Two-source Capture-recapture Method Research Articles

SINAVE’s quality: completeness for Meningococcal Disease – Northern Portugal, 2020-2022

Abstract Due to Meningococcal’s Disease (MD) severity and impact in public health, in Portugal it is mandatory to notify the suspicious cases to implement effective control measures. MD cases are notified in the National Surveillance System (SINAVE), which triggers epidemiological investigation, risk assessment and community intervention. The quality of SINAVE is defined by various attributes, being their evaluation crucial to improve and guarantee quality standards. Our goal is to evaluate the external and internal completeness of SINAVE for MD in northern Portugal from 2020 to 2022. We have conducted a cross-sectional study, using MD cases from 2020 to 2022. External Completeness was estimated using a two-source capture-recapture method, with data from SINAVE and Diagnostic-Related Group (DRG) cases. Hospital readmissions’, duplicates and cases from other regions were excluded. Internal completeness of SINAVE was accessed for each case and for each non-mandatory variable. For external completeness (EC) analysis, 21 of the 23 DRG cases were eligible for matching. Out of 31 SINAVE confirmed cases, 20 were eligible for matching. EC of SINAVE was 66,7%. For internal completeness (IC) analysis, we excluded 7 cases that did not meet the criteria for inclusion. The mean IC was 73,5% (min 38,5%, max 85,7%) when analysing by case. When assessing each of the 30 non-mandatory variables of the reports, 7 (23,3%) had an IC of 100% and 13 (43,3%) had an IC of 0%, the mean value was 49,7%. SINAVE assessment, as a routine, is crucial to identify the need for improvement. Completeness is fundamental to ensure an effective public health response. Our results confirm under-reporting and incomplete report of MD. There is a need to strengthen the improvement of data quality of SINAVE. Future studies may be important to estimate true incidence of MD and compare the results for other diseases in order to improve public health actions. Key messages • Meningococcal disease requires timely public health intervention. • valuation of the surveillance system is crucial, with completeness playing an important role for data quality and prompt response.

Estimating regional prevalence of chronic hepatitis C with a capture-recapture analysis

BackgroundThe hepatitis C virus (HCV) infection is a candidate disease for micro-elimination. Accurate baseline HCV prevalence estimation is essential to monitor progress to micro-elimination but can be methodologically challenging in low-endemic regions like the Netherlands due to lack of disaggregated data by age or risk-groups on the number of chronic HCV patients (i.e. HCV RNA positive). This study estimates the number of patients that has had a chronic HCV infection (ever-chronic) in the Utrecht region of the Netherlands.MethodsIn the Utrecht province in the Netherlands, positive HCV tests from the period 2001–2015 from one diagnostic center and four hospital laboratories were collected. A two-source capture-recapture method was used to analyze the overlap between the two registries (with 92% HCV RNA and 8% HCV immunoblot confirmed infections) to obtain the number of ever-chronic HCV infections in the Utrecht region. The Utrecht region was defined as an area with a 25 km radius from the Utrecht city center. The current viremic HCV prevalence was calculated by taking into account the proportion of cured and deceased HCV patients from a local HCV retrieval (REACH) project.ResultsThe estimated number of ever-chronic HCV patients was 1245 (95% CI 1164–1326) and would indicate a prevalence of 0.10 (95% CI 0.09–0.10) in the Utrecht region. This is 30% (95% CI 21–38%) more than the number of known HCV patients in the records. The ever-chronic HCV prevalence was highest in the 1960–1969 age cohort (0.16; 95% CI 0.14–0.18). Since 50% of the HCV patients were cured or deceased in the REACH-project, the number of current viremic HCV patients was estimated at 623 individuals in the Utrecht region (prevalence 0.05%).ConclusionThe results of this study suggest a low ever-chronic and current HCV prevalence in the Utrecht area in the Netherlands, but other studies need to confirm this.

