Relative Incidence Ratios Research Articles

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.

Risk of peripheral facial palsy following parenteral inactivated influenza vaccination in the elderly Chinese population.

Concern about the risk of peripheral facial palsy (PFP) following vaccination is one reason for hesitancy in influenza vaccination. However, the association between the flu vaccine and PFP is still controversial, and further evidence is urgently needed. This self-controlled case series study evaluated PFP risk following inactivated influenza vaccine in the elderly using a large linked database in Ningbo, China. Relative incidence ratios (RIRs) and 95% confidence intervals (CIs) estimated using conditional Poisson regression were utilized to determine whether the risk of PFP was increased after vaccination. This study included 467 episodes, which occurred in 244 females and 220 males. One hundred twenty-four episodes happened within 1-91 days after vaccination, accounting for 26.7%. The adjusted RIRs within 1-30 days, 31-60 days, 61-91 days, and 1-91 days after influenza vaccination were 0.95 (95% CI 0.69-1.30), 1.08 (95% CI 0.78-1.49), 1.01 (95% CI 0.70-1.45), and 1.00 (95% CI 0.81-1.24), respectively. Similar results were found in subgroup analyses and sensitivity analyses. Influenza vaccination does not increase PFP risk in the elderly population. This finding provides evidence to overcome concerns about facial paralysis after influenza vaccination.

Safety of routine childhood vaccine coadministration versus separate vaccination

IntroductionAs 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...

Unequal burden of COVID-19 in Hungary: a geographical and socioeconomic analysis of the second wave of the pandemic

IntroductionWe describe COVID-19 morbidity, mortality, case fatality and excess death in a country-wide study of municipalities in Hungary, exploring the association with socioeconomic status.MethodsThe spatial distribution of morbidity, mortality and...

The relative incidence of COVID-19 in healthcare workers versus non-healthcare workers: evidence from a web-based survey of Facebook users in the United States.

Background: Healthcare workers are at the forefront of the COVID-19 pandemic and it is essential to monitor the relative incidence rate of this group, as compared to workers in other occupations. This study aimed to produce estimates of the relative incidence ratio between healthcare workers and workers in non-healthcare occupations. Methods: Analysis of cross-sectional data from a daily, web-based survey of 1,822,662 Facebook users from September 8, 2020 to October 20, 2020. Participants were Facebook users in the United States aged 18 and above who were tested for COVID-19 because of an employer or school requirement in the past 14 days. The exposure variable was a self-reported history of working in healthcare in the past four weeks and the main outcome was a self-reported positive test for COVID-19. Results: On October 20, 2020, in the United States, there was a relative COVID-19 incidence ratio of 0.73 (95% UI 0.68 to 0.80) between healthcare workers and workers in non-healthcare occupations. Conclusions: In fall of 2020, in the United States, healthcare workers likely had a lower COVID-19 incidence rate than workers in non-healthcare occupations.

The relative incidence of COVID-19 in healthcare workers versus non-healthcare workers: evidence from a web-based survey of Facebook users in the United States

Background: Healthcare workers are at the forefront of the COVID-19 pandemic and it is essential to monitor the relative incidence rate of this group, as compared to workers in other occupations. This study aimed to produce estimates of the relative incidence ratio between healthcare workers and workers in non-healthcare occupations.Methods: Analysis of cross-sectional data from a daily, web-based survey of 1,822,662 Facebook users from September 8, 2020 to October 20, 2020. Participants were Facebook users in the United States aged 18 and above who were tested for COVID-19 because of an employer or school requirement in the past 14 days. The exposure variable was a self-reported history of working in healthcare in the past four weeks and the main outcome was a self-reported positive test for COVID-19.Results: On October 20, 2020, in the United States, there was a relative COVID-19 incidence ratio of 0.73 (95% UI 0.68 to 0.80) between healthcare workers and workers in non-healthcare occupations.Conclusions: In fall of 2020, in the United States, healthcare workers likely had a lower COVID-19 incidence rate than workers in non-healthcare occupations.

