Underreporting of Meningococcal Disease Incidence in the Netherlands: Results from a Capture–Recapture Analysis Based on Three Registration Sources with Correction for False Positive Diagnoses

Invasive Pneumococcal Disease in Tuscany Region, Italy, 2016-2017: Integrating Multiple Data Sources to Investigate Underreporting

Invasive pneumococcal disease (IPD) is a vaccine-preventable disease characterized by the presence of Streptococcus pneumoniae in normally sterile sites. Since 2007, Italy has implemented an IPD national surveillance system (IPD-NSS). This system suffers from high rates of underreporting. To estimate the level of underreporting of IPD in 2016–2017 in Tuscany (Italy), we integrated data from IPD-NSS and two other regional data sources, i.e., Tuscany regional microbiological surveillance (Microbiological Surveillance and Antibiotic Resistance in Tuscany, SMART) and hospitalization discharge records (HDRs). We collected (1) notifications to IPD-NSS, (2) SMART records positive for S. pneumoniae from normally sterile sites, and (3) hospitalization records with IPD-related International Classification of Diseases, Ninth Revision, Clinical Modification (ICD9) codes in discharge diagnoses. We performed data linkage of the three sources to obtain a combined surveillance system (CSS). Using the CSS, we calculated the completeness of the three sources and performed a three-source log-linear capture–recapture analysis to estimate total IPD underreporting. In total, 127 IPD cases were identified from IPD-NSS, 320 were identified from SMART, and 658 were identified from HDRs. After data linkage, a total of 904 unique cases were detected. The average yearly CSS notification rate was 12.1/100,000 inhabitants. Completeness was 14.0% for IPD-NSS, 35.4% for SMART, and 72.8% for HDRs. The capture–recapture analysis suggested a total estimate of 3419 cases of IPD (95% confidence interval (CI): 1364–5474), corresponding to an underreporting rate of 73.7% (95% CI: 34.0–83.6) for CSS. This study shows substantial underreporting in the Tuscany IPD surveillance system. Integration of available data sources may be a useful approach to complement notification-based surveillance and provide decision-makers with better information to plan effective control strategies against IPD.

Estimating the prevalence of congenital heart disease among adolescents and adults in Colorado adjusted for incomplete case ascertainment

BACKGROUND

Congenital heart defects (CHDs), the most common type of birth defect in the United States, are increasing in prevalence in the general population. Though CHD prevalence at birth has been well described in the United States at about 1%, little is known about long-term survival and prevalence of CHDs beyond childhood. This study aimed to estimate the prevalence of CHDs among adolescents and adults in Colorado.

METHODS

The prevalence of CHDs among adolescents and adults residing in Colorado during 2011 to 2013 was estimated using log-linear capture-recapture methods to account for incomplete case ascertainment. Five case-finding data sources were used for this analysis including electronic health record data from 4 major health systems and a state-legislated all payer claims database.

RESULTS

Twelve thousand two hundred ninety-three unique individuals with CHDs (2481 adolescents and 9812 adults) were identified in one or more primary data sources. We estimated the crude prevalence of CHDs in adolescents and adults in Colorado to be 3.22 per 1000 individuals (95% CI 3.19-3.53). After accounting for incomplete case ascertainment, the final capture-recapture model yielded an estimated total adolescent and adult CHD population of 23,194 (95% CI 22,419-23,565) and an adjusted prevalence of 6.07 per 1000 individuals (95% CI 5.86-6.16), indicating 47% of the cases in the catchment area were not identified in the case-identifying data sources.

CONCLUSION

This statewide study yielded new information on the prevalence of CHDs in adolescents and adults. These high prevalence rates underscore the need for additional specialized care facilities for this population with CHDs.