Two-Source Capture-Recapture Method to Estimate the Incidence of Acute Flaccid Paralysis in the Marches Region (Italy).

A combination of high infant immunization coverage and surveillance of acute flaccid paralysis (AFP) cases, plays a critical role in polio eradication. This study aimed to estimate the incidence of AFP, to evaluate the completeness of AFP ascertainment during the years, age groups and gender, and to define the main associated diagnosis among children aged under 15 in the Marches region of Italy. Analysis was performed on data from the active AFP surveillance system and the hospital discharge records in the 2006–2014 period. The two-source capture-recapture method was applied. After cross-validation, 30 AFP compatible conditions as defined by the WHO were identified, with an incidence estimate of 1.91 cases of AFP per 100,000 children under 15 years (95% CI = 1.4–2.6/100,000). Guillain–Barrè syndrome was the most common diagnosis. A significant difference (p < 0.05) has been registered in the estimated probability of case ascertainment in females. The reasons for the lower reporting of cases in females are unknown. Specific research and the implementation of a more sensitive surveillance system are essential in verifying potential inequalities and to succeed in the polio eradication initiative.

Incidence of motor neuron disease/amyotrophic lateral sclerosis in South Africa: a 4-year prospective study.

Little is known about the epidemiological features of amyotrophic lateral sclerosis (ALS) in sub-Saharan Africa, and data from the region are limited to clinical series or case reports. The aim of the study was to investigate the incidence rate and presentation of ALS in an ethnically diverse region of South Africa. We performed a 4-year prospective incidence study in the Western Cape Province of South Africa between 1 July 2014 and 30 June 2018, and used a two-source capture-recapture method for case ascertainment. Age- and sex-adjusted incidence rates (ASAIRs) were calculated using the 2010 US population as the reference. A total of 203 incident cases were identified over the study period, resulting in a crude incidence rate (IR) of 1.09 [95% confidence interval (CI) 0.94-1.24] per 100000 person-years in the at-risk population (aged >15years). Capture-recapture analysis resulted in an estimated IR of 1.11 (95% CI 1.01-1.22) per 100000 person-years. The ASAIR was 1.67 (95% CI 1.09-2.26) overall; 1.99 (95% CI 1.60-2.39) for men and 1.37 (95% CI 1.06-1.68) for women. When analysed separately, there was a substantial difference in ASAIRs between the different population groups, with the highest in the European ancestry group (2.62; 95% CI 2.49-2.75), the lowest in the African ancestry group (0.56, 95% CI 0.0-1.23), and an ASAIR in between these two in the mixed ancestry group (1.09, 95% CI 0.80-1.37). The overall incidence of ALS in the Western Cape Province of South Africa appears to be lower than in North African and Western countries, but higher than in Asian countries. As suggested by previous epidemiological studies, ALS may be less frequent in people of African ancestry.

Surveillance of malaria in mainland Portugal in 2016 after the introduction of an electronic system: is it enough?

Since 2014, imported cases of malaria have been notified by SINAVE, the Portuguese nationwide electronic surveillance system that replaced paper-based notification. Nevertheless, the disease is still believed to be under-reported. Completeness of notification of malaria cases in 2016 was estimated using a two-source capture-recapture method, with SINAVE and the Diagnostic-Related Group cases. Completeness of SINAVE and the diagnosis-related group sources was computed in 32.9% and 72.3%, respectively. The results confirm that malaria is under-reported and highlight the need for more effective notification strategies, especially given the risk of resurgence of locally acquired cases.

Estimating road traffic injuries in Jinja district, Uganda, using the capture-recapture method

ABSTRACTRoad traffic injuries (RTIs) are commonly under-reported in low-and-medium-income countries. This study aimed to estimate the number of RTIs and determine the magnitude of under-reporting by traffic police and hospital registries. A two-source capture-recapture method was applied to RTI data from police and hospital registries. Seven matching variables; sex of the injured, date, place, time, day of crash and road user type were used to get the matched cases. Police independently reported 46 RTIs and the hospitals reported 206 RTIs. Using the capture-recapture analysis, both sources estimated 313 RTIs (95% CI 273–343). The police registry captured 14.4% of the estimated number of RTIs and the hospitals captured 60.4%. The estimated number of RTIs was higher than reported by either the police or the hospitals alone. Neither the police nor the hospitals provided accurate data on RTIs, calling for the strengthening of both sources of data.

