Burden of Disease Across Chronic Diseases: a Health Survey That Measured Prevalence, Function, and Quality of Life

Objective: To assess health related quality of life (HRQOL) and functional ability across groups of chronic diseases in Spain.

Methods: A national health survey was conducted during 1999-2000. Participants were randomly selected from city censuses among persons aged over 20 years. All 2192 participants (response rate 73%) completed generic instruments measuring functional ability in activities of daily living [Health Assessment Questionnaire (HAQ)] and HRQOL [Short-Form 12 (SF-12)]. Chronic diseases were defined by self-report and elicited from 2 specific questions: "Have you ever been told you have a chronic disease by a physician?" and "Are you taking any chronic medication?". Only diagnoses present for > or = 3 months were included as chronic. We estimated mean HAQ and SF-12 scores for the different groups of chronic diseases. We then adjusted the scores for covariates and compared them between diseases by multiple linear regressions.

Results: Over half the population had at least one chronic disease [n = 1276 (58.2%)], and 22.6% had any rheumatic disease. Rheumatic diseases have an adverse effect on daily functioning [HAQ beta-coefficient 0.11 (95% CI 0.06-0.15)] and HRQOL [SF-12 physical beta-coefficient -5.78 (95% CI -6.27 to -4.28); SF-12 mental beta-coefficient -2.61 (95% CI -3.79 to -1.41)]. Thus, the influence of the rheumatic diseases is greater when their prevalence is taken into account.

Conclusion: When the definition of burden of disease includes a measure of function and HRQOL that is weighted by disease prevalence, rheumatic diseases as a group can be ranked alongside neurological, cardiac, or pulmonary conditions as a major disease.