Clinical surveillance
Encyclopedia
Clinical surveillance refers to the surveillance
of health data about a clinical syndrome
that has a significant impact on public health
, which is then used to drive decisions about health policy and health education
. This is distinct from active surveillance
, which applies to individuals.
and the CDC
, have created databases and modern computer systems (public health informatics
) that can track and monitor emerging outbreaks of illnesses such as influenza
, SARS, HIV
, and even bioterrorism
, such as the 2001 anthrax attacks
on federal agencies in the United States.
Many regions and countries have their own cancer registry
, one function of which is to monitor the incidence of cancers to determine the prevalence and possible causes of these illnesses.
Other illnesses such as one-time events like stroke
and chronic conditions such as diabetes, as well as social problems such as domestic violence, are increasingly being integrated into epidemiologic databases called disease registries that are being used in cost-benefit analysis
in determining governmental funding for research and prevention.
Many see this health outcomes data as greatly beneficial, but this kind of work is often controversial because many of measures such as quality-adjusted life years and disability-adjusted life years, which involve quantifying benefit according to subjective concepts such as survival, quality of life, and productivity measures. In addition, civil-libertarians
believe that without disclosure or provisions to enable a way of opting out of such registries is a violation of both personal civil liberties and the doctor-patient privilege
. Population-based healthcare is being promoted as registries are integrated, and health outcomes are increasingly being monitored.
Systems that can automate the process of identifying adverse drug events, are currently being used, and are being compared to traditional written reports of such events. These systems intersect with the field of medical informatics, and are rapidly becoming adapted by hospitals and endorsed by institutions that oversee healthcare providers (such as JCAHO in the United States). Issues in regards to healthcare improvement are evolving around the surveillance of medication errors within institutions.
outbreak
s. According to a CDC
definition, "the term 'syndromic surveillance' applies to surveillance using health-related data that precede diagnosis and signal a sufficient probability of a case or an outbreak to warrant further public health response. Though historically syndromic surveillance has been utilized to target investigation of potential cases, its utility for detecting outbreaks associated with bioterrorism
is increasingly being explored by public health officials."
The first indications of disease outbreak or bioterrorist attack may not be the definitive diagnosis of a physician or a lab.
Using a normal influenza outbreak as an example, once the outbreak begins to affect the population, some people may call in sick for work/school, others may visit their drug store and purchase medicine over the counter, others will visit their doctor's office and other's may have symptoms severe enough that they call the emergency telephone number
or go to an emergency room.
Syndromic surveillance systems monitor data from school absenteeism logs, emergency call systems, hospitals' over-the-counter drug sale records, Internet searches, and other data sources to detect unusual patterns. When a spike in activity is seen in any of the monitored systems disease epidemiologists and public health professionals are alerted that may be an issue.
An early awareness and response to a bioterrorist attack could save many lives and potentially stop or slow the spread of the outbreak. The most effective syndromic surveillance systems automatically monitor these systems in real-time, do not require individuals to enter separate information (secondary data entry), include advanced analytical tools, aggregate data from multiple systems, across geo-political boundaries and include an automated alerting process.
A syndromic surveillance system based on search queries was first proposed by Gunther Eysenbach
, who began work on such a system in 2004 .
Inspired by these early, encouraging experiences, Google
launched Google Flu Trends in 2008. More flu-related searches are taken to indicate higher flu activity. The results closely match CDC
data, and lead it by - 1–2 weeks. The results appeared in Nature
. Extending Google
's work researchers from the Intelligent Systems Laboratory (University of Bristol
, UK) created Flu Detector; an online tool which based on Information Retrieval
and Statistical Analysis methods uses the content of Twitter
to nowcast flu rates in the UK.
is a syndromic surveillance system based on voluntary reports of symptoms via the internet. Residents of the participant countries are invited to provide regularly information regarding the presence or absence of flu related symptoms. The system runs since 2003, in The Netherlands and Belgium. The success of this first initiative, led to the implementation, in 2005, of Gripenet in Portugal, followed by Italy in 2008, and Brasil, Mexico and United Kingdom, in 2009.
, are supposed to be routinely managed with frequent laboratory measurements. Since many laboratory results, at least in Europe and the US, are automatically processed by computerized laboratory information systems, the results are relatively easy to inexpensively collate in special purpose databases or disease registries. Unlike most syndromic surveillance systems, in which each record is assumed to be independent of the others, laboratory data in chronic conditions can be theoretically linked together at the individual patient level. If patient identifiers can be matched, a chronological record of each patient's laboratory results can be analyzed as well as aggregated to the population level.