Vaccine-preventable child deaths in New South Wales from 2005 to 2014: How much is preventable?

To identify and describe potentially vaccine-preventable child deaths in New South Wales (NSW). Child deaths in NSW from 2005 to 2014 potentially preventable by vaccination were identified from the NSW Child Death Register (maintained by the NSW Ombudsman) and the Notifiable Conditions Information Management System (NSW Health). Medical and post-mortem records were reviewed. Cases were classified as vaccine-preventable based on the strength of evidence for the relevant infection causing death and likelihood that death was preventable through vaccination. A two-source capture-recapture method was used to estimate the true number of deaths. Age-specific mortality rate and number of deaths by disease, area of residence and comorbidity were analysed. Deaths were classified as preventable based on vaccine availability, eligibility under the National Immunisation Program, age and presence of any contraindications. Fifty-four deaths were identified as definitely or probably due to diseases for which a vaccine was available, with a total average annual mortality rate of 0.33 per 100 000 children and 2.1 per 100 000 infants. Two thirds of deaths occurred in children with no identified comorbidities. Twenty-three deaths were classified as preventable or potentially preventable by vaccination, with influenza (12 deaths) and meningococcal disease (five deaths) most common. An additional 15 deaths would be potentially preventable as of August 2016 due to immunisation recommendation changes including maternal vaccination. Maternal vaccination along with increased uptake of childhood influenza vaccination could reduce child deaths, particularly from influenza.

Surveillance of imported hospital requiring malaria in Portugal: can it be improved?

Although eradicated in Portugal, malaria keeps taking its toll on travellers and migrants from endemic countries. Completeness of hospital requiring malaria notification in Portugal 2000-11 was estimated, using two-source capture-recapture method. Data sources were: national surveillance database of notifiable diseases and the national database of the Diagnosis-Related Groups resulting from National Health Service (NHS) hospital episodes. The completeness of notification was 21,2% for all malaria cases and 26,5% for malaria deaths, indicating significant underreporting and urging for complementary data source in surveillance, for disease burden estimates and retrospective monitoring, namely hospital episodes statistics.

Using the two-source capture-recapture method to estimate the incidence and case ascertainment of congenital rubella syndrome in Australia, 1993-2013.

Using the two-source capture-recapture method to estimate the incidence and case ascertainment of congenital rubella syndrome in Australia, 1993-2013.

Estimation of the Gastric Cancer Incidence in Tehran by Two-Source Capture-recapture

Capture-recapture methods have been suggested for reducing costs of disease registration as well as reducing bias in incidence estimations. This study aimed to estimate the gastric cancer incidence in theTehran metropolis population during 2002-2006. We investigated new cases of gastric cancer reported by three sources; death certificates, pathology reports, and medical records to Tehran population-based cancer registry during 2002-2006. G2 statistics and the two-source capture-recapture method were used to select the best-fitted log-linear model and to estimate incidence, respectively. EXCEL software version 2007 and SPSS software version 16 were used for this research. The number of reported cases was 4,463, with an average age of 68.5 (±12.9) years. We found the model that combined two sources of data including pathology reports and medical records and furthermore complemented by death certificates as the best model. The reported and the estimated incidences were 11.0 and 27.1 per 100,000 respectively. The incidence estimated by two- source capture-recapture method is about three times higher than the incidence reported by the sources under investigation. It is recommended to move towards the implementation of population-based cancer registration using various sources of data collection to achieve more accurate data.