Evaluation of measles and rubella integrated surveillance system in Apulia region, Italy, 3 years after its introduction

This study aimed at evaluating the integrated measles and rubella surveillance system (IMRSS) in Apulia region, Italy, from its introduction in 2013 to 30 June 2016. Measles and rubella case reports were extracted from IMRSS. We estimated system sensitivity at the level of case reporting, using the capture–recapture method for three data sources. Data quality was described as the completeness of variables and timeliness of notification as the median-time interval from symptoms onset to initial alert. The proportion of suspected cases with laboratory investigation, the rate of discarded cases and the origin of infection were also computed. A total of 127 measles and four rubella suspected cases were reported to IMRSS and 82 were laboratory confirmed. Focusing our analysis on measles, IMRSS sensitivity was 82% (95% CI: 75–87). Completeness was >98% for mandatory variables and 57% for ‘genotyping’. The median-time interval from symptoms onset to initial alert was 4.5 days, with a timeliness of notification of 33% (41 cases reported ⩽48 h). The proportion of laboratory investigation was 87%. The rate of discarded cases was 0.1 per 100 000 inhabitants per year. The origin of infection was identified for 85% of cases. It is concluded that IMRSS provides good quality data and has good sensitivity; still efforts should be made to improve the completeness of laboratory-related variables, timeliness and to increase the rate of discarded cases.

Utility of Capture-Recapture Methodology to Estimate Prevalence of Congenital Heart Defects Among Adolescents in 11 New York State Counties: 2008 to 2010

BACKGROUND

Congenital heart defects (CHDs) are the most common birth defects in the United States, and the population of individuals living with CHDs is growing. Though CHD prevalence in infancy has been well characterized, better prevalence estimates among children and adolescents in the United States are still needed.

METHODS

We used capture-recapture methods to estimate CHD prevalence among adolescents residing in 11 New York counties. The three data sources used for analysis included Statewide Planning and Research Cooperative System (SPARCS) hospital inpatient records, SPARCS outpatient records, and medical records provided by seven pediatric congenital cardiac clinics from 2008 to 2010. Bayesian log-linear models were fit using the R package Conting to account for dataset dependencies and heterogeneous catchability.

RESULTS

A total of 2537 adolescent CHD cases were captured in our three data sources. Forty-four cases were identified in all data sources, 283 cases were identified in two of three data sources, and 2210 cases were identified in a single data source. The final model yielded an estimated total adolescent CHD population of 3845, indicating that 66% of the cases in the catchment area were identified in the case-identifying data sources. Based on 2010 Census estimates, we estimated adolescent CHD prevalence as 6.4 CHD cases per 1000 adolescents (95% confidence interval: 6.2-6.6).

CONCLUSION

We used capture-recapture methodology with a population-based surveillance system in New York to estimate CHD prevalence among adolescents. Future research incorporating additional data sources may improve prevalence estimates in this population. Birth Defects Research 109:1423-1429, 2017.© 2017 Wiley Periodicals, Inc.

Invasive meningococcal disease in the Veneto region of Italy: a capture-recapture analysis for assessing the effectiveness of an integrated surveillance system

BACKGROUND

Epidemiology of Neisseria meningitidis has been changing since the introduction of universal vaccination programmes against meningococcal serogroup C (MenC) and meningococcal serogroup B (MenB) has now become dominant. This study aimed to analyse the cases reported in institutional data recording systems to estimate the burden of invasive meningococcal diseases (IMDs) and assess the effectiveness of surveillance in Veneto region (Italy).

METHODS

Analysis was performed from 2007 to 2014 on data recorded in different systems: Mandatory Notification System, National Surveillance of Invasive Bacterial Diseases System and Laboratories Surveillance System (LSS), which were pooled into a combined surveillance system (CSS) and hospital discharge records (HDRs). A capture-recapture method was used and completeness of each source estimated. Number of cases with IMD by source of information and year, incidence of IMD by age group, case fatality rate (CFR) and distribution of meningococcal serogroups by year were also analysed.

