Importance of ICD-10 coding directive change for acute gastroenteritis (unspecified) for rotavirus vaccine impact studies: illustration from a population-based cohort study from Ontario, Canada

Cumulative incidence of chronic health conditions recorded in hospital inpatient admissions from birth to age 16 in England

BACKGROUND

Monitoring the incidence of chronic health conditions (CHCs) in childhood in England, using administrative data to derive numerators and denominators, is challenged by unmeasured migration. We used open and closed birth cohort designs to estimate the cumulative incidence of CHCs to age 16 years.

METHODS

In closed cohorts, we identified all births in Hospital Episode Statistics (HES) from 2002/3 to 2011/12, followed to 2018/19 (maximum age 8 to 16 years), censoring on death, first non-England residence record or 16th birthday. Children must have linked to later HES records and/or the National Pupil Database, which provides information on all state school enrolments, to address unmeasured emigration. The cumulative incidence of CHCs was estimated to age 16 using diagnostic codes in HES inpatient records. We also explored temporal variation. Sensitivity analyses varied eligibility criteria. In open cohorts, we used HES data on all children from 2002/3 to 2018/19 and national statistics population denominators.

RESULTS

In open and closed approaches, the cumulative incidence of ever having a CHC recorded before age 16 among children born in 2003/4 was 25% (21% to 32% in closed cohort sensitivity analyses). There was little temporal variation. At least 28% of children with any CHC had more than one body system affected by age 16. Multimorbidity rates rose with later cohorts.

CONCLUSIONS

Approximately one-quarter of children are affected by CHCs, but estimates vary depending on how the denominator is defined. More accurate estimation of the incidence of CHCs requires a dynamic population estimate.

Impact of rotavirus vaccination on diarrheal hospitalizations in children younger than 5 years of age in a rural southern Mozambique

BACKGROUND

Rotavirus vaccine(Rotarix®) was introduced in Mozambique through its Expanded Program of Immunization in September 2015. We assessed the impact of rotavirus vaccination on childhood gastroenteritis-associated hospitalizations post-vaccine introduction in a high HIV prevalence rural setting of southern Mozambique.

METHODS

We reviewed and compared the trend of hospitalizations (prevalence) and incidence rates of acute gastroenteritis (AGE), and rotavirus associated-diarrhea (laboratory confirmed rotavirus) in pre- (January 2008-August 2015) and post-rotavirus vaccine introduction periods (September 2015-December 2020), among children <5 years of age admitted to Manhiça District Hospital.

RESULTS

From January 2008 to December 2020, rotavirus vaccination was found to contribute to the decline of the prevalence of AGE from 19% (95% CI: 18.14-20.44) prior to the vaccine introduction to 10% (95% CI: 8.89-11.48) in the post-introduction period, preventing 40% (95 % IE: 38-42) and 84% (95 % IE: 80-87) of the expected AGE and laboratory confirmed rotavirus cases, respectively, among infants. Similarly, the overall incidence of rotavirus was 11.8-fold lower in the post-vaccine introduction period (0.4/1000 child-years-at-risk [CYAR]; 95% CI: 0.3-0.6) compared with the pre-vaccination period (4.7/1000 CYAR; 95% CI: 4.2-5.1) with the highest reduction being observed among infants (16.8-fold lower from the 15.1/1000 CYAR in the pre-vaccine to 0.9/1000 CYAR in the post-vaccine eras).

CONCLUSIONS

We documented a significant reduction in all-cause diarrhea hospitalizations and rotavirus positivity after vaccine introduction demonstrating the beneficial impact of rotavirus vaccination in a highly vulnerable population.

Falling admissions to hospital with febrile seizures in the UK

OBJECTIVES

There was a reduction in febrile seizure admissions in Scotland after 2008. Our hypothesis was that a similar trend would be seen in other countries.

METHODS

We obtained the number of febrile and non-febrile seizure admissions in England and Scotland 2000-2013 and the incidence of all seizure admissions 2000-2013 in European countries. We compared the incidence of admission for febrile seizure (Scotland and England) and all seizures (all countries) between 2000-2008 and 2009-2013.

