Sources of Epidemiologic Data | PDF

Sources of Epidemiologic Data Edric D. Estrella, PhD, MPH, RPh Principles of Epidemiology Diploma in International Health Program Faculty of Management and Development Studies University of the Philippines Open University  Learning Objectives: At the...

Sources of Epidemiologic Data Edric D. Estrella, PhD, MPH, RPh Principles of Epidemiology Diploma in International Health Program Faculty of Management and Development Studies University of the Philippines Open University  Learning Objectives: At the end of the presentation, the students are expected to: 1. identify sources of epidemiologic data; 2. discuss the criteria for assessing the quality and utility of epidemiologic data; 3. indicate privacy and confidentiality issues that pertain to epidemiologic data; 4. Discuss the uses, strengths and weaknesses of various epidemiologic data sources; and 5. Locate a given source of data using the available resources on the internet.  Types of data Primary data Secondary data  Specific Data Useful in Epidemiologic Studies Data on vital events Disease statistics Data on physiologic and pathologic conditions Data on health resources and services Data on environment Demographic data Socio-cultural data (KAP)  Criteria for Evaluating the Quality of Epidemiologic Data Nature of the Permissible study Data design Availability of Possible statistical the Data analyses Completeness Appropriate inferences Strength vs. Quality assurance limitations  Nature of the Data whether the sources of data are vital statistics, case registries, records from medical practice, survey data, cases from health facilities affects the type of statistical analyses and inferences that are possible  Availability of the data investigator’s access Medical records and any associated data with personal identifiers usually are not available without a release from the individual patient and explicit approval of IRB. Data perturbation – modifying identifying characteristics of data in order to protect the privacy of individual respondents Completeness of Population Coverage Representativeness – degree to which a sample resembles a parent population Generalizability (external validity) – ability to apply the findings of a study to the population that did not participate in the study Thoroughness – care that has been taken to identify all cases of a given disease including subclinical cases  Strengths versus Limitations data’s usefulness for various types of epidemiologic research includes whether there are limiting factors inherent in the data (e.g. incomplete diagnostic information, case duplication) On-line Sources of Epidemiologic Data MEDLINE, the main part of PubMed®, focuses on biomedicine and contains a repository of over 21 million journal articles (as of 2012) from the life sciences. It uses MESH® as indexing system. On-line Sources of Epidemiologic Data On-line Sources of Epidemiologic Data On-line Sources of Epidemiologic Data Wide-ranging ONline Data for Epidemiologic Research  Confidentiality, Sharing of Data, and Record Linkages Data sharing – voluntary release of information by one investigator or institution to another for the purposes of scientific research e.g. linkages of large data sets, pooling of multiple studies in meta-analyses Issues: P.I. potential loss of control, over intellectual property  Confidentiality, Sharing of Data, and Record Linkages Record linkage – joining data about a single entity from two or more sources e.g. employment records and social security records Vital Records  Death Certificate (Mortality Statistics) Information Completeness/accuracy 1. Fact of death Satisfactory (death unlikely to go unrecorded) 2. Cause of death Not satisfactory 19 20 21  Cause-of-death statement Immediate COD-can directly lead to death Antecedent COD-can lead to the stated immediate COD Underlying COD- disease or injury that initiated the train of events that led directly to death, or the injury that initiated the train of morbid events that led directly to death, or the circumstances of an accident or violence that produced the fatal injury 22  Problems in Death Certificate 1. Diagnostic inaccuracy 2. Unavailability of cause of death statements 3. Lack of standardization of diagnostic criteria What constitutes a cause of death? Acceptable COD? 23  Possible Causes of Problems in Death Certificate 1. Medically unattended deaths 2. Lack of training of certifying MDs on COD 3. Attitude of MDs 24  Research findings: US: (n=198 medical examiners) 13% received training in medical school 29% received training during residency 25  Knowledge, Attitude and Problems of Municipal Health Officers on Cause-of-death Certification, Cavite (Tolabing MCC, 1997) (Unpublished) 26 MHOs 8% received training, graduate school (MPH) none remembered receiving any training in medical school 26  Interrupted Time Series Study on the Completeness and Acceptability of the Cause of Death Statement in Death Certificates (Tolabing et al., 2013) 19% completely filled up (95%CI:13-26) Of the 19%, only 12 were filled up in an acceptable manner (95%CI=8-16) Among the 3 items, underlying