• Clinical science

Preventive medicine

Summary

Preventive medicine is the branch of medicine that deals not only with preventing disease from occurring, but also with halting disease progression and averting complications after disease onset. Disease prevention occurs on five levels, with measures ranging from health policies that affect the general population to specific treatments for particular patient groups: primordial prevention (actions that address environmental, socioeconomic, behavioral risk factors; e.g., smoking cessation campaigns), primary prevention (actions that inhibit the occurrence of specific diseases; e.g., immunization), secondary prevention (actions that inhibit the progress of specific diseases at an early stage to prevent or limit complications; e.g., screening), tertiary prevention (actions that inhibit the progress of specific diseases at an advanced stage to prevent or limit complications; e.g., blood pressure management in patients with hypertension), and quartenary prevention (actions that prevent over-medicalization and offer ethically acceptable interventions; e.g., pursuing nonaddictive strategies to managing chronic pain rather than prescribing opioids). One of the greatest challenges to preventive medicine is the “prevention paradox,” which states that preventive measures that benefit large populations have little impact on most people (e.g., even without measles immunization, only a relatively small proportion of the population would contract the disease). This leads to the common misconception that preventive measures provide no benefit to the individual as part of a larger population. Another challenge is poor medical adherence, i.e., the extent to which an individual follows prescribed drug regimens and medical advice, especially in patients who do not feel ill and, therefore, perceive the burden of prevention rather than its long-term benefits. Strategies to encourage adherence include a patient-centered approach, frequent follow-ups, and education regarding long-term consequences of medical conditions, behaviors, and lifestyle.

Primordial prevention

Definition

  • Actions that address environmental, socioeconomic, and behavioral risk factors that affect a population as a whole to prevent potential disease or injury.

Measures [1][2]

  • Target: entire population
  • Health promotion beginning in childhood to encourage positive and discourage negative lifestyle habits
  • Mass education
  • Legislation

Examples

  • Programs on food safety and nutrition guidelines
  • Campaigns discouraging tobacco and drug use (e.g., smoke-free air laws in public buildings)
  • Building bicycle and sidewalks to promote physical activity

Primordial prevention aims to prevent risk factors from developing in the first place, whereas primary prevention targets existing risk factors to prevent the onset of a disease.

Primary prevention

Definition

  • Actions targeted at preventing specific diseases from occurring to decrease the incidence and, subsequently, the prevalence of those diseases

Measures [2][3]

  • Target: entire population and select groups (healthy individuals)
  • Decrease incidence and, in turn, prevalence of a specific disease
  • Primarily done through
    • Health promotion (health interventions, lifestyle modifications)
    • Environmental modifications (e.g., work safety)
    • Specific protection interventions (immunizations, chemoprophylaxis, safety of drugs and food)

Examples

Secondary prevention

Definition

  • Actions targeted at early detection of disease in asymptomatic patients (or while the symptoms of the condition are still mild) to promote early intervention

Measures [2]

  • Target: patient groups
  • Prevent further progression and complications from the disease
  • Consists of a two-step process: screening test to identify disease and a follow-up for management of the disease