RESULTS

The incidence of febrile seizure admissions per 1000 children in 2009-2013 was lower than 2000-2008 in Scotland (0.79 vs 1.08, p=0.001) and England (0.92 vs 1.20, p<0.001). The incidence of all seizure admissions (but not non-febrile seizures) was lower in 2009-2013 compared with 2000-2008 in Scotland (1.84 vs 2.20, p=0.010) and England (2.71 vs 2.91, p=0.001). Across 12 European countries (including the UK), there was no difference in all seizure admissions after 2008. We explored the possibility that the fall was related to the introduction of routine pneumococcal vaccination in 2006 but there were insufficient data.

CONCLUSION

A fall in admissions for febrile (but not afebrile) seizures after 2008 in Scotland and England explains a fall in all emergency admissions for seizure. A fall in all seizure admissions has not occurred in other European countries, and more research is required to understand the different outcomes in the UK and non-UK countries.

[Infectious diseases and their ICD coding : What could be improved by the introduction of ICD-11?]

Die Revision der Internationalen statistischen Klassifikation der Krankheiten und verwandter Gesundheitsprobleme (International Classification of Diseases – ICD) geht mit grundlegenden Änderungen der Morbiditäts- und Mortalitätsstatistik einher, die auch den Bereich der Infektionskrankheiten betreffen. Die Zuordnung der einzelnen Infektionskrankheiten zu den Kapiteln in der aktuellen ICD-10 erfolgt aufgrund unterschiedlicher Konzepte, teilweise nach auslösendem Agens, nach betroffenem Organsystem oder nach Lebensperiode. Besondere Herausforderungen der Klassifizierung der Infektionskrankheiten bestehen u. a. darin, dass regelmäßig ein Anpassungsbedarf durch neu auftretende Erreger entstehen kann. Außerdem reichen die Angaben hinsichtlich Umfang und Tiefe in der ICD-10 teilweise nicht aus, um epidemiologische Auswertungen der Daten durchzuführen.

Die ICD ermöglicht den weltweiten Vergleich von Statistiken zu Infektionskrankheiten. Zunehmend wird die ICD jedoch auch für die Erhebung von Surveillance- und Forschungsdaten eingesetzt, z. B. im Rahmen des Meldewesens (Identifizierung von Meldetatbeständen), aber auch in der syndromischen Surveillance akuter Atemwegsinfektionen und für den Aufbau neuer Surveillance-Systeme sowie der Evaluation der Datenqualität durch Abgleich mit Sekundärdaten.

Die Chancen der ICD-11 liegen vor allem darin, dass Infektionskrankheiten eindeutiger codiert werden können und ihre Codierung mehr relevante Informationen für die epidemiologische Bewertung enthält. Durch die hohe Komplexität können jedoch Verzerrungen in den Daten entstehen, die die Fortschreibung der Morbiditäts- und Mortalitätsstatistiken erschweren.

Do hospital pressures change following rotavirus vaccine introduction? A retrospective database analysis in a large paediatric hospital in the UK

OBJECTIVE

Hospitals in the UK are under increasing clinical and financial pressures. Following introduction of childhood rotavirus vaccination in the UK in 2013, rotavirus gastroenteritis (RVGE) hospitalisations reduced significantly. We evaluated changes in 'hospital pressures' (demand on healthcare resources and staff) following rotavirus vaccine introduction in a paediatric setting in the UK.

DESIGN

Retrospective hospital database analysis between July 2007 and June 2015.

SETTING

A large paediatric hospital providing primary, secondary and tertiary care in Merseyside, UK.

PARTICIPANTS

Hospital admissions aged <15 years. Outcomes were calculated for four different patient groups identified through diagnosis coding (International Classification of Disease, 10th edition) and/or laboratory confirmation: all admissions; any infection, acute gastroenteritis and RVGE.

METHODS

Hospital pressures were compared before and after rotavirus vaccine introduction: these included bed occupancy, hospital-acquired infection rate, unplanned readmission rate and outlier rate (medical patients admitted to surgical wards due to lack of medical beds). Interrupted time-series analysis was used to evaluate changes in bed occupancy.

RESULTS

There were 116 871 admissions during the study period. Lower bed occupancy in the rotavirus season in the postvaccination period was observed for RVGE (-89%, 95% CI 73% to 95%), acute gastroenteritis (-63%, 95% CI 39% to 78%) and any infection (-23%, 95% CI 15% to 31%). No significant overall reduction in bed occupancy was observed (-4%, 95% CI -1% to 9%). No changes were observed for the other outcomes.