Laboratory registries allow for the analysis of the incidence and prevalence of the target condition as well as trends in the level of control. For instance, an NIH-funded program called the Vermedx Diabetes Information System maintains a registry of laboratory values of diabetic adults in Vermont and northern New York State in the US that contains many years of laboratory results on thousands of patients. The data include measures of blood sugar
control (glycosolated hemoglobin A1C
), cholesterol
, and kidney function (serum creatinine
and urine protein), and have been used to monitor the quality of care at the patient, practice, and population levels. Since the data contain each patient's name and address, the system has also been used to communicate directly with patients when the laboratory data indicate the need for attention. Out of control test results generate a letter to the patient suggesting they take action with their medical provider. Tests that are overdue generate reminders to have testing performed. The system also generates reminders and alerts with guideline-based advice for the practice as well as a periodic roster of each provider's patients and a report card summarizing the health status of the population.
A similar system, The New York City A1C Registry, is in used to monitor the estimated 600,000 diabetic patients in New York City
, although unlike the Vermont Diabetes Information System, there are no provisions for patients to have their data excluded from the NYC database. The NYC Department of Health and Mental Hygiene aims to link additional patient services to the registry such as health information and improved access to health care services. The NYC Health Department promised that the registry would help to reduce the risk of blindness, kidney failure, leg amputations and early death among people with diabetes, but as of 2010, the department has provided little (if any) solid evidence to validate these assertions.
In May 2008, the City Council of San Antonio, Texas
approved the deployment of an A1C registry for Bexar County. Authorized by the Texas Legislature and the state Health Department, the San Antonio Metropolitan Health District has begun implementation of the registry which will draw results from the major clinical laboratories in San Antonio. If successful, the registry may be expanded to the rest of Texas.
The real reason laboratory surveillance differs from population-wide surveillance in the case of diabetes is that in that it can only monitor glycemic control of patients who are already receiving medical treatment and therefore having these lab tests done, while simultaneously ignoring patients who never have the tests done, the segments who are often most at-risk. This limits the ability of public health officials to implement interventions that are effective on a population-wide basis.
Surveillance
Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...
of health data about a clinical syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...
that has a significant impact on public health
Public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
, which is then used to drive decisions about health policy and health education
Health education
Health education is the profession of educating people about health. Areas within this profession encompass environmental health, physical health, social health, emotional health, intellectual health, and spiritual health...
. This is distinct from active surveillance
Watchful waiting
Watchful waiting is an approach to a medical problem in which time is allowed to pass before medical intervention or therapy is used. During this time, repeated testing may be performed....
, which applies to individuals.
Clinical surveillance
Techniques of clinical surveillance have been used in particular to study infectious diseases. Many large institutions, such as the WHOWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
and the CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
, have created databases and modern computer systems (public health informatics
Public health informatics
Public Health Informatics has been defined as the systematic application of information and computer science and technology to public health practice, research, and learning...
) that can track and monitor emerging outbreaks of illnesses such as influenza
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
, SARS, HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
, and even bioterrorism
Bioterrorism
Bioterrorism is terrorism involving the intentional release or dissemination of biological agents. These agents are bacteria, viruses, or toxins, and may be in a naturally occurring or a human-modified form. For the use of this method in warfare, see biological warfare.-Definition:According to the...
, such as the 2001 anthrax attacks
2001 anthrax attacks
The 2001 anthrax attacks in the United States, also known as Amerithrax from its Federal Bureau of Investigation case name, occurred over the course of several weeks beginning on Tuesday, September 18, 2001, one week after the September 11 attacks. Letters containing anthrax spores were mailed to...
on federal agencies in the United States.
Many regions and countries have their own cancer registry
Cancer registry
A cancer registry is a systematic collection of data about cancer and tumor diseases. The data is collected by Cancer Registrars. Cancer Registrars capture a complete summary of patient history, diagnosis, treatment, and status for every cancer patient in the United States, and other countries as...
, one function of which is to monitor the incidence of cancers to determine the prevalence and possible causes of these illnesses.