Completeness of reporting and case ascertainment for neonatal tetanus in rural Pakistan

The objectives of this study were to assess the case ascertainment and completeness of neonatal tetanus (NT) reporting and to estimate the incidence of NT in Dadu District, Pakistan. We conducted active surveillance and hospital record reviews for suspected NT cases. We compared the cases of NT reported to the routine surveillance system with the cases identified through the hospital record reviews for 1993 through 2003. The two-source capture-recapture method was used to evaluate case ascertainment in the routine surveillance system and to estimate the incidence of cases of NT. Active surveillance and hospital record reviews identified 134 cases in addition to 274 cases in the routine surveillance system. The two-source capture-recapture method indicated that there would have been 463 cases during this period (95% confidence interval (CI)=418-508), representing an average annual incidence of 0.62 per 1000 live-births. The overall completeness of routine reporting was 59.2%. The proportions of cases reported were 68.1% for government hospitals and 53.8% for private reporting sites. Reporting of NT cases is incomplete. Active promotion of private sector participation, community involvement, and strengthening of the government sector as a way of improving NT reporting and surveillance is strongly suggested.

Evaluation of cancer surveillance completeness among the Italian army personnel, by capture–recapture methodology

Objective: This study provides an assessment of completeness of cancer surveillance and incidence estimates for all malignancies, Hodgkin's lymphoma and thyroid cancer in the Italian army, for the years 2001–2007. Methods: The two-source capture–recapture method was employed, using both Chapman's and Chao's formulae, on the basis of cancer notifications from military hospitals and unit infirmaries. The estimated incident cases were then confronted with the corresponding expected cases; the standardized incidence ratios and 95% confidence intervals (SIR [95% CI]) were then calculated. Results: A total of 442 cancer notifications, concerning 371 cases, were reported (311 from army hospitals and 131 from unit infirmaries; of these, 71 were overlapping). The estimated total number of cases, by Chapman's and Chao's formulae, was 571 and 688, respectively. Overall, sensitivity of the surveillance system was 65% by Chapman's and 54% by Chao's estimators. Completeness of notification was significantly higher in younger patients, in those previously deployed in Bosnia or Kosovo, and for cases of Hodgkin's lymphoma. Estimated SIRs, using both formulae, were not significant for all malignancies and Hodgkin's lymphoma, but significant for thyroid cancer (SIR: 2.25 [1.61–2.89] by Chapman's formula, and 3.12 [1.81–4.43] by Chao's estimator). Conclusion: Completeness of cancer registry of the Italian military is low, and methods to improve its sensitivity are discussed. Overall, the estimated number of incident cancer cases, including Hodgkin's lymphoma, is not significantly higher than expected, except thyroid cancer. The increased incidence of this malignancy requires further investigation; however, in the military, as well as in the general population, this may be partly due to the growing availability of diagnostic opportunities in the last decades. Moreover, detection of thyroid cancer may be further facilitated by a selection bias generated by the annual and pre-/post-deployment medical examinations and blood tests routinely performed on all military personnel.

Evaluation of childhood acute leukemia incidence and underreporting in Brazil by capture–recapture methodology

Background: Population-based cancer registries (PBCR) are important in cancer epidemiology as they provide the basis for monitoring cancer incidence. Childhood acute lymphoblastic leukemia (ALL) is said to have lower incidence in developing countries, which has implications for its pathogenesis, but there are few studies concerning the completeness of cancer registries in developing countries. This study analyzes the number of cases and incidence of childhood acute lymphoblastic leukemia in three different cities in Brazil and estimates underreporting cases and possible PBCR failures. Methods: We evaluated the completeness of PBCR and the incidence rates of childhood ALL from three different Brazilian cities using the two-source capture–recapture method. The sources used were a population-based registry and databases from a diagnosis reference laboratory in 2001 and the Chapman's formula was used to calculate the estimates. Results: The estimated incidence was 5.76, 6.32 and 5.48 per 100,000 inhabitants for Salvador, Recife and Belo Horizonte, respectively. The estimated completeness of childhood ALL in PBCRs was 15.5%, 35.4% and 29.2%, respectively, for Salvador, Recife and Belo Horizonte. Conclusions: There was a high estimated underreporting of childhood leukemia cases in some Brazilian cities. The relationship between information systems and the capture–recapture method application improved epidemiological estimates. Childhood acute lymphoblastic leukemia incidence rates are similar to those of developed countries.