CONCLUSIONS

Rotavirus vaccine introduction was not associated with reduced hospital pressures. A reduction in RVGE hospitalisation without change in overall bed occupancy suggests that beds available were used for a different patient population, possibly reflecting a previously unmet need.

TRIALS REGISTRATION NUMBER

NCT03271593.

Equity and impact: Ontario's infant rotavirus immunization program five years following implementation. A population-based cohort study

BACKGROUND

Ontario implemented a publicly-funded rotavirus (RV) immunization program in 2011. Our objectives were to evaluate its impact on hospitalizations and emergency department (ED) visits for acute gastroenteritis (AGE) five years after implementation.

METHODS

We performed a population-based longitudinal retrospective cohort study to identify hospitalizations and ED visits for RV-AGE and overall AGE in all age groups using ICD-10 codes between August 1, 2005 and March 31, 2016. A negative binomial regression model that included the effect of time was used to calculate rates, rate ratios (RRs) and 95% confidence intervals (CIs) for AGE before and after the program's implementation, after adjusting for age, seasonality and secular trends. We examined the seasonality of RV-AGE hospitalizations among children under five before and after the program and explored its equity impact.

RESULTS

Following program implementation, RV-AGE hospitalizations and ED visits among children under five years declined by 76% (RR 0.24, 95% CI 0.20-0.28) and 68% (RR 0.32, 95% CI 0.21-0.50), respectively. In addition, hospitalizations and ED visits for overall AGE declined by 38% (RR 0.62, 95% CI 0.59-0.65) and 26% (RR 0.74, 95% CI 0.73-0.76), respectively, among children under age five. Significant reductions in both outcomes were also found across a range of age-strata. In the pre-program period, the mean monthly hospitalization rate for RV-AGE among children residing in the most marginalized neighbourhoods was 33% higher than those residing in the least marginalized (RR 1.33, 95% CI 1.17-1.52), this disparity was not evident in the program period (RR 0.95, 95% CI 0.69-1.32). We found no evidence of a seasonal shift in rotavirus pediatric hospitalizations.

INTERPRETATION

The introduction of routine infant rotavirus immunization has had a substantial population impact in Ontario. Our study confirms herd effects and suggests the program may have reduced previous inequities in the burden of pediatric rotavirus hospitalizations.

Evaluation of the Impact of a Rotavirus Vaccine Program on Pediatric Acute Gastroenteritis Hospitalizations: Estimating the Overall Effect Attributable to the Program as a Whole and as a Per-Unit Change in Rotavirus Vaccine Coverage

Estimation of the overall effect of a vaccine program is essential, but the effect is typically estimated for a whole program. We estimated the overall effect of the Quebec rotavirus vaccine program, launched in November 2011, and the effect for each 10% increase in rotavirus vaccine coverage on pediatric hospitalizations for all-cause acute gastroenteritis. We implemented negative binomial regressions adjusted for seasonality, long-term trends, and infection dynamics, to estimate the effect of the vaccine program as: 1) a dichotomous variable, representing program presence/absence, and linear term to account for changes in trend in the period after the program began; and 2) a continuous variable, representing rotavirus vaccine coverage. Using exposure 1, the vaccine program was associated with a 51.2% (95% confidence interval (CI): 28.5, 66.7) relative decline in adjusted weekly hospitalization rates for all-cause acute gastroenteritis as of December 28, 2014. Using exposure 2, a 10% increase in rotavirus ≥1-dose coverage was associated with a 7.1% (95% CI: 3.5, 10.5) relative decline in adjusted weekly rates, with maximum coverage of 87.0% associated with a 47.2% (95% CI: 26.9, 61.9) relative decline. Estimation of the overall effect attributable to a change in vaccine coverage might be a useful addition to standard measurement of the overall effect.

Rotavirus vaccine impact and socioeconomic deprivation: an interrupted time-series analysis of gastrointestinal disease outcomes across primary and secondary care in the UK

BACKGROUND

Rotavirus causes severe gastroenteritis in infants and young children worldwide. The UK introduced the monovalent rotavirus vaccine (Rotarix®) in July 2013. Vaccination is free of charge to parents, with two doses delivered at 8 and 12 weeks of age. We evaluated vaccine impact across a health system in relation to socioeconomic deprivation.