Other illnesses such as one-time events like stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
and chronic conditions such as diabetes, as well as social problems such as domestic violence, are increasingly being integrated into epidemiologic databases called disease registries that are being used in cost-benefit analysis
Cost-benefit analysis
Cost–benefit analysis , sometimes called benefit–cost analysis , is a systematic process for calculating and comparing benefits and costs of a project for two purposes: to determine if it is a sound investment , to see how it compares with alternate projects...
in determining governmental funding for research and prevention.
Many see this health outcomes data as greatly beneficial, but this kind of work is often controversial because many of measures such as quality-adjusted life years and disability-adjusted life years, which involve quantifying benefit according to subjective concepts such as survival, quality of life, and productivity measures. In addition, civil-libertarians
Civil liberties
Civil liberties are rights and freedoms that provide an individual specific rights such as the freedom from slavery and forced labour, freedom from torture and death, the right to liberty and security, right to a fair trial, the right to defend one's self, the right to own and bear arms, the right...
believe that without disclosure or provisions to enable a way of opting out of such registries is a violation of both personal civil liberties and the doctor-patient privilege
Physician-patient privilege
Physician–patient privilege is a legal concept, related to medical confidentiality, that protects communications between a patient and his or her doctor from being used against the patient in court. It is a part of the rules of evidence in many common law jurisdictions...
. Population-based healthcare is being promoted as registries are integrated, and health outcomes are increasingly being monitored.
Systems that can automate the process of identifying adverse drug events, are currently being used, and are being compared to traditional written reports of such events. These systems intersect with the field of medical informatics, and are rapidly becoming adapted by hospitals and endorsed by institutions that oversee healthcare providers (such as JCAHO in the United States). Issues in regards to healthcare improvement are evolving around the surveillance of medication errors within institutions.
Syndromic surveillance
Syndromic surveillance is the analysis of medical data to detect or anticipate diseaseDisease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
outbreak
Outbreak
Outbreak is a term used in epidemiology to describe an occurrence of disease greater than would otherwise be expected at a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent. Two linked cases of a rare infectious...
s. According to a CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
definition, "the term 'syndromic surveillance' applies to surveillance using health-related data that precede diagnosis and signal a sufficient probability of a case or an outbreak to warrant further public health response. Though historically syndromic surveillance has been utilized to target investigation of potential cases, its utility for detecting outbreaks associated with bioterrorism
Bioterrorism
Bioterrorism is terrorism involving the intentional release or dissemination of biological agents. These agents are bacteria, viruses, or toxins, and may be in a naturally occurring or a human-modified form. For the use of this method in warfare, see biological warfare.-Definition:According to the...
is increasingly being explored by public health officials."
The first indications of disease outbreak or bioterrorist attack may not be the definitive diagnosis of a physician or a lab.
Using a normal influenza outbreak as an example, once the outbreak begins to affect the population, some people may call in sick for work/school, others may visit their drug store and purchase medicine over the counter, others will visit their doctor's office and other's may have symptoms severe enough that they call the emergency telephone number
Emergency telephone number
Many countries' public telephone networks have a single emergency telephone number, sometimes known as the universal emergency telephone number or occasionally the emergency services number, that allows a caller to contact local emergency services for assistance. The emergency telephone number may...
or go to an emergency room.
Syndromic surveillance systems monitor data from school absenteeism logs, emergency call systems, hospitals' over-the-counter drug sale records, Internet searches, and other data sources to detect unusual patterns. When a spike in activity is seen in any of the monitored systems disease epidemiologists and public health professionals are alerted that may be an issue.
An early awareness and response to a bioterrorist attack could save many lives and potentially stop or slow the spread of the outbreak. The most effective syndromic surveillance systems automatically monitor these systems in real-time, do not require individuals to enter separate information (secondary data entry), include advanced analytical tools, aggregate data from multiple systems, across geo-political boundaries and include an automated alerting process.
A syndromic surveillance system based on search queries was first proposed by Gunther Eysenbach
Gunther Eysenbach
Gunther Eysenbach is a researcher on Open access publishing, health policy, eHealth, and consumer health informatics.Eysenbach was born on 22 March 1967 in Berlin, Germany. While a medical student, he served on the executive board as elected Communication Director, later as Vice-President of the...
, who began work on such a system in 2004 .