RESULTS

Combining the four data systems enabled the identification of 179 confirmed cases with IMD, achieving an overall sensitivity of 94.7% (95% CI: 90.8% to 98.8%), while it was 76.7% (95% CI: 73.6% to 80.1%) for CSS and 77.2% (95% CI: 74.1% to 80.6%) for HDRs. Typing of isolates was done in 80% of cases, and 95.2% of the typed cases were provided by LSS. Serogroup B was confirmed in 50.3% of cases. The estimated IMD notification rate (cases with IMD diagnosed and reported to the surveillance systems) was 0.48/100 000 population, and incidence peaked at 6.2/100 000 in children aged <1 year old (60.9% due to MenB), and increased slightly in the age group between 15 and 19 years (1.1/100 000). A CFR of 14% was recorded (8.7% in paediatric age).

CONCLUSIONS

Quality of surveillance systems relies on case ascertainment based on serological characterisation of the circulating strains by microbiology laboratories. All available sources should be routinely combined to improve the epidemiology of IMD and the information used by public health departments to conduct timely preventive measures.

Completeness of Neisseria meningitidis reporting in New York City, 1989-2010

Invasive meningococcal disease (IMD) completeness of reporting has never been assessed in New York City (NYC). We conducted a capture–recapture study to assess completeness of reporting, comparing IMD reports made to the NYC Department of Health and Mental Hygiene (DOHMH) and records identified in the New York State hospital discharge database [Statewide Planning and Research Cooperative System (SPARCS)] by ICD-9 codes from 1989 to 2010. Reporting completeness estimates were calculated for the entire study period, and stratified by year, age group, clinical syndrome, and reporting system. A chart review of hospital medical records from 2008 to 2010 was conducted to validate hospital coding and to adjust completeness estimates. Overall, 2194 unique patients were identified from DOHMH (n = 1300) and SPARCS (n = 1525); 631 (29%) were present in both. Completeness of IMD reporting was 41% [95% confidence interval (CI) 40–43]. Differences in completeness were found by age, clinical syndrome, and reporting system. The chart review found 33% of hospital records from 2008 to 2010 had no documentation of IMD. Removal of those records improved completeness of reporting to 51% (95% CI 49–53). Our data showed a low concordance between what is reported to DOHMH and what is coded by hospitals as IMD. Additional guidance to clinicians on IMD reporting criteria may improve completeness of IMD reporting.

Estimation of the Impact of Meningococcal Serogroup C Universal Vaccination in Italy and Suggestions for the Multicomponent Serogroup B Vaccine Introduction

In Italy, the meningococcal C conjugate vaccine (MenC) has been offered in most regions since 2009-2010. The incidence of Invasive Meningococcal Disease (IMD) was 0.25 confirmed cases per 100,000 in 2011, but this may be considerably underestimated due to underdetection and underreporting. This study estimates the impact of the MenC universal vaccination (URV) in the Puglia region by assessing the completeness of three registration sources (notifications, hospitalizations, and laboratory surveillance). Capture-recapture analysis was performed on meningococcal meningitis collected within 2001-2013. The impact of URV among ≤ 18-year-olds was assessed by attributable benefit, preventable fraction, and prevented fraction. Missed opportunities for vaccination were evaluated from surveillance of IMD. The proportion of detected serogroups was applied to the number of IMD in the postvaccination period to compute the cases still preventable. The sensitivity of the three sources was 36.7% (95% CI: 17.5%-57.9%) and registrations lost nearly 28 cases/year in the period. Attributable benefit of URV was -0.5 cases per 100,000, preventable fraction 19.6%, and prevented fraction 31.3%. Three adolescent cases missed the opportunity to be vaccinated. The multicomponent serogroup B meningococcal vaccine has the potential to further prevent at least three other cases/year. Vaccination strategy against serogroup B together with existing programmes makes IMD a 100% vaccine-preventable disease.

