Prognosis is a medical
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

 term to describe the likely outcome of an illness.

When applied to large statistical population
Statistical population
A statistical population is a set of entities concerning which statistical inferences are to be drawn, often based on a random sample taken from the population. For example, if we were interested in generalizations about crows, then we would describe the set of crows that is of interest...

s, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock
Septic shock
Septic shock is a medical emergency caused by decreased tissue perfusion and oxygen delivery as a result of severe infection and sepsis, though the microbe may be systemic or localized to a particular site. It can cause multiple organ dysfunction syndrome and death...

 will die within 28 days" can be made with some confidence, because previous research found that this proportion of patients died. However, it is much harder to translate this into a prognosis for an individual patient: additional information is needed to determine whether a patient belongs to the 45% who will succumb, or to the 55% who survive.

A complete prognosis includes expected time, function, and a description of the disease course such as progressive decline, intermittent crisis, or sudden, unpredictable crisis.

Disease and prognostic indicators

Prognostic scoring is also used for other cancer outcome predictions. A Manchester score
Manchester score
Manchester score is an indicator of prognosis in small cell lung cancer. It is calculated from a number of physical and biochemical markers.A patient with small cell lung cancer scores one point for each of the following: -...

 is an indicator of prognosis in small cell lung cancer
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...

. In Non-Hodgkin lymphoma, physicians have developed the International Prognostic Index
International Prognostic Index
The International Prognostic Index is a clinical tool developed by oncologists to aid in predicting the prognosis of patients with aggressive non-Hodgkin's lymphoma...

 to predict patient outcome.

Other medical areas where prognostic indicators are used is in Drug-Induced Liver Injury (DILI) (Hy's law
Hy's law
Hy's law is a prognostic indicator that a pure drug-induced liver injury leading to jaundice, without a hepatic transplant, has a case fatality rate of 10% to 50%...

) and use of an exercise stress test as a prognostic indicator after myocardial infarction
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...


End of life

Medical studies have demonstrated that most doctors are overly optimistic when giving prognostic information, that is, they tend to overstate how long the patient might live. For patients who are critically ill, particularly those in an intensive care unit
Intensive Care Unit
thumb|220px|ICU roomAn intensive-care unit , critical-care unit , intensive-therapy unit/intensive-treatment unit is a specialized department in a hospital that provides intensive-care medicine...

, there are numerical prognostic scoring systems that are more accurate. The most famous of these is the APACHE II
APACHE II is a severity-of-disease classification system , one of several ICU scoring systems...

 scale. However, this scale is most accurate in the seven days prior to a patient's predicted death.

Knowing the prognosis helps determine whether it makes more sense to attempt certain treatments or to withhold them, and thus plays an important role in end-of-life decisions.


In statistics, an estimator is a rule for calculating an estimate of a given quantity based on observed data: thus the rule and its result are distinguished....

s that are commonly used to describe prognoses include:
  • Progression-free survival - the length of time during and after medication or treatment during which the disease being treated (usually cancer) does not get worse.
  • Survival rate
    Survival rate
    In biostatistics, survival rate is a part of survival analysis, indicating the percentage of people in a study or treatment group who are alive for a given period of time after diagnosis...

    - indicating the percentage of people in a study or treatment group who are alive for a given period of time after diagnosis.
  • Survival time - the remaining duration of life. If not else specified, it is generally starting from the time of diagnosis.


For the 19th century physicians, particularly the French school, the main aim of medicine was not to cure disease, but rather to give a medical diagnosis
Medical diagnosis
Medical diagnosis refers both to the process of attempting to determine or identify a possible disease or disorder , and to the opinion reached by this process...

 and achieve a satisfying prognosis of the patient's chances. Only several decades later did the focus of efforts in Western medicine shift to curing disease.

See also

  • Diagnosis
    Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...

  • Nocebo
    In medicine, a nocebo reaction or response refers to harmful, unpleasant, or undesirable effects a subject manifests after receiving an inert dummy drug or placebo...

  • Optimism bias
    Optimism bias
    Optimism bias is the demonstrated systematic tendency for people to be overly optimistic about the outcome of planned actions. This includes over-estimating the likelihood of positive events and under-estimating the likelihood of negative events. Along with the illusion of control and illusory...

  • Placebo (origins of technical term)
  • Prognostics
    Prognostics is an engineering discipline focused on predicting the time at which a system or a component will no longer perform its intended function . This lack of performance is most often a failure beyond which the system can no longer be used to meet desired performance...

  • Reference class forecasting
    Reference class forecasting
    Reference class forecasting is the method of predicting the future, through looking at similar past situations and their outcomes.Reference class forcasting predicts the outcome of a planned action based on actual outcomes in a reference class of similar actions to that being forecast. The theories...

  • Sign (medicine)
  • Symptom
    A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

  • Thought experiment
    Thought experiment
    A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

External links

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