Self-rated health as a valid indicator for health-equity analyses: evidence from the Italian health interview survey

In spite of international consensus on the validity of Self-rated Health (SRH) as a good predictor of morbidity and mortality [1‐5], health policy-makers in Italy have disregarded SRH measures to shape health-related policies, predict healthcare demand and run health equity analysis. Using data from the 2015 Health Interview Survey (HIS), this study investigates in particular whether SRH measures can be a valuable indicator for health equity analysis in the Italian national health service and potentially elsewhere too.

Several health population surveys include one or multiple questions on self-rated health (SRH) [2]. There is little doubt that the question used to measure SRH is meaningful to respondents [6, 7]. Evidence also exists that self-rated health is a stable concept, as it is formed in adolescence and remains highly consistent throughout adulthood so that people express the same opinion on their health when experiencing the same internal feelings [8].

However, in spite of these and more studies showing that SRH can accurately predict mortality and morbidity, its validity is still contended [9]. Part of the controversy originates from the debate on whether SRH is an accurate measure of an objective health status. SRH measures have been under the severe scrutiny of those arguing that one’s understanding of their health (the “internal” view) might be very misaligned with the opinion of medical experts (the “external” view) [10]. Questions have been raised, for instance, on how psychological traits such as a fatalism or hypochondria [11, 12], larger cultural values and social norms [13, 14] or gender [15‐17] might both influence responses to SRH questions, and limit the potential of SRH measures for cross-country comparisons. SRH measures can also sometimes show erratic trends in short-term analysis, as sometimes the data rely on a limited number of respondents, although useful insights can come from examining datasets collected over multiple years [10]. However, much of the available research suggests that the two (SRH and objective health status) are certainly related. In a seminal study, Blaxter [18] found that self-reported chronic conditions and diagnosed chronic conditions overlapped in 80% of the cases. More recently, using a large sample from five major Chinese cities, Wu and colleagues [19] found SRH to be largely consistent with objective health status. And before then, Haddock and colleagues [20] came to a similar conclusion on the validity of SRH analysing a cross-sectional health survey of military personnel. Other SRH-related measures, such as self-reported functional limitations, have also been found to be fairly accurate, especially when respondents have physical (as opposed to mental and social) limitations [21] and have been increasingly used to inform public health resource allocation policies [22].

Other commentators, however, have argued that the debate on SRH should not focus on whether it overlaps with diagnosed diseases. Rather, they have suggested that the discussion on the use of SRH is an ethical one, that relates to the goal of a national public health system and, potentially, to the very definition of what health is. Waller [23], for instance, argued that SRH is an extremely valuable measure of health as it measures what really matters: “Doctors can liberate patients and empower them to health rather than oppressing them with diagnosis, risk factors, and seeing problems. Focusing on self-rated health can help to empower patients” (p.110). One might go as far as to argue that it would be better for people to feel well, despite the presence of pathological conditions, than for them to feel bad in the absence of those conditions. The health system should thus increase its capacity to help people feel that “things go well with them” [24]. If a medical diagnosis cannot help to improve how one person feels or will feel in the future, why would that diagnosis be necessary? That is, why should the health system increase service demand of the people who feel well (beyond prevention purposes)? If people feel healthy, a therapy should only be necessary to prevent the worsening of their SRH in the future. Such an approach to health and healthcare – fairly controversial among Italian public health policy makers – is not new: Marinker [25] famously (and revolutionarily) asked over twenty years ago: why should we make people patients? And, more recently, Misselbrook, Dean Emeritus of the Royal Society of Medicine, suggested that the health system should focus more on helping people be well, beyond just telling them why they are sick [26]. In this paradigm of health, where subjective health matters as the ultimate goal, the health system would need to be more concerned with people’s illnesses, the experience of “unhealth … interior to the person of the patient,” rather than largely focussing on their diseases, the “pathological processes, most often physical … [associated with] some deviation from a biological norm” [27].