Inspired by these early, encouraging experiences, Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
launched Google Flu Trends in 2008. More flu-related searches are taken to indicate higher flu activity. The results closely match CDC
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
data, and lead it by - 1–2 weeks. The results appeared in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
. Extending Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
's work researchers from the Intelligent Systems Laboratory (University of Bristol
University of Bristol
The University of Bristol is a public research university located in Bristol, United Kingdom. One of the so-called "red brick" universities, it received its Royal Charter in 1909, although its predecessor institution, University College, Bristol, had been in existence since 1876.The University is...
, UK) created Flu Detector; an online tool which based on Information Retrieval
Information retrieval
Information retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...
and Statistical Analysis methods uses the content of Twitter
Twitter
Twitter is an online social networking and microblogging service that enables its users to send and read text-based posts of up to 140 characters, informally known as "tweets".Twitter was created in March 2006 by Jack Dorsey and launched that July...
to nowcast flu rates in the UK.
Influenzanet
InfluenzanetInfluenzanet
Influenzanet is a syndromic surveillance system that monitors the activity of influenza-like illness with the help of volunteers via the Internet...
is a syndromic surveillance system based on voluntary reports of symptoms via the internet. Residents of the participant countries are invited to provide regularly information regarding the presence or absence of flu related symptoms. The system runs since 2003, in The Netherlands and Belgium. The success of this first initiative, led to the implementation, in 2005, of Gripenet in Portugal, followed by Italy in 2008, and Brasil, Mexico and United Kingdom, in 2009.
Laboratory-based surveillance
Some conditions, especially chronic diseases such as diabetes mellitusDiabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, are supposed to be routinely managed with frequent laboratory measurements. Since many laboratory results, at least in Europe and the US, are automatically processed by computerized laboratory information systems, the results are relatively easy to inexpensively collate in special purpose databases or disease registries. Unlike most syndromic surveillance systems, in which each record is assumed to be independent of the others, laboratory data in chronic conditions can be theoretically linked together at the individual patient level. If patient identifiers can be matched, a chronological record of each patient's laboratory results can be analyzed as well as aggregated to the population level.
Laboratory registries allow for the analysis of the incidence and prevalence of the target condition as well as trends in the level of control. For instance, an NIH-funded program called the Vermedx Diabetes Information System maintains a registry of laboratory values of diabetic adults in Vermont and northern New York State in the US that contains many years of laboratory results on thousands of patients. The data include measures of blood sugar
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
control (glycosolated hemoglobin A1C
Glycosylated hemoglobin
Glycated hemoglobin is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. It is formed in a non-enzymatic glycation pathway by hemoglobin's exposure to plasma glucose...
), cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
, and kidney function (serum creatinine
Creatinine
Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...
and urine protein), and have been used to monitor the quality of care at the patient, practice, and population levels. Since the data contain each patient's name and address, the system has also been used to communicate directly with patients when the laboratory data indicate the need for attention. Out of control test results generate a letter to the patient suggesting they take action with their medical provider. Tests that are overdue generate reminders to have testing performed. The system also generates reminders and alerts with guideline-based advice for the practice as well as a periodic roster of each provider's patients and a report card summarizing the health status of the population.
A similar system, The New York City A1C Registry, is in used to monitor the estimated 600,000 diabetic patients in New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
, although unlike the Vermont Diabetes Information System, there are no provisions for patients to have their data excluded from the NYC database. The NYC Department of Health and Mental Hygiene aims to link additional patient services to the registry such as health information and improved access to health care services. The NYC Health Department promised that the registry would help to reduce the risk of blindness, kidney failure, leg amputations and early death among people with diabetes, but as of 2010, the department has provided little (if any) solid evidence to validate these assertions.
In May 2008, the City Council of San Antonio, Texas
San Antonio, Texas
San Antonio is the seventh-largest city in the United States of America and the second-largest city within the state of Texas, with a population of 1.33 million. Located in the American Southwest and the south–central part of Texas, the city serves as the seat of Bexar County. In 2011,...
approved the deployment of an A1C registry for Bexar County. Authorized by the Texas Legislature and the state Health Department, the San Antonio Metropolitan Health District has begun implementation of the registry which will draw results from the major clinical laboratories in San Antonio. If successful, the registry may be expanded to the rest of Texas.
The real reason laboratory surveillance differs from population-wide surveillance in the case of diabetes is that in that it can only monitor glycemic control of patients who are already receiving medical treatment and therefore having these lab tests done, while simultaneously ignoring patients who never have the tests done, the segments who are often most at-risk. This limits the ability of public health officials to implement interventions that are effective on a population-wide basis.