Hospitalisation for lower respiratory tract infection is associated with an increased incidence of acute myocardial infarction and stroke in tropical Northern Australia

Acute respiratory infections appear to precipitate vascular events. Acute myocardial infarction (AMI) and stroke are the leading cause of death and disability globally. This study was based on a cohort of patients admitted to Townsville University Hospital between January 2006 and December 2016. Using a self-controlled case series design, we investigated the risk of AMI or ischaemic stroke after an episode of pneumonia. We defined the ‘risk interval’ as the first 14 days after hospitalisation for pneumonia and the ‘control interval’ as one year before and one year after the risk interval. Among a population (N = 4557) with a median age of over 70, a total of 128 AMI and 27 stroke cases were identified within 1 year of an episode of pneumonia in this study. Ten and two admissions occurred during the risk interval, while 118 and 25 admissions occurred during the control period. The relative incidence ratios (RIR) of AMI increased after an episode of pneumonia (RIR=4.85, 95% confidence interval (CI) 2.44–9.67). The risk for stroke after the exposure period of 14 days was 4.94 (95% CI 1.12–21.78) considering only the first stroke incidence. The RIR results for AMI and stroke were not altered by adjusting for age, sex or Indigenous status. The risk of AMI and stroke were significantly higher two weeks after an episode of pneumonia.

The relative incidence of COVID-19 in healthcare workers versus non-healthcare workers: evidence from a web-based survey of Facebook users in the United States

Background: Healthcare workers are at the forefront of the COVID-19 pandemic and it is essential to monitor the relative infection rate of this group, as compared to workers in other occupations. This study aimed to produce estimates of the relative incidence ratio between healthcare workers and workers in non-healthcare occupations. Methods: Analysis of cross-sectional data from a daily, web-based survey of 1,788,795 Facebook users from September 6, 2020 to October 18, 2020. Participants were Facebook users in the United States aged 18 and above who were tested for COVID-19 because of an employer or school requirement in the past 14 days. The exposure variable was a self-reported history of working in healthcare in the past four weeks and the main outcome was a self-reported positive test for COVID-19. Results: On October 18, 2020, in the United States, there was a relative COVID-19 incidence ratio of 0.7 (95% UI 0.6 to 0.8) between healthcare workers and workers in non-healthcare occupations. Conclusions: Currently in the United States, healthcare workers have a substantially and significantly lower COVID-19 incidence rate than workers in non-healthcare occupations.

Severe Salmonella spp. or Campylobacter spp. Infection and the Risk of Biliary Tract Cancer: A Population-Based Study.

Simple SummaryAlthough it is known that bacterial infection may increase risk of cancer, the relationship between certain infections and cancer remains ill-quantified. To identify potential risk factors, this study compared the incidence of biliary tract cancer (BTC) in patients with Salmonella spp. or Campylobacter spp. infection to the general population in a large Western cohort of 16,252 salmonellosis and 27,668 campylobacteriosis patients. Standardized relative incidence ratio for BTC was 1.53 (95% CI 0.70–2.91) in salmonellosis patients and 0.97 (95% CI 0.39–2.00) in campylobacteriosis patients. Patients with Salmonella spp. infection and BTC were significantly younger than BTC patients without Salmonella spp. infection. Potentially, the study was underpowered to detect differences in cancer incidence, or cancer etiology in Western patients differs from those in non-Western countries and instead of bacterial infection, other factors contribute to cancer risk. Better understanding of cancer etiology is needed to identify risk factors and facilitate screening and early detection of cancer patients.Salmonella spp. infection has shown to have oncogenic transformative effects and thereby increases the risk of certain cancers. For Campylobacter spp., similar effects have been demonstrated. Risk factor identification may allow for timely diagnosis and preventive treatment. To substantiate the oncogenic potential of Salmonella and Campylobacter spp., this study compared the incidence of extrahepatic biliary tract cancer (BTC) in patients with diagnosed Salmonella or Campylobacter spp. infection with BTC incidence in the Netherlands. National infectious diseases surveillance records of patients diagnosed with a laboratory-confirmed Salmonella or Campylobacter spp. infection during 1999–2016 were linked to the Netherlands Cancer Registry. Incidence of BTC in Salmonella and Campylobacter spp. patients was compared to the incidence of BTC in the general population using Standardized Incidence Ratios (SIRs). In total, 16,252 patients were diagnosed with Salmonella spp. and 27,668 with Campylobacter spp. infection. Nine patients developed BTC at a median of 46 months (13–67) after Salmonella spp. infection and seven at a median of 60 months (18–138) after Campylobacter spp. infection. SIR of BTC in salmonellosis patients was 1.53 (95% CI 0.70–2.91). In patients aged <60 years, the SIR was 1.74 (95% CI 0.36–5.04). For campylobacteriosis patients, the SIR was 0.97 (95% CI 0.39–2.00). Even though Salmonella or Campylobacter spp. infection was not significantly associated with increased BTC risk in this cohort, it remains extremely important to study potential risk factors for cancer to facilitate screening and ultimately improve prognosis of cancer patients.

