Measurig Cause Specific Mortality Usin g Verbal Autopsy

8/12/2019 Measurig Cause Specific Mortality Usin g Verbal Autopsy

1/24

Measuring cause specific mortality:

the use of verbal autopsies

Alan Lopez

Chalapati Rao


2/24

Uses of cause of death data

To study and explain levels, trends and differentials in age

specific mortality (Preston and disciples)

To guide priorities for resource allocation for intervention

programs, biomedical and sociomedical research

To monitor public health programs

To provide clues for epidemiological research


3/24

Sources of national cause-specific mortality data

vital registration systemsGOLD STANDARD

sample registration systems

household surveys

population laboratories and surveillance systems

epidemiological estimates

For deaths registered in these systems, cause of death is

eithercertified by a medical practitioner

based on "verbal autopsies"

not given at all


4/24

VR: Data availability, around 2000

WHO Region Useable dataComplete

enumerationTotal countries in

region

Africa 4 1 46

The Americas 32 14 35

Eastern Mediterranean 7 4 22

Europe 47 39 51

South-East Asia 4 0 11

Western Pacific 21 8 27

World 115 66 192


5/24

Data quality

Quality Criterion used CountriesHigh ICD 9 or 10 coding, and

completeness >90% and ill-defined codes 20%

Albania, Argentina, Armenia, Bahrain, Bosnia and Herzegovina*, Cyprus*,Dominica*, Dominican Republic*, Ecuador, Egypt, Fiji, Greece*, Iran,Jamaica*, Kiribati, Nicaragua, Paraguay, Peru, Poland, Portugal, Qatar, SanMarino, Serbia and Montenegro, South Africa*, Sri Lanka*, Suriname*,Syrian Arab Republic, Tajikistan*, Thailand, Tonga*, Tuvalu


6/24

Strategies to improve COD data availability

Accelerate development of civil registration

SLOW, EXPENSIVE, LOW GOVERNMENT PRIORITY

Introduce / improve physician certification, ICD coding, andstatistical processing of data

CRITICAL, NEEDS BIG WHO PUSH, NO CHAMPIONS

Introduce and develop local applications of verbal autopsyprocedures for data acquisition through

vital registration

sample registration

demographic surveillance systems

household surveys


7/24

What is VA ?

VERBAL AUTOPSY (VA), a two step procedure

Data collection: interview of bereaved relatives to

collect information on symptoms experienced by

deceased before death, using some form of surveyinstrument

COD assignment : methods include

physician review of VA data ICD certification, coding, and tabulation

computerised algorithms for population fractions


8/24

Principles of VA

Based on recall by relatives of symptoms \ illness prior to death,

sometimes difficult for adult deaths (similar symptoms)

Requires identification of clearly distinguishable symptom complexesfor each cause of interest, not available for some adult causes

lung cancer, TB, diabetes, different forms of liver disease etc

So far, found useful and validated for infant and maternal deaths;

deaths due to injuries

Recent experiences suggest utility of gathering information frommedical documents if available within household


9/24

Historical use of VA

Measuring cause specific mortality in populations SCDR / SRS - India

DSP / VRChina

AMMP (Tanzania)

Investigating COD in specific age-sex cause groups infant / child deaths

maternal causes of death

Injury related deaths

Investigating outbreaks / epidemics Ebola fever epidemic in West Africa

Diarrhoeal disease in Bangladesh


10/24

Historical use (contd)

Assessing coverage and effectiveness of disease

specific interventions insecticide impregnated bed nets in Africa

Pneumococcal vaccine trials in Bohol

Home based neonatal care in India

In developed countries

confidential enquiries of maternal mortality Sudden infant death syndrome

QOL / mental health status in terminal illness among elderly


11/24

VA in IndiaSurvey of causes of deathrural (SCDR) 19671998 (1400 PHCs, rep)

Structured instrument, lay assignment of cause, ICD classification since 1996

problems with incomplete coverage, inadequate investigator training /

physician verification of cause

New system being implemented in SRS, covering 8 million

New instruments, field protocols, training support

Five year retrospective survey planned soon

independent field studies by Ind C Med Res in 5 zones, 1 million pop each

Need for integrated approach, involving civil registration systems


12/24

SCDR Results

Leading causes of death, 1996-1998 and GBD 2000 estimates for India

1996 1997 1998 GBD 2000

Ill defined causes 20.6 19 18.4 0

Respiratory (incl TB) 17.8 16.4 17.2 15

Infectious (excl TB) 14.8 13.1 12 16

Cardiovascular (excl stroke) 10.2 12.1 12.5 19

External causes 8.4 8.9 9.6 10.3

Perinatal 7.9 8.7 7.9 8

Neuropsych (incl stroke) 6.2 6.5 6.6 6.6

Cancers 3.6 4.3 4.3 6.9

Anaemia 3.4 3.2 3.3 0.4

Digestive 2 2.1 2.1 3.3

Endocrine 1.2 1.1 1.2 1

Other causes 3.9 4.6 4.9 13.5

Total 100 100 100 100

Deaths 43168 44409 40351 10109157

Year

Cause group


13/24

VA in China

Two mortality statistics systemsNMS, DSP

NMS (VR)medical certification (urban) / lay reporting (rural) 120 m pop

DSP1981, now 145 points, nationally representative, 10 m pop

medical certification / VA for household deaths (80%)

Semi structured instrument, physician COD assignment, ICD classification

since 1987

Household visit by township hospital staff

Much reliance on free text response to What was the cause of death in this

person?

