Application of Epidemiology (Part 3)

Maternal Mortality Rate

defined as death of a female from any cause related to or aggravated by pregnancy or its management (excluding accidental or incidental causes) during pregnancy and childbirth or within 42 days of termination of pregnancy, irrespective of the duration and the site of pregnancy

Perinatal Mortality Rate

measures deaths occurring during the perinatal period or the period of time surrounding the event of birth, including the time that a fetus spends in utero after it has reached 22 weeks of gestation and continues through the birth process until the end of the 1st of life after birth

Case Fatality Rate

- the proportion of cases that end up fatally

- gives us the risk of dying among persons afflicted with a particular disease

Case Fatality Rate

- Magnitude depends on the nature of the disease itself, the diagnostic test/labs, and the level of reporting in a population

- rate of the hospital statistics will be higher than that from the community since the hospitalized cases are usually the more severe cases of the disease

Other Mortality Indicators

- Proportional Mortality Rate

- Swaroop's Index

- Fetal Death Rate

Population Indicators

include not only the indicators but also other population dynamics (migration) that can affect the age-sex structure of the population and vice-versa

Population Indicators

- crude birth rate

- general fertility rate

- total fertility rate

- annual growth rate

crude birth rate

- measures how fast the people are added to the population through births

- a useful measure of the population growth

45/1000 live births

rate of live birth that implies high fertility

20/1000 live births

rate of live birth that implies low fertility

General Fertility Rate

a more specific rate that CBR since births are related to the segment of the population deemed capable of giving birth, women in reproductive years

15-44 years old

definition of women of reproductive age in the Philippines

200/1000 population

number of population that implies high fertility

60/1000 population

number of population that implies low fertility

Age-Specific Fertility Rate (ASFR)

permits a more in-depth of the differences in fertility as specific ages throughout the reproductive period and the impact of birth control measures on fertility

Health Millennium Development Goals

Goal 4: Reduce child mortality

Target 5: Reduce by two-thirds between 1990 and 2015, the under-five mortality rate

Health Indicators of Goal 4 and Target 5

- Under-five mortality rate

- infant mortality rate

- proportion of 1 year-old children immunized against measles

Health Millennium Development Goals

Goals 5: Improve maternal health

Target 6: Reduce by three-quarters; between 1990 and 2015, the maternal mortality ratio

Health Indicators of Goal 5 and Target 6

- maternal mortality ratio

- proportion of births attended by skilled health personnel

Health Millennium Development Goals

Goal 6: Combat HIV/AIDS, malaria, and other diseases

Target 7: Have halted by 2015 and begun to reverse the spread of HIV/AIDS

Target 8: Have halted by 2015 and begun to reverse the incidence of malaria and other major diseases

Health Indicators of Goal 6 and Targets 7 and 8

- HIV prevalence among pregnant women aged 15-24 years

- Condom use rate of the contraceptive prevalence rate

- Ratio of school attendance of orphans to school attendance of nonorphanage aged 10-14 years

- Prevalence and death rates associated with malaria

Health Indicators of Goal 6 and Targets 7 and 8

- Proportion of population in malaria-risk areas using effective malaria prevention and treatment measures

- Prevalence and death rates associated with tuberculosis

- Proportion of tuberculosis cases detected and cured under DOTS (directly observed short-course)

Sources of Data for Calculation of Health Indicators

- several sources of information for the purpose of assessing the health status of the community

- Many are lodged primarily in government agencies such as DOH and DICT

- Others are generated by research institutions, private sector like insurance companies and etc

Disease Notification

- an integral part of disease surveillance

- In the Phil. All individuals, health facilities, both private and public, in all levels of governance (barangay - national) are mandated by Act 3573 to notifiable diseases (dengue, rabies, and etc.) to Local and National Health Authorities

Act 3573

Law of Reporting of Communicable Disease

Disease Notification

- Many people don't have access to health facilities; and

- Private Health Care Providers/Practitioners have minimal vigilance in reporting cases of the notifiable disease which leads to gross underreporting and hence, distort the picture of health problems in the community.