Analysis of Pregnancy and Birth Rates Among Black and White Medicaid-Enrolled Teens

PurposeIn the United States, black teens overall have higher pregnancy and birth rates than whites, and it is commonly believed that minority race and low income account for this disparity. We examined racial differences in pregnancy and birth rates among teens from low-income households using Medicaid-enrollment as a proxy for low income. MethodsThis was a retrospective study of Louisiana Medicaid claims data for female teens aged 15–17 years in 2014 (n = 66,069). Pregnancy and pregnancy outcome codes were identified (n = 2,276) and analyzed for differences by black and white race. We conducted validity analyses with different rate definitions and teens' claims status. ResultsThe cohort was 36% white and 54% black. More black teens than whites lacked any claims data (15.6% vs. 12.6%; p < .001). Rates calculated as events per 1,000 person-years of Medicaid coverage showed no difference in live birth rates between white and black teens (24.6 vs. 25.8; relative incidence ratio, 1.05; 95% confidence interval, .93–1.18; p = .43); however, pregnancy rates for whites were higher than those for blacks (42.7 vs. 36.1; relative incidence ratio, .85; 95% confidence interval, .77–.93; p < .001). ConclusionIn contrast to national trends, which include teens from diverse racial and socioeconomic backgrounds, Louisiana Medicaid-enrolled teens aged 15–17 years had equal birth rates regardless of black or white race, and whites had higher pregnancy rates. Decreased racial disparities in pregnancy and birth rates among these adolescents highlights socioeconomic influences in sexual health behavior and a need to examine the interplay of risk factors contributing to racial disparities seen among adolescents nationally.

Effects of sex and birth weight on non-specific health services use following whole-cell pertussis vaccination: a self-controlled case series analysis

ABSTRACT Previous studies from low-resource countries have highlighted concerns surrounding non-specific effects of whole-cell pertussis vaccination, particularly in females. We sought to examine the effects of sex and birth weight on health services utilization following first exposure to whole-cell pertussis vaccine. Using a self-controlled case series design and by calculating relative incidence ratios (RIRs), we compared the relative incidence of emergency department visits and/or hospital admissions between sexes and between birth weight quintiles. Females had a higher relative incidence of events following vaccination compared to males (RIR = 1.13, 95% CI: 0.99, 1.30), which persisted after adjustment for birth weight (RIR = 1.12, 95% CI: 0.97, 1.28). We also observed a trend of increasing relative incidence of events over decreasing quintiles of birth weight; infants in the lowest quintile had a 26% higher relative event rate compared to the highest quintile, which was robust to adjustment for sex (Unadjusted RIR = 1.26, 95% CI: 1.01, 1.56; Adjusted RIR = 1.23, 95% CI: 0.99, 1.53). The risk of all-cause health services utilization immediately following vaccination, was elevated in female infants and infants having lower birth weight. Further study is warranted to determine if vaccine dosing should take infant weight into account.

Mortality and cancer incidence among female Australian firefighters

ObjectivesTo investigate the mortality and cancer incidence of female firefighters, a group where there are limited published findings.MethodsParticipating fire agencies supplied records of individual firefighters including the number and type...

Cholecystectomy Risk in Crohn’s Disease Patients After Ileal Resection: a Long-term Nationwide Cohort Study