Using linked birth, notification, hospital and mortality data to examine false-positive meningococcal disease reporting and adjust disease incidence estimates for children in New South Wales, Australia

Meningococcal disease is a rare, rapidly progressing condition which may be difficult to diagnose, disproportionally affects children, and has high morbidity and mortality. Accurate incidence estimates are needed to monitor the effectiveness of vaccination and treatment. We used linked notification, hospital, mortality and birth data for all children of an Australian state (2000-2007) to estimate the incidence of meningococcal disease. A total of 595 cases were notified, 684 cases had a hospital diagnosis, and 26 cases died from meningococcal disease. All deaths were notified, but only 68% (466/684) of hospitalized cases. Of non-notified hospitalized cases with more than one clinical admission, most (90%, 103/114) did not have meningococcal disease recorded as their final diagnosis, consistent with initial 'false-positive' hospital meningococcal disease diagnosis. After adjusting for false-positive rates in hospital data, capture-recapture estimation suggested that up to four cases of meningococcal disease may not have been captured in either notification or hospital records. The estimated incidence of meningococcal disease in NSW-born and -resident children aged 0-14 years was 5·1-5·4 cases/100 000 child-years at risk, comparable to international estimates using similar methods, but lower than estimates based on hospital data.

Assessment of tuberculosis surveillance by capture-recapture in the Balearic Islands, Spain, 2005-2007

The tuberculosis surveillance system in the Balearic Islands was assessed from 2005 to 2007. Applying the capture-recapture method the completeness of this system was evaluated to be 58.4%. When a new electronic recorded data was included in Primary Health Care, up to 66.5% was obtained. This new source of data increased the detected cases of pulmonary tuberculosis from 572 to 681. As a result, the estimated annual incidence rate increases from 18.9 cases/10(5) to 22.6 cases/10(5) [95% CI, 20.9-24.3], similar to figures issued by WHO.

Cost-effectiveness of vaccination against meningococcal B among Dutch infants: Crucial impact of changes in incidence

OBJECTIVE

Recently, a vaccine with the capacity to protect against serogroup B meningococcal (MenB) disease received a positive opinion of the European Medicines Agency. Previously, such a vaccine was estimated to be cost-effective. However, since then, the MenB disease incidence has declined drastically in the Netherlands. Therefore, we re-assessed the potential incremental cost-effectiveness ratio (ICER) of vaccinating infants in the Netherlands with a MenB vaccine.

RESULTS

Routine infant vaccination (2, 3, 4+11 mo) could prevent 39 cases of MenB disease in a single birth cohort, corresponding to a total gain of 133 quality-adjusted life years (QALYs). However, this strategy is unlikely to be cost-effective if the vaccine costs €40 per dose (€243,778 per QALY). At a disease incidence of 5.7 per 100,000 person-years or a vaccine price of €10 per dose including administration costs, the ICER becomes more acceptable and remains below a threshold of €50,000 per QALY.

METHODS

A cohort of 185,000 Dutch newborns was followed in a Markov model to compare routine vaccination against MenB disease with no vaccination. The ICER was estimated for different disease incidences. The study was performed from a societal perspective.

CONCLUSIONS

At the current low level of disease incidence, introduction of routine infant vaccination, following a 2, 3, 4+11 mo schedule, against MenB disease is unlikely cost-effective in the Netherlands. If the MenB disease incidence increases or the vaccine price is substantially lower than €40, routine infant vaccination has the potential to be cost-effective.

Utility of capture-recapture methodology to assess completeness of amyotrophic lateral sclerosis case ascertainment

BACKGROUND

With the establishment of a national amyotrophic lateral sclerosis (ALS) registry in the United States, methods are needed to ascertain the completeness of case ascertainment, especially in view of the proposal to rely largely on existing data sources.

