaccine (IRR: 2.823; 95% CI: 1.423-5.600). However, in non-dialysis patients there was no increase in risks during any of the post-exposure risk periods. For ESRD patients under hemodialysis, the first dose of ChAdOx1 nCoV-19 vaccine was associated with a 2.8-fold increase in risk of thrombosis.