BackgroundThe risk of gallstone disease necessitating cholecystectomy after ileal resection (IR) in Crohn’s disease (CD) patients is not well established. We studied the incidence, cumulative and relative risk of cholecystectomy after IR in CD patients, and associated risk factors. MethodsCD patients with a first IR between 1991 and 2015 were identified in PALGA, a nationwide pathology database in the Netherlands. Details on subsequent cholecystectomy and IR were recorded. Yearly cholecystectomy rates from the general Dutch population were used as a reference. ResultsA cohort of 8302 (3466 (41.7%) males) CD patients after IR was identified. During the 11.9 (IQR 6.3–18.0) years median follow-up, the post-IR incidence rate of cholecystectomy was 5.2 (95% CI 3.5–6.4)/1000 persons/year. The cumulative incidence was 0.5% at 1 year, 2.4% at 5 years, 4.6% at 10 years, and 10.3% after 20 years. In multivariable analyses, female sex (HR 1.9, CI 1.5–2.3), a later calendar year of first IR (HR/5-year increase, HR 1.27, CI 1.18–1.35), and ileal re-resection (time-dependent HR 1.37, CI 1.06–1.77) were associated with cholecystectomy. In the last decade, cholecystectomy rates increased and were higher in our postoperative CD population than in the general population (relative incidence ratio 3.13 (CI 2.29–4.28; p < 0.0001) in 2015). ConclusionsAlthough higher in females, increasing in recent years, and higher than in the general population, the overall risk of cholecystectomy in CD patients following IR is low and routine prophylactic measures seem unwarranted.

Mortality and cancer incidence among male volunteer Australian firefighters

ObjectivesThis study aims to investigate mortality and cancer incidence of Australian male volunteer firefighters and of subgroups of firefighters by duration of service, era of first service and the number...

The use of relative incidence ratios in self-controlled case series studies: an overview.

BackgroundThe self-controlled case series (SCCS) is a useful design for investigating associations between outcomes and transient exposures. The SCCS design controls for all fixed covariates, but effect modification can still occur. This can be evaluated by including interaction terms in the model which, when exponentiated, can be interpreted as a relative incidence ratio (RIR): the change in relative incidence (RI) for a unit change in an effect modifier.MethodsWe conducted a scoping review to investigate the use of RIRs in published primary SCCS studies, and conducted a case-study in one of our own primary SCCS studies to illustrate the use of RIRs within an SCCS analysis to investigate subgroup effects in the context of comparing whole cell (wcp) and acellular (acp) pertussis vaccines. Using this case study, we also illustrated the potential utility of RIRs in addressing the healthy vaccinee effect (HVE) in vaccine safety surveillance studies.ResultsOur scoping review identified 122 primary studies reporting an SCCS analysis. Of these, 24 described the use of interaction terms to test for effect modification. 21 of 24 studies reported stratum specific RIs, 22 of 24 reported the p-value for interaction, and less than half (10 of 24) reported the estimate of the interaction term/RIR, the stratum specific RIs and interaction p-values. Our case-study demonstrated that there was a nearly two-fold greater RI of ER visits and admissions following wcp vaccination relative to acp vaccination (RIR = 1.82, 95 % CI 1.64–2.01), where RI estimates in each subgroup were clearly impacted by a strong healthy vaccinee effect.ConclusionsWe demonstrated in our scoping review that calculating RIRs is not a widely utilized strategy. We showed that calculating RIRs across time periods is useful for the detection of relative changes in adverse event rates that might otherwise be missed due to the HVE. Many published studies of vaccine-associated adverse events could have missed/underestimated important safety signals masked by the HVE. With further development, our application of RIRs could be an important tool to address the HVE, particularly in the context of self-controlled study designs.

Mortality and cancer incidence in a cohort of male paid Australian firefighters

ObjectivesTo investigate mortality and cancer incidence of paid male Australian firefighters and of subgroups of firefighters by era of first employment, duration of employment and number and type of incidents...

Psoriasis and risk of incident atrial fibrillation: A systematic review and meta-analysis.

Patients with psoriasis might have a higher risk of developing atrial fibrillation as a result of chronic inflammation. This study aimed to investigate this association by comprehensively reviewing all available evidence. We conducted a systematic review and meta-analysis of cohort studies that reported relative risk, hazard ratio, incidence ratio or standardized incidence ratio with 95% confidence intervals comparing the risk of incident atrial fibrillation in patients with psoriasis versus participants without psoriasis. Both retrospective and prospective cohort studies were eligible. Pooled risk ratio and 95% confidence intervals were calculated using random-effect, generic inverse variance methods of DerSimonian and Laird. Three retrospective studies with 110,568 cases of psoriasis and 5,352,817 participants without psoriasis were included in this meta-analysis. The pooled risk ratio of subsequent development of atrial fibrillation in patients with psoriasis versus participants without psoriasis was 1.21 (95% confidence interval, 1.14-1.29). The statistical heterogeneity was low with an I2 of 29%. Coding-based design of the primary studies that had limited accuracy. Our meta-analysis demonstrated a statistically significant increase in the risk of incident atrial fibrillation among patients with psoriasis.

