Evaluating Hospital-Based Surveillance for Outbreak Detection in Bangladesh: Analysis of Healthcare Utilization Data

Abstract

BackgroundThe International Health Regulations outline core requirements to ensure the detection of public health threats of international concern. Assessing the capacity of surveillance systems to detect these threats is crucial for evaluating a country’s ability to meet these requirements.Methods and FindingsWe propose a framework to evaluate the sensitivity and representativeness of hospital-based surveillance and apply it to severe neurological infectious diseases and fatal respiratory infectious diseases in Bangladesh. We identified cases in selected communities within surveillance hospital catchment areas using key informant and house-to-house surveys and ascertained where cases had sought care. We estimated the probability of surveillance detecting different sized outbreaks by distance from the surveillance hospital and compared characteristics of cases identified in the community and cases attending surveillance hospitals.We estimated that surveillance detected 26% (95% CI 18%–33%) of severe neurological disease cases and 18% (95% CI 16%–21%) of fatal respiratory disease cases residing at 10 km distance from a surveillance hospital. Detection probabilities decreased markedly with distance. The probability of detecting small outbreaks (three cases) dropped below 50% at distances greater than 26 km for severe neurological disease and at distances greater than 7 km for fatal respiratory disease. Characteristics of cases attending surveillance hospitals were largely representative of all cases; however, neurological disease cases aged <5 y or from the lowest socioeconomic group and fatal respiratory disease cases aged ≥60 y were underrepresented.Our estimates of outbreak detection rely on suspected cases that attend a surveillance hospital receiving laboratory confirmation of disease and being reported to the surveillance system. The extent to which this occurs will depend on disease characteristics (e.g., severity and symptom specificity) and surveillance resources.ConclusionWe present a new approach to evaluating the sensitivity and representativeness of hospital-based surveillance, making it possible to predict its ability to detect emerging threats.

Incidence of Acute Diarrhea-Associated Death among Children < 5 Years of Age in Bangladesh, 2010–12

“…20 Our findings are consistent with another study in Bangladesh that distance from health care facility is a major barrier for seeking care, even for severe illnesses. 21 These findings suggested that basic improvement in transportation infrastructure could reduce child mortality in rural Bangladesh.…”

Hospital-based zoonotic disease surveillance in Bangladesh: design, field data and difficulties

“…The difficulties of poor populations reaching hospitals include limited geographical accessibility as well as substantial financial barriers [30]. Models using healthcare utilization data collected from the catchment areas of the same surveillance hospitals in Bangladesh presented here showed that case detection probabilities decrease steeply as distance from the hospital site increases [31] and that hospital-based surveillance misses nearly half of all Nipah outbreaks [32]. Finally, the selection of hospitals as surveillance sites and the requirement that patients be admitted to meet the case definition likely biases our system to detect more severe disease, as patients with more mild illnesses either do not come to hospitals or do not require admission.…”

Factors Influencing Community Event-based Surveillance: Lessons Learned from Pilot Implementation in Vietnam

“…Direct community involvement in the detection and reporting of potentially important public health events can overcome many limitations of routine indicator-based surveillance in detecting outbreaks while they are small and localized. [13][14][15][16][17] In the past, most community-based surveillance programs have focused on reporting single diseases, such as a specific vaccine-preventable disease, or one targeted for elimination (eg, guinea worm). 4,5,13,18 The current community event-based surveillance study took a broad approach, targeting the pathogens of highest concern to the ministry of health, and included signals that may detect emerging and reemerging threats as part of the development of an early warning and response system.…”