cause was the least filled up (28%) (IM=92%; An=57%) 5% underlying cause are unacceptable entries (cardiac arrest, respiratory arrest, CR arrest, heart failure, DOA, shock) 28  Evaluation of death certificates in the pediatric hospitals in Khartoum State during 2004 (El-nour AAM et al., 2007) The pediatric hospitals in Khartoum State, Sudan 12% completely filled up 77.6% had incorrect immediate cause 56.2% of the incorrect entries were modes of dying 29  Death certification errors at an academic institution (Pritt BS et al., 2005) Mock death certification Results: 82% with errors in certification 30 Other Factors affecting Accuracy of Cause of Death: Easily diagnosed cases are most likely to be recorded accurately Longer period between onset of disease and death can affect accuracy of cause of death e.g. chronic leukemia Diseases to which stigma is attached may be underreported Incorrect codes assigned to diseases 31  Uses of Mortality data: Indicator of disease frequency May help epidemiologist obtain leads about etiologic agents by identifying demographic subgroups at high risk, facilitating study of trends in disease occurrence over time Enable comparisons of disease occurrence in different populations and geographic areas 32  Birth Certificate Information Completeness/accuracy 1. Fact of birth Satisfactory (births unlikely to be unrecorded) 2. Conditions of child at birth Satisfactory (wt, Abn, etc.) (observation) 3. Conditions of mother during Not Satisfactory pregnancy (recall) 33 34 35 Reportable Disease Statistics (Notifiable)  MDs/health facilities legally required to report cases of certain diseases to health authorities-System of reporting is in place Issues/problems: – Not all will seek medical attention; asymptomatic – Failure of MDs to fill out the required reporting forms – MDs concern over confidentiality of information – WHO: reluctance to admit occurrence of certain diseases – Unsatisfactory source: (incomplete population coverage) 37  Notifiable Diseases (2001, FHSIS) Anthrax Neonatal Tetanus Cholera Non-neonatal tetanus Diphtheria Meningococcal infection Viral encephalopathy Paralytic shellfish poisoning Leprosy Rabies Leptospirosis Typhoid and Paratyphoid fever Malaria Pertussis Measles 38  Notifiable Diseases (Syndromes) Acute Flaccid Paralysis Acute Hemorrhagic Syndrome Acute Lower Respiratory Tract Infection & Pneumonia Acute Watery Diarrhea Acute Bloody Diarrhea Food Poisoning Chemical Poisoning 39 Disease Registries  Centralized database for collection of information about a disease (cancer, trauma, etc) Newly recognized cases are entered and maintained in a file until recovery, death, or migration Source of data for: – Duration of illness – Outcome of illness (Case fatality) – Incidence and prevalence – Natural history of disease Satisfactory source of data only for some diseases 41 Morbidity Surveys  Sample population → representative National Demographic and Health Survey (NSO) – Every 5 years (2003) National nutrition survey (FNRI) – Every 5 years National Weighing, Operation Timbang (DOH) – On going (every year) Prevalence surveys (periodic)- TB, Disability, STD 43 Screening Surveys  Sample population → non-representative sample Neighborhood screening clinics Health fare (civic groups) Not satisfactory source 45 Hospital Data  In-patient and outpatient records Does not represent a specific population Type of information not standardized 47  Comparison of data from multiple sources Agreement between medical record and interview is variable Excellent agreement (inherent features of patient’s clinical condition-surgical procedures, family history of cancer Poor agreement (pharma use) 48  Agencies concerned with collection, management, and publication of health data 1. DOH Philippine Morbidity & Mortality Report (quarterly) Field Health Service Info System – Stat indicators of health programs of DOH – Vital Stats, by province, city, region Philippine Health Statistics – Vital stats, stats on Notifiable diseases 49  Agencies concerned with collection, management, and publication of health data 2. NSO – Vital events (births, deaths, marriages) – National Demographic Survey (every 5 years-2003) – Demographic, maternal and child health statistics 3. FNRI – National Nutrition Survey (yearly) 51  References: Aschengrau, A. and G.R. Seage III, Essentials of Epidemiology in Public Health, 2nd ed. Jones and Bartlett Learning, 2008. Friis, R.H. and T.A. Seller, Epidemiology for Public Health Practice, 5th ed. Jones and Bartlett Learning, 2014. Tolabing, C.C. et al., Interrupted Time Series Study on the Completeness and Acceptability of the Cause of Death Statement in Death Certificates, 2013. Tolabing, C.C., Sources of Data, Epidemiology 201. www.apa.org/pubs/index.aspx (accessed on 11 August 2014) www.psa.gov.ph (accessed on 11 August 2014) www.ncbi.nlm.nih.gov (accessed on 11 August 2014) www.herdin.ph (accessed on 11 August 2014) www.doh.gov.ph (accessed on 14 August 2014) www.fnri.dost.gov.ph (accessed on 14 August 2014) http://wonder.cdc.gov/ (accessed on 14 August 2014) http://who.int/research/en/ (accessed on 14 August 2014) 53