We set up this study with three objectives. Objective 1 was “to explore response distribution across dimensions of age, chronic health conditions, functional limitations and SRH in Italy”. We found that age, chronic health conditions, and functional limitations had an independent summative effect on SRH. Objective 2 was “to explore associations between SRH and healthcare demand in Italy”. We found that, even though age affects significantly the likelihood of receiving a drug prescription, SRH predicted healthcare demand more than the diagnosed presence of chronic health conditions. Objective 3 was: “to explore the association between SRH and income”. We found that SRH increased the risk of having a lower PEI more than the presence of a chronic health condition. We hypothesis this difference to be due to the fact that people with a lower PEI might struggle more to compensate for their chronic health condition. That is, we suggest that the experience of a condition (rather than the condition itself) affects more the SRH of poorer than that of richer people.

We suggest three critical implications for health policy-makers in Italy and possibly Europe at large following our result as contextualised in the relevant literatures. These implications are related to using SRH measures to: 1) predict healthcare demand for effective allocation of resources; 2) assess subjective effectiveness of treatments; and 3) understand geosocial pockets of health inequity that require special attention.

Whether SRH can be used as a predictor of service utilisation has been the subject of an intricate and unresolved debate. Some have argued that SRH measures in equations for the utilisation of healthcare are endogenous; that is, respondents might be more likely to rate their health bad if they have recently visited a doctor [22] and, for this reason, that SRH cannot be used as a prediction measure (but, rather, as post-diction measures, as people’s SRH might be dependent on having visited the health service before the survey) [34]. This is a valid objection, yet the level of bias produced by the potential endogeneity of the indicator should be carefully assessed, especially since other studies have provided evidence of the usefulness of using SRH to this predictive purpose. Our findings suggest that, in 2015 in Italy, hospitalization and specialist consultations were generally less influenced by the presence of an actual disease than by people’s belief of being in a poor health state. Integrating SRH status survey instruments within studies would help the Italian national health system allocate resource more effectively, contributing to predicting the volume of future medical consultations.

Treatment effectiveness evaluations in Italy tend to focus on objective clinical measures of disease. This preference is due to both the fact these measures are often considered easier to quantify and interpret, as well as the fact that self-rated measures do not have the same aura of “medical expertise” [48]. A considerable body of literature is emerging on the importance of integrating measures of patient reported experience and patient reported outcomes as part of a National Health System effectiveness evaluations [49‐51]. Drawing from that literature, we suggest that SRH measures can be critically important for the Italian national health system, as they allow to measure what matters to the people that the system is supposed to serve: how these people feel. Clinical diagnostic practices are used to compare objective measures (as, for instance, laboratory exams) with subjective accounts of one’s medical history. Clinicians know that these are both important and work to integrate them, even when their combined interpretation is not straightforward. Similarly, in public health, policy-making practices in Italy have the opportunity to combine objective and subjective health indicators to evaluate the effectiveness of the health system from both perspectives: that of medical experts and that of the population.

Finally, we suggest that integrating SRH measures within Italian national health studies would help understand how social determinants – such as income or education – affect SRH on the Italian territory. A national health system concerned with how people feel (not just with what disease they have) would want to address social disparities in SRH, in concertation with policy-makers across other departments in the government.

In this paper, we have used a subset of Italian respondents from the Health Interview Survey to look at the validity of self-rated health (SRH) as an indicator for equity analysis. We found that SRH measures were independently associated with age, chronic health conditions and functional limitations, three variables that had a summative effect on SRH. We also found that SRH could predict hospitalisation and specialist consultation better than diagnosed health conditions. Finally, we found that SRH was more significantly associated with income than actual diagnosed health conditions.

Our findings suggest that integrating SRH measures within national health studies and policy-making will help Italian health policy-makers in three ways. Firstly, SRH measures will help predict healthcare demand and allocate resources across the national healthcare system more effectively. Secondly, SRH measures will also help assess the subjective effectiveness of the treatment offered by the national healthcare system. Finally, SRH measures will help identify areas of inequity that require special attention.

A national health system able to integrate SRH measures within its indicators for policy-making will be in a better position to achieve its mission of helping people feel well. We look forward to a national health system increasingly concerned with people’s feeling of wellbeing and not simply with their diseases.