METHODS

We used interrupted time-series analyses to assess changes in monthly health-care attendances in Merseyside, UK, for all ages, from July 2013 to June 2016, compared to predicted counterfactual attendances without vaccination spanning 3-11 years pre-vaccine. Outcome measures included laboratory-confirmed rotavirus gastroenteritis (RVGE) hospitalisations, acute gastroenteritis (AGE) hospitalisations, emergency department (ED) attendances for gastrointestinal conditions and consultations for infectious gastroenteritis at community walk-in centres (WIC) and general practices (GP). All analyses were stratified by age. Hospitalisations were additionally stratified by vaccine uptake and small-area-level socioeconomic deprivation.

RESULTS

The uptake of the first and second doses of rotavirus vaccine was 91.4% (29,108/31,836) and 86.7% (27,594/31,836), respectively. Among children aged < 5 years, the incidence of gastrointestinal disease decreased across all outcomes post-vaccine introduction: 80% (95% confidence interval [CI] 70-87%; p < 0.001) for RVGE hospitalisation, 44% (95% CI 35-53%; p < 0.001) for AGE hospitalisations, 23% (95% CI 11-33%; p < 0.001) for ED, 32% (95% CI 7-50%; p = 0.02) for WIC and 13% (95% CI -3-26%; p = 0.10) for GP. The impact was greatest during the rotavirus season and for vaccine-eligible age groups. In adults aged 65+ years, AGE hospitalisations fell by 25% (95% CI 19-30%; p < 0.001). The pre-vaccine risk of AGE hospitalisation was highest in the most socioeconomically deprived communities (adjusted incident rate ratio 1.57; 95% CI 1.51-1.64; p < 0.001), as was the risk for non-vaccination (adjusted risk ratio 1.54; 95% CI 1.34-1.75; p < 0.001). The rate of AGE hospitalisations averted per 1,000 first doses of vaccine was higher among infants in the most deprived communities compared to the least deprived in 2014/15 (28; 95% CI 25-31 vs. 15; 95% CI 12-17) and in 2015/16 (26; 95% CI 23-30 vs. 13; 95% CI 11-16).

CONCLUSIONS

Following the introduction of rotavirus vaccination, incidence of gastrointestinal disease reduced across the health-care system. Vaccine impact was greatest among the most deprived populations, despite lower vaccine uptake. Prioritising vaccine uptake in socioeconomically deprived communities should give the greatest health benefit in terms of population disease burden.

Changing characteristics of hospital admissions but not the children admitted-a whole population study between 2000 and 2013

There are increasing numbers of emergency medical paediatric admissions. Our hypothesis was that characteristics of children and details of their emergency admissions are also changing over time. Details of emergency admissions in Scotland 2000-2013 were analysed. There were 574,403 emergency admissions, median age 2.3 years. The age distribution, proportion of boys and socioeconomic status of children admitted were essentially unchanged. Emergency admissions rose by 49% from 36/1000 children per annum to 54/1000 between 2000 and 2013. Emergency admissions that were discharged on the same day rose by 186% from 8.6/1000 to 24.6/1000. The mean duration of emergency admission fell from 1.7 to 1.0 days. The odds for an emergency admission with upper respiratory infection, "viral infection", tonsillitis, bronchiolitis and lower respiratory tract infection all rose. In contrast the odds for an emergency admission with asthma and gastroenteritis fell.

CONCLUSIONS

The demographics of children with emergency admissions have not changed substantially but characteristics of admissions have changed considerably, in particular admissions which are short stay and due to respiratory infection are much more common. The fall in the absolute number of children with some acute medical diagnoses suggests that the rise in admissions is not necessarily inexorable. What is Known: • Emergency admission prevalence is rising in many countries across Europe. What is New: • Our paper is the first to comprehensively analyse emergency medical paediatric admissions by exploring how characteristics of admissions and the children admitted have changed over time for a whole population. • The "take home message" is that whilst characteristics of emergency admissions have changed (e.g. number, duration of stay, readmissions, diagnoses), the characteristics of the children have not changed.

An Ontology to Improve Transparency in Case Definition and Increase Case Finding of Infectious Intestinal Disease: Database Study in English General Practice

BACKGROUND

Infectious intestinal disease (IID) has considerable health impact; there are 2 billion cases worldwide resulting in 1 million deaths and 78.7 million disability-adjusted life years lost. Reported IID incidence rates vary and this is partly because terms such as "diarrheal disease" and "acute infectious gastroenteritis" are used interchangeably. Ontologies provide a method of transparently comparing case definitions and disease incidence rates.