Use of supportive medical documentation available at home / from hospital

records

Needs to be tested for reliability, and if possible, validity

Research projects underway (UQ, Harvard)


14/24

DSP Results

5q0 45q15 Males 45q15 Fem

DSP 17.3 122 75

GBD 2000Leading causes of death in 2000Cause DSP 2000 GBD 2000

Stroke 18.7 17.7

COPD 12.9 13.7

Other cardiac diseases 8.2 2.6

IHD 6.3 7.5

Ill-defined diseases 5.0

Trachea, bronchus and lung cancers 3.9 3.5

Liver cancer 3.8 3.6

Hypertensive heart disease 3.6 2.3

Stomach cancer 3.5 4.5

Lower respiratory infections 3.0 3.3

Self-inflicted injuries 2.7 3

Road traffic accidents 2.3 2.6

Oesophagus cancer 2.1 2.4

Other malignant neoplasms 2.0 0.6

All other causes 22.1 32.7

Total deaths 45716 875873


15/24

VA in Tanzania

Adult morbidity and mortality project in 3 districts 1992 onwards

Instruments developed by LSHTMAMMP

Physician assignment of cause

Non ICD mortality classification

Recent introduction of ICD certification / coding (2003) Validation study underway (UQ, Harvard, LSHTM)


16/24

AMMP results - 2000

Cause Percent

TB/AIDS 21.4

Acute febrile illnesses 20.4

Ill defined causes 11.2

Cardiovascular 8.3

Perinatal (incl stillbirths) 7.9

Others 7.4

Acute respiratory infections 6.1

External causes 5.2

Diarrhoea 5.0

Neoplasms 4.3

Digestive 2.8

Total 100.0

Deaths 3721


17/24

Important issues in VA Standard survey instruments including modules for

Free text narrative Structured questions

Recording household medical document information

Interviewer Education background, training

Choice of respondent Proximity to deceased, education, age and sex, cultural factors

Recall periods Minimum and maximum intervals

Cause of death assignment and ICD coding Physician / trained health professional review using standard protocols

Computerized programs

ICD mortality tabulation lists

Validation studies


18/24

Validation studies

To develop standard verbal autopsy instruments andprocedures that are applicable in different epidemiologicaland cultural settings with minimal modifications

To measure biases in community cause of death patternswhen using VA instruments validated in hospital basedstudies

To improve understanding of quality of cause of deathinformation for estimating global and regional mortality

patterns


19/24

Methods

VA validation study in Tanzania

VA validation and mortality statistics evaluation

study in China


20/24

Study design - Tanzania

For each death

3000 deaths

Medical record Verbal autopsy

DC/ underlyingcause

from reviewer 1

MR Underlying cause VA Underlying cause

Agreement

Verbal autopsy validation

DC/ underlying causefrom reviewer 2

Disagreementreconciled by

consensus


Agreement



21/24

Study design - China

Medical recordDeath certificate

Verbal autopsydeath

certificate

Verbal autopsy

validation

Routinesystem death

certificate

Routine system

reliability

rural areas

Routine system

validation urban

areas

1900 deaths 3500 deaths

2700 deaths


22/24

Future research

Gates proposal Africa, Bangladesh, Philippines

New UQ sites in Indonesia, Thailand

Egypt, Syria, other EMRO countries ?

Expression of interest by Indian SRS to adopt WHOVA methodology ?

Other opportunities in Africa through PEPFAR?

l i


23/24

Conclusions

Information on symptoms could be combined with available clinicalevidence for judging cause of death at individual level

Scope for application of Bayesian principles in deriving population levelcause specific mortality fractions from data gathered in surveys

For adult deaths, could be useful for understanding broad cause groupmortality at population level

A measure of discriminatory power of individual questions / algorithms foridentifying specific causes of adult deaths would be useful


24/24

Conclusions (contd)

Need to evaluate biases from VA instrument validation in hospitalstudies, and cross cultural comparability of responses to specificquestionnaire items

Need for standardization of protocols for both data collection andcause of death assignment

All VA implementation should contain elements of validation

Examples of potential application

Sentinel sites in northern Brazil

Representative sites in Tanzania

Data quality improvement in Thailand, China

No other option to rapidly increase usability of cause ofdeath data from developing countries

Measurig Cause Specific Mortality Usin g Verbal Autopsy

Documents

Transcript of Measurig Cause Specific Mortality Usin g Verbal Autopsy