Private health screening

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Private health screening

• can cause you harm

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What is screening?

• Looking for disease in the absence of symptoms
• Remember First do no harm
• Wilsons criteria have been used to test the
  validity of screening tests

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False positives (1)

• ie saying theres something wrong when there
  isnt
• A common problem with screening tests eg PSA
• Creates enormous anxiety and a need for further
  tests

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False positives (2)

• Either saying theres a problem when in reality
  there isnt ie technical issue/reading error etc
  (about 3 in every 20 normals are erroneously
  called abnormal)or
• Finding a real abnormality which is irrelevant ie
  incidentalomas or pseudodisease

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False negative

• Not detecting a disease when its actually
  present ie false reassurance
• Has been estimated that about 1 in 20 cases of
  significant disease are missed by scans

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True positive

• Finding disease which really is thereyippee!!!
• Surely cant cause harm?
• Oh yes it can
• by overdiagnosis
• you just discover something youd have been
  better off not knowing about
• Youre simply iller for longer

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True negative

• Correctly stating theres no disease
• Surely just reassures the anxious and cant
  possibly cause problems
• Can it?
• Yes
• May reinforce an unhealthy lifestyle
• Individual may ignore symptoms after a negative
  screen
• Many not bother with more relevant screening

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COMARE summary (12/07)

• Taking all the possible outcomes into account,
  made the following estimate
• There are between 5-10 times as many individuals
  suffering detriment.

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Other issues (1)

• It may be the wrong test
• The NHS picks up the tab
• Concerns about radiation dose
• COMARE quote If scanning is repeated every year
  to 5 years from 40 onwards, it would lead to a
  high cumulative radiation exposure which could
  lead to 1 in 50 of those individuals so exposed
  dying from a malignancy induced by the CT
  scanning.

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Other issues (2)

• Tests without a context dont make sense eg
  stress testing
• It over-values screening and underemphasises the
  importance of symptoms
• Sold as empowering
• There is no good scientific evidence that CT
  screening of individuals is a worthwhile exercise

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The Bandolier Screening Blacklist (1995)

• Chest X-ray in older patients, smokers and
  travellers.
• Haemoglobin for anaemia.
• ESR for inflammatory infective or malignant
  disease.
• Liver function tests in blood.
• Renal function tests.
• Calcium in blood.
• Uric acid in blood.
• Glucose in blood.
• Cholesterol.
• HDL/LDL ratio.
• Mammography in women over 40 years.
• Ultrasound examination of the ovaries.
• Bone density in women.
• Resting ECG.
• Exercise ECG on a treadmill.
• Ultrasound examination of the aorta in men over
  55 years.
• PSA in men over 50 years.
• Helicobacter pylori.

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End quotes

• We recommend therefore that services offering
  whole body CT scanning of asymptomatic
  individuals should stop doing so immediately.
  (COMARE)
• The harms arising from these scans currently
  appear to be far more likely and in some cases
  may not be insignificant. (FDA 2002)
• They are a waste, unethical and cruel. (Dr C
  Gerada, RCGP chair of ethics, BMJ 2007)

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