Problems in using birth certificate files in the capture‐recapture model to estimate the completeness of case ascertainment in a population‐based birth defects registry in New York State

The limitations and underlying assumptions of the capture-recapture methods have hindered their application in epidemiological settings, especially in evaluating the completeness of birth defects registries. This study explored the possibility of using birth certificates as the secondary data source in a simple two-source capture-recapture model to estimate the completeness of case ascertainment of the Congenital Malformations Registry (CMR) for selected major birth defects. The CMR and the birth certificates were used as the primary and secondary sources, respectively. Children who were born in 1996-2001 and had selected major birth defects were identified from the two sources. The accuracy of the diagnoses was examined by comparing the individual birth defect categories of the children from the two sources. Discrepancies in birth defect categories in the two data sources and false positives in the birth certificates were the major problems encountered in estimating the completeness of the CMR using the simple two-source capture-recapture method. The estimated completeness for selected major birth defects was only about 71%. Stratified analyses resulted in relatively high estimated completeness for oral clefts (90%) and Down syndrome (88%). CONCLUSIONS Although the birth certificate data was not a good source for estimating the completeness of case ascertainment of the CMR using capture-recapture methods, the analyses provided reasonable estimates for some conditions that were relatively easy to identify and diagnose at birth, such as oral clefts and Down syndrome.

Capture–recapture analysis to estimate the incidence of invasive meningococcal disease in Germany, 2003

The incidence of invasive meningococcal disease (IMD) in Germany in 2003 was estimated by the two-source capture-recapture method. As a unique personal identifier was unavailable, cases with IMD tested at the National Reference Centre for Meningococci (NRZM) were matched with cases reported to the Robert Koch Institute (RKI) through the statutory surveillance system by using demographic and disease-specific variables common to both datasets. The estimated overall incidence was 1.1 IMD cases/100,000 inhabitants, with a sensitivity of ascertainment of 64.8% for NRZM and 89.4% for RKI. Case-fatality rate was estimated at 8.8%. Adjustment for heterogeneity of capture according to age, region and serogroup observed in the NRZM (but not RKI) source had minimal effect on the estimated incidence. The IMD incidence estimated by capture-recapture analysis is thus only slightly higher than through statutory surveillance data. As a degree of positive dependence between the systems cannot be ruled out, this estimate may still be an underestimate. However, under ascertainment appears insufficient to explain the low incidence of IMD in Germany compared to other European countries.

Completeness of malaria notification in the Netherlands 1995-2003 assessed by capture-recapture method

In 1999 in the Netherlands, the duty to notify malaria was transferred from physicians to laboratories by the new Infectious Diseases Law. To evaluate the effect of this change, we aimed to estimate completeness of malaria notification in the Netherlands from 1995-2003. We calculated it relative to sentinel laboratory and hospital admission data. Using the two-source capture-recapture method (CRM), we estimated the total number of cases to assess the completeness relative to this number. The completeness of notification relative to sentinel data was 18.2 % (95% CI of 15.7-20.7) from 1995-1998 and 56.4 % (95% CI of 47.0-65.8) for 2000-2003. The completeness relative to the number of malaria cases admitted to the hospital was 35.1 % for the period 1995-2003. The estimated numbers of cases of malaria between 1995 and 1998 were 3123 (95% CI of 2796-3449) and 5043 (95% CI of 4343-5742) between 2000 and 2003. The completeness relative to this numbers changed from 35.5 % (95% CI of 32.1-39.7) in 1995-1998 to 36.1 % (95% CI of 31.7-41.9) for the years 2000-2003. Laboratory-based notification has significantly increased the absolute number of malaria notifications, but there was no change in completeness relative to hospital admissions. The increase in estimated malaria cases may be artificial, due to the extent of violation of CRM requirements over the study period.