METHODS

Data about ALS patients residing in the 5-county metropolitan Atlanta area (within the State of Georgia) from 2001 to 2005 were categorized according to their source--ALS Association, clinical (Emory Healthcare, community neurologist, Veterans Health Administration, Veterans Benefits Administration), Medicare and death certificates. ALS diagnoses were verified using chart review. Capture-recapture analyses were carried out using log-linear modeling, stratified by age and race.

RESULTS

The final model (based on 798 cases), which included the 4 main sources and 3 two-way interaction terms, yielded an estimated total population of 880 (95% CI 816-965), indicating that the combination of case-finding methods identified about 90.7% of cases. The estimated 5-year period prevalence is 38.5/100,000 (95% CI 35.66-42.19).

CONCLUSION

This study highlights gaps in data based on existing data sources and illustrates a method for combining data from multiple sources to help facilitate the successful establishment of a US national ALS registry.

Estimation of the underreporting of malaria measurement in ten municipalities of the Pacific coast of Nariño during 2009

Introducción. La recolección de información completa y efectiva de los casos de paludismo es fundamental para elaborar planes operativos, así como para el desarrollo y la aplicación de las políticas de prevención y control. Sin embargo, no todos los casos identificados son notificados y no todos son incorporados en el sistema de información. El subregistro representa un problema para quienes toman las decisiones.Objetivo. Estimar el tipo y la cantidad de errores cometidos al llenar la ficha de notificación de los casos de paludismo y su nivel de digitación, mediante el uso y seguimiento de la ficha de notificación en diez municipios nariñenses durante 2009.Materiales y métodos. Se trata de un estudio descriptivo, transversal en muestra no probabilística, de conveniencia, de los puestos de diagnóstico y tratamiento. Se obtuvieron copias de la fichas y de la base de datos de la notificación del sistema de vigilancia y se compararon caso a caso. Se calcularon las proporciones.Resultados. De 2.816 fichas de notificación de casos positivos, se evidenció que en más de 60 % de los casos no se reportó la información de las variables municipio de residencia, municipio de origen y código de ocupación. En la comparación caso a caso se encontró que 845 (30,0 %) fichas no habían sido digitadas. La información de variables como el nombre del municipio de residencia y la fecha del inicio de síntomas, no fue completa ni exacta en más de 50 % de los casos.Conclusiones. El empleo de las fichas de notificación con copia permite conocer el subregistro de la notificación debida a la falta de digitación. Una tercera parte de los casos pueden ser recuperados.

Evaluation of mandatory case-based reporting system for varicella in the prevaccine era

Varicella is a mandatory reportable disease in Slovenia but it is not notifiable in most European countries. The aim of the study was to explore the completeness of mandatory varicella reporting in Slovenia. Data were extracted from three electronic datasets, including: mandatory notifiable communicable diseases dataset (SURVIVAL), health statistics dataset - consultations in primary care (ZUBSTAT), and health statistics dataset --hospitalizations (BOLOB). Age- and sex-specific reporting rates were compared during the period 1997-2006. During the ten-year period studied 168,089 cases were recorded via ZUBSTAT, and 128,222 cases by SURVIVAL. On average 76.2% (range: 62.9%-94.9%) were notified. In both datasets, the notified incidence of varicella was highest for preschool children, with a downward shift in age at contracting varicella. The percentage of notified cases decreased with increasing age. The number of hospitalized cases was low for BOLOB and SURVIVAL. On average 74% of hospitalized cases were reported. The mandatory notification system in Slovenia provides enough information to survey age/sex-specific varicella trends in the prevaccine era.

Review article: communicable diseases surveillance lessons learned from developed and developing countries: literature review

BACKGROUND

Surveillance of infectious diseases is recognized as the cornerstone of public health decision-making and practice. The aim of the evaluation of communicable diseases surveillance systems (CDSS) is ensuring that communicable diseases are monitored efficiently and effectively. The aim of this paper is to reflect on the experiences of both developed and developing countries in the evaluation of CDSS in order to learn lessons from these experiences to improve systems everywhere.

