Community and Public Health Nursing
Community items test population-level reasoning as well as home-based clinical judgement. You will be asked to classify a prevention activity, interpret a rate, decide whether a screening result matters, or sequence an outbreak response. Read the denominator carefully; most errors in this domain are arithmetic or definitional.
Levels of prevention
- Primary: prevent onset, for example immunisation, seat belt legislation, health education on smoking.
- Secondary: detect early, for example cervical screening, mammography, contact tracing and testing.
- Tertiary: limit disability and restore function, for example cardiac rehabilitation and stroke day-hospital programmes.
Measures of frequency
- Incidence counts new cases in the population at risk over a defined period. Prevalence counts all existing cases at a point or over a period, so prevalence rises when survival improves even if incidence is unchanged.
- Crude rates are affected by age structure, so compare populations using age-standardised rates.
- Sensitivity is the proportion of true cases detected. Positive predictive value depends heavily on prevalence, so a highly specific test used in a low-prevalence population still yields many false positives.
Screening and outbreak control
- Screening is justified when the condition is important, the test is acceptable and valid, early detection improves outcome, and the programme is cost-effective.
- Outbreak investigation sequence: verify the diagnosis, define and count cases, active case finding, describe by person, place and time, generate a hypothesis, institute control measures, and communicate openly.
- Notifiable diseases must be reported to the Centre for Health Protection. Notification is a legal duty, not a discretionary courtesy.
Health promotion and home visiting
- The Ottawa Charter action areas are healthy public policy, supportive environments, community action, personal skills and reorientation of health services.
- Before a home visit: confirm the address and contact, assess environmental and personal risk, carry identification, tell someone your schedule, and carry hand hygiene supplies.
Worked example
A district has a population of 50,000. Over one year, 250 new cases of a disease are diagnosed and 400 cases in total are known. What do these figures represent? Reasoning: incidence is 250 divided by 50,000, which is 500 per 100,000 person-years. Prevalence is 400 divided by 50,000, which is 800 per 100,000. The difference reflects cases diagnosed in earlier years who remain alive and in the population. Quoting 400 as the incidence is the commonest error.
Traps that cost marks
- Confusing incidence with prevalence.
- Assuming a high specificity makes a test reliable in a low-prevalence population.
- Treating notification of a notifiable disease as optional or as the clinician's private decision.