Hazardous waste site frequency: use of the capture-recapture method

This investigation used a two-source capture-recapture method (CRM) for determining ascertainment and undercounts of non-national priority listed hazardous waste sites in the states of Arizona, Maine and Pennsylvania. These findings suggest that ascertainment of hazardous waste sites vary greatly, with some more accurate (i.e., Maine) than others (i.e., Pennsylvania). These data suggest that nontraditional manufacturing states (e.g., Maine) have a higher ascertainment rate than traditional manufacturing states (e.g., Pennsylvania). These results indicate that resources for locating hazardous waste sites should be more heavily allotted to industrialized areas. We suggest that the CRM is a convenient, low cost and effective method for determining (1) the accuracy of previous estimates, and (2) the number of sites in a locale with 95% confidence intervals along with an estimate of the undercount. Findings suggest that estimates of hazardous waste sites should use the CRM to determine and improve accuracy.

Using the two-source capture-recapture method to estimate the incidence of acute flaccid paralysis in Victoria, Australia.

To estimate the incidence and the completeness of ascertainment of acute flaccid paralysis (AFP) in Victoria, Australia, in 1998-2000 and to determine its common causes among children aged under 15 years. : The two-source capture-recapture method was used to estimate the incidence of cases of AFP and to evaluate case ascertainment in the routine surveillance system. The primary and secondary data sources were notifications from this system and inpatient hospital records, respectively. The routine surveillance system indicated that there were 14 cases and the hospital record review identified 19 additional cases. According to the two-source capture-recapture method, there would have been 40 cases during this period (95% confidence interval (CI) = 29-51), representing an average annual incidence of 1.4 per 100000 children aged under 15 years (95% CI = 1.1- 1.7). Thus case ascertainment based on routine surveillance was estimated to be 35% complete. Guillain-Barré syndrome was the commonest single cause of AFP. Routine surveillance for AFP in Victoria was insensitive. A literature review indicated that the capture-recapture estimates obtained in this study were plausible. The present results help to define a target notification rate for surveillance in settings where poliomyelitis is not endemic.

A Model and Application for Estimating Completeness of Registration

Completeness of population-based registration systems is recognized to be an important aspect of the quality of information in registries which has to be examined. In this paper a model is presented which was used to estimate completeness of reporting of Down syndrome data notified to the Styrian Malformation registry between 1985-92. The model introduced is based on the two-source capture-recapture method allowing for time-varying parameters. For estimation of the parameters a discrete-time filtering algorithm was developed. For the used data set, an estimate of completeness derived from this model was in good agreement with an independent estimator based on demographic data and maternal age-specific Down syndrome risks whereas the usual two-source capture-recapture method gave a higher estimate.

Application of Capture-Recapture Methods for Disease Monitoring: Potential Effects of Imperfect Record Linkage

Capture-recapture methods are increasingly employed to correct for underascertainment of cases in disease monitoring. Routine systems of disease monitoring, such as morbidity registries, are often prone to specific threats of validity, such as in imperfect diagnoses or imperfect record linkage. A quantitative assessment is given of the performance of the two-source capture-recapture method for disease monitoring in the presence of imperfect record linkage. The capture-recapture approach can eliminate underestimation of the number of eligible cases, which is typical for most disease monitoring systems, under certain conditions, including independence of sources of case ascertainment and perfect record linkage. Correction for underestimation remains less than perfect, however, in the case of false-positive matches, whereas application of capture-recapture methods leads to overestimation of case numbers in the presence of false-negative matches. A simple correction procedure to overcome potential overestimation by false-negative matches is outlined.