Examples

Overview of screening tests [4][5][6]
Condition Test Population Frequency
Risk Group Age group
Cardiovascular disorders
Hypertension
  • General population
  • ≥ 18 years
  • Every 3–5 years
  • Individuals at high risk for hypertension (e.g., high-normal blood pressure, obese patients)
  • ≥ 40 years
  • Every 1–2 years
Hyperlipidemia [7]
  • Lipid panel
  • All age groups
  • Every year
  • General population
  • Men: 20–45 years
  • Women: 20–55 years
  • Every 5 years
  • Men: 45–65 years
  • Women: 55–65 years
  • Every 1–2 years
  • > 65 years
  • Every year
  • 3 years
  • Repeat at 9–11 years of age
  • Repeat at 18 years of age
  • > 16 years
  • Every 5 years
  • Men: > 35 years
  • Women: > 45 years
  • Every 5 years
  • Once between 9–11 years and once between 17–21 years
  • Children
  • 9–11 years
  • 17–21 years
Abdominal aortic aneurysm
  • 65–75 years
  • Once
Endocrinological disorders
Diabetes mellitus
  • Fasting blood glucose
  • 40–70 years
  • Every 6 months
  • Individuals with blood pressure > 135/80 mmHg
  • > 45 years
  • Once
Osteoporosis
  • DXA (measures bone mineral density)
  • Women
  • > 65 years
  • Once
  • < 65 years
Malignancy
Colorectal cancer
  • Colonoscopy
  • General population
  • 50–75 years
  • Every 10 years
  • All age groups, beginning 8 years after diagnosis
  • Every 1–2 years
  • 10 years
  • Every year
  • 20 years
  • Every 1–2 years
  • Sigmoidoscopy
  • General population
  • 50 years
  • Every 5 years
  • Fecal occult blood test
  • General population
  • 50 years
  • Every year
Breast cancer
  • Women
  • 50–75 years
  • Every 2 years
Lung cancer
  • Smoker ≥ 30 pack year
  • Current smoker or ex-smoker for 15 years or less
  • 55–80 years
  • Every year up to 3 consecutive times
Cervical cancer
  • Women
  • 21–29 years
  • Every 3 years
  • Women
  • 30–65 years
  • Every 5 years
Infection
HIV
  • High-risk individuals (e.g., men who have sex with men, IV drug users, sex workers, patients with multiple sex partners with unknown HIV status, partner with HIV)
  • All pregnant women
  • 15–64 years
  • All age groups at first prenatal visit
Hepatitis B
  • All age groups
  • All age groups at first prenatal visit
  • Once each year
  • Regular screening for high-risk patients
Hepatitis C
  • Adults born between 1945–1965 [8]
  • High-risk individuals (e.g., IV drug users, individuals who received blood transfusions before 1992, individuals with sexual partners at high risk)
  • All age groups
  • Adults born between 1945–1965
  • Once
  • Regular screening in high-risk individuals
STDs
  • Sexually active women
  • < 24 years
  • Individuals who engage in risky sexual behavior
  • ≥ 24 years
  • Individuals who engage in risky sexual behavior (especially men who have sex with men)
  • Individuals with HIV infection
  • All pregnant women
  • Sexually active individuals of all age groups
  • All age groups at first prenatal visit
  • Sexually active individuals every 3 months
Asymptomatic bacteriuria
  • Pregnant women
  • All age groups at 12–16 weeks gestation of first prenatal visit
  • All age groups at first prenatal visit (if later than 16 weeks gestation)
  • Once
Other
Rh incompatibility
  • Pregnant women
  • All age groups at first prenatal visit

Major depressive disorder

  • 13–17 years
  • Once
  • General adult population (including pregnant and postpartum women)
  • All age groups
Amblyopia
  • Vision test
  • Children
  • 3–5 years
  • Once

Screening complements diagnostics, but it is not a substitute.

Tertiary prevention

Definition

  • Actions taken to optimize care of patients with an existing disease to improve well-being and prevent complications

Measures [2]

  • Target: select patient groups
  • Decrease the risk of relapse
  • Decrease morbidity and mortality after the onset of symptoms

Examples

Quarternary prevention

Definition

  • Actions taken to avoid unnecessary medical interventions by identifying actions that might cause harm rather than benefit patients

Measures [9][10][2]

  • Target: patient groups
  • Prevent overmedicalization (e.g., overdiagnosis, overtreatment)
  • Avoid unnecessary diagnostic studies or treatments without proven efficacy (e.g., only offer ethically acceptable interventions, use treatments previously assessed by randomized controlled trial with low risk of bias)
  • Avoid disease mongering, i.e., widening the definition of certain medical illnesses, to expand markets for those who deliver and/or sell medical treatments.

Examples [11]

Medical adherence

Definition

  • The degree to which an individual follows prescribed medication regimens and medical advice [12]

Common reasons for poor adherence [13][14]

  • Medication
    • Forgetfulness (mostly occurs in older patients or patients with cognitive disabilities)
    • Financial burden (e.g., cost of medications)
    • Polypharmacy (e.g., multiple comorbidities, complex treatment regimen)
    • Poor education by healthcare provider regarding medication use, side effects, and consequences of poor adherence
  • Lifestyle modification: lack of motivation
  • Cultural and personal beliefs
    • Personal health care beliefs (e.g., homeopathy)
    • Personal health care misconceptions (e.g., vaccine hesitancy)
    • Distrust of health care system

Strategies to encourage adherence

  • Identify potential barriers (e.g., disease-related knowledge)
  • A patient-centered approach
  • Communication about treatment options
  • Provide patient education
    • Written instructions regarding medication
    • Discuss medication side effects
  • Reminder system
    • Regular follow-up visits
    • Email reminder programs
    • Electronic alerts
    • Phone call reminders

