Appendix 2: Subjective, objective and diagnosed measures of health and social care need

Activities of daily living (ADLs)

ADLs have limitations when used as a proxy for need for social care support. Firstly ADLs represent social care need from a system perspective rather than from an individual perspective. ADL limitations are used to assess whether an individual needs help with a social care need. In reality an individual may have a social care need but not have any ADL limitations.

Various studies instead use a measure of dependency – which takes into account how often someone needs support. These studies use evidence based on data from the Cognitive Function and Ageing Studies (CFAS) – a population-based study of individuals living in the community and institutional settings., The use of dependency, rather than simply ADLs, is a better measure of the level of resources that would be needed to support the individual. It also recognises that not all individuals needing support with an ADL have the same needs; some will require more support than others. However, it is not possible to create a dependency metric using ELSA – the primary data source of this report. We therefore rely on simpler measures of the quantity of ADLs someone needs support with.

We use ADLs as measured in ELSA, which is a self-reported survey. It is therefore a subjective measure of someone’s own views of their abilities to complete tasks of daily living. ADLs can also be measured subjectively by local authorities, as part of their assessments of whether someone reaches the threshold of need to qualify for local authority funded care.

Long-term conditions

People have needs for which they potentially need long-term care and support, either in primary care (eg condition and medication review, advice and support), the community, in residential care settings, in day care settings and at home.

These needs will derive from long-term health conditions that require ongoing management, and conditions such as diabetes or those which involve neurological impairment which make it more difficult to undertake activities of daily living. Information about these conditions and needs can come from a variety of sources – some objective, some subjective and some diagnostic. Each has its advantages and flaws.

There is information from direct objective measurement of an individual’s health across a sample of the population. Examples include BMI as a measure of obesity and blood pressure as a measure of cardiovascular health. There are also objective social care measures – such as an individual’s ability to balance or walk in a straight line – indications of their ability to safely undertake daily activities.

If a population is randomly sampled and their health measured using an objective instrument, we can get a good idea of population prevalence – either of the condition itself or the risk factors associated with it. But there are relatively few such measures readily available for a representative sample, mainly due to the cost of carrying out diagnostic tests at scale.

The second source is information from diagnosis or assessment. This may be recorded in a person’s health record or social care records. For example, following a consultation or health check, a GP may record the long-term conditions that a person has. Following an episode in hospital, an individual’s hospital record may record any conditions they have, regardless of whether it was directly relevant to the reason for admission. However, information from these sources may not always tell us a reliable story about the prevalence of needs in the population as a whole.

The information will not necessarily be recorded for everyone who has that condition (or a representative sample). For example, someone who has not visited their GP may not have a condition recorded. GPs may also not always diagnose a condition that an individual has if they have no reason to suspect it.

What is diagnosed and recorded in health records will depend on policy and practice and these change over time. For example, diagnosis of dementia in health records has increased hugely over the past 10 years. Internal analysis using primary care records shows that the prevalence of diagnosed dementia among people aged 65 and older more than doubled from 1.2% to 3.2% between 2000 and 2015. This is not because the prevalence of dementia has grown, but because awareness of the condition and its symptoms has grown and because there have been policy pushes to encourage diagnosis.

The third source is information from individuals themselves about their health and its impact on their life. For example, the English Longitudinal Study of Ageing asks people aged 50 and older about the long-term conditions they have and whether they have difficulty with ADLs. For some measures of need information from self-reports is more relevant than objective measures. For example, asking about how someone’s health affects what they can do may be more relevant than knowing that they have a certain condition.

The weakness of self-reported measures is that individuals do not always know about and accurately report their conditions. The Institute for Fiscal Studies compares self-reported information on the incidence of heart attacks, stroke and cancer in the past 2 years with diagnostic information from hospital records. They found that more than half of respondents diagnosed in hospital with a condition in the previous 2 years fail to report the condition when surveyed. Conversely, half of those who self-report a cancer or heart attack diagnosis, and two-thirds of those who self-report a stroke diagnosis, have no corresponding hospital record. A major driver of this reporting error appears to be misunderstanding or being unaware of their diagnoses, with false negative reporting rates falling significantly for heart attacks and strokes when using only primary hospital diagnoses to define objective diagnoses. 

If people’s reporting biases do not change over time, self-reported measures may be more reliable in telling us about the changes that have taken place over time.

There are links between these measures. As the real and actual prevalence across the population changes, this would be reflected in all three measures. If the prevalence by age and sex (eg the proportion of women aged 80–84 with a condition) is not changing but awareness is, this may be reflected in GP and hospital records (if more diagnoses are made and recorded) and may also be reflected in self-reports.

Previous