OBJECTIVE

This study sought to show how differences in case definition in part account for variation in incidence estimates for IID and how an ontological approach provides greater transparency to IID case finding.

METHODS

We compared three IID case definitions: (1) Royal College of General Practitioners Research and Surveillance Centre (RCGP RSC) definition based on mapping to the Ninth International Classification of Disease (ICD-9), (2) newer ICD-10 definition, and (3) ontological case definition. We calculated incidence rates and examined the contribution of four supporting concepts related to IID: symptoms, investigations, process of care (eg, notification to public health authorities), and therapies. We created a formal ontology using ontology Web language.

RESULTS

The ontological approach identified 5712 more cases of IID than the ICD-10 definition and 4482 more than the RCGP RSC definition from an initial cohort of 1,120,490. Weekly incidence using the ontological definition was 17.93/100,000 (95% CI 15.63-20.41), whereas for the ICD-10 definition the rate was 8.13/100,000 (95% CI 6.70-9.87), and for the RSC definition the rate was 10.24/100,000 (95% CI 8.55-12.12). Codes from the four supporting concepts were generally consistent across our three IID case definitions: 37.38% (3905/10,448) (95% CI 36.16-38.5) for the ontological definition, 38.33% (2287/5966) (95% CI 36.79-39.93) for the RSC definition, and 40.82% (1933/4736) (95% CI 39.03-42.66) for the ICD-10 definition. The proportion of laboratory results associated with a positive test result was 19.68% (546/2775).

CONCLUSIONS

The standard RCGP RSC definition of IID, and its mapping to ICD-10, underestimates disease incidence. The ontological approach identified a larger proportion of new IID cases; the ontology divides contributory elements and enables transparency and comparison of rates. Results illustrate how improved diagnostic coding of IID combined with an ontological approach to case definition would provide a clearer picture of IID in the community, better inform GPs and public health services about circulating disease, and empower them to respond. We need to improve the Pathology Bounded Code List (PBCL) currently used by laboratories to electronically report results. Given advances in stool microbiology testing with a move to nonculture, PCR-based methods, the way microbiology results are reported and coded via PBCL needs to be reviewed and modernized.

Population-Level Impact of Ontario's Infant Rotavirus Immunization Program: Evidence of Direct and Indirect Effects

OBJECTIVE

To evaluate the direct and indirect population impact of rotavirus (RV) immunization on hospitalizations and emergency department (ED) visits for acute gastroenteritis (AGE) in Ontario before and after the publicly-funded RV immunization program.

METHODS

Administrative data was used to identify ED visits and hospitalizations for all Ontarians using ICD-10 codes. We used two outcome definitions: RV-specific AGE (RV-AGE) and codes representing RV-, other viral and cause unspecified AGE ("overall AGE"). The pre-program and public program periods were August 1, 2005 to July 31, 2011; and August 1, 2011 to March 31, 2013, respectively. A negative binominal regression model that included the effect of time was used to calculate rates and rate ratios (RRs) and 95% confidence intervals (CIs) for RV-AGE and overall AGE between periods, after adjusting for age, seasonality and secular trends. Analyses were conducted for all ages combined and age stratified.

RESULTS

Relative to the pre-program period, the adjusted RRs for RV-AGE and overall AGE hospitalizations in the public program period were 0.29 (95%CI: 0.22-0.39) and 0.68 (95%CI: 0.62-0.75), respectively. Significant reductions in RV-AGE hospitalizations were noted overall and for the following age bands: < 12 months, 12-23 months, 24-35 months, 3-4 years, and 5-19 years. Significant declines in overall AGE hospitalizations were observed across all age bands, including older adults > = 65 years (RR 0.80, 95%CI: 0.72-0.90). The program was associated with adjusted RRs of 0.32 (95% CI: 0.20-0.52) for RV-AGE ED visits and 0.90 (95% CI: 0.85-0.96) for overall AGE ED visits.

CONCLUSIONS

This large, population-based study provides evidence of the impact of RV vaccine in preventing hospitalizations and ED visits for RV-AGE and overall AGE, including herd effects.