Prevention paradox

Definition

  • A preventive measure that benefits a population as a whole will offer little benefit to each individual member of that population (population approach to prevention; primordial and primary prevention)

Definition [15][16]

  • A preventive measure that benefits a group of individuals susceptible to a particular disease will offer little benefit to the population as a whole (high-risk approach to prevention; secondary and tertiary prevention).
  • The high-risk approach and the population approach to prevention are complementary, but preventive medicine should prioritize preventing the underlying causes of disease (primordial and primary prevention) over reducing the impact of disease after it occurs (secondary and tertiary prevention).
  • The prevention paradox may lead to the misconception that a measure that provides no immediate benefit to the individual, provides no benefit to the entire population and that a small risk involved in a measure (e.g., vaccination) outweighs the benefits of that measure.
    • Misconceptions derived from the prevention paradox may negatively affect epidemiological policy as well as adherence in the population.
    • Primordial and primary prevention require consistent, long-term education programs for health care professionals as well as the general population to be effective.

Examples

  • While heavy drinking carries a greater risk than moderate drinking, moderate drinking has a greater negative impact on the general population because the number of moderate drinkers is greater than that of heavy drinkers.
  • Seatbelt laws have prevented many severe injuries, yet the overall risk of dying in an accident due to not wearing a seatbelt is still low.
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  • 2. Kisling LA, M Das J. Prevention Strategies. StatPearls. 2020. pmid: 30725907.
  • 3. Crider KS, Bailey LB, Berry RJ. Folic Acid Food Fortification—Its History, Effect, Concerns, and Future Directions. Nutrients. 2011; 3(3): pp. 370–384. doi: 10.3390/nu3030370.
  • 4. U.S. Preventive Services Task Force. USPSTF A and B Recommendations. https://www.uspreventiveservicestaskforce.org/Page/Name/uspstf-a-and-b-recommendations/#dag. Updated September 1, 2019. Accessed October 7, 2019.
  • 5. Bibbins-Domingo K, Grossman DC, et al. Screening for Syphilis Infection in Nonpregnant Adults and Adolescents. JAMA. 2016; 315(21): p. 2321. doi: 10.1001/jama.2016.5824.
  • 6. Mauch KF. Mksap 17 General Internal Medicine. Philadelphia, PA: American College of Physicians; 2016.
  • 7. Jellinger PS et al. AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE. Endocrine Practice. 2017; 23(Supplement 2): pp. 1–87. doi: 10.4158/ep171764.appgl.
  • 8. Joshi SN. Hepatitis C screening. The Ochsner journal. ; 14(4): pp. 664–8. pmid: 25598732.
  • 9. Martins C et al. Quaternary prevention: reviewing the concept. Eur J Gen Pract. 2018; 24(1): pp. 106–111. doi: 10.1080/13814788.2017.1422177.
  • 10. Pandve HT. Quaternary prevention: need of the hour. Journal of family medicine and primary care. ; 3(4): pp. 309–10. pmid: 25657934.
  • 11. Alber K, Kuehlein T, Schedlbauer A, Schaffer S. Medical overuse and quaternary prevention in primary care – A qualitative study with general practitioners. BMC Fam Pract. 2017; 18(1). doi: 10.1186/s12875-017-0667-4.
  • 12. ANONIMO, de la santé Om, Organization WH, Who WH. Adherence to Long-term Therapies. World Health Organization; 2003.
  • 13. Crane M. Best ways to deal with noncompliant patients. url: https://www.medscape.com/viewarticle/703674_2 Accessed July 25, 2018.
  • 14. Stevenson FA et al. A systematic review of the research on communication between patients and health care professionals about medicines: the consequences for concordance. Health Expectations. 2004; 7(3): pp. 235–245. doi: 10.1111/j.1369-7625.2004.00281.x.
  • 15. Dr Adrian Davis. Essential Evidence on a page: No 109 The prevention paradox and population strategies applied to transport. https://travelwest.info/project/ee-109-prevention-paradox-population-strategies-applied-transport. Updated November 13, 2014. Accessed December 18, 2019.
  • 16. Rose G. Strategy of prevention: lessons from cardiovascular disease. BMJ. 1981; 282(6279): pp. 1847–1851. doi: 10.1136/bmj.282.6279.1847.
  • Newberger DS. Down Syndrome: Prenatal Risk Assessment and Diagnosis. American Family Physician. 2000. url: https://www.aafp.org/afp/2000/0815/p825.html.
last updated 11/09/2020
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