Disease Registry

- a compilation of information about a particular disease

- aim is to include all cases of the disease in the registry without duplication

Disease Registry

- Attainment of the aim is dependent on the cooperation of agencies and health facilities that feed the registry

- On a unique patient identifier that will allow record linkage

Disease Registry

Example: Cancer Registry that covers Metro Manila and province of Rizal HIV/AIDS Registry that is intended to include all newly detected cases of HIV infection and AIDS in the Phil.

Application of epidemiologic principles and methods

essential to ensure that a public health surveillance system would achieve its primary goal of serving as an early warning system for impending epidemics of diseases and other public health emergencies

Public Health Surveillance

the ongoing, systematic collection, analysis and interpretation of health-related data needed for the planning, implementation, and evaluation of public health practice

Public Health Surveillance

Traditionally, surveillance systems were developed for monitoring high burden diseases, detecting disease outbreaks that could escalate into epidemic proportions, and monitoring progress toward attainment of targets for the control, elimination or eradication of a specific disease

Philippine Integrated Behavioral and Serologic Surveillance (IHBSS)

monitors not only seropositivity among most at-risk groups for HIV infection but also their behaviors that put them at risk for the infection

Disease Surveillance

can be:

- passive

- active

Passive Surveillance

- system by which public health staff receives reports from hospitals, clinics, public health units and other sources.

- Counts of cases is expected to be underestimated and the utility of the data may be greatly diminished as it may become available when it is no longer needed (late reporting)

Active Surveillance

- a system in which public health staff members actively and regularly contact health care providers or the population to obtain information about the disease of interest

- This strategy is more expensive but it yields more accurate and timely data

Philippine Integrated Disease Surveillance and Response (PIDSR)

integrates health statistics generated through the major disease surveillance systems in the country

major disease surveillance systems

- Notifiable Disease Reporting System (NDRS)

- Field Health Service Information System (FHSIS)

- National Epidemiology Sentinel Information System (NESSS

major disease surveillance systems

- Expanded Program on Immunization Surveillance System (EPI Surveillance)

- HIV-AIDS registry

Sources of Health Data

- Census

- Vital Registration System

- Disease Notification

- Disease Registries

- Surveillance System

Sources of Health Data

- Hospital Data

- Health Insurance

- School Health Program

- Downloadable Data Sets

- Surveys (morbidity, demographic, and health)

Epidemic-prone diseases

- acute bloody diarrhea

- acute encephalitis

- acute hemorrhagic fever syndrome

- acute viral hepatitis

- Anthrax

Epidemic-prone diseases

- Cholera

- Dengue

- Human avian influenza

- Influenza-like illness

- Leptospirosis

Epidemic-prone diseases

- Malaria

- Meningococcal disease

- Paralytic shellfish poisoning

- Severe acute respiratory syndrome

- Typhoid and paratyphoid fever

Diseases targeted for eradication or elimination

- Poliomyelitis (acute flaccid paralysis)

- Measles

- Neonatal Tetanus

Other diseases of public health importance

- Adverse events following immunization (AEFI)

- Diphtheria

- Non-neonatal tetanus

- Pertussis

- Rabies

Considerations in the Analysis and Interpretation of Health Indicators

1. Is the denominator of the rate the most appropriate one? It should be the population in which the events in the numerator are expected to or could have occurred.

Considerations in the Analysis and Interpretation of Health Indicators

2. Is the numerator an accurate count of the number of events?

Inaccuracies can arise due to under registration, underreporting or duplication.

Considerations in the Analysis and Interpretation of Health Indicators

3. There should be correspondence in time and geographical location of the events in the numerator and the population in the denominator.

Considerations in the Analysis and Interpretation of Health Indicators

4. Time specifications are usually on an annual basis. However, special indicators may have other period specifications and these should be stated.

Considerations in the Analysis and Interpretation of Health Indicators

5. The factor used in the computation of the different rates may be any number of the base 10.