Risk of incident atrial fibrillation in patients with rheumatoid arthritis: a systematic review and meta-analysis.

Patients with rheumatoid arthritis (RA) might be at an increased risk of developing atrial fibrillation (AF) as a result of deleterious effects of inflammatory cytokines on cardiomyocytes. This study aimed to comprehensively review all available evidence to further characterize this possible association. We conducted a systematic review and meta-analysis of cohort studies that reported relative risk, hazard ratio, incidence ratio or standardized incidence ratio with 95% confidence intervals comparing the risk of incidence of AF in patients with RA versus non-RA participants. Pooled risk ratio and 95% confidence interval were calculated using random-effect, generic inverse-variance methods of DerSimonian and Laird. Three retrospective cohort studies with 39 912 cases of RA and 4 269 161 non-RA controls were included in the data analysis. The pooled risk ratio of subsequent development of AF in patients with RA versus controls was 1.29 (95% CI, 1.05-1.59). The statistical heterogeneity was moderate with an I2 of 71%. Our meta-analysis demonstrated a statistically significant increased risk of subsequent development of AF among patients with RA.

Risk of incident chronic obstructive pulmonary disease in patients with rheumatoid arthritis: A systematic review and meta-analysis

ObjectiveTo investigate the risk of subsequent development of chronic obstructive pulmonary disease (COPD) in patients with rheumatoid arthritis (RA). MethodsWe conducted a systematic review and meta-analysis of cohort studies that reported relative risk, hazard ratio or standardized incidence ratio with 95% confidence interval (CI), comparing risk of incident COPD in patients with RA versus non-RA participants. Pooled risk ratio and 95% CI were calculated using a random-effect, generic inverse variance method of DerSimonian and Laird. ResultsFour retrospective cohort studies with 32,675 patients with RA and 122,204 controls were included in the data analysis. The pooled risk ratio of incident COPD in patients with RA versus control was 1.99 (95% CI, 1.61–2.45). The statistical heterogeneity was high with an I2 of 81%. ConclusionOur study demonstrated a statistically significant increased risk of subsequent development of COPD among patients with RA.

Individual non-steroidal anti-inflammatory drugs and risk of acute kidney injury: A systematic review and meta-analysis of observational studies

BackgroundThe association between acute kidney injury (AKI) and use of non-steroidal anti-inflammatory drugs (NSAIDs) is well established. However, little is known about the comparative risk of individual NSAIDs, including specific COX-2 inhibitors. MethodsWe conducted a systematic review and meta-analysis of cohort studies that reported relative risk, hazard ratio or standardized incidence ratio with 95% confidence comparing AKI risk in NSAID users versus non-users. Pooled risk ratios and 95% confidence intervals for individual NSAIDs were calculated using random-effect, generic inverse variance methods. ResultsFive studies were identified and included in our data analysis. Pooled risk ratios were calculated for seven traditional NSAIDs and two specific COX-2 inhibitors, including indomethacin, piroxicam, ibuprofen, naproxen, sulindac, diclofenac, meloxicam, rofecoxib and celecoxib that were evaluated in at least two studies. Our meta-analysis was able to demonstrate a statistically significant elevated AKI risk among most of the included traditional NSAIDs. The pooled risk ratios were fairly consistent among individual traditional NSAIDs, ranging from 1.58 to 2.11. Differences between pooled risk ratios did not reach statistical significance (p≥0.19 for each comparison). Elevated AKI risk was also observed in diclofenac, meloxicam, rofecoxib and celecoxib users, although did not achieve a statistical significance. ConclusionA statistically significant elevated AKI risk among traditional NSAID users has been demonstrated in this meta-analysis. The pooled risk ratios among individual traditional NSAIDs were not significantly different. The pooled risk ratios of specific COX-2 inhibitors and the two traditional NSAIDs with the most COX-2 selectivity (diclofenac and meloxicam) were also comparable with other traditional NSAIDs even though they did not achieve a statistical significance.