METHODS

A literature review of studies published in English in PubMed and databases of the World Health Organization (WHO), and Center of Diseases Control (CDC) from 1981 to 2007 was undertaken assessing CDSS. The studies were divided into those from developed and developing countries.

RESULTS

A total of 32 studies were included, 20 from developed and twelve from developing countries. Both developed and developing countries faced difficulties in CDSS. Studies from the developed countries have been analysed based on the quality of the system alone. In developing countries, most of the studies have been on the integrated diseases surveillance (IDSR) and have been performed shortly after the adoption of the IDSR. Thus it might be too early to make a fair evaluation. Some of the systems over-centralized, while some lacked private health sector involvement in the system. Further, some of the systems were affected by conflicts and civil wars which are common problems in developing countries.

CONCLUSIONS

None of the countries had ideal CDSS. The strategy of integrated diseases surveillance seems to be functioning well especially in Africa.

Pre-admission clinical course of meningococcal disease and opportunities for the earlier start of appropriate intervention: a prospective epidemiological study on 752 patients in the Netherlands, 2003-2005

To improve the timeliness of health care delivery to patients with meningococcal disease, the early disease evolution and clinical manifestation at admission were studied in all 752 patients with invasive meningococcal disease in the Netherlands in 2003-2005. Eighty-eight percent (88%) had serogroup B disease. The case fatality rate (CFR) was 6.7% overall, but reached 16% among adults over 50 years of age. The CFR was similar for serogroups B (6.3%) and C (5.2%). Admission followed 17 h (median) after the onset of symptoms. The CFR in patients admitted within 12 h, 12-18 h, 18-36 h or >36 h after the first symptoms was 10.2, 7.8, 3.5 and 2.2%, respectively. Only 60% of patients had skin lesions, and admission followed 2 h (median) later. Earlier recognition can be achieved when non-petechial clues are included in the diagnosis. A short duration of disease before admission is a simple tool in the recognition of patients with severe disease.

Incidence and completeness of notification of Legionnaires' disease in The Netherlands: covariate capture-recapture analysis acknowledging regional differences

To estimate incidence and completeness of notification of Legionnaires' disease (LD) in The Netherlands in 2000 and 2001, we performed a capture-recapture analysis using three registers: Notifications, Laboratory results and Hospital admissions. After record-linkage, 373 of the 780 LD patients identified were notified. Ascertained under-notification was 52.2%. Because of expected and observed regional differences in the incidence rate of LD, alternatively to conventional log-linear capture-recapture models, a covariate (region) capture-recapture model, not previously used for estimating infectious disease incidence, was specified and estimated 886 LD patients (95% confidence interval 827-1022). Estimated under-notification was 57.9%. Notified, ascertained and estimated average annual incidence rates of LD were 1.15, 2.42 and 2.77/100 000 inhabitants respectively, with the highest incidence in the southern region of The Netherlands. Covariate capture-recapture analysis acknowledging regional differences of LD incidence appears to reduce bias in the estimated national incidence rate.

Estimating infectious diseases incidence: validity of capture-recapture analysis and truncated models for incomplete count data

Capture-recapture analysis has been used to evaluate infectious disease surveillance. Violation of the underlying assumptions can jeopardize the validity of the capture-recapture estimates and a tool is needed for cross-validation. We re-examined 19 datasets of log-linear model capture-recapture studies on infectious disease incidence using three truncated models for incomplete count data as alternative population estimators. The truncated models yield comparable estimates to independent log-linear capture-recapture models and to parsimonious log-linear models when the number of patients is limited, or the ratio between patients registered once and twice is between 0.5 and 1.5. Compared to saturated log-linear models the truncated models produce considerably lower and often more plausible estimates. We conclude that for estimating infectious disease incidence independent and parsimonious three-source log-linear capture-recapture models are preferable but truncated models can be used as a heuristic tool to identify possible failure in log-linear models, especially when saturated log-linear models are selected.