Background The expected effectiveness of public health programmes can be estimated by knowing the impact that each condition or group of conditions has on adverse outcomes we intend to prevent. Population attributable fraction (PAF), i.e. the proportion of an adverse outcome occurrence that could be avoided by eliminating a disease from the population, is a useful measure for quantifying the impact of a disease on a particular adverse health outcome at the population level.
Objectives To examine the population-level impacts of chronic conditions on objective and subjective adverse health outcomes in the Portuguese population.
Methods We analysed data from a nationally representative sample of 41 094 individuals from the 4th Portuguese National Health Survey (2005/2006). Sociodemographic characteristics and self-reported chronic conditions (diabetes, hypertension, rheumatic disease, chronic obstructive pulmonary disease (COPD), stroke, depression, myocardial infarction) were assessed. Frequent health care utilization was defined as 2 or more medical appointments in the previous 3 months. Individuals who rated their health as poor or very poor were considered to have a negative self-rated health (SRH). Short-term disability was considered present when individuals reported having stopped his normal activity at work, home or leisure, for health reasons, during at least one day in the previous 2 weeks. Respondents with any severe limitation in function or restriction in daily activities were categorized as having long-term disability. For each chronic condition, we estimated the risk of having an adverse outcome (frequent use of health care, negative SRH, short- and long-term disability) using prevalence ratios adjusted for age, sex, education and other diseases (adjPR). We estimated PAF for each condition on the outcomes (PAF= proportion of those with the outcome reporting the condition × [(adjPR-1) / adjPR)].
Results Prevalence of diabetes, hypertension, rheumatic disease, COPD, stroke, depression, myocardial infarction was 6.4%, 19.4% 14.6% 3.4% 1.6% 7.5% and 1.2%, respectively. Depression and diabetes were associated with frequent health care utilization (adjPR= 1.60, 95%CI:1.49;1.73 and adjPR= 1.36, 95%CI:1.26;1.47, respectively) but, because of their high prevalence, hypertension and rheumatic diseases had the greatest population-level impact (PAF=9.5% and 5.7%, respectively). At the individual level, depression was also strongly associated with negative SRH (adjPR= 1.84, 95%CI:1.69;2.00) and short-term disability (adjPR= 1.83, 95%CI:1.60;2.09) and stroke was associated with an increased risk of negative SRH (adjPR= 1.64, 95%CI:1.47;1.83) and long-term disability (adjPR= 1.57, 95%CI:1.34;1.85). However, at a population level, rheumatic diseases had the greatest population-level impact on negative SRH (PAF=15.6%), short- and long-term disability (PAF=10.5% and 11.3%, respectively) due to the strength of the associations but mainly to its high frequency in the population.
Conclusions Differences in the relative ranking of risks and PAF for different diseases and outcomes were substantial. Ultimately, rheumatic diseases account for the most substantial proportion of adverse outcomes in the population and are priority targets to improve objective and subjective health outcomes in the population.
